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BIOTECHNOLOGY (227 journals)                  1 2 | Last

Showing 1 - 200 of 227 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
Advances in Bioscience and Biotechnology     Open Access   (Followers: 14)
Advances in Genetic Engineering & Biotechnology     Hybrid Journal   (Followers: 7)
African Journal of Biotechnology     Open Access   (Followers: 6)
Algal Research     Partially Free   (Followers: 9)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 69)
American Journal of Bioinformatics Research     Open Access   (Followers: 8)
American Journal of Polymer Science     Open Access   (Followers: 30)
Animal Biotechnology     Hybrid Journal   (Followers: 9)
Annales des Sciences Agronomiques     Full-text available via subscription  
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 42)
Applied Bioenergy     Open Access  
Applied Biosafety     Hybrid Journal  
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 62)
Applied Mycology and Biotechnology     Full-text available via subscription   (Followers: 5)
Arthroplasty Today     Open Access   (Followers: 1)
Artificial Cells, Nanomedicine and Biotechnology     Hybrid Journal   (Followers: 2)
Asia Pacific Biotech News     Hybrid Journal   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Pacific Journal of Tropical Biomedicine     Open Access   (Followers: 2)
Australasian Biotechnology     Full-text available via subscription   (Followers: 1)
Banat's Journal of Biotechnology     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 4)
Bio-Algorithms and Med-Systems     Hybrid Journal   (Followers: 1)
Bio-Research     Full-text available via subscription   (Followers: 2)
Bioactive Materials     Open Access   (Followers: 1)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (Followers: 4)
Biocybernetics and Biological Engineering     Full-text available via subscription   (Followers: 5)
Bioethics UPdate     Hybrid Journal  
Biofuels     Hybrid Journal   (Followers: 11)
Biofuels Engineering     Open Access   (Followers: 1)
Biological & Pharmaceutical Bulletin     Full-text available via subscription   (Followers: 5)
Biological Cybernetics     Hybrid Journal   (Followers: 10)
Biomarkers and Genomic Medicine     Open Access   (Followers: 5)
Biomarkers in Drug Development     Partially Free   (Followers: 1)
Biomaterials Research     Open Access   (Followers: 4)
BioMed Research International     Open Access   (Followers: 6)
Biomédica     Open Access  
Biomedical Engineering Research     Open Access   (Followers: 7)
Biomedical glasses     Open Access  
Biomedical Reports     Full-text available via subscription  
BioMedicine     Open Access  
Bioprinting     Hybrid Journal  
Bioresource Technology Reports     Hybrid Journal  
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 22)
Biosimilars     Open Access   (Followers: 1)
Biosurface and Biotribology     Open Access  
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 2)
BioTechniques : The International Journal of Life Science Methods     Full-text available via subscription   (Followers: 28)
Biotechnologia Acta     Open Access   (Followers: 1)
Biotechnologie, Agronomie, Société et Environnement     Open Access   (Followers: 2)
Biotechnology     Open Access   (Followers: 6)
Biotechnology & Biotechnological Equipment     Open Access   (Followers: 5)
Biotechnology Advances     Hybrid Journal   (Followers: 33)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 44)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 160)
Biotechnology and Bioprocess Engineering     Hybrid Journal   (Followers: 6)
Biotechnology and Genetic Engineering Reviews     Hybrid Journal   (Followers: 14)
Biotechnology and Health Sciences     Open Access   (Followers: 1)
Biotechnology and Molecular Biology Reviews     Open Access   (Followers: 1)
Biotechnology Annual Review     Full-text available via subscription   (Followers: 7)
Biotechnology for Biofuels     Open Access   (Followers: 10)
Biotechnology Frontier     Open Access   (Followers: 2)
Biotechnology Journal     Hybrid Journal   (Followers: 15)
Biotechnology Law Report     Hybrid Journal   (Followers: 4)
Biotechnology Letters     Hybrid Journal   (Followers: 33)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Biotechnology Reports     Open Access  
Biotechnology Research International     Open Access   (Followers: 2)
Biotechnology Techniques     Hybrid Journal   (Followers: 10)
Biotecnología Aplicada     Open Access  
Biotribology     Hybrid Journal  
BMC Biotechnology     Open Access   (Followers: 15)
Chinese Journal of Agricultural Biotechnology     Full-text available via subscription   (Followers: 3)
Communications in Mathematical Biology and Neuroscience     Open Access  
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computer Methods and Programs in Biomedicine     Hybrid Journal   (Followers: 8)
Contributions to Tobacco Research     Open Access   (Followers: 3)
Copernican Letters     Open Access   (Followers: 1)
Critical Reviews in Biotechnology     Hybrid Journal   (Followers: 20)
Crop Breeding and Applied Biotechnology     Open Access   (Followers: 4)
Current Bionanotechnology     Hybrid Journal  
Current Biotechnology     Hybrid Journal   (Followers: 3)
Current Opinion in Biomedical Engineering     Hybrid Journal   (Followers: 1)
Current Opinion in Biotechnology     Hybrid Journal   (Followers: 55)
Current Pharmaceutical Biotechnology     Hybrid Journal   (Followers: 9)
Current Research in Bioinformatics     Open Access   (Followers: 14)
Current trends in Biotechnology and Pharmacy     Open Access   (Followers: 9)
EBioMedicine     Open Access  
Electronic Journal of Biotechnology     Open Access   (Followers: 1)
Entomologia Generalis     Full-text available via subscription  
Environmental Science : Processes & Impacts     Full-text available via subscription   (Followers: 4)
Experimental Biology and Medicine     Hybrid Journal   (Followers: 3)
Folia Medica Indonesiana     Open Access  
Food Bioscience     Hybrid Journal  
Food Biotechnology     Hybrid Journal   (Followers: 12)
Food Science and Biotechnology     Hybrid Journal   (Followers: 9)
Frontiers in Bioengineering and Biotechnology     Open Access   (Followers: 6)
Frontiers in Systems Biology     Open Access   (Followers: 2)
Fungal Biology and Biotechnology     Open Access   (Followers: 1)
GM Crops and Food: Biotechnology in Agriculture and the Food Chain     Full-text available via subscription   (Followers: 1)
GSTF Journal of BioSciences     Open Access  
HAYATI Journal of Biosciences     Open Access  
Horticulture, Environment, and Biotechnology     Hybrid Journal   (Followers: 11)
IEEE Transactions on Molecular, Biological and Multi-Scale Communications     Hybrid Journal   (Followers: 1)
IET Nanobiotechnology     Hybrid Journal   (Followers: 2)
IIOAB Letters     Open Access  
IN VIVO     Full-text available via subscription   (Followers: 4)
Indian Journal of Biotechnology (IJBT)     Open Access   (Followers: 2)
Indonesia Journal of Biomedical Science     Open Access   (Followers: 1)
Indonesian Journal of Biotechnology     Open Access   (Followers: 1)
Industrial Biotechnology     Hybrid Journal   (Followers: 18)
International Biomechanics     Open Access  
International Journal of Bioinformatics Research and Applications     Hybrid Journal   (Followers: 15)
International Journal of Biomechatronics and Biomedical Robotics     Hybrid Journal   (Followers: 4)
International Journal of Biomedical Research     Open Access   (Followers: 2)
International Journal of Biotechnology     Hybrid Journal   (Followers: 5)
International Journal of Biotechnology and Molecular Biology Research     Open Access   (Followers: 2)
International Journal of Biotechnology for Wellness Industries     Partially Free   (Followers: 1)
International Journal of Environment, Agriculture and Biotechnology     Open Access   (Followers: 5)
International Journal of Functional Informatics and Personalised Medicine     Hybrid Journal   (Followers: 4)
International Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 3)
International Journal of Radiation Biology     Hybrid Journal   (Followers: 4)
Iranian Journal of Biotechnology     Open Access  
ISABB Journal of Biotechnology and Bioinformatics     Open Access  
Italian Journal of Food Science     Open Access   (Followers: 1)
Journal of Biometrics & Biostatistics     Open Access   (Followers: 3)
Journal of Bioterrorism & Biodefense     Open Access   (Followers: 6)
Journal of Petroleum & Environmental Biotechnology     Open Access   (Followers: 2)
Journal of Advanced Therapies and Medical Innovation Sciences     Open Access  
Journal of Advances in Biotechnology     Open Access   (Followers: 5)
Journal Of Agrobiotechnology     Open Access  
Journal of Analytical & Bioanalytical Techniques     Open Access   (Followers: 7)
Journal of Animal Science and Biotechnology     Open Access   (Followers: 6)
Journal of Applied Biomedicine     Open Access   (Followers: 3)
Journal of Applied Biotechnology     Open Access   (Followers: 2)
Journal of Applied Biotechnology Reports     Open Access   (Followers: 2)
Journal of Applied Mathematics & Bioinformatics     Open Access   (Followers: 5)
Journal of Biologically Active Products from Nature     Hybrid Journal   (Followers: 1)
Journal of Biomaterials and Nanobiotechnology     Open Access   (Followers: 6)
Journal of Biomedical Photonics & Engineering     Open Access  
Journal of Biomedical Practitioners     Open Access  
Journal of Bioprocess Engineering and Biorefinery     Full-text available via subscription  
Journal of Bioprocessing & Biotechniques     Open Access  
Journal of Biosecurity, Biosafety and Biodefense Law     Hybrid Journal   (Followers: 3)
Journal of Biotechnology     Hybrid Journal   (Followers: 68)
Journal of Chemical and Biological Interfaces     Full-text available via subscription   (Followers: 1)
Journal of Chemical Technology & Biotechnology     Hybrid Journal   (Followers: 10)
Journal of Chitin and Chitosan Science     Full-text available via subscription  
Journal of Colloid Science and Biotechnology     Full-text available via subscription  
Journal of Commercial Biotechnology     Full-text available via subscription   (Followers: 6)
Journal of Crop Science and Biotechnology     Hybrid Journal   (Followers: 7)
Journal of Essential Oil Research     Hybrid Journal   (Followers: 3)
Journal of Experimental Biology     Full-text available via subscription   (Followers: 25)
Journal of Genetic Engineering and Biotechnology     Open Access   (Followers: 5)
Journal of Ginseng Research     Open Access  
Journal of Industrial Microbiology and Biotechnology     Hybrid Journal   (Followers: 16)
Journal of Integrative Bioinformatics     Open Access  
Journal of International Biotechnology Law     Hybrid Journal   (Followers: 3)
Journal of Medical Imaging and Health Informatics     Full-text available via subscription  
Journal of Molecular Microbiology and Biotechnology     Full-text available via subscription   (Followers: 14)
Journal of Nano Education     Full-text available via subscription  
Journal of Nanobiotechnology     Open Access   (Followers: 4)
Journal of Nanofluids     Full-text available via subscription   (Followers: 2)
Journal of Organic and Biomolecular Simulations     Open Access  
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 6)
Journal of Science and Applications : Biomedicine     Open Access  
Journal of the Mechanical Behavior of Biomedical Materials     Hybrid Journal   (Followers: 11)
Journal of Trace Elements in Medicine and Biology     Hybrid Journal   (Followers: 1)
Journal of Tropical Microbiology and Biotechnology     Full-text available via subscription  
Journal of Yeast and Fungal Research     Open Access   (Followers: 1)
Marine Biotechnology     Hybrid Journal   (Followers: 5)
Messenger     Full-text available via subscription  
Metabolic Engineering Communications     Open Access   (Followers: 4)
Metalloproteinases In Medicine     Open Access  
Microalgae Biotechnology     Open Access   (Followers: 2)
Microbial Biotechnology     Open Access   (Followers: 9)
MicroMedicine     Open Access   (Followers: 3)
Molecular and Cellular Biomedical Sciences     Open Access  
Molecular Biotechnology     Hybrid Journal   (Followers: 16)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 3)
Nanobiomedicine     Open Access  
Nanobiotechnology     Hybrid Journal   (Followers: 3)
Nanomaterials and Nanotechnology     Open Access  
Nanomaterials and Tissue Regeneration     Open Access  
Nanomedicine and Nanobiology     Full-text available via subscription  
Nanomedicine Research Journal     Open Access  
Nanotechnology Reviews     Hybrid Journal   (Followers: 5)
Nature Biotechnology     Full-text available via subscription   (Followers: 521)
Network Modeling and Analysis in Health Informatics and Bioinformatics     Hybrid Journal   (Followers: 3)
New Biotechnology     Hybrid Journal   (Followers: 4)
Nigerian Journal of Biotechnology     Open Access  
Nova Biotechnologica et Chimica     Open Access  
NPG Asia Materials     Open Access  
npj Biofilms and Microbiomes     Open Access  
OA Biotechnology     Open Access  
Plant Biotechnology Journal     Open Access   (Followers: 10)
Plant Biotechnology Reports     Hybrid Journal   (Followers: 4)
Preparative Biochemistry and Biotechnology     Hybrid Journal   (Followers: 4)

        1 2 | Last

Journal Cover Journal of Chemical Technology & Biotechnology
  [SJR: 0.82]   [H-I: 84]   [10 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0268-2575 - ISSN (Online) 1097-4660
   Published by John Wiley and Sons Homepage  [1597 journals]
  • Immobilization of glycerol dehydrogenase and NADH oxidase for enzymatic
           synthesis of 1,3-dihydroxyacetone with in situ cofactor regeneration
    • Authors: Meng-Yao Zhuang; Xiao-Ping Jiang, Xiao-Min Ling, Meng-Qiu Xu, Yi-Hao Zhu, Zhang Ye-Wang
      Abstract: BACKGROUNDNicotinamide cofactor-dependent oxidoreductases have been widely applied to the bioproduction of varieties of useful compounds. Efficient cofactor regeneration is often required for these oxidoreductases catalyzed reactions. Herein, enzymatic production of 1, 3-dihydroxyacetone (DHA) via immobilized enzymes with in situ cofactor regeneration was reported.RESULTSGlycerol dehydrogenase (GDH) and NADH oxidase (Nox) were immobilized on two carriers: macroporous resin and epoxy functionalized magnetic nanoparticles (EFMN). Higher enzyme loading capacity and activity recovery were achieved on EFMN. A high immobilization yield of 90% and>70% recovery activity were obtained for both enzymes using EFMN as carriers. Besides, both immobilized enzymes showed enhanced pH stability and temperature tolerance. Co-immobilized and mixed immobilized enzymes were evaluated for synthesis of DHA, and mixed immobilized enzymes showed higher catalytic rate. The mixed reaction system was also investigated in view of various operational factors. Under the optimal conditions, a high DHA concentration with mixed immobilized enzymes system can reach up to 3.5 mM, which was about 4 times higher than that without cofactor regeneration system.CONCLUSIONThe immobilized GDH and Nox onto magnetic nanoparticles showed enhanced stabilities. Cofactor regeneration system with immobilized enzymes could be utilized for efficient production of DHA from the inexpensive substrate.
      PubDate: 2018-01-13T00:00:36.175577-05:
      DOI: 10.1002/jctb.5579
  • Responses of flocculent and granular sludge in anaerobic sequencing batch
           reactor (ASBR) to azithromycin wastewater and its impact on microbial
    • Authors: Peng-yu Liu; Jia-rong Chen, Lei Shao, Jun Tan, Dai-jie Chen
      Abstract: BACKGROUNDAzithromycin (AZM), a 15-member macrolide antibiotic, has caused widespread pollution in China, where anaerobic digestion is the predominant wastewater treatment technology. However, the type of anaerobic sludge more suitable to treating antibiotic wastewater is unclear. Therefore, this study aimed to determine the response of anaerobic flocculent and granular sludge to AZM wastewater, and, using a high-throughput sequencing technique, explain the diverse microbial community structures.RESULTSAnaerobic granular sludge provided better resistance to the decline of chemical oxygen demand (COD) removal caused by AZM and more biodegradation efficiency than flocculent sludge. Furthermore, there was stronger resistance to AZM-induced reactive oxygen species in the granular sludge than in the flocculent sludge. The granular sludge exhibited richer microbial communities than the flocculent sludge after AZM exposure to the phylum Proteobacteria and Bacteroidetes.CONCLUSIONAt high AZM concentration, anaerobic granular sludge was superior to flocculent sludge in COD removal and AZM degradation. This is attributed to less cell death and more microbial diversity and richness in the granular sludge than in the flocculent sludge following exposure to AZM. Proteobacteria and Bacteroidetes contributed to the resistance to AZM in the granular sludge.
      PubDate: 2018-01-12T23:45:23.715979-05:
      DOI: 10.1002/jctb.5578
  • Preparation of metal-organic frameworks hybridizing with attapulgite and
           adsorption behaviors for glutathione reduced
    • Authors: Yi Liu; Yongfeng Liu, Hao Wang, Ling Dong, Duolong Di
      Abstract: BACKGROUNDA series of metal organic frameworks (MOFs) hybrid materials resulting from the hybridization of MOFs and attapulgite were constructed using a facile reflux route under relatively low reaction temperature and characterized by FTIR spectra, nitrogen adsorption-desorption isotherms, X-ray diffraction and TGA. For the first time, the MOFs hybridizing with attapulgite were employed to enrich peptides with high adsorption selectivity for glutathione reduced on the basis of selected three model peptides such as glutathione reduced, bradykinin and insulin from bovine pancreas, due to pore structure, change in microenvironment and composition of the prepared MOFs materials, molecular size of the selected peptides.RESULTSThe adsorption capacities of MOFs materials prepared at three different temperatures for glutathione reduced were 66.80, 88.91 and 79.55 mg/g in turn, while those of MOFs hybridization materials greatly enhanced, were 83.49, 99.64 and 97.47 mg/g, respectively. The prepared MOFs materials exhibited excellent reusability. The results of FTIR spectra and XPS showed that hydrogen bonding, sieving effect, p-π and coordination effect were involved in the adsorption process.CONCLUSIONSThe excellent adsorption property and selectivity make the present materials highly promising and potential for utilization as adsorbents for peptides with small molecular size like glutathione reduced in practical application.
      PubDate: 2018-01-12T23:35:29.396771-05:
      DOI: 10.1002/jctb.5577
  • Fluid dynamic characterization of a fluidized-bed perfusion bioreactor
           with CFD-DEM simulation
    • Authors: Zheqing Huang; Akinlolu Oyekunle Oluseun Odeleye, Hua Ye, Zhanfeng Cui, Aidong Yang
      Abstract: BACKGROUNDIn the recent development of regenerative medicine, the low yields of progenitor cells have limited the large-scale clinical applications. To overcome the limitation, a novel fluidized bed bioreactor has emerged. However, a detailed understanding of the fluid dynamics is still lacking.RESULTSA three-dimensional modelling approach that couples computational fluid dynamics (CFD) and discrete element method (DEM) was used to simulate the liquid and solid flows in a bioreactor being designed for stem cells expansion. The model was validated by comparing the simulation results with literature experimental data (Chem. Eng. Sci. 60: 1889-1900 (2005)), which showed a good agreement. Using the validated model, the effects of the superficial liquid velocity, particle size and particle density on the solids volume fraction, shear stress on the particles and liquid-solid mass transfer coefficient of dissolved oxygen and glucose were analyzed.CONCLUSIONSSimulation results show that particle size and density have an important impact on the shear stress distribution, and that the liquid velocity affects the shear stress distribution rather modestly when its value is beyond the minimum fluidization velocity. The liquid-particle mass transfer coefficient of dissolved oxygen and glucose can be improved by raising the liquid velocity, and the adoption of a high-density material allows the reactor to operate with higher liquid velocities before reaching shear stress heterogeneities. Furthermore, the two objectives, (i) maintaining lower and homogeneously distributed shear stress and (ii) improving mass transfer, pose conflicting requirements on certain design parameters which need to be carefully considered in the reactor design.
      PubDate: 2018-01-09T10:42:59.42503-05:0
      DOI: 10.1002/jctb.5576
  • Feedforward control application in aerobic and anoxic biotrickling filters
           for H2S removal from biogas
    • Authors: L.R. López; J. Brito, M. Mora, F. Almenglo, J.A. Baeza, M. Ramírez, J. Lafuente, D. Cantero, D. Gabriel
      Abstract: BACKGROUNDFeedforward control was implemented at lab-scale in an aerobic and an anoxic biotrickling filter (BTF) operating under fluctuating H2S loading rate (LR) conditions in order to show the capabilities and added value of this control strategy. Dynamic, long-term tests with variable H2S LR were performed to simulate disturbances in the inlet gas concentration with and without the implementation of a feedforward control loop based on trickling liquid velocity (TLV) and nitrate feeding rate manipulation for the aerobic and anoxic BTFs, respectively.RESULTSAverage LR of 80 g S-H2S m−3 h−1 with peaks and valleys of 141 and 28 gS-H2S m−3 h−1 were tested. At the highest H2S LR a 68.4% and 62.6% reduction of maximum outlet H2S concentration and 50.0% and 26.6% reduction of H2S cumulative mass emitted were reached in the aerobic and anoxic BTFs, respectively, thanks to the application of feedforward control strategies. The sulfate selectivity in the aerobic BTF was enhanced up to 100.6 ± 5.0% under controlled conditions. In the anoxic BTF the sulfate selectivity was kept constant at 32.8% ± 0.8%.CONCLUSIONDespite the feedforward controller showed to reduce significantly the impact of disturbances, the utilization of TLV as manipulated variable in the aerobic reactor showed performance problems. Instead, the feedforward controller through nitrate addition was shown as an adequate, robust strategy to reduce load perturbations impact in anoxic BTFs.
      PubDate: 2018-01-08T10:15:21.831771-05:
      DOI: 10.1002/jctb.5575
  • A Model for Reaction Kinetics of Main and Side Reactions during Industrial
           Production of Trioxane and Its Applications
    • Authors: Xianming Zhang; Yufeng Hu, Weiting Ma
      Abstract: BACKGROUNDTrioxane is industrially synthesized by cyclotrimerization of formaldehyde in [formaldehyde–H2SO4(catalyst)–H2O]. A rapid expansion of trioxane production facilities has occurred worldwide, which requires a reliable model for reaction kinetics of main and side reactions and a deep understanding of underlying mechanisms of conversion and selectivity.RESULTSHere such a model is developed on the basis of our newly established reaction pathways for product and by‐products and component activities calculated by the extended UNIFAC models. Reaction kinetics data are measured and utilized to determine model parameters. The new model offers correct descriptions of reaction kinetics of main and side reactions that occur under industrial working conditions. The model calculation results are used to illustrate the mechanisms that govern conversion and selectivity, and illustrate the roles of catalysts and salt additives in industrial production of trioxane through reactive distillation process.CONCLUSIONSThe principal prediction results are that both conversion and selectivity can be significantly enhanced by developing new catalysts and salt additives to decrease the rate constant for decomposition reaction of trioxane to formaldehyde, and new catalytic mixtures should integrate catalysis with extractive distillation. All the model predictions are consistent with experimental results.
      PubDate: 2018-01-05T06:25:28.002141-05:
      DOI: 10.1002/jctb.5574
  • Effect of Packing Material Configuration and Liquid Recirculation Rate on
           the Performance of a Biotrickling Filter treating VOCs
    • Authors: Francisco Caicedo; José M. Estrada, Juan P. Silva, Raúl Muñoz, Raquel Lebrero
      Abstract: BACKGROUNDGas‐liquid mass transfer still constitutes an important constraint for hydrophobic volatile organic compounds (VOCs) removal in biotrickling filters (BTFs), packing material and liquid recirculation rate being two key parameters governing this mass transfer. The combined impact of both parameters on the abatement of VOCs has not been yet assessed. This work evaluated the influence of the trickling liquid velocity on process performance under two packed bed configurations (random vs. structured) in a BTF treating toluene and ethylbenzene.RESULTSSimilar removal efficiencies > 90 % for both toluene and ethylbenzene (corresponding to elimination capacities of ~50 and 32 g m‐3 h‐1, respectively) were achieved regardless of the configuration. However, less intensive operating conditions were applied in the structured BTF compared to those implemented in the random packed‐bed BTF (optimal trickling liquid velocities of 10 and 20 m h‐1 and liquid renewal rates of 400 and 800 mL d‐1, respectively).CONCLUSIONThe superior performance of the structured monolith packing at milder operating conditions was attributed to an improved liquid distribution and the reduction of dead volumes and preferential gas flow channels. Proper selection of the packing material would result in an important reduction in both energy and fresh water consumption.
      PubDate: 2018-01-05T06:10:20.439402-05:
      DOI: 10.1002/jctb.5573
  • Purification and characterization of polyhydroxyalkanoate (PHA) from
           Bacillus megaterium strain using various dehydration techniques
    • Authors: Murat Akdoğan; Eda Çelik
      Abstract: BACKGROUNDPolyhydroxyalkanoates (PHAs) are natural biodegradable polymers synthesized by several microorganisms. Poly(3‐hydroxybutyrate) (PHB) is the most well characterized biopolymer produced abundantly by Bacillus species. In order to get a better PHA recovery, efficient pretreatment steps, especially dehydration, have a large impact on PHA purification from microbial PHA‐rich biomass. In this study, we have described the effects of various dehydration techniques, i.e. lyophilization (‐L), microwave‐assisted drying (‐M) and ethanol/heat‐treatment (‐E) on PHA production by B. megaterium NRRL B‐14308 strain.RESULTSAfter 66 h of batch cultivation, cells reached the maximum PHA accumulation (PHA‐L: 1.36 g/L, PHA‐E: 1.55 g/L, PHA‐M: 2.08 g/L). The highest overall volumetric productivity for PHA was obtained as 0.226 g L‐1h‐1 for PHA‐M, which was 1.5‐fold higher than PHA‐L. Structural and thermal properties of PHA were characterized by GC‐MS, FTIR, 1H‐NMR, TGA and DSC analyses. Analyses of the accumulated PHA by GC‐MS, FTIR and 1H‐NMR revealed that the biopolymer was made up of 3‐hydroxybutyrate (3HB) and 3‐hydroxyvalerate(3HV) monomers, irrespective of the dehydration technique.CONCLUSIONThe present study offers an alternative biomass drying technique (microwave‐assisted drying) against conventional drying techniques, favorable in terms energy efficiency and processing times, and should help to enhance biopolymer production processes.
      PubDate: 2018-01-05T06:00:40.576091-05:
      DOI: 10.1002/jctb.5572
  • New surface cross‐linking method to fabricate positively charged
           nanofiltration membranes for dye removal
    • Authors: Xiao Wang; Xiaohui Ju, Tian-Zhi Jia, Qian-Cheng Xia, Jia-Lin Guo, Chen Wang, Zhaoliang Cui, Yong Wang, Weihong Xing, Shi-Peng Sun
      Abstract: BACKGROUNDAt present, most commercial nanofiltration (NF) membranes are negatively charged. An effective way to prepare positively charged NF membrane is to cross‐link polyimide (PI) substrate with polyethyleneimine (PEI). However, lacking of an efficient process for selecting proper cross‐linking conditions is an important issue. Therefore, the major objective of this work is to develop an efficient method to cross‐link only the top surface of the membranes.RESULTSThe optimum cross‐linking condition was found to be at cross‐linking temperature of 70 °C, cross‐linking time of 80 minutes and stirring speed of 500 rpm. Comparison of membrane before and after cross‐linked, the MWCO changed from 17520 Da to 458 Da and the membrane surface became positive from negative. The cross‐linked membrane showed high rejection (>95%) for basic dyes with different molecular weights and relatively high antifouling properties to these dyes (FRR>92%, DRt
      PubDate: 2018-01-04T06:25:27.118159-05:
      DOI: 10.1002/jctb.5571
  • Adsorption of Phenol from Aqueous Solutions Using Interlayer Modified
           Titanate Nanotubes
    • Authors: Lihe Hu; Jixiang Zhang, Nian Li, Shudong Zhang, Fa Chen, Bo Ji, Haifeng Li, Zhenyang Wang
      Abstract: BackgroundLayered titanate nanostructures have long been studied as efficient adsorbents for different kinds of pollutants such as heavy metals and dye cations. As to the electro‐neutral and anionic organic pollutants, titanates show relatively low adsorption capacity due to negatively charged surface and lack of organophilic affinity. This research focuses on the interlayer modification of titanate nanotubes for adsorption of this kind of organic pollutants. Phenol was chosen as a representative target.ResultsTwo surfactants, hexadecyl trimethyl ammonium bromide (HTAB) and dodecyl dimethyl benzyl ammonium bromide (DDBAB), were chosen as organic modifier for the interlayer modification. Detailed characterization proved that surfactant molecules were intercalated into the interlayer and surface properties of titanates were successfully modified. Adsorption behavior of phenol was then systematically investigated. Results show that DDBAB modified titanates are efficient phenol adsorbents, possessing better performance than HTAB modified titanates. The high adsorption capacity is attributed to the special structure of titanates and the affinity between phenyl groups in DDBAB and phenol. Subsequently, thermally induced phase change of spent adsorbents led to complete regeneration.ConclusionInterlayer modified titanate nanotubes were efficient phenol adsorbents with a maximum adsorption capacity of 226.24 mg/g. Complete regeneration of spent adsorbents was also achieved.
      PubDate: 2018-01-03T11:07:09.553354-05:
      DOI: 10.1002/jctb.5562
  • A Full‐Scale Thermophilic Biofilter in the Treatment of Sludge Drying
           Exhaust: Performance, Microbial Characteristics and Bioaerosol Emission
    • Authors: Kaixiong Yang; Lin Li, Wenjie Ding, Junxin Liu, Song Xue
      Abstract: BACKGROUNDVolatile organic compounds (VOCs), NH3, and SO2 generated from sludge drying process were treated by a full‐scale thermophilic biofilter (FTB). The correlation of gaseous pollutants removal and the microbial community structure in the FTB were studied. Bioaerosols emission from the FTB was also investigated.RESULTSMore than 90% of VOCs, NH3, and SO2 were removed in steady state. The maximum elimination capacities of VOCs, NH3, and SO2 were 3.01, 1.83, and 5.13 g·m‐3·h‐1, respectively. Analysis of clone libraries indicated that the structure of bacterial communities showed temporal variation. Species that have the abilities of desulfuring and denitrifying, e.g., Alcaligenes sp., Comamonas sp., Sphingobacterium sp., and Bacillus sp., were abundant in the FTB. High bioaerosols concentration of nearly 2.3×103 CFU·m‐3 was detected in the FTB outlet. Most of the bacteria in bioaerosols were assigned to the Pseudomonas sp., which were the main bacteria attached on the surface of packing materials.CONCLUSIONThe FTB was highly efficient and showed potential for the removal of real complexity gases with high temperature. The composition of inlet stream influenced the species and abundance of microorganisms in the FTB. Control of bioaerosols emission should take into account in the future.
      PubDate: 2018-01-03T11:05:57.177912-05:
      DOI: 10.1002/jctb.5563
  • Increasing mass transfer of volatile organic compounds in air scrubbers:
           Relation between partition coefficient and mass transfer coefficient in a
           pilot‐scale scrubber
    • Authors: Joren Bruneel; Christophe Walgraeve, Peter Demeyer, Herman Van Langenhove
      Abstract: BACKGROUNDThe mass transfer of volatile organic compounds (VOCs) from waste gas streams towards liquid in scrubbers is determined by the overall volumetric mass transfer coefficient (Kga), which is dependent on the air‐to‐water partition coefficient (KAW, dimensionless). The application of additives in the water phase can alter this KAW towards lower values thus increasing the Kga. Previous research provided partitioning data of new scrubber liquids and this study will link the partitioning data with mass transfer characteristics in a pilot‐scale scrubber.RESULTSThe Kga was experimentally determined using a VOC pulse addition response (PAR) method in a pilot‐scale scrubber with randomised or structured packing (1.6 m height, diameter 0.1 m). VOCs were injected at the inlet of the scrubber. SIFT‐MS was used for the online measurement of the VOC concentration. An advection‐absorption model was used to calculate the Kga values for a set of VOCs and different scrubber liquid properties. Scrubber liquids and VOCs were applied to evaluate the Kga values in a KAW range from 2.6 10‐3 to 4.0 101, a gas velocity between 0.34 to 1.17 m s‐1 and liquid flow of 0.4 m3 h‐1. The obtained Kga ranged from 0 to 2.27 s‐1.CONCLUSIONA relationship between the Kga, gas velocity and KAW was established. Based on this mathematical model, the economical/technical suitability of applying an additive to the scrubbing liquid of industrial installations can be evaluated. β‐cyclodextrin was applied as additive in the scrubber and Kga values were significantly higher than pure water.
      PubDate: 2018-01-03T11:01:23.762619-05:
      DOI: 10.1002/jctb.5558
  • Effect of surfactants on the treatment of radioactive laundry wastewater
           by direct contact membrane distillation
    • Authors: Xia Wen; Fuzhi Li, Bei Jiang, Xue Zhang, Xuan Zhao
      Abstract: BACKGROUNDDirect contact membrane distillation (DCMD) was applied to treat the radioactive laundry wastewater produced from nuclear power plants (NPPs), with surfactants.RESULTSThe experimental results show that when 0.08 mM surfactants was added into feed solution, the permeate flux reduced sharply by 3%‐30% in one hour, and the largest reduction was found in the case with non‐ionic surfactant. The decontamination factors (DF) of Sr(II), Co(II), and Cs(I) were correspondingly decreased 10‐100 times within 4‐8 hours. Compared to the no salt‐added case, the addition of high concentration salt (100‐300 g·L‐1) could slow down the reduction rate of the permeate flux caused by sodium dodecyl benzene sulfonate (SDBS). The wetting of membranes by surfactants mainly results from the spontaneous adsorption of surfactant molecules onto the membrane surface and the reduction of solution surface tension. However, the high concentration of NaNO3in SDBS solution declines the critical micelle concentration (CMC) of SDBS to less than 0.06 mM, and thus the SDBS micelles formed, which was hard to be absorbed on the membrane surface.CONCLUSIONOur study shows that surfactants could cause serious reduction in permeate flux and rejection of nuclides, and thus they should be removed from the feed solution of DCMD.
      PubDate: 2018-01-03T11:01:20.978278-05:
      DOI: 10.1002/jctb.5568
  • Decontamination of Cr(VI) by graphene oxide@TiO2 in aerobic atmosphere:
           Effects of pH, ferric ions, inorganic anions, and formate
    • Authors: Xinjiang Hu; Yunlin Zhao, Hui Wang, Xiaoxi Cai, Xi Hu, Chunfang Tang, Yunguo Liu, Yuanxiu Yang
      Abstract: BACKGROUNDIn this study, a graphene oxide@TiO2 composite (GO/TiO2) was prepared and characterized by SEM, EDX, XRD, Nitrogen adsorption‐desorption isotherm, and XPS. Photocatalytic reduction and removal of Cr(VI) using this composite in aerobic atmosphere were studied under UV irradiation. The effects of pH, ferric ions, inorganic anions, and formate were investigated systematically.RESULTSThe Cr(VI) reduction rate decreased with increasing the solution pH. The presence of ferric ions in the system could improve the photocatalytic reduction process. The effects of SO42− and PO43− on the process were higher than the Cl− and NO3−. The formate could slightly inhibit adsorption of Cr(VI), while it could improve the Cr(VI) reduction. GO/TiO2 has good stability and it could maintain full photoreduction activity for at least three cycles.CONCLUSIONThe results indicated that the GO/TiO2 can thermodynamically reduce Cr(VI) to Cr(III) under UV light. The environmental conditions and wastewater characteristics (e.g., pH, ferric ions, inorganic anions, and formate) can influence the decontamination process due to that they can affect the interactions between chromium ions and GO/TiO2 and alter the electron‐transfer pathways. The results supported that the GO/TiO2 is an attractive material for removing hexavalent chromium from water using a photocatalytic process.
      PubDate: 2018-01-03T10:51:25.530089-05:
      DOI: 10.1002/jctb.5565
  • Biofiltration of hexane, acetone and dimethyl sulphide using wood, compost
           and silicone foam
    • Authors: Joren Bruneel; Christophe Walgraeve, Juvenal Mukurarinda, Nico Boon, Herman Van Langenhove
      Abstract: BACKGROUNDBiofiltration is a technique to remove Volatile Organic Compounds (VOCs) from waste gas streams. It can be regarded as a sustainable treatment technology with low operational costs and good performance. The treatment of hydrophobic compounds is however difficult, due to the low mass transfer towards the water phase on top of the biofilm present on the packing material. To overcome this mass transfer limitation, a hydrophobic silicone foam was added to a conventional biofilter containing compost and wood dowels.RESULTSThe biofilter was operated for 180 days to treat acetone, hexane and dimethyl sulphide (DMS) at an EBRT of 57 s with IL varying up to 4.5 g m3 h‐1. The highest RE of acetone, DMS and hexane was respectively 99%, 80% and 50%. The affinity of the target compounds towards the packing material was quantified in terms of the packing material‐to‐air partitioning coefficient, measured using a SIFT‐MS based breakthrough approach. These experiments revealed that hexane has 20 to 100 times higher affinity for silicone foam than compost and wood. Microbial community analysis was performed on the different substituents of the packing material at the inlet and outlet. No significant differences in relative abundance were observed between the types of packing materials. Comparison with literature revealed the presence of bacterial strains that were not yet reported in biofilter studies.CONCLUSIONSilicone foam in a biofiltration set‐up showed good performances against the degradation of the target VOCs and mass transfer to the packing material can be increased.
      PubDate: 2018-01-03T10:51:13.445503-05:
      DOI: 10.1002/jctb.5566
  • Synergistic effects of acclimated bacterial community and zero valent iron
           for removing 1,1,1‐trichloroethane and 1,4‐dioxane co‐contaminants
           in groundwater
    • Authors: Jie Yang; Li Yang Zhou, Hui Li
      Abstract: BACKGROUNDTCA and 1,4‐dioxane have caused significantly combined pollution in soil and groundwater. By establishing the Zero valent iron (ZVI) and the acclimated bacterial community coupled system, this study aimed to improve the treatment of 1,1,1‐trichloroethane (TCA) and 1,4‐dioxaneco‐contamination in groundwater and to investigate the synergistic mechanism of ZVI and acclimated bacterial community coupled system for transformation TCA and 1,4‐dioxane.RESULTSThe results showed that the ZVI effectively strengthened the acclimated bacterial community to degrade 70 mg∙L‐1 TCA and 1,4‐dioxane with the enhancement factors (Q) of 1.20 and 2.20. The removal percentages reached 97.8% and 92.5%, respectively. The degradation rate was consistent with the first‐order reaction kinetics. The reductive dechlorination byproducts of TCA were 1,1‐dichloroethane (DCA) and chloroethane (CA), while 1,4‐dioxane was mainly converted to CO2 in the system. The corrosion products on the ZVI surface were mainly FeCO3 and FeS. Phylogenetic analysis revealed that the dominant bacteria were dechlorinating bacteria (DhB), sulfate reducing bacteria (SRB) and iron‐reducing bacteria (IRB) in the microbial community.CONCLUSIONIt is a potential technique to apply ZVI and the acclimated bacterial community to deal with TCA and 1,4‐dioxane co‐contaminants in groundwater.
      PubDate: 2018-01-03T10:46:50.1105-05:00
      DOI: 10.1002/jctb.5567
  • Two‐step persulfate and Fenton oxidation of naphthenic acids in
    • Authors: Xiyan Xu; Gema Pliego, Juan A. Zazo, Shuming Liu, Jose A. Casas, Juan J. Rodriguez
      Abstract: BACKGROUDIn the current study, two‐step persulfate and Fenton oxidation has been investigated for the mineralization of naphthenic acids at 80 oC and initial pH ≈ 8. This pH evolves during the persulfate oxidation step towards the optimum for Fenton oxidation (≈ 3). The effects of persulfate and H2O2 doses, iron concentration, duration of the persulfate oxidation step and operating temperature have been assessed.RESULTSThe combined treatment allowed up to ≈ 80% mineralization of cyclohexanoic acid using fairly low relative amounts of reagents (20 and 30% of the stoichiometric for persulfate and H2O2, respectively). For mineralization of cyclohexanoic acid, 115 and 87 kJ mol‐1 were obtained as representative values of the apparent activation energy for the persulfate and Fenton oxidation steps, respectively. The system was also successfully tested with other naphthenic acids, including cyclohexanebutyric acid, 2‐naphthoic acid and 1,2,3,4‐tetrahydro‐2‐naphthoic acid. Treatment of the naphthenic acids tested by this system gave rise to easily biodegradable effluents consisting mainly of short‐chain organic acids. The biodegradability was confirmed by the BOD5/COD ratio and respirometric tests.CONCLUSIONThe results show the potential application of this approach as a promising cost‐effective solution for the treatment of naphthenic acids‐bearing aqueous wastes. This approach has significant advantage compared to the single thermally‐activated persulfate or Fenton oxidation, since it allows a high mineralization at reduced reagent cost upon replacing part of the persulfate by less expensive H2O2.
      PubDate: 2018-01-03T10:42:27.974448-05:
      DOI: 10.1002/jctb.5569
  • An efficient heterogeneous LiBr/γ‐Al2O3 catalyst for the cycloaddition
           of CO2 with diglycidyl ethers
    • Authors: Hongguang Liang; Junwei Wang, Feng Wang, Yuelan Feng, Maoqing Kang, Zhijie Wang
      Abstract: BACKGROUNDThe cycloaddition reaction of CO2 with diglycidyl ethers was an an effective way both to reduce CO2 and to obtain bis (cyclic carbonate)s, which were applied in the synthesis of green non‐isocyanate polyurethanes (NIPUs). In this reaction, it was highly important and desirable to develop an efficient heterogeneous catalyst. The sustainable supported LiBr catalysts were prepared by a simple impregnation method. And the structures and catalytic activities of catalysts were studied.RESULTSThe work has discovered that with the increase of the loading amount of LiBr/γ‐Al2O3 catalyst, the catalytic activity increased first and then decreased, and when the calcination temperature increased, the catalytic activity increased first, then decreased and increased finally. The effects of loading amount and the calcination temperature on the catalyst structure, interactions of components and surface properties were systematically studied by XRD, FT‐IR, BET, XPS, CO2‐TPD, NH3‐TPD techniques. Among the investigated LiBr/γ‐Al2O3 catalysts, the catalyst with 20wt% LiBr and calcined at 450°C for 4h exhibited the highest catalytic activity.CONCLUSIONIt was found that the formed bifunctional catalysis system was highly important for the cycloaddition reaction. The heterogeneous LiBr/γ‐Al2O3 was advantageous in practical application for its good activity, sustainability and simplicity.
      PubDate: 2018-01-03T10:41:10.202253-05:
      DOI: 10.1002/jctb.5570
  • Electrochemical Promotion of carbon supported Pt, Rh and Pd catalysts for
           H2 oxidation in aqueous alkaline media
    • Authors: Michail Athanasiou; Bjorn Hasa, John. Vakros, Labrini Sygellou, Alexandros Katsaounis
      Abstract: BACKGROUNDThe effect of electrochemical promotion of catalysis (EPOC) for the case of H2 oxidation reaction over commercial M (M=Pt, Rh, Pd) / Vulcan XC72 (ETEK) electrodes immersed in alkaline media was explored in this study. Various reactant mixtures (H2 and O2) fed simultaneously through a glass frit to the anodic electrode which was immersed in the electrolyte. Both positive and negative currents were applied between anode and cathode while all products were followed by mass spectrometry.RESULTSIn the case of Pt electrode, it was found that application of small positive currents resulted in a reversible enhancement of both oxygen and hydrogen consumption rate, higher than the expected faradaic one (I/2F). Pd and Rh electrodes exhibited lower catalytic activity at ambient temperature while positive current applications induced an acceleration of the catalytic reaction. Interestingly, the modification of the catalytic activity of Pd and Rh electrodes was found to be irreversible even under negative current applications.CONCLUSIONCommercially available, carbon supported metal (Pt, Rh, Pd) catalysts, can be electrochemically promoted during hydrogen oxidation reaction in alkaline media. The rate enhancement could be explained by the modification of the work function of the catalytic surface (thus the strength of the reactant's adsorption bond) during potential or current application as well as the modification of the catalyst surface composition.
      PubDate: 2018-01-02T09:58:08.953397-05:
      DOI: 10.1002/jctb.5564
  • Advanced treatment of biotreated coking wastewater with peroxymonosulfate
           oxidation catalyzed by granular activated carbon
    • Authors: Xiulan Song; Meiqin Liu
      Abstract: BACKGROUNDAfter biological treatment, coking wastewater contains high concentrations of toxic organic contaminants and thus requires further treatment.RESULTSAdvanced treatment of biotreated coking wastewater (BTCW) with peroxymonosulfate (PMS) oxidation catalyzed by granular activated carbon (GAC) at ambient temperature (25 °C) was comprehensively investigated. The GAC/PMS system exhibited higher efficiency for total organic carbon (TOC) removal from BTCW than did the PMS‐only and GAC‐only systems. Up to 75.7% of TOC was removed over a 5‐h period with 2 g/L of KHSO5 and 10 g/L of GAC under an initial pH of approximately 5. The TOC removal efficiency increased with PMS concentration and GAC dosage; however, the superfluous PMS was not conducive to organic degradation. The PMS decomposition followed a first‐order kinetics behavior. The GAC/PMS system's capacity for TOC removal gradually weakened with an increase in the number of times the GAC was reused. Almost half of the removal rate was retained after four uses of GAC. The excitation–emission matrix fluorescence demonstrated that humic‐acid‐like substances are effectively adsorbed and preferentially decomposed in wastewater.CONCLUSIONThe study suggests that it is feasible for advanced treatment of BTCW with PMS oxidation catalyzed by GAC, achieving high efficiency for TOC removal.
      PubDate: 2017-12-30T01:35:25.60123-05:0
      DOI: 10.1002/jctb.5560
  • Oxygen barrier and catalytic effect of the cathodic biofilm in single
           chamber microbial fuel cells
    • Authors: Nuria Montpart; Laura Rago, Juan Antonio Baeza, Albert Guisasola
      Abstract: BACKGROUNDImplementation of microbial fuel cells (MFC) requires high coulombic efficiency (CE) for its operation to be more efficient. However, cathodic environments in air cathode MFC provide both carbon source and oxygen and, therefore, a naturally growing heterotrophic biofilm is developed. A priori this biofilm would decrease the power generated in the system since it acts as an electron sink.RESULTSThe effect of the biofilm presence was studied and cyclic voltammetries demonstrated a 46% increase of peak current intensity when the biofilm was present. Cathodic biofilm growth represented an increase in working cathode potential from -280 mV to -225 mV when the biofilm was grown, denoting its catalytic effect. CE also improved when the biofilm was present. 16S rRNA gene based pyrosequencing showed a mixed community composed mainly of aerobic (e.g. Fluviicola, Azoarcus and Flavobacterium genera) and anaerobic bacteria (e.g. Desulfovibrio and Proteinphilum genera) colonizing the biocathode. This result suggests a multilayer distribution of microbial community according to the oxygen concentration in the biofilm.CONCLUSIONSThe biofilm presence is not detrimental but positive since it can perform a double task, both preventing oxygen diffusion into the anode surroundings and decreasing the cathode overpotential, allowing higher CE and power generation.
      PubDate: 2017-12-28T05:45:30.839173-05:
      DOI: 10.1002/jctb.5561
  • Continuous enzymatic hydrolysis of lignocellulosic biomass in a
           membrane-reactor system
    • Authors: Jonathan J. Stickel; Birendra Adhikari, David A. Sievers, John Pellegrino
      Abstract: BACKGROUNDConverting abundant lignocellulosic biomass to sugars as fungible precursors to fuels and chemicals has the potential to diversify the supply chain for those products, but further process improvements are needed to achieve economic viability. In the current work, process intensification of the key enzymatic hydrolysis unit operation is demonstrated by means of a membrane reactor system that was operated continuously.RESULTSLignocellulosic biomass (pretreated corn stover) and buffered enzyme solution were fed to a continuously stirred-tank reactor, and clarified sugar solution was withdrawn via a commercial tubular ultrafiltration membrane. The membrane permeance decline and membrane cleaning efficacy were studied and did not vary significantly when increasing fraction insoluble solids (FIS) from 2.5% to 5%. Continuous enzymatic hydrolysis was successfully operated for more than 80 h. A model for the reactor system was able to predict dynamic behavior that was in reasonable agreement with experimental results.CONCLUSIONThe modeled technical performance of anticipated commercial batch and continuous enzymatic hydrolysis processes were compared and showed that continuous operation would provide at least twice the volumetric productivity for the conditions studied. Further improvements are anticipated by better membrane selection and by increasing FIS.
      PubDate: 2017-12-28T05:33:50.078432-05:
      DOI: 10.1002/jctb.5559
  • Magnetic Glutamine‐grafted Polymer for the Sorption of U(VI),
           Nd(III) and Dy(III)
    • Authors: Mohammed F. Hamza; Adel A.-H. Abdel-Rahman, Eric Guibal
      Abstract: BackgroundNuclear power industry and High‐Tech industries are requiring increasing quantities of uranium and rare‐earth elements (REEs). There is a need for elaborating materials that can competitively recover these metals from ore leachates (such as produced in the leaching of Egyptian ores).ResultsA sorbent based on the chemical grafting of glutamine moieties on a magnetic polyacrylonitrile support was synthesized: polyacrylonitrile, crosslinked with 10 % divinyl benzene in the presence of magnetite, was chemically modified by a series of grafting steps to produce a magnetic polyglutamine sorbent (MGLU). The sorbent was characterized by titration, elemental analysis, X‐ray diffraction (XRD) , thermogravimetric analysis, Fourier‐Transform Infra‐Red (FTIR) spectrometry and scanning electron microscopy (SEM). The sorption properties were tested in function of pH; the sorption isotherms were modeled using the Langmuir equation (maximum sorption capacities: 2 mmol U g‐1 and up to 3.5 mmol g‐1 for Nd(III) and Dy(III)). The equilibrium is achieved within 1 h of contact. Metal desorption and sorbent recycling are highly efficient using acidic solutions; sorption/desorption performance remains stable for a minimum of 5 cycles. MGLU was tested for metal binding in multi‐metal solutions at different pH values.ConclusionThis sorbent could be used for the recovery of REEs and uranium from simulated ore leachates.
      PubDate: 2017-12-27T10:30:24.082244-05:
      DOI: 10.1002/jctb.5557
  • Evaluation of a sequential biotrickling‐biofiltration unit for removal
           of VOCs from the headspace of crude oil storage tanks
    • Authors: Shooka Khoramfar; Kim D. Jones, James Boswell, Jalil Ghobadi, Jan Paca
      Abstract: BACKGROUNDPetrochemical refineries and production sites are considered as the second greatest source of VOC emissions after vehicle exhausts. The feasibility and performance of a novel sequential biotrickling‐biofiltration unit for the treatment of mixture of VOCs at the headspace of an oil and gas production tank battery was evaluated for three months at the Apache TAMU#2 well storage tank battery in Snook, Texas.RESULTSThe results demonstrated that the main VOC constituents of the headspace of the storage tanks were alkanes along with smaller amounts of aromatics such as benzene, toluene and xylenes. Monitoring results for the biotreatment unit showed an average removal efficiency of 50‐60% at an empty bed residence time of 120 seconds in each tank of the unit. After inoculation of the system with wastewater from a sedimentation basin of a local refinery, the removal efficiency of the system increased dramatically which demonstrated the importance of inoculation to achieve a rapid and successful start‐up in industrial biofilters. The most optimal performance was achieved after 77 days, obtaining the highest elimination capacity of 23 g/ at total VOCs loading rate of 39 g/ operation of the field scale sequential BTF‐BF unit for more than three months demonstrated the robustness of this technology and the degradation capabilities of a combination of the suspended and attached growth treatment. The project results have demonstrated the potential for even more optimization for improved effectiveness of this novel biological treatment technology for removal of highly variable aromatic VOC concentrations.
      PubDate: 2017-12-27T10:23:14.013149-05:
      DOI: 10.1002/jctb.5556
  • Ultrasound‐assisted emerging technologies for chemical processes
    • Authors: Anton A. Kiss; Rob Geertman, Matthias Wierschem, Mirko Skiborowski, Bjorn Gielen, Jeroen Jordens, Jinu J. John, Tom van Gerven
      Abstract: The chemical industry has witnessed many important developments during the past decades largely enabled by process intensification techniques. Some of them are already proven at commercial scale (e.g. reactive distillation) while others (e.g., ultrasound‐assisted extraction / crystallization / reaction) are on their way to become the next‐generation technologies.This article focuses on the advances of ultrasound (US)‐assisted technologies that could lead in the near future to significant improvements in commercial activities. The aim is to provide an authoritative discussion on US‐assisted technologies that are currently emerging from the research environment into the chemical industry, as well as give an overview of the current state‐of‐the‐art applications of US in chemical processing (e.g. enzymatic reactive distillation, crystallization of API). Sufficient information is included to allow the assessment of US‐assisted technologies and the challenges for implementation, as well as their potential for commercial applications.
      PubDate: 2017-12-27T10:11:26.212873-05:
      DOI: 10.1002/jctb.5555
  • Enhanced production of carotenoids and lipids by Rhodococcus opacus PD630
    • Authors: Tharatron Suwaleerat; Anusith Thanapimmetha, Maythee Srisaiyoot, Yusuf Chisti, Penjit Srinophakun
      Abstract: BACKGROUNDLow‐value waste organics can be upgraded to higher‐value products using microorganisms. The bacterium Rhodococcus opacus PD630 was used to produce colorants (carotenoids) and lipids (potential fuel oils) from glycerol.RESULTSSubmerged culture of R. opacus PD630 produced carotenoids and lipids on glycerol as the primary carbon source, although supplementation with glucose was necessary. A 1:1 mixture (50 g/L each) of glucose and glycerol in a batch culture afforded a final biomass concentration of nearly 9.0 g/L, a carotenoids concentration of 0.75 mg/L and a lipids concentration of nearly 2.2 g/L. Compared to using only glycerol (100 g/L) in the medium, the final biomass concentration was nearly 4‐fold greater, the carotenoids concentration was 7.5‐fold greater and the lipids concentration was 8.6‐fold greater when a 1:1 mixture of glucose and glycerol was used. A combination of glucose (70 g/L), glycerol (30 g/L) and ammonium acetate (4.32 g/L) further increased the final biomass concentration to nearly 10.2 g/L. With this formulation, the carotenoids concentration rose to 0.99 mg/L and lipids concentration rose to nearly 2.4 g/L in batch culture. A repeated fed‐batch operation with an optimal feeding regimen, raised the final biomass concentration to 12.1 g/L. The final concentration of carotenoids was 0.7 mg/L and the final lipids concentration was nearly 4.9 g/L.CONCLUSIONGlycerol can partly displace the more expensive glucose in production of carotenoids and lipids from R. opacus PD630. Biomass with ~40% lipids (dry basis) can be produced.
      PubDate: 2017-12-27T09:52:02.118812-05:
      DOI: 10.1002/jctb.5554
  • Potential of Aqueous Two‐Phase Systems for the Separation of Levodopa
           from Similar Biomolecules
    • Authors: Rita de Cássia S. Sousa; Catarina M. S. S. Neves, Matheus M. Pereira, Mara G. Freire, João A. P. Coutinho
      Abstract: BACKGROUNDLevodopa is a precursor of several neurotransmitters, such as dopamine, and is used in the treatment of the Parkinson's disease. In this work, an alternative strategy was studied to separate levodopa from similar biomolecules using aqueous two‐phase systems (ATPS).RESULTSTernary ATPS composed of polyethylene glycol (PEG) 400 or ionic liquids (ILs), citrate buffer (K3C6H5O7/C6H8O7) at pH 7.0 and water, and quaternary ATPS composed of PEG 400, K3C6H5O7/C6H8O7 at pH 7.0, water and the same ILs at 5 wt%, were studied. The respective liquid‐liquid phase diagrams were determined at 298 K to appraise the mixture compositions required to form two‐phase systems, followed by studies of the partition of levodopa and structurally similar biomolecules (dopamine, L‐phenylalanine, and L‐tyrosine). Their partition coefficients and extraction efficiencies have been determined, and the selectivity of the ATPS to separate levodopa from the remaining biomolecules evaluated.CONCLUSIONThe results obtained indicated that PEG‐based ATPS were the most effective to separate levodopa from L‐phenylalanine while the separation from the other biomolecules was better using IL‐based ATPS, in particular those based on [P4444]Cl and [N4444]Cl, with extraction efficiencies of levodopa to the salt‐rich phase ranging between 62.7 and 74.0%, and of the remaining biomolecules to polymer/IL‐rich phase up to 91.5%.
      PubDate: 2017-12-27T09:20:27.300057-05:
      DOI: 10.1002/jctb.5553
  • Characterization of polymer inclusion membranes (PIM) containing
           phosphonium ionic liquids and their application for separation of Zn(II)
           from Fe(III)
    • Authors: Monika Baczyńska; Żaneta Słomka, Martyna Rzelewska, Michał Waszak, Marek Nowicki, Magdalena Regel-Rosocka
      Abstract: BACKGROUNDHydrometallurgical separation of Zn(II) from Fe(III) from HCl solutions is an important issue to regenerate spent effluents. Polymer inclusion membranes (PIMs) became an attractive technique for selective separation and concentration of low concentrated target metal ions, proposed as an alternative to liquid‐liquid extraction.RESULTSPIMs containing phosphonium ionic liquids trihexyl(tetradecyl)phosphonium chloride (Cyphos IL101) or bis(2,4,4‐trimethylpentyl)phosphinate (Cyphos IL104), as metal ion carriers, o‐nitrophenyloctyl ether (NPOE) as a plasticizer and triacetate cellulose (CTA) as a polymer matrix were prepared and characterized by contact angle measurements, scanning electron microscopy, atomic force microscopy and nanoindentation measurements. An important aspect was to determine the influence of PIMs aging on their morphology and efficiency of Zn(II) transport. Finally, PIMs were applied for separation of Zn(II) from Fe(III).CONCLUSIONSurface of the IL‐containig PIMs was characterized as hydrophilic, rough, without apparent pores. However, phase contrast images indicated that the plasticized membranes were not fully homogeneous. Stability of the PIMs, particularly of these without the plasticizer or without the carrier, is affected by ageing. Finally, a membrane‐based successful separation of Zn(II) from Fe(III) was developed with 1 M HCl as a striping phase for Fe(III), while majority of Zn(II) retained in the feed phase (SFe(III)/Zn(II) = 8.85).
      PubDate: 2017-12-27T09:10:36.982748-05:
      DOI: 10.1002/jctb.5552
  • A Simplified Implementation of the Stationary Liquid Mass Balance Method
           for On‐line O.U.R Monitoring in Animal Cell Cultures
    • Authors: Andreu Fontova; Martí Lecina, Jonatan López-Repullo, Iván Martínez-Monge, Pere Comas, Ramon Bragós, Jordi Joan Cairó
      Abstract: BACKGROUNDCompared to other methods, the stationary liquid mass balance method for O.U.R. determination offers advantages in terms of estimation accuracy and reduction of stress. However, the need for sophisticated instrumentation, like mass flow controllers and gas analysers, has historically limited a wider implementation of such method.In this paper, a new simplified method based on inexpensive valves for the continuous estimation of O.U.R. in animal cell cultures is evaluated. The determination of O.U.R. values is based on the accurate operation of the D.O. control loop and monitoring of its internal variables.RESULTSThe method developed was empirically tested in 2‐L bioreactor HEK293 batch cultures. O.U.R. profiles obtained by dynamic method, global mass balance method and the developed simplified method were monitored and compared. The results show how O.U.R. profile obtained with the proposed method better follows the off‐line cell density determination. The O.U.R. estimation frequency was also increased, improving the method capabilities and applications.The method's theoretical rationale was extended to the sensitivity analysis which was analytically and numerically approached.CONCLUSIONSThe results demonstrated to be not only a cheap method, but also a reliable alternative to monitor the metabolic activity in bioreactors in many biotechnological processes, being a useful tool for high cell density culture strategies implementation based on O.U.R. monitoring.
      PubDate: 2017-12-27T09:05:32.895486-05:
      DOI: 10.1002/jctb.5551
  • Characterization of natural Yemeni zeolites as powder sorbents for
           ammonium valorization from domestic waste water streams using high rate
           activated sludge processes
    • Authors: Amel Jmayai; Mehrez Hermassi, Rabeh Alouani, Jose Luis Cortina, Abdesslem Ben Hadj Amara
      Abstract: BACKGROUNDIn this study three natural Yemeni zeolites (NZ1, NZ2 and NZ3) having major minerals as clinoptilolite and mordenite, were evaluated as low cost sorbents for the removal and recovery of ammonium ions.RESULTSThe zeolite samples, with pHPZC=9.1±0.2, 7.9±0.2 and 7.4±0.2 for NZ1, NZ2 and NZ3 respectively, showed high ammonium sorption capacities. At pH 8, for treated waste waters: i) with low NH4+ levels (from 25 to 100 mgNH4/L) and ii) for concentrated NH4+ side streams generated from the anaerobic digestion of sewage sludge (from 400 up to 1500mg/L), maximum loading capacities of 27 to 51 mgNH4/g for the studied zeolites were measured. Measured sorption isotherms, in the range of concentration of 0.05 to 5 g/L, were well described by the Langmuir isotherm. The ammonium sorption kinetics was controlled by particle diffusion as it was well described by both the Homogeneous Diffusion (HPDM) and Shell Progressive (SPM) models.CONCLUSIONComparison of the equilibrium data with results for natural and synthetic zeolites demonstrate the higher performance of the studied zeolites providing low residual ammonium values of
      PubDate: 2017-12-27T08:50:52.908087-05:
      DOI: 10.1002/jctb.5550
  • Volatile Fatty Acids Production from Cheese Whey: Influence of pH, Solid
           Retention Time and Organic Loading Rate
    • Authors: R. Calero; B. Lagoa-Costa, C. Kennes, M.C. Fernandez-Feal, M.C. Veiga
      Abstract: BACKGROUNDThe influence of pH, sludge retention time (SRT) and organic loading rate (OLR) were evaluated in the fermentation of cheese whey to produce volatile fatty acids (VFA) in a sequencing batch reactor (SBR). The reactor performance was studied at SRT of 4, 6 and 10 d and the influence of pH (5, 5.5 and 6) was determined at each SRT. The OLR effect was also studied in the range of 3 to 12 g COD L‐1 d‐1, while keeping constant the other parameters mentioned above.RESULTSA more acidic pH (5), improved the degree of acidification at short SRT (4 and 6 d), reaching 76 and 84%, respectively, meanwhile at pH 6 the degree of acidification (DA) improved and reached 85 % at longer SRT (10 d). Regarding the VFA profile, a pH shift from 5 to 6 stimulated the production of acetic and propionic acids, whereas the production of butyric and valeric acids decreased irrespective of the SRT applied. Moreover, the increase of the SRT from 4 to 10 d boosted propionic and valeric acids production regardless of the pH applied. Lower OLR favoured the production of propionic and valeric acids, while higher OLR increased the production of butyric acid. Lactose degradation and VFA production followed the Michaelis‐Menten model.CONCLUSIONA Selective VFA distribution can be reached by modifying parameters such as pH, SRT and OLR in acidogenic reactors, therefore, they could be suitable for further valorisation purposes in the production of polyhydroxyalkanoates from such VFA.
      PubDate: 2017-12-27T02:38:28.546445-05:
      DOI: 10.1002/jctb.5549
  • Strategies of valorization of sludge from wastewater treatment
    • Authors: Shuai Shi; Guoren Xu, Huarong Yu, Zhao Zhang
      Abstract: Sludge is regarded as a kind of potential source to achieve valorization via strategies such as resource recovery, sludge based adsorbents preparation, bioflucculants production, sludge manufacturing construction materials preparation, sludge composting and thermal valorization, which are currently common and effective strategies. Appropriate treatment strategies of sludge are of great importance world widely for the fast growing population and rapidly increasing waste. This mini review summarized some widely used and effective strategies to achieve sludge valorization based on whether the strategy would utilize or reuse the potential source in sludge to get valuable product and eliminate secondary pollution. Anaerobic digestion of sludge is perceived as a potentially cost‐effective method to achieve sludge reduction and resource recovery including carbon, nitrogen, phosphorus resource recovery coupled with other technologies. Utilizing sludge as raw material for preparation of valuable products including sludge based adsorbents, bioflocculants, construction materials is another aspect to achieve sludge valorization. Sludge composting and thermal valorization are also introduced in the mini review since the two strategies could also excellently achieve sludge valorization. In addition, the strategies mentioned were discussed and analyzed in the mini review from environmental and economic aspects.
      PubDate: 2017-12-21T09:30:40.392401-05:
      DOI: 10.1002/jctb.5548
  • Enhanced adsorption capacity for phosphate in wastewater from thermally
           activated flue gas desulfurization gypsum
    • Authors: Peng Cheng; Dong Chen, Haibo Liu, Xuehua Zou, Yaqing Zhang, Jingjing Xie, Chengsong Qing, Tianhu Chen
      Abstract: BACKGROUNDIn this study, a flue gas desulfurization (FGD) gypsum was calcined as phosphate sorbent materials for the remediation of phosphate wastewater.RESULTSin addition to the main crystalline phase of gypsum, FGD gypsum contains a small quantity of quartz, dolomite, calcite and magnesite. Moreover, FGD gypsum has a prismatic structure with a dense and smooth surface, whereas a pore structure and flaky structure appear with an increasing calcination temperature. The kinetic adsorption process was well described by a pseudo‐second‐order model with a high correlation coefficient (R2 ˃ 0.99). The adsorption isotherms indicated that phosphate removal can be fitted by the Langmuir model.CONCLUSIONSCalcination improved the performance of FGD gypsum towards phosphate sorption. The precipitation following chemical adsorption dominated the phosphate removal by the calcined FGD gypsum, and phosphate was ultimately immobilized by hydroxyapatite. Calcined FGD gypsum has excellent capacity for phosphate removal for three reasons: an enhanced content of active Ca by calcination, a novel nanoscale prismatic structure with a high specific surface area, and a favorable reactivity and alkaline environment produced by the decomposition of magnesite, dolomite and calcite.
      PubDate: 2017-12-19T11:00:34.862772-05:
      DOI: 10.1002/jctb.5546
  • Solvent Extraction of Pt(IV), Pd(II), and Rh(III) with the ionic liquid
           trioctyl(dodecyl)phosphonium chloride
    • Authors: Mochamad L. Firmansyah; Fukiko Kubota, Masahiro Goto
      Abstract: BACKGROUNDRecycling of spent platinum group metals (PGMs) has attracted attention for overcoming the problems associated with the low natural abundance of these resources. To recycle such metals, efficient hydrometallurgical processes are required. To improve the efficiency of these processes, we have designed a new phosphonium‐based ionic liquid as an extraction solvent. This paper reports on the potential use of the ionic liquid for extraction and separation of PGMs, namely Pt(IV), Pd(II), and Rh(III).RESULTSAn ionic liquid, trioctyl(dodecyl)phosphonium chloride, P88812Cl, which was newly synthesized, showed highly efficient extraction for Pt(IV), Pd(II), and Rh(III). P88812Cl features several advantages as an extraction solvent, such as high hydrophobicity and low viscosity compared with those features of a commercial analogue, trihexyl(tetradecyl)phosphonium chloride (P66614Cl). The favorable features of our novel ionic liquid were reflected by its high extraction efficiency and low release of phosphorus from the ionic liquid into the aqueous feed solution. Stripping operations were possible, and the high reusability of the ionic liquid was confirmed.CONCLUSIONThe novel ionic liquid P88812Cl is potentially useful as an extraction solvent for PGMs. Our results highlight the strengths of ionic liquids and the tuneability of their properties through design of their molecular structure.
      PubDate: 2017-12-19T10:05:33.105999-05:
      DOI: 10.1002/jctb.5544
  • Heterogeneous and homogeneous photocatalytic degradation of psychoactive
           drug Fluvoxamine: Kinetic study, inorganic ions and phytotoxicity
    • Authors: Sophia Tsoumachidou; Athanasios Kouras, Ioannis Poulios
      Abstract: BACKGROUNDPharmaceutically active compounds, emerging extensively in ecosystems as pollutants, have become an important environmental and public health issue, since they can contaminate drinking water and pose threat to wildlife and human health. As a result, efforts should be made to develop methods to inactivate or eliminate this class of substance in the environment.RESULTSThe photocatalytic degradation of psychoactive drug Fluvoxamine has been investigated. In the case of heterogeneous photocatalytic oxidation, the effect of TiO2 P25 concentration (0.1–1 g L‐1), initial concentration of H2O2 (0.25‐0.2 g L‐1) and Fe3+ (0.00175‐0.014 g L‐1) and pH of the solution (3‐10) on initial reaction rates were evaluated, while for homogeneous photocatalytic oxidation the effect of the amount of H2O2 (0.25–0.2 g L‐1) and Fe3+ (0.00175–0.014 g L‐1) were investigated. Additionally, the conversion of the heteroatoms in the molecule of FVX to inorganic ions (NO3‐, NH4+, F‐) during photocatalytic process has been observed and phytotoxicity testing, using three plant species, was carried out in order to examine the effect of photocatalytic oxidation on the toxicity of FVX.CONCLUSIONAccording to the results presented in this study, both heterogeneous and homogeneous photocatalytic oxidation is an efficient methodology for FVX degradation.
      PubDate: 2017-12-18T01:20:49.455909-05:
      DOI: 10.1002/jctb.5543
  • Enzymatic synthesis and structural characterization of
           methacryloyl‐D‐fructose‐ and methacryloyl‐D‐glucose‐based
           monomers and poly(methacryloyl‐D‐fructose)‐based hydrogels
    • Authors: Giovanni Bortoloni Perin; Maria Isabel Felisberti
      Abstract: BACKGROUNDCarbohydrates are important renewable raw materials and their modification by enzymatic reactions with polymerizable groups is of great importance due the possibility of production of polymers with properties for biomedical applications. In this study, D‐fructose‐ and D‐glucose‐based monomers were prepared by enzymatic reactions and structurally characterized. Moreover, hydrogels based on poly(methacryloyl‐D‐fructose) were also prepared and characterized.RESULTSThe conversions of 99% and 34% for D‐fructose and D‐glucose, respectively, were achieved using 2,2,2‐trifluoroethyl methacrylate as the methacrylic donor and commercial lipase Novozyme® 435 (EC as enzymatic catalyst in t‐butanol. The molar ratios of D‐fructose and D‐glucose mono‐ and dimethacrylate were 57/43 and 87/13, respectively. These monomers are an isomeric mixture related to the tautomeric equilibrium of the carbohydrates in solution. Methacryloyl‐D‐fructose was polymerized in the presence of a controlled amount of ethyleneglycol dimethacrylate as crosslinker achieving hydrogels with different crosslinking densities which are mechanically stable when subject to compression‐decompression cycles and have a high water swelling capability.CONCLUSIONThe combination of 2,2,2‐trifluoroethylmethacrylate and Novozym® 435 in a heterogeneous media lead to the continuous carbohydrate solubilization and reaction with the formation of carbohydrates‐based monomers. The control of the monomer functionality enable the synthesis of hydrogels with different crosslinking densities that tunable their properties.
      PubDate: 2017-12-18T00:37:14.931467-05:
      DOI: 10.1002/jctb.5542
  • Microwave‐assisted extraction of phenolic compounds from Morus nigra
           leaves: optimization and characterization of the antioxidant activity and
           phenolic composition
    • Authors: Marija Radojković; Manuela M. Moreira, Cristina Soares, M. Fátima Barroso, Aleksandra Cvetanović, Jaroslava Švarc-Gajić, Simone Morais, Cristina Delerue-Matos
      Abstract: BACKGROUNDMorus nigra (mulberry) fruits has been reported as a source of bioactive compounds, although information about their leaves is very limited. Usually, they are considered wastes and have been traditionally used only for tea preparation. The main objective of this work was to explore the valorisation of mulberry leaves by polyphenols microwave‐assisted extraction (MAE) and characterization of their antioxidant activity and phenolic composition. A 23 factorial design combined with response surface methodology were applied to characterize the effect of main microwave parameters on total phenolic content (TPC).RESULTSThe optimized MAE conditions were 20 mL of ethanol:water (1:1; v/v), 120 °C, 28 min, 0.414 g and medium stirring speed. Under these conditions, TPC was 19.7±2.0 mg gallic acid equivalents (GAE)/g dry plant (DP), and antioxidant activity was 15.3±1.0 mg ascorbic acid (AA)/g DP (ferric reduction activity power –FRAP– assay), 18.6±1.3 mg Trolox equivalents (TE)/g DP (2,2‐diphenyl‐1‐picrylhydrazyl –DPPH– assay) and 186±15 mg TE/g DP (oxygen radical absorbance capacity –ORAC– assay). When compared to ultrasound extraction and Pharmacopeia reference method, MAE was more efficient representing a valuable technology. Out of the 13 identified compounds by HPLC, the most abundant were rutin, chlorogenic, β‐resorcylic and caffeic acids.CONCLUSIONThese results indicate that mulberry leaves can have potential interest for agro food industries as a new source of natural antioxidants.
      PubDate: 2017-12-12T03:08:43.156789-05:
      DOI: 10.1002/jctb.5541
  • An adsorptive bioprocess for production and recovery of resveratrol with
           Corynebacterium glutamicum
    • Authors: A. Braga; M. Silva, J. Oliveira, R. Silva, P. Ferreira, M. Ottens, I Rocha, N. Faria
      Abstract: BackgroundThe growing interest in polyphenols has led to the design of industrial-scale processes able to produce them by fermentation and recover them in a more sustainable way. The goal of this work is to present two integrated approaches for the recovery of resveratrol, obtained through fermentation. The production of resveratrol using Corynebacterium glutamicum and its continuous removal using an hydrophobic resin is described. Batch production is compared with in-situ product removal, where Amberlite XAD-7HP is either directly added to the medium (direct adsorption) or is present in an external column (external adsorption).ResultsFor both adsorption strategies tested, the amount of extracellular resveratrol increased from 75% to at least 90% of the total amount produced. However, lower total resveratrol concentrations were attained – 3.6 and 2.2 mg L−1, for the external and direct contact strategies, respectively, versus 5.3 mg L−1 for batch experiments.ConclusionsThe proposed in-situ removal strategies demonstrated the potential of increasing the excretion of resveratrol produced intracellularly.. These process configurations may not only lead to a simpler downstream process design, but also to the avoidance of potential problems with the toxicity of polyphenols to the cells, especially when larger titers are obtained.
      PubDate: 2017-12-05T03:36:13.205664-05:
      DOI: 10.1002/jctb.5538
  • Process for production and purification of Lethal Toxin Neutralizing
           Factor (LTNF) from E. coli and its economic analysis
    • Authors: Vishwanath Hebbi; P. Kathiresan, Devendra Kumar, Claire Komives, Anurag S. Rathore
      Abstract: BACKGROUNDPurification of peptides offers unique challenges with respect to obtaining the desired process yield and selectivity. Lethal Toxin Neutralizing Factor (LTNF) is a peptide that is known to neutralize snake venom in mice when the peptide is preincubated with the venom prior to intravenous injection. A process for producing highly purified recombinant LTNF has been developed. The process has been modelled in SuperPro designer using laboratory data for a plant capable of producing 10 Kg of purified rLTNF. Economic analysis has been performed for manufacturing 3 ton of purified rLTNFRESULTSThe process developed produces peptide in the form of concatemer that has been specifically designed to accumulate as insoluble inclusion bodies (IB) during expression in E. coli. A cation exchange chromatography step has been developed to capture the rLTNF concatemer at 140 g/L dynamic binding capacity. Further, the purified concatemer is cleaved completely into monomeric rLTNF using alpha-chymotrypsin enzyme. Finally, a reversed phase high performance liquid chromatography has been designed to purify rLTNF with a recovery of more than 90% and purity greater than 98%. The overall process recovery is 78 ± 2% resulting in 3.36 g of purified product per batch. Techno-economic evaluation of the process has been performed to demonstrate its economic feasibility against currently marketed antivenom products.CONCLUSIONSThe developed process is able to produce purified rLTNF with 78 ± 2% recovery. The study shows that recombinant technology can be used to produce rLTNF cost effectively and shows potential as a substitute for currently available antivenoms against snakebite.
      PubDate: 2017-12-05T03:31:25.744848-05:
      DOI: 10.1002/jctb.5537
  • A novel food-grade lactococcal expression system and its use for secretion
           and delivery of an oral vaccine antigen
    • Authors: Rongguang Zhang; Dan Qiao, Xiaoyan Peng, Guangcai Duan, Qingfeng Shi, Linghan Zhang, Chen Wang, Wenjuan Liang, Shuaiyin Chen, Qingtang Fan
      Abstract: BACKGROUNDFood-grade bacterial expression systems are relatively rare, and increasing evidences indicate that subcellular location of antigens in bacterial vector vaccines may markedly affect the immune efficacy.RESULTSThis study developed a novel food-grade secretory expression system for heterologous protein production and oral vaccine delivery. Furthermore, by using the expression system, an engineered L. lactis strain secreting H. pylori UreB was constructed, and used to vaccinate SPF BALB/c mice. As results, the UreB expressed in L. lactis was detected in both cell lysates and culture supernatant of the engineered strain, constituting roughly 50% of the culture supernatant proteins, and recognized by mouse anti-H. pylori sera. Oral vaccination with the engineered L. lactis produced a significantly elevated anti-UreB serum antibody level in mice (P
      PubDate: 2017-12-04T02:55:27.350418-05:
      DOI: 10.1002/jctb.5536
  • Bioactive compounds of sweet and sour cherry stems obtained by subcritical
           water extraction
    • Authors: Jaroslava Švarc-Gajić; Víctor Cerdà, Sabrina Clavijo, Ruth Suárez, Pavle Mašković, Aleksandra Cvetanović, Cristina Delerue-Matos, Ana P. Carvalho, Vesna Novakov
      Abstract: BACKGROUNDSweet cherries (Prunus avium L.) and sour cherries (Prunus cerasus L.) contain substantial amounts of anthocyanins and polyphenolics, and their stems have been used in traditional medicine for ages. However, comparative data on sweet and sour cherry stems composition using the same analytical methodologies are limited. Moreover, there is no data in terms of biological activity of subcritical water extracts of cherries stems.RESULTS AND DISSCUSIONResults obtained by using several assays that focused on different mechanisms showed that subcritical water extracts of sour and sweet cherry stems were proved to be powerful antiradicals and antioxidants. Anti‐proliferative properties measured by MTT test showed prominent cytotoxicity against different tumor cell lines. Obtained inhibitory concentrations were in the range 8.38‐11.40 μg/mL. GC‐MS analysis showed the presence of alcohols, fatty acids, organic acids and other organic compounds. However, the chemical compositions of those two observed samples were similar indicating similar chemical composition of sour and sweet cherry stems.CONCLUSIONSubcritical water extracts of cherry stem demonstrated excellent biological activity and a potential to be used for pharmaceuticals or supplements due to confirmed high antioxidant, antiradical and antitumor activity.
      PubDate: 2017-12-01T02:55:39.886902-05:
      DOI: 10.1002/jctb.5532
  • Enhanced trans‐2,3‐dihydro‐3‐hydroxyanthranilic acid production by
           pH control and glycerol feeding strategies in engineered Pseudomonas
           chlororaphis GP72
    • Authors: Sheng-Jie Yue; Muhammad Bilal, Shu-Qi Guo, Hong-Bo Hu, Wei Wang, Xue-Hong Zhang
      Abstract: BACKGROUNDTrans‐2, 3‐dihydro‐3‐hydroxyanthranilic acid (DHHA) is a valuable metabolic intermediate for the biosynthesis of wide‐ranging benzoic acid derivatives with enormous biological or pharmaceutical activities. Pseudomonas chlororaphis GP72 is a non‐pathogenic biocontrol strain that displays unique capability to produce phenazines including DHHA. Nevertheless, DHHA production is quite low by the wide type strains that necessitate yield improvement by constructing engineered strains for large‐scale biotechnological applications.RESULTSIn this study, two negative regulatory genes namely rsmE and lon were successively knocked out in DA4 strain. The resulting engineered DA6 strain produced a significantly high titer of DHHA which is 20.6% higher than that of DA4. The influence of varying pH ranging from 6.2 to 8.2 on DHHA production was studied in a 6‐L benchtop fermenter. A controlled broth pH of 7.2 stimulated the maximum DHHA production by engineered DA6 strain. Moreover, a DO‐stat based fed‐batch system maintaining a constant DO level (about 20%) accompanied by a glycerol feeding strategy was applied. Highest DHHA production using this approach was recorded to be 10.06 g/L, which was 31% higher in contrast with traditional batch cultivation.CONCLUSIONThe production of DHHA in metabolically engineered GP72 was considerably improved by inactivating two negative regulatory genes in a fed‐batch mode. It is concluded that fed‐batch fermentation with intermittent glycerol feeding and pH‐control was an effective approach to improve DHHA production yield.
      PubDate: 2017-12-01T02:45:52.073394-05:
      DOI: 10.1002/jctb.5531
  • Reduction of platinum (IV) ions to elemental platinum nanoparticles by
           anaerobic sludge
    • Authors: Alvaro Simon-Pascual; Reyes Sierra-Alvarez, Adriana Ramos-Ruiz, Jim A. Field
      Abstract: BackgroundThe future supply of platinum group metals (PGM) is at risk because of their scarcity combined with a high demand. Thus recovery of platinum (Pt) from waste is an option worthy of study to help alleviate future shortages. This research explored the microbial reduction of platinum (Pt). The ability of anaerobic granular sludge to reduce Pt(IV) ions under different physiological conditions was studied.ResultsX‐Ray diffraction (XRD) and transmission electron microscope (TEM) analyses demonstrated the capacity of the microbial mixed culture to reduce Pt(IV) to Pt(0) nanoparticles, which were deposited on the cell‐surface and in the periplasmic space. Ethanol supported the biologically catalyzed Pt(IV) reduction, meanwhile other electron donors; hydrogen (H2) and formate, promoted the chemical reduction of Pt(IV) with some additional biological stimulation in the case of H2. A hypothesis is proposed in which H2 formed from the acetogenesis of ethanol is implicated in subsequent abiotic reduction of Pt(IV) indicating an integrated bio‐chemical process. Endogenous controls also resulted in slow Pt(IV) removal from aqueous solution. Selected redox mediators, exemplified by riboflavin, enhanced the Pt(IV) reduction rate.ConclusionThis study reported for the first time the ability of an anaerobic granular sludge to reduce Pt(IV) to elemental Pt(0) nanoparticles.
      PubDate: 2017-12-01T02:25:39.369264-05:
      DOI: 10.1002/jctb.5530
  • Effects of light intensity and wavelength on the production of lactobionic
           acid from whey by Pseudomonas taetrolens in batch cultures
    • Authors: Chin-Hang Shu; Kevin Tseng, Rajan Jaiswal
      Abstract: BACKGROUNDLactobionic acid production from dairy waste using Psedomonas taetrolens has gained rapid momentum as it is economically feasible and environment friendly approach. Although photoreceptors have been identified in P. taetrolens, the effect of light on the production of lactobionic acid has not been investigated. This research successfully demonstrates the influence of light on lactobionic acid production by P. taetrolens from cheese whey.RESULTSExperimental results indicated that while red light promoted both cell growth and lactobionic acid production, blue light could only promote cell growth. Xmax and μmax increased from 12.78 to 15.83 gL−1 and 17.4 to 24.5 gL−1 respectively, under red LED light at 500 lux. On the other hand, Xmax increased from 12.78 to 15.18 gL−1, but μmax decreased from 17.4 to 15.4 gL−1 under blue LED light at 100 lux. A novel two‐stage LED photo‐bioreactor process was successful to reduce fermentation time by 24 h compared with that of the photo‐bioreactor under red LED light at 500 lux.CONCLUSIONWe propose that light of varying wavelength and intensities can be used as modulator to enhance lactobionic production by P. taetrolens using cheese way.
      PubDate: 2017-11-29T01:20:24.913911-05:
      DOI: 10.1002/jctb.5528
  • Critical Issues in the Performance of Yeast Based Microbial Fuel Cell
    • Authors: Enas Taha Sayed; Nobuyoshi Nakagawa
      Abstract: BACKGROUNDYeast, Saccharomyces cerevisiae, is quite safe, easily available, rapid‐growing and one of few microorganisms that can metabolize complex organic materials. The effect of different anode materials such as carbon cloth (CC), carbon paper (CP), Teflon‐treated carbon paper (CP‐T), and porous carbon plate (PCP) on the performance of mediatorless yeast, S. Cerevisiae‐based MFC was investigated to explore some issues that are affecting the performance.RESULTSThe variation in the open circuit voltage (OCV), and power generation for CC, CP and CP‐T, were explained by the different areal densities of the yeast cells that adhered to the anode surface. The highest power obtained using the CP anode. On the other hand, the PCP anode with a dense adhesion of the yeast cells, which was expected to give the highest performance; showed the lowest performance. Modifying the PCP surface with a thin nanolayer of cobalt significantly increased the performance over fifty times.CONCLUSIONThe performance of a mediatorless yeast‐based microbial fuel cell, i.e., OCV and current density, was affected by the adhesion density of the yeast cell on the electrode surface. However, it was not the only factor affecting the cell performance. The yeast cell adhesion on the anode surface was dependent on the carbon materials. The improvement of the interfacial electron transfer between the anode and yeast cells is a key for the development of yeast based mediatorless MFCs.
      PubDate: 2017-11-29T01:10:23.045264-05:
      DOI: 10.1002/jctb.5527
  • Preferential crystallization for the purification of similar hydrophobic
    • Authors: Marcelo Silva; Briana Vieira, Marcel Ottens
      Abstract: BACKGROUNDPreferential crystallization is a common technique used in the purification of enantiomers, proving that crystallization may also be applied to the purification of very similar molecules by seeding the solution with the desired compound. Nonetheless, its application to other organic molecules is less documented in literature. Knowing that chemically related polyphenols are generally co‐produced by fermentation and their purification can be too expensive for their market value, this technique may contribute to developing a downstream process with less expensive steps. The goal of this work is to show the applicability of the preferential crystallization concept to the purification of similar polyphenols ‐ naringenin and trans‐resveratrol ‐ with either single or coupled crystallizers.RESULTSAfter developing the needed crystallization kinetic models, an experiment using two coupled vessels was devised, where a 63% yield of naringenin and 44% yield of trans‐resveratrol was obtained, with ≥98% purity in both cases. When the vessels were working independently, 81% of pure trans‐resveratrol (started 60% pure) and 70% of pure naringenin (started 68% pure) were recovered.CONCLUSIONThe performed experiments show the possibility of separately purifying two similar molecules (from 60% to roughly 100%) with promising yields, despite their similar solubility. This method, which can be largely improved, might provide an economically attractive way for the production of low added value products.
      PubDate: 2017-11-28T09:36:25.843293-05:
      DOI: 10.1002/jctb.5526
  • Fractionation of secondary effluents of wastewater treatment plants in
           view of the evaluation of membrane fouling in a further ultrafiltration
    • Authors: E. Ferrer-Polonio; M. Mc Cabe, J.A. Mendoza-Roca, Mª Cinta Vincent-Vela
      Abstract: BACKGROUNDUltrafiltration is used as tertiary treatment in wastewater treatment plants (WWTP) for wastewater reclamation. However, membrane fouling is the main drawback of the process. In this work a new effluent organic matter fractionation procedure with adsorption resins (XAD‐8, XAD4 and IRA‐958) has been applied without recovering the adsorbed fractions. In this way, strong and weak hydrophobic and charged hydrophilic substances of the dissolved organic matter (DOM) were removed for further ultrafiltration, in order to know the most fouling fraction. For it, secondary effluents of two WWTP and two membranes with different molecular weight cut‐offs (100 kDa and 3 kDa) were used in ultrafiltration experiments in a laboratory plant.RESULTSThe hydrophobic substances (especially the strong hydrophobics) predominated over the hydrophilic compounds. Membrane fouling was higher for the membrane with the highest molecular weight cut‐off (100 kDa). Thus, flux decline was around 25‐47% higher than that measured for 3 kDa membrane. The charged hydrophilic substances (CHi) were identified as the most fouling compounds with 100 kDa membrane. Reversible fouling was predominant.CONCLUSIONSThe proposed fractionation system enabled to know the contribution of the different fractions to the DOM.
      PubDate: 2017-11-25T10:10:31.90607-05:0
      DOI: 10.1002/jctb.5520
  • Reductive dehalogenation of a chloroacetanilide herbicide in a flow
           electrochemical cell fitted with Ag‐modified Ni foams
    • Authors: Wenyan He; Yaoyin Lou, Enrico Verlato, Isabelle Soutrel, Didier Floner, Florence Fourcade, Abdeltif Amrane, Marco Musiani, Florence Geneste
      Abstract: BACKGROUNDThe aim of this work is to adapt the electrochemical reduction of AlachlorTM, using Ag‐modified Ni foam electrodes to environmental applications. In this context, preparative electrolyses of AlachlorTM were performed in a flow electrochemical cell in different electrolytic media.RESULTSThe highest catalytic activity towards the reduction of AlachlorTM was obtained in 0.05 mol L‐1 NaOH, with a conversion yield of 93%. The dechlorination yield of AlachlorTM estimated from the Cl‐ concentration was 77%, significantly lower than its conversion yield, but higher than the yield of deschloroalachlor (69%), the main dehalogenated by‐product, indicating the presence of other by‐products.CONCLUSIONSA total reduction of AlachlorTM was achieved in conditions adapted to environmental applications, showing that this process can be used for dechlorination treatment of AlachlorTM in aqueous media. Although a high dechlorination yield was obtained, biodegradability estimated from BOD5 measurements remained low, showing that the C‐Cl bond is not the only functional group that is responsible for the biorecalcitrance of AlachlorTM.
      PubDate: 2017-11-25T10:10:29.455023-05:
      DOI: 10.1002/jctb.5523
  • Enhancement of furfural‐cyclopentanone aldol condensation using binary
           water‐ethanol mixtures as solvent
    • Authors: Jennifer Cueto; Laura Faba, Eva Díaz, Salvador Ordóñez
      Abstract: BACKGROUNDCyclopentanone (CPO) – furfural (FFL) aldol condensation is a very interesting reaction for upgrading the furfural obtained in the depolymerization – dehydration reaction of cellulosic materials. Reaction is faster with cyclopentanone than with other ketones, and resulting condensation adducts are attractive for manufacturing drop – in fuels. However, the most important problem is that this adducts present low water solubility.RESULTSBinary systems combining water (needed to promote the aldol condensation) and ethanol (for enhancing the condensation adducts solubility) at different ratios have been tested. Operation parameters, such as water/ethanol ratio, temperature and reaction time, were optimized for this reaction. Best results (global yield to condensation adducts higher than 36 %) were achieved using 1:2 water/ethanol ratio, and working at 303 K. Higher water ratios lead to the precipitation of condensation products, whereas higher ethanol concentrations hinder the catalyst performance. A reaction mechanism, considering a first order kinetic model on cyclopentanone concentration, was proposed. Kinetic constants have been empirically correlated with ethanol concentration in the reaction medium.CONCLUSIONSThe use of binary ethanol‐water binary mixtures with controlled solvent ratios can avoid the precipitation of condensation adducts. This precipitation leads to important operation problems in the reactor as well as to catalyst deactivation. The negative effect of the presence of ethanol on the reaction kinetics can be overcome by increasing reaction temperature.
      PubDate: 2017-11-25T10:10:26.870143-05:
      DOI: 10.1002/jctb.5522
  • Towards a methodology for recovering K‐struvite from manure
    • Authors: E. Tarragó; M. Ruscalleda, J. Colprim, M. D. Balaguer, S. Puig
      Abstract: BACKGROUNDThis study provides a methodology for recovering two essential macronutrients (potassium and phosphorus) from the liquid fraction of manure. This methodology paves the way for K‐struvite recovery from manure by determining the suitable operational conditions (pH and temperature).RESULTSThe theoretically operational conditions were established by modelling and experimentally adjusted with manure, achieving the highest recoveries (80% of P‐recovery) at pH 10 and 38 °C when using a 10% manure solution. Then, the suitable operational conditions were evaluated using 0‐10‐50‐100% manure solutions. Lowest percentages of manure (0‐10%) favoured the co‐precipitation of other products besides K‐struvite (magnesium phosphate and magnesium hydroxide); and at the highest percentages of manure (50‐100%), all the phosphate was recovered as K‐struvite, but also the co‐precipitation of magnesium hydroxide due to the Mg/P molar ratio applied (Mg/P = 2). Suspended particles acted as nuclei for heterogeneous nucleation and favoured the aggregation of crystals resulting in a star‐asterisk form.CONCLUSIONThe viability of the process was demonstrated, being this study the first proof‐of‐concept of K‐struvite recovery from complex waste streams.
      PubDate: 2017-11-21T10:10:24.801964-05:
      DOI: 10.1002/jctb.5518
  • Stimulation of the Germination and Growth of Different Plant Species Using
           an Electric Field Treatment with IrO2‐Ta2O5 Ti electrodes
    • Authors: Gustavo Acosta-Santoyo; Rosa Alhelí Herrada, Stefan De Folter, Erika Bustos
      Abstract: BACKGROUNDThe goal of this research was to develop the electro‐culturing process for different species of plants including Arabidopsis thaliana and Mammillaria mathildae using IrO2‐Ta2O5 Ti Ti (anode) electrodes while applying a constant direct current electric field. Germination rate was increased in both plant species, growth rate was also enhanced during early life stages of A. thaliana, while the size of the Cactaceae M. mathildae was also increased. Root structure was analyzed in an in vitro analysis using A. thaliana and several enhanced aspects were observed.CONCLUSIONSThisTesting showed that an electro‐culturing process was beneficial during testing as soil ions underwent electro‐migration allowing the permeation of the nutrients to the seeds. Furthermore, a decrease in pH was observed near the IrO2‐Ta2O5 Ti anodes, due to electrolysis of the water during the electro‐culture process (pH = 1), and generation of hydroxyl radicals (·OH) was observed during this electrolysis when seeds were exposed to low intensity direct current electric fields for a short time.
      PubDate: 2017-11-21T10:00:26.211497-05:
      DOI: 10.1002/jctb.5517
  • Experimental and theoretical consideration of the factors influencing
           cationic pollutants retention by seashell waste
    • Authors: Marija Egerić; Ivana Smičiklas, Ana Mraković, Mihajlo Jović, Marija Šljivić-Ivanović, Davor Antanasijević, Mirjana Ristić
      Abstract: BACKGROUNDSeashell waste (SW) is rich in biogenic calcium carbonate and potentially can substitute geological sources in various applications, such as the separation of heavy metals and radionuclides from contaminated solutions. This study aims to compare SW sorption efficiency towards different chemical species (Cu2+, Zn2+, Pb2+ and Sr2+) and to evaluate the effects of various factors based on the experimental data and modeling approach.RESULTSThe reaction of SW with aqueous metal solutions is a combination of several processes that result in metal retention, Ca2+ release, and changes in pH. SW demonstrates variable selectivity for investigated cations, depending on their concentrations and reaction times. Maximum sorption capacities declined in the order Zn2+ > Pb2+ ≈ Sr2+ > Cu2+. The model based on general regression neural network (GRNN) architecture was developed, which enabled prediction of removal efficiency taking into account the process specific, metal specific parameters and their non‐linear interactions. Initial concentration and covalent radii of a cation exhibit the highest, while the initial pH the lowest significance.CONCLUSIONEcological problems caused by SW accumulation in the coastal areas could be mitigated by mastering technologies for their practical utilization. The results obtained facilitate the understanding of cationic pollutants removal by SW in the range of experimental conditions, while the GRNN approach demonstrates advantages in modeling complex sorption processes.
      PubDate: 2017-11-21T09:51:08.922819-05:
      DOI: 10.1002/jctb.5516
  • Increasing mass transfer of volatile organic compounds in air scrubbers: a
           fundamental study for different gas‐liquid systems
    • Authors: Joren Bruneel; Christophe Walgraeve, Stefanie Dumortier, Jonas Stockman, Peter Demeyer, Herman Van Langenhove
      Abstract: BACKGROUNDAir scrubbers are commonly used as treatment techniques for industrial waste gases containing volatile organic compounds (VOCs). Mass transfer of hydrophobic compounds to liquid can be increased using water soluble additives in the scrubbing liquid or applying water‐miscible or immiscible solvents. The design of air scrubbers requires reliable partition data, which are limited in literature. This manuscript provides partitioning data of new scrubber liquids and subsequent research will link the partitioning data with mass transfer characteristics in a pilot‐scale scrubber.RESULTSThe DynAb method was applied for the first time to a broad set gas‐liquid systems to study the partitioning behaviour of volatile organic sulphides and aldehydes. Cyclodextrins (CD) were chosen as water soluble additives. Silicone oil (SO) and isopropylmyristate (IPM) were used as water immiscible solvents, whereas dipropylene glycol methyl ether was applied as a water‐miscible solvent. The inclusion of VOCs into the CD structure is very compound specific. Binding constants were calculated to quantify the CD‐VOC affinity and the partitioning behaviour of the VOCs with oils and solvents were quantified. The air‐to‐water partition coefficient of hexanal could be reduced more than 50 times with a concentration of 72 g L‐1 α‐CD. IPM (100% v/v) could reduce the air‐to‐IPM partitioning coefficient with factor 120 for dimethyl disulphide.CONCLUSIONThe determined partition coefficients can be used for suitability evaluation for the design and modelling of air treatment systems. A broad range of evaluated gas‐liquid systems provides quantitative knowledge about VOC behaviour.
      PubDate: 2017-11-17T10:45:22.466048-05:
      DOI: 10.1002/jctb.5515
  • Effective bioremediation of Cu(II) contaminated waters with immobilized
           sulfate‐reducing bacteria‐microalgae beads in a continuous treatment
           system and mechanism analysis
    • Authors: Yongchao Li; Xiaoyan Yang, Bing Geng, Xue Liu
      Abstract: BACKGROUNDMicroalgae which have greater biodegradable fractions than other organics were chosen as a carbon source for sulfate‐reducing bacteria (SRB). Immobilized SRB–microalgae beads were then prepared and used for bioremediation of synthetic copper mine wastewater.RESULTSWe observed hydrolysis fermentation of the microalgae and noted that the microalgae were first degraded to volatile fatty acids by co‐existing fermentative bacteria; they then served as a carbon source for SRB. Freshly prepared immobilized SRB beads not only possessed high mechanical strength and mass transfer ability, but also showed better sulfate reduction than that of suspended SRB. Moreover, immobilized SRB‐Scenedesmus obliquus beads packed in the upflow bioreactor were satisfactory for the treatment of copper mine wastewater, as shown by the high removal efficiency of their sulfate (182.17 mg SO42‐·g‐1 microalgae·day‐1) and copper ions (45.28 mg Cu2+·g‐1 microalgae·day‐1), and low discharge of chemical oxygen demand. After the reaction, metal sulfides were not produced on the bead surfaces, but likely within them.CONCLUSIONSThe anaerobic bioreactor, filled with immobilized SRB‐Scenedesmus obliquus beads, demonstrated excellent removal efficiency and low discharge of chemical oxygen demand, which may provide a promising strategy for dealing with heavy metal pollution in water.
      PubDate: 2017-11-17T10:15:21.467655-05:
      DOI: 10.1002/jctb.5513
  • Electrochemical treatment of copper complexed by chelating agent and
           chelating surfactant in alkaline solution using a membrane cell
    • Authors: Alireza Eivazihollagh; Joakim Bäckström, Magnus Norgren, Håkan Edlund
      Abstract: BACKGROUNDThe electrochemical recovery of copper from DTPA and C12‐DTPA (a surface‐active derivative of DTPA) complex solutions was investigated in a membrane flow cell. Electrolysis time, solution flow rate, applied current density, and solution pH were evaluated.RESULTSThe chelating surfactant C12‐DTPA can promote the kinetics of copper electrodeposition more than DTPA depending on the experimental conditions. At a current density of 30 A m–2, a solution flow rate of 0.6 L min–1, and pH 10 after 180 min treatment, the copper recovery and current efficiency were 50% and 43.3%, respectively, in the Cu(II)‐DTPA system and about 65% and 53.6%, respectively, in the Cu(II)‐C12‐DTPA system. The differences in the amount of recovery could be explained in terms of differences in the diffusion of copper complexes with DTPA and C12‐DTPA to the cathode, as well as their solution behavior and pH‐dependent conditional stability constants (log10 K’CuDTPA3‐).CONCLUSIONElectrochemical methods could be effectively combined with foam flotation for the chelating surfactant C12‐DTPA, to recover copper and C12‐DTPA. This makes the overall treatment more sustainable, and can be helpful in complying with the increasingly stringent environmental regulations.
      PubDate: 2017-11-14T05:11:19.891164-05:
      DOI: 10.1002/jctb.5510
  • Sulfonated poly(arylene ether nitrile)/polypyrrole core/shell nanofibrous
           mat: an efficient absorbent for the removal of hexavalent chromium from
           aqueous solution
    • Authors: Yingqing Zhan; Xinyi Wan, Shuangjiang He, Yi He
      Abstract: BACKGROUNDSulfonated poly(arylene ether nitrile)/polypyrrole core/shell nanofibrous mats were prepared by electrospinning technique, followed by in situ polymerization of pyrrole monomer. Their removal behaviour of hexavalent chromium (Cr (VI)) from aqueous solution was systematically investigated. The structure and composition of core/shell PEN/PPy nanofibrous mats were examined and confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).RESULTSThe adsorption results revealed that the adsorption capacity of core/shell PEN/PPy nanofibrous mats increased with the decrease of initial solution pH and adsorption process can be described by using the pseudo‐second order model. These core/shell PEN/PPy nanofibrous mats showed a high Cr (VI) adsorption capacity up to 165.3 mg/g at room temperature, which can be largely maintained after four adsorption/desorption cycles. Furthermore, the adsorption isotherms of PEN/PPy nanofibrous mats for Cr(VI) removal fitted the Langmuir isotherm model. The adsorption mechanism of electrostatic attraction between PEN/PPy nanofibrous mats was also presented.CONCLUSIONThe core/shell PEN/PPy nanofibrous mats in the form of flexible membrane allowed easy handling during application, which can be considered as a stable and effective adsorbent for removal of heavy metals and other anionic contaminants from wastewater.
      PubDate: 2017-11-14T02:10:28.026221-05:
      DOI: 10.1002/jctb.5511
  • Promising abilities of mercapto‐degrading Staphylococcus capitis strain
           SH6 in both crude oil and waste motor oil as sole carbon and energy
           sources: its biosurfactant production and preliminary characterization
    • Authors: Alif Chebbi; Dorra Hentati, Meriam Cheffi, Rihab Bouabdallah, Cyrine Choura, Sami Sayadi, Mohamed Chamkha
      Abstract: BACKGROUNDWe showed previously that a Staphylococcus capitis strain SH6 was found to be able to degrade several malodorous mercaptans and simultaneously reduce the surface tension.RESULTSHerein, we revealed the capacity of strain SH6 to grow on various hydrocarbons, used as the only carbon and energy sources. Based on GC‐MS analyses, the substantial ability to degrade up to 45% and 64% of aliphatic hydrocarbons (n‐alkanes) of crude oil and waste motor oil, respectively, after 30 days of incubation at 37 °C and 180 rpm, was shown. Moreover, the properties of biosurfactant produced by strain SH6 grown on different oil substrates; diesel oil and waste motor oil, were studied. Biosurfactants exhibited enhanced emulsification capacities and significant stabilities over a wide range of salinity (20‐150 g/l), temperature (‐20‐100 °C), pH (2‐12) and also a promising abilities in crude oil removal from contaminated soils. Their CMC were of 800 mg/l. FTIR analyses suggested the lipopetide nature of biosurfactants.CONCLUSIONOverall, the stabilities of biosurfactants under a wide pH range, high temperatures and variable concentrations of salt, as well as its emulsifying properties, suggest potential applications in bioremediation processes.
      PubDate: 2017-11-14T00:20:33.553663-05:
      DOI: 10.1002/jctb.5508
  • Deep Eutectic Solvents: Designer Fluids for Chemical Processes
    • Authors: Irfan Wazeer; Maan Hayyan, Mohamed K. Hadj-Kali
      Abstract: The increasing demand for multi‐task green solvents has spurred the development of next‐generation liquid media such as deep eutectic solvents (DESs), which have recently attracted increased attention. DESs are mixtures of salts and complexing agents, having freezing points lower than those of starting individual components. Similarly to ionic liquids, DESs exhibit distinctive properties such as chemical and thermal stability, biodegradability, non‐flammability, and cost effectiveness. These features account for their wide range of applications, e.g., as extractants, reactants, catalysts, reaction media, additives, and lubricants. This review summarizes the recent research efforts directed at exploring the potential applications of DESs in various chemical processes. With the rapid publication on this new generation of solvents, other roles also are expected to be seen sooner or later.
      PubDate: 2017-10-26T04:46:54.555998-05:
      DOI: 10.1002/jctb.5491
  • Sustainable approach to biotransform industrial sludge into organic
           fertilizer via vermicomposting: A mini‐review
    • Authors: Leong Hwee Lee; Ta Yeong Wu, Katrina Pui Yee Shak, Su Lin Lim, Kok Yew Ng, Minh N. Nguyen, Wen Hui Teoh
      Abstract: Currently, industrial sludge is generated in large amount annually. Industrial sludge is a solid or semi‐solid material consisting of all compounds removed from wastewater, as well as any substances added to the biological and chemical operation units during the treatment process. The composition of sludge may vary considerably. Furthermore, distinctive treatment and disposal methods are necessary as sludge produced from different industries would have different characteristics. Therefore, processing and disposing of industrial sludge is a challenging and complex environmental problem. Landfilling, incineration and agricultural land application are the three most commonly employed methods for the disposal of industrial sludge. Among the three methods, the agricultural land application is a convenient and economical disposal alternative for industrial sludge. However, industrial sludge could have high putrescible content and pathogenic hazards. One possible way to ensure that the industrial sludge could be reused on agricultural land is by conditioning and stabilizing the sludge using a pretreatment process. One of the pretreatment processes which could be employed in this context is vermicomposting. Vermicomposting is an alternative for biological stabilization of organic wastes, with the addition of earthworms. Through vermicomposting, industrial sludge could be transformed into matured organic fertilizer or vermicompost in a shorter period. Thus, this paper reviewed the recent literature on utilizing the vermicomposting process to manage industrial sludge in order to assess the feasibility of this technology. The present review would also provide a brief overview of the production and treatment methods of industrial sludge.
      PubDate: 2017-10-25T11:00:55.84424-05:0
      DOI: 10.1002/jctb.5490
  • Recovery of Butanol from Clostridium beijerinckii P260 Fermentation Broth
           by Supercritical CO2 Extraction
    • Authors: N. Qureshi; F. Eller
      Abstract: BACKGROUNDButanol is a superior biofuel to ethanol because of its blend properties and higher energy density. However, its recovery by distillation from the fermentation broth is energy intensive. For this reason, we studied butanol recovery by supercritical CO2 extraction from simulated and actual fermentation broths. Recovery of butanol by this technique has numerous advantages including being environmentally favorable, avoiding use of costly chemicals or membranes, and compatible with the microbial culture.RESULTSFor the model solution extraction process, feed contained 7.00, 12.00, and 1.00 gL‐1 acetone, butanol, ethanol (ABE), respectively, to mimic the actual concentrations obtained in the fermentation broth. In the extract phase, butanol concentration that was obtained ranged from 460.4 to 573.2 gL‐1 with butanol selectivities ranging from 128 to 204.8. ABE recovery was also successfully demonstrated using actual fermentation broth of C. beijerinckii P260.CONCLUSIONSupercritical CO2 was successfully used for recovery of all three (ABE) components. Fermentation broth raffinate (feed depleted in ABE after recovery) was also reused for a second fermentation thus allowing process water recycle.
      PubDate: 2017-10-20T10:30:22.089939-05:
      DOI: 10.1002/jctb.5482
  • Nitric Oxide Generating Copper‐Chitosan Particles for Wound Healing
    • Abstract: BACKGROUNDNitric oxide (NO) is a signaling molecule that plays many roles during infection, inflammation, and wound healing processes. Due to NO's role in wound repair, we have developed a novel NO generation system based on copper‐chitosan complexes that can be used for the topical generation of NO. Chitosan, a biocompatible polymer, chelates copper ions. Copper in the +1 state can reduce nitrite (NO2–) and convert it into NO. With glucose, a reducing sugar, present in the system, Cu+2 can be returned to Cu+1 to complete the catalytic cycle.RESULTSCopper‐chitosan milli‐ and micro‐ sized particles were produced using microfluidic techniques. Copper‐chitosan milli‐particles (Cu‐chito) did produce nitric oxide (NO). The maximum rates of NO production were ~ 1.40 nmol/min/g (Cu‐chito) and 1.08 nmol/min/g (Cu‐chito + glucose). The milli‐particles were tested with ARPE‐19 cell lines in cell proliferation assays. Cu‐chito particle treatments with nitrite showed 130% more growth in comparison to chitosan milli‐particles not containing copper. Furthermore, Cu‐chito treatments of nitrite + glucose showed 152% more growth in comparison to control groups, and 118% in comparison to Cu‐chito with nitrite alone. The activity of intracellular NO target, matrix metalloproteinases (MMP‐2 and ‐9), were shown to increase by 60% after 48 hours of Cu‐chito ± glucose treatments.CONCLUSIONWe have produced NO‐releasing copper chitosan derivatives, with proof of concept for nitric oxide release and positive effects on a cell culture model of wound healing.
  • Synergistic effects of components in deep eutectic solvents relieve
           toxicity and improve the performance of steroid biotransformation
           catalyzed by Arthrobacter simplex
    • Abstract: BACKGROUNDThe discovery of deep eutectic solvents (DESs) has introduced a new class of promising green solvents to overcome many drawbacks associated with the organic solvents. In this study, the synergistic effects of the components in the form of DESs on bacterial viability, membrane integrity, and retention of metabolic activity as well as the efficiency of Δ1,2‐dehydrogeneration of cortisone acetate (CA) using whole cells of Arthrobacter simplex were investigated.RESULTSThe agar disc diffusion method, viability assays and the retention of sugar metabolic activity were used to investigate their toxicity to A. simplex. The results indicated that colinium salts were more toxic than the corresponding hydrogen bond donor (HBDs), but their deleterious effect could be weakened by incorporating them into DESs. Moreover, the best catalytic performance was found in the ChCl:U(DES)‐containing system when Δ1,2‐dehydrogeneration using Arthrobacter simplex was carried out in three different systems followed by the addition of DES, their components and their mixtures respectively. Additionally, metabolites with significantly changed concentration were identified by means of GC‐MS and principal component analysis, which revealed five compounds that may be used as potential indicators to discriminate the effects of different concentrations of DESs on A. simplex.CONCLUSIONThe cholinium salts used in this study, were toxic to A. simplex to some extent, while the synergistic effects were observed after DES formation. The efficient biotransformation in DESs especially in ChCl:U(DES)‐containing system potentially offers a promising strategy for the production of many different steroids.
  • An optimal blend of single autodisplayed cellulases for cellulose
           saccharification—a proof of concept
    • Abstract: BACKGOUNDTo date, it has been challenging to optimally proportionate the individual cellulases in crude extracts and multienzyme systems to promote enzyme synergism. The application of single surface‐display of enzymes may obviate such challenges. This article presents a proof of concept of the optimal mixing of single surface‐displayed cellulases for cellulose hydrolysis using Simplex lattice mixture design.RESULTSThe recently discovered maximized autotransporter‐mediated expression system was used to express the three cellulases. The biochemical screening analysis revealed that the enzymes have a broad range of functional pH (4‐9) and temperature (30‐100 oC) characteristics. The evaluated optima were pH 6 and 60 oC. Through the statistical design of experiment, a blend ratio of 1: 1.6: 1.4 of endoglucanase: exoglucanase: β‐glucosidase was identified as the “sweet spot” for optimum sugar yield. The application of this blend generated about 0.354 mg/mL and 0.446 mg/mL of sugars from filter paper (Ø 6 mm, ~2.5 mg) and 2.5% pretreated EFB, respectively, within 12 hours. Supplementing the enzyme blend with CaCl2 and Tween 20 improved the sugar yield.CONCLUSIONThis research has revealed an interesting concept of efficiently addressing cellulase synergism. The overall outcome of this research is promising for the derivation of value from lignocellulose.
  • Fabrication of WO2.72/UiO‐66 nanocomposites and effects of WO2.72 ratio
           on photocatalytic performance: judgement of the optimal content and
           mechanism study
    • Abstract: BACKGROUNDRecently, the hybrid nanocomposites based on metal‐organic frameworks (MOFs) and inorganic nanomaterials have been actively investigated as a potential technology for solving the environmental pollution problems. However, to our knowledge, there are still no composites of WO2.72 and MOFs reported until now. In this study, highly dispersed WO2.72 nanorods were first grown in situ upon UiO‐66 through a hydrothermal process.RESULTSThe optimal content of the WO2.72 (30 wt%) could be intuitively judged by Field emission scanning electron microscopy. The degradation efficiency of methyl orange (MO) in photocatalysis with 30 wt% WO2.72 loading exhibited better photocatalytic activity than bare UiO‐66, WO2.72 and other WO2.72 loadings. The enhancement of photocatalytic activity over hybrid WO2.72/UiO‐66 can be ascribed to the difference of conduction band between WO2.72 and UiO‐66, which could cause the photoelectron inject to the WO2.72 from UiO‐66, and the lone pair electrons of –OH and –COOH groups of the UiO‐66, which not only repel excited electrons but also attract photogenerated holes.CONCLUSIONSThe enhanced separation of photoexcited carriers between WO2.72 and UiO‐66 led to the enhancement of photocatalytic activity. The photocatalytic reaction mechanism for MO treatment was also studied.
  • Nano layered TiO2 for effective bacterial disintegration of waste
           activated sludge and biogas production
    • Abstract: BACKGROUNDProper management of the huge amount of waste activated sludge generated during the conventional treatment of wastewater is nowadays a major environmental issue. Proper treatment of sludge needs huge investment and proper handling. To address this issue, the immobilized photocatalyst (TiO2) mediated exocellular fractionation of bacterial pretreatment for anaerobic digestion was utilized as a sludge treatment technique.RESULTTi was deposited on glass substrate by a DC spluttering technique, and a TiO2 layer was formed by annealing in oxygen atmosphere. This immobilized TiO2 efficiently extricated the extracellular components at 45 min by removing 99 % of the total extractable extracellular polymeric substances. The exocellular fractionated bacterial pretreatment induced 20 % of COD solubilization with methane generation of about 0.0217 g COD/ g COD.d, which was higher than the sludge without any treatment and sludge with bacterial pretreatment only.CONCLUSIONAn 8 % increase in COD solubilization was achieved, which generated high quantities of methane. With the advantage of methane generation, the maximum profitable sludge reduction was obtained. Thin film deposition of TiO2 enables easy recovery of TiO2. The cost, energy, and solid balance analysis confirmed that this treatment method is field applicable.
  • Mathematical modeling, steady state simulation, parametric analysis and
           optimization of SO2 capture in a countercurrent moving bed (CaO and C)
    • Abstract: The use of absorbents, which are based on calcium, for the reduction of SO2 emissions from power plants has been studied for the last 30 years. The present work is a part of a research project, which aims at the development of a moving bed limestone filter. It is placed after the burning, in order to capture the SO2 from the flue gases of pulverized lignite combustors. A heterogeneous mathematical model was developed for the steady state simulation of a gas‐solid countercurrent moving bed reactor. The mathematical model was solved with the method of finite elements and gave results for the temperature and conversion profile along the reactor. Also, parametric analysis (for Tg,in, Ts,in, us, qo, , , do, zo) was performed and useful conclusions for the behavior of moving bed reactor in different conditions came out. Finally, optimization of conditions was performed, so that the SO2 conversion is higher than 0.95. The results prove an important technological interest for dry process in applications of SO2 capture.
  • Experiments and modelling of a biotrickling filter (BTF) for removal of
           styrene from airstreams
    • Abstract: BACKGROUNDThe studies on the removal of styrene from airstreams carried out in pilot‐scale biotrickling filter (BTF) are still scarce thus making difficult its industrial application. Moreover, it seems necessary to develop a comprehensive description of the phenomena occurring in the bioreactor that could be used as a tool for BTF design and performance prediction.RESULTSThe removal of styrene from airstreams in the pilot‐scale biotrickling filter (BTF) inoculated with Pseudomonas sp. E‐93486 bacteria was investigated (operational parameters: = 100 ‐150 m3h‐1, = 8 m3h‐1, = 0.2‐1 gm‐3, EBRTs = 41‐62 s, T=303 K). The experiments performed during the period of more than 120 days confirmed high effectiveness of the examined process; RE=78‐94.2% was obtained for all the sets of operational parameters.The experimental data‐base was exploited to validate every of the three mathematical models of the process. All the tested models approximate very well experimental data; the mean percentage error of the RE value prediction did not exceed 3%.CONCLUSIONThe formulated approximate Simple One‐Substrate Model (SOSM) described the investigated process with excellent accuracy (eY = 2.72%) and was numerically relatively simple. Therefore, this model was recommended as a useful tool for modelling the biodegradation processes of moderately hydrophobic compounds carried out in BTF.
  • Highly efficient removal of toxic Pb2+ from wastewater by an
           alginate‐chitosan hybrid adsorbent
    • Abstract: BACKGROUNDIn this study, a low‐cost and environment‐friendly alginate‐chitosan hybrid adsorbent (depicted as Alg‐Chi) was developed for the removal of Pb2+ from water.RESULTSExperimental results showed that the Alg‐Chi exhibits high selectivity and affinity to Pb2+. The selectivity coefficients of the Alg‐Chi for Pb2+/Cr3+, Pb2+/Co2+ Pb2+/Cd2+, Pb2+/Zn2+, and Pb2+/Cu2+ are all over 5. It can uptake 96.8% of Pb2+ from Pb2+‐containing solutions (1.5 mM), and the maximum adsorption capacity for Pb2+ reaches 468.5 mg/g, which is higher than that of most reported adsorbents for Pb2+. Moreover, the Alg‐Chi can also be regenerated via simple acid elution and used repeatedly without loss in adsorption ability.CONCLUSIONSThe analysis of the adsorption mechanism indicated that the Alg‐Chi adsorbed Pb2+ mainly through ion exchange and chemical coordination. Green and low‐cost raw materials, simple preparation process, efficient removal efficiency and recyclable, these characteristics make the synthetic Alg‐Chi have a broad application prospects in the field of Pb2+‐containing wastewater treatment.
  • Application of a thermostable Baeyer‐Villiger monooxygenase for the
           synthesis of branched polyester precursors
    • Abstract: BACKGROUNDIt is widely accepted that the poor thermostability of Baeyer‐Villiger monooxygenases limits their use as biocatalysts for applied biocatalysis in industrial applications. The goal of this study was to investigate the biocatalytic oxidation of 3,3,5‐trimethylcyclohexanone using a thermostable cyclohexanone monooxygenase from Thermocrispum municipale (TmCHMO) for the synthesis of branched ε‐caprolactone derivatives as building blocks for tuned polymeric backbones. In this multi‐enzymatic reaction, the thermostable cyclohexanone monooxygenase was fused to a phosphite dehydrogenase (PTDH) in order to ensure co‐factor regeneration.RESULTSUsing reaction engineering, the reaction rate and product formation of the regio‐isomeric branched lactones were improved and the use of co‐solvents and the initial substrate load were investigated. Substrate inhibition and poor product solubility were overcome using continuous substrate feeding regimes, as well as a biphasic reaction system with toluene as water‐immiscible organic solvent. A maximum volumetric productivity, or space‐time‐yield, of 1.20 g L‐1 h‐1 was achieved with continuous feeding of substrate using methanol as co‐solvent, while a maximum product concentration of 11.6 g L‐1 was achieved with toluene acting as a second phase and substrate reservoir.CONCLUSIONThese improvements in key process metrics therefore demonstrate progress towards the up‐scaled Baeyer‐Villiger monooxygenase‐biocatalyzed synthesis of the target building blocks for polymer application.
  • The combine use of continuous‐flow microchannel reactor and ionic liquid
           cosolvent for efficient biocatalysis of unpurified recombinant enzyme
    • Abstract: BACKGROUNDMicrofluidic biocatalysis has advantages in terms of heat transfer and mass transfer. However, mass transfer in microscale conditions is often limited by excessive enzyme agglomeration, resulting in reduced reactor performance. In the present study, to establish an efficient and inexpensive micro‐reaction system for obtaining high‐value fine chemicals, a novel combine use of continuous‐flow microchannel reactor and ionic liquid cosolvent for efficient production of isoquercitrin from rutin catalysed by unpurified recombinant enzyme RhaB1 was successfully carried out.RESULTSThe unpurified RhaB1 was expressed by BL21‐pET21a‐rhaB1 and the amino acid sequence was confirmed by Maldi‐TOF‐TOF, which was directly applied in microchannel reactors with an increase activity of 37.7% compared to the purified RhaB1, with [Toma][Tf2N] used as a cosolvent to avoid enzymatic agglomeration. A yield of 99.3±4.3% was achieved in 10 min using crude RhaB1 in microchannel reactors under optimum conditions, and the circular dichroism spectroscopy confirmed that [Toma][Tf2N] had a positive effect on RhaB1 activity. Compared with a batch reactor, the reaction time was reduced by 98.3%, the Km was decreased to 1/3 and the productivity was improved 61.4 times.CONCLUSIONThe results indicated that the developed cosolvent system in the microfluidic reactor could improve the solubility and liquidity of the recombinant RhaB1, which protocol is promising for industrial applications due to higher productivity and better economic effects with lower costs.
  • Controllable of monoacrylate‐modified adsorption resins and enhancing
           adsorption toward fermentation inhibitors from rice straw hydrolysate
    • Abstract: BACKGROUNDA series of monoacrylate modified adsorption resins from reactive mixture with different amounts and types of monoacrylate have been synthesized by oil/water (O/W) suspension polymerization technique and utilized to remove fermentation inhibitors and pigments from rice straw hydrolysate for the first time. The modified resin was characterized by Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscope (SEM) and N2 adsorption‐desorption isotherms. Batch experiments were carried out to determine the adsorption performance of the modified resin for fermentation inhibitors. The regeneration and reusability experiments were performed to evaluate the economic value.RESULTSThe modified resin with 80% glycidyl methacrylate (GMA) feeds amount and epoxy group performed optimal selectivity to fermentation inhibitors from rice straw hydrolysate. The adsorption capacities of acid soluble lignin (ASL), formic acid, acetic acid, levulinic acid, 5‐hydroxymethylfurfural (5‐HMF) and furfural onto 80% GMA modified resin were enhanced by 45%, 156%, 86%, 79%, 131%, 52%, respectively. Furthermore, the decolorization rate was improved by 12% than unmodified styrene‐divinylbenzene (St‐DVB) adsorption resin with approximately 5% sugar loss.CONCLUSIONThis work not only provides a potential adsorbent for practical applications for remove fermentation inhibitors from rice straw hydrolysate, but also provides guidance for choosing and modifying adsorbent for detoxify lignocellulose hydrolysate.
  • Synthesis of polyglycerol mediated covalent construction of a
           core‐satellite superparamagnetic mesoporous carbon nanocomposite:
           application on dye adsorption
    • Abstract: BackgroundIn this work, we used a polyglycerol (PG) mediated covalent linkage to produced a core‐satellite superparamagnetic nanocomposite, termed MMCN composed of superparamagnetic iron oxide nanoparticles (SPIONs) covalently bound to core mesoporous carbon nanoparticle (MCN). Magnetic separation was a very useful method for removing and recycling pollutant in the water by applying external magnetic field. SPIONs were good candidates that guide the MCN to desired sites using a magnet to achieve water purification. And it was used as an adsorbent for removal of methylene blue (MB) from aqueous solutions.ResultsThe magnetism of the MMCN nanocomposites were still enough to be magnetically separated by applying a magnetic field. The MMCN found to be a sufficient dye adsorbent with a maximum adsorption capacity of 250 mg/g. And the adsorbent could be regenerated and reused effectively by ethanol solution and allowed the treatment of wastewater contamination by MB in industry.ConclusionThe MMCN nanocomposites obtained such high dispersibility, superamagnetic and good recyclability through PG mediated covalent linkage. The optical properties of these multifunctional nanocomposites indicate that high efficient removal of water pollutants such as dyes, and that quickly separated by applying a magnetic field.
  • Cover Image, Volume 93, Issue 4
    • Abstract: The cover image, by Zhi‐wei Zeng et al., is based on the Research Article Comparative study of rice husk biochars for aqueous antibiotics removal,
      DOI : 10.1002/jctb.5464.The cover image, by Zhi‐wei Zeng et al., is based on the Research Article Comparative study of rice husk biochars for aqueous antibiotics removal,
      DOI : 10.1002/jctb.5464.
  • Issue Information
  • Synthesis, characterization and evaluation of amphoteric chitosan‐based
           grafting flocculants for removing contaminants with opposite surface
           charges from oilfield wastewater
    • Abstract: BACKGROUNDContaminants with either negative or positive surface charges in wastewater generated from oilfields are normally very difficult to remove by traditional flocculants owing to their strong pH‐dependence and high health risks. Natural polymer flocculants, especially chitosan‐based flocculants, have attracted much interest for their environmental friendliness, excellent flocculation efficiencies and cost‐effectiveness.RESULTSA series of amphoteric chitosan‐based grafting flocculants (CM‐chi)‐g‐PDMDAAC (denoted as CgPD) were successfully synthesized by grafting diallyl dimethyl ammonium chloride (DMDAAC) onto carboxymethyl chitosan (CM‐chi) with different grafting ratios. By carboxymethyl and grafting modification, dramatically increased water solubility of chitosan was obtained. The physicochemical structure of CgPD products was characterized by 1H NMR and elemental analysis proving that DMDAACC was grafted onto CM‐chi appropriately. Flocculation effects of CgPD were studied in kaolin and hematite suspensions having opposite surface charges. These CgPD flocculants demonstrated an excellent performance in respect of flocculation window, optimal dosage and pH sensitivity. In addition, CgPD was proven to be applicable as a flocculant in water treatment of oilfield sites.CONCLUSIONThe biodegradability flocculants, CgPD, can effectively remove contaminants with opposite surface charges from oilfield wastewater with low optimal dosage, wide flocculation window, low pH sensitivity and less environmental impacts than traditional flocculants. © 2017 Society of Chemical Industry
  • Microbial community dynamics reflect reactor stability during the
           anaerobic digestion of a very high strength and sulfate‐rich vinasse
    • Abstract: BACKGROUNDMicrobial community dynamics during the anaerobic digestion of vinasse has been little studied. However, having knowledge about it is essential for early detection of reactor operational difficulties to apply preventive actions. This research studies the microbial community dynamics in the anaerobic digestion of vinasse, linking to experimental observations about product yields and organic matter degradation.RESULTSMethane and sulfide yields decreased with increasing SO42‐/COD ratio, while the fraction of organic matter degraded by sulfate reducing bacteria increased from 4.5 ± 0.3% to 27.1 ± 0.6%. The archaeal community showed that acetoclastic Methanosaetaceae were little affected by the increase of the SO42‐/COD ratio, in contrast to the Methanomicrobiales and Methanobacteriales population, which decreased during the experiment. The total bacterial diversity was influenced mainly by substrate composition, showing that the increase of the SO42‐/COD ratio above 0.10 shifted the bacterial community to a lower richness.CONCLUSIONThese results provide knowledge on the dynamics of the microbial communities, which can be useful to control the anaerobic digestion of sulfate‐rich vinasses, showing that reactor stability equates to the higher ratios between total methanogens and total bacteria gene copy numbers, whereas operational difficulties can be associated to lower bacterial richness and higher community organization. © 2017 Society of Chemical Industry
  • An immobilized and highly stabilized self‐sufficient monooxygenase as
           biocatalyst for oxidative biotransformations
    • Abstract: BACKGROUNDThe requirement for expensive cofactors that must be efficiently recycled is one of the major factors hindering the wide implementation of industrial biocatalytic oxidation processes. In this research, a sustainable approach based on immobilized self‐sufficient Baeyer–Villiger monooxygenases is discussed.RESULTSA bifunctional biocatalyst composed of an NADPH‐dependent cyclohexanone monooxygenase (CHMO) fused to an NADP+‐accepting phosphite dehydrogenase (PTDH) catalyzes ϵ‐caprolactone synthesis from cyclohexanone, using phosphite as a cheap sacrificial substrate for cofactor regeneration. Several immobilized derivatives of the fused enzyme have been prepared with high immobilization yield (97%); the one obtained by affinity adsorption on Co‐IDA (Co: cobalt chelated; IDA: iminodiacetic acid) support has shown to be highly stable affording average yields of 80% after 18 reaction cycles.CONCLUSIONSThe immobilized self‐sufficient monooxygenase has demonstrated to be able to perform Baeyer–Villiger oxidation with efficient cofactor recovery and biocatalyst recycling. The proposed biocatalytic process offers access to valuable molecules with high atom economy and limited waste generation. © 2017 Society of Chemical Industry
  • Polyethyleneimine grafting and Cibacron Blue F3GA modifying
           poly(methylmethacrylate) magnetic microspheres for protein adsorption
    • Abstract: BACKGROUNDPolyethyleneimine (PEI) has attracted wide interest due to not only its good hydrophilicity but also its high density of amino groups across the polymer chain. In order to study in depth the effect of PEI as spacer arm on dye ligand modification and further protein adsorption, poly(methylmethacrylate) (PMMA) magnetic microspheres were fabricated, grafted with PEI, and further modified with an affinity dye‐ligand, Cibacron Blue F3GA (CB).RESULTSCB density of these CB‐PEI‐PMMA microspheres was determined to be 370.7 µmol g‐1 for CB‐PEI 600‐PMMA, 355.2 µmol g‐1 for CB‐PEI 1800‐PMMA, and 317.6 µmol g‐1 for CB‐PEI 70000‐PMMA microspheres, respectively. Moreover, bovine serum albumin (BSA) adsorption capacity of PEI‐PMMA and CB‐PEI‐PMMA microspheres increased greatly compared with PMMA microspheres. The effects of temperature, BSA initial concentration, pH and ionic strength on BSA adsorption were studied. CB‐PEI 70000‐PMMA microspheres exhibited the maximum adsorption of 103.6 mg g‐1.CONCLUSIONThe results demonstrated the versatility of PEI as spacer arm. The information obtained from the present work could be utilized for rational design of carriers for protein adsorption or enzyme immobilization. © 2017 Society of Chemical Industry
  • Simultaneous removal of selenite and phenol from wastewater in an upflow
           fungal pellet bioreactor
    • Abstract: BACKGROUNDThe simultaneous treatment of wastewater containing selenite and phenol in batch and continuous systems, inoculated with pellets of Phanerochaete chrysosporium, was evaluated in this study.RESULTSSynthetic oil refinery wastewater containing 15 mg L−1 selenite and 100–600 mg L−1 phenol was used in batch incubations for 5 days. Orange‐red colored pellets developed during selenite incubations in the presence of up to 400 mg L−1 of phenol, which confirms the formation of elemental selenium with removal efficiencies ranging from 57–78.5% and 75–90.8% for, respectively, phenol and selenite. Continuous experiments in two upflow fungal pelleted bioreactors (30 °C, pH 4.5, hydraulic retention time of 16.7 h) fed the synthetic oil refinery wastewater containing phenol or phenol with selenite were performed for 38 days. The maximum removal efficiency of phenol in the fungal bioreactor was 100% (up to day 26).CONCLUSIONSelenite mass balance showed that the overall maximum removal efficiency of selenite in the presence of phenol was 67.3%. The critical phenol and selenite loading rates of the upflow bioreactors were ∼12 and 4.3 mg L−1 h−1, respectively. © 2017 Society of Chemical Industry
  • Evaluation of a low‐cost magnesium product for phosphorus recovery
           by struvite crystallization
    • Abstract: BackgroundThe development of a cost‐effective process of struvite crystallization requires the selection of appropriate sources of alkali and magnesium. In this study, the effectiveness of two industrial grade products, MgO and Mg(OH)2, as magnesium and alkali sources to recover phosphorus as struvite were investigated and compared in a first set of experiments. Subsequently, the use of industrial Mg(OH)2 was compared in two different struvite crystallization systems, an upflow fluidized bed reactor (FBR) and a continuous stirred tank reactor (CSTR) coupled to a settler tank.ResultsAt the same operational conditions, the consumption of MgO was higher than Mg(OH)2 consumption. Moreover, industrial Mg(OH)2 consumption for FBR and the CSTR operation was 1.6 and 1.1 1 mol Mg added mol‐1 P precipitated, respectively. This difference was caused by the high mixing intensity and the higher contact time between the Mg(OH)2 slurry and the influent in the CSTR, favouring the conversion.ConclusionsBoth industrial grade magnesium products are promising options for struvite crystallization. However, Mg(OH)2 was more effective than the starting material, MgO, to recover phosphorus. Struvite crystallization by adding an industrial grade Mg(OH)2 could be economically viable with regard to alternative physico‐chemical P removal processes using metal salts, increasing the attractiveness of this P recovery process. © 2017 Society of Chemical Industry
  • Pilot scale production of extracellular thermo‐alkali stable laccase
           from Pseudomonas sp. S2 using agro waste and its application in
           organophosphorous pesticides degradation
    • Abstract: BackgroundLaccases are multicopper oxidases that are able to oxidize various aromatic or nonaromatic compounds owing to their multifarious applications. However, till now only a few bacterial laccases have been isolated and characterized. Hence there is an urgent need to study an extracellular thermo‐alkali stable laccase.ResultsIn the present study, an extracellular thermo‐alkali stable laccase was produced from Pseudomonas sp. S2 in a 100 L bioreactor using agro waste (potato peel). Production was 17‐fold higher than in the control. The enzyme (S2LAC) was purified 12.16 ± 1.6‐fold to homogeneity with specific activity of 1089.70 ± 16.8 U mg−1 and molecular mass of 38 kDa. The temperature and pH for maximum enzyme activity were 80 °C and 9.0, respectively. The metal ions Na+, K+, Pb+2, Ca+2, Cu+2 and Co+2 enhanced enzyme activity. The purified enzyme showed maximum specificity to Pyrogallol > PPD > L‐DOPA > Hydroquinone. The S2LAC was able to degrade organ‐phosphorous pesticide including dichlorophos, chlorpyrifos, monocrotophos and profenovos upto 45.99 ± 0.3%, 80.56 ± 0.6%, 75.45 ± 1.3%, 81.84 ± 0.6%, respectively, in the absence of any mediator.ConclusionS2LAC produced using agro waste was stable and capable of degrading organophosphorous pesticides making it attractive for industrial applications. © 2017 Society of Chemical Industry
  • Prediction of overall glucose yield in hydrolysis of pretreated sugarcane
           bagasse using a single artificial neural network: good insight for process
    • Abstract: BACKGROUNDIn this work a single artificial neural network (ANN) was used to model the overall yield of glucose (YGLC) as a function of a wide range of operating conditions of both pretreatment and enzymatic hydrolysis.RESULTSThe model was validated experimentally and presented good predictions of YGLC. Sensitivity analysis using the ANN model indicated that most of the operating parameters, except for pretreatment time, were statistically significant (P‐value
  • Enhancement of biomass retention in an EGSB reactor used to treat
    • Abstract: BACKGROUNDAn expanded granular sludge bed (EGSB) reactor is commonly used in anaerobic treatment of industrial wastewater. To develop applications to remove solvents, the granular sludge retention within the reactor must be improved.RESULTSThis work evaluated the addition of chitosan as a strategy to enhance granulation in an EGSB reactor used to treat a wastewater containing 1‐methoxy‐2‐propanol and ethanol. Two reactors, one with chitosan supplementation and the other without chitosan (control), were operated in parallel. Greater particle size was obtained in the reactor with chitosan. The retention of solids within the reactor was clearly improved. Moreover, the settling properties were clearly enhanced in the first stages (days 0–44) in terms of settling velocity and sludge volume index. The time required to obtain 80% removal of 1‐methoxy‐2‐propanol was shortened from 38 days to 22 days when chitosan was supplemented.CONCLUSIONSThe addition of chitosan is a promising alternative to enhance granulation in EGSB reactors that are used to treat glycol ethers. A single addition rapidly improves the settling properties of the granular sludge; this method could be used as an operational strategy when partial degranulation occurs. This work provides useful guidelines on the enhancement of biomass retention while operating an EGSB. © 2017 Society of Chemical Industry
  • Hydrogenolysis of glycerol to 1,2‐propanediol in a continuous flow
           trickle bed reactor
    • Abstract: BACKGROUNDHydrogenolysis of glycerol to glycols in continuous flow three phase reactors is of practical importance due to the need to give value to huge amounts of surplus glycerol. Thermodynamic and kinetic aspects must be revised for a proper design. The system was studied in a trickle‐bed reactor using copper chromite and Cu/Al2O3 as catalysts.RESULTSPhase equilibrium and flow pattern were verified. Solid, liquid and gas phases were present, with the liquid phase in ‘trickling’ flow. Catalysts were characterized by inductively coupled plasma (ICP), nitrogen sortometry, X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), temperature programmed reduction (TPR) and pyridine thermal programmed desorption (TPD). The average reaction rate was found to be practically constant under different process conditions. A theoretical analysis indicated that the resistance to the transfer of hydrogen from the gas to the liquid phase dominated the overall kinetics. Selectivity to 1,2‐propanediol varied with temperature, with a maximum at 230 °C (97%). Selectivity was a function of the catalyst acidity. When the pressure was increased the selectivity to 1,2‐propanediol was increased, up to 97% at 14 bar. Higher pressures did not modify this value.CONCLUSIONSOptimum reaction conditions for maximum selectivity to 1,2‐propanediol with Cu‐based catalysts are 230 °C and 14 bar. System kinetics are, however, dominated by the gas–liquid mass transfer resistance. © 2017 Society of Chemical Industry
  • Development of synthetic perfluorinated photobioreactor system for
           simultaneous carbon dioxide separation and promotion of microalgae growth
           and productions
    • Abstract: BACKGROUNDCO2 is the primary impurity in many fuel gases and may reduce the efficiency of fuel combustion and generate incomplete residues in the product, leading to energy waste and environmental issues after emission. Currently although plants/microalgae‐mediated approaches have been widely used for CO2 separation/digestion, they usually emphasize CO2 removal efficacy for the purpose of environment protection, but give less consideration to subsequent CO2 manipulation for cell culture that restricts their effectiveness thereafter. To address the above issues, a perfluorinated photobioreactor system (PPBRS) enabling CO2 separation and controlled microalgae cultivation was developed in this study.RESULTSResults showed that the PPBRS provided >85% CO2 separation efficiency from 60%‐N2/40%‐CO2 within 5 days by using perfluorocarbon as the CO2 absorbent. Nannochloropsis oculata cultured with 20 mL min‐1 perfluorocarbon containing 2% CO2 isolated from the gas mixture exhibited 2‐fold higher cell concentration and yielded 1.8‐, 2.5‐, and 2‐fold (P < 0.05 for all) increased productions of biomass, lipid, and eicosapentaenoic acid, respectively, compared with the group with air aeration without PFC for 5 days.CONCLUSIONPerfluorocarbon is recyclable and all procedures including CO2 extraction, collection of purified gas, and delivery of isolated CO2 to cell culture are a continuous process without need for additional handling. The PPBRS thus provides an efficacious, easy‐to‐use, and cost‐effective means for simultaneous CO2 separation and enhanced microalgae production that can be applied for use in industry. © 2017 Society of Chemical Industry
  • Comparative study of rice husk biochars for aqueous antibiotics removal
    • Abstract: BACKGROUNDAntibiotics are widely used for the treatment of bacterial infections in humans and animals, but it can be released into water sources due to incomplete metabolism in humans or via discharge from drug manufacturers.RESULTSThe efficiency of removal of three antibiotics was enhanced with increasing biochar dosage. The adsorption of three antibiotics by RH700 was much higher than by RH300 and RH500, which might be due to the larger surface area and adsorption pore volume of RH700 (211.76 m2 g‐1 and 6.25 nm, respectively). In addition, the adsorption capacity was greatly affected by the solution pH, background electrolyte and humic acid. The kinetics experiment data were well fitted by the pseudo‐second‐order kinetic model. The maximum adsorption capacities of tetracycline hydrochloride (TC), doxycycline hydrochloride (DC) and ciprofloxacin (CF) based on the Langmuir model by RH700 at 318 K were 80.9, 85.2 and 36.1 mg g‐1, respectively. RH700 exhibited high affinity for antibiotics, mainly ascribed to the chemical interaction between oxygen‐containing functional groups (phenolic hydroxyl group, carboxyl and alkoxy groups) of the biochar surface and TC, DC and CF.CONCLUSIONThe rice husk biochar produced at high temperature could be applied as a potential adsorbent for removal of antibiotics from water. © 2017 Society of Chemical Industry
  • Energy efficient harvesting of Arthrospira sp. using ceramic membranes:
           analyzing the effect of membrane pore size and incorporation of flocculant
           as fouling control strategy
    • Abstract: BACKGROUNDBiomass harvesting is an important issue in commercialization of algal biofuel production. In the present study focus has been given to develop a robust ultrafiltration membrane on low cost ceramic substrate for efficient harvesting of Arthrospira sp. The effect of membrane pore size and flocculant addition as fouling reduction strategy was investigated. The study represents a comparative analysis in terms of flux, fouling, volume reduction factor (VRF) and energy consumption of different processes, viz. microfiltration (MF), ultrafiltration (UF), guar gum induced bioflocculation followed by MF and bioflocculation followed by UF, respectively.RESULTSThe MF process showed higher volume reduction factor (11.11) and concentration factor (12.5) with stabilized flux of 230 L m‐2 h‐1 under optimized conditions. In terms of fouling, the UF membranes were less prone to fouling, with a flux recovery of about 93% during long‐term operation. Incorporation of bioflocculant caused significant reduction in fouling of both the MF and UF membrane. Energy uptake in the MF process was lower (0.908 kWh m‐3) than that of the UF process (2.625 kWh m‐3). Among the various processes permeate from the UF showed the highest CO2 dissolution capacity (657 ± 7 mg L‐1), hence could be reused for algal cultivation with negligible reduction in growth.CONCLUSIONThe present study reveals that clay‐alumina based ceramic MF and UF membrane can be effectively used in harvesting of algal biomass with suitable fouling control strategy based on the algal species and required biomass concentration. The processes developed exhibited less energy consumption compared with other existing processes. © 2017 Society of Chemical Industry
  • A new source for developing multi‐functional products: biological and
    • Abstract: BACKGROUNDTo obtain bioactive fractions from plant material subcritical water is notably advantageous in comparison to any other technique. Excellent solvating properties and selectivity combined with finely tuned reactivity of subcritical water enable exploitation of the potential of plants. Herein subcritical water extraction was used for recovery of bioactive compounds from leaves, roots and fruits of Sambucus ebulus L. Extracts obtained were characterized in terms of biological and chemical fingerprints.RESULTS AND DISCUSSIONResults obtained by using several antioxidant assays that focused on different mechanisms showed that subcritical water extracts of Sambucus ebulus were powerful antioxidants. Enzyme inhibitory effects were tested against α‐amylase, α‐glucosidase and tyrosinase, and the results showed the anti‐diabetic potential of the extracts as well as its possible use with skin disorders. Antiproliferative properties were detected on three cell lines (A‐549; LS‐174 T; HeLa) and showed prominent cytotoxicity against all tumor cell lines. Inhibitory concentrations obtained were in the range 0.58–8.10 μg mL‐1. Generally, the SCW extracts from leaves exhibited stronger biological activities with higher levels of phenolic compounds compared with the roots and fruits of Sambucus ebulus. Gallic acid, catechin and caffeic acid were identified as major components in these extracts and these components seem to relate with observed biological activity.CONCLUSIONThe results obtained suggest that Sambucus ebulus has great potential for preparing new phyto‐pharmaceuticals and functional food ingredients. © 2017 Society of Chemical Industry
  • The effect of hot water pretreatment on the heavy metal adsorption
           capacity of acid insoluble lignin from Paulownia elongata
    • Abstract: BACKGROUNDBiorefinery processes utilize carbohydrates from biomass in order to produce biochemical and biomaterials. Lignin as the byproduct after biorefinery needs to be studied for applications. This study evaluated how hot water pretreatment, a typical biorefinery process, will impact on the heavy metal adsorption capacity of lignin.RESULTSPaulownia elongata acid insoluble lignin was tested for its heavy metal adsorption capacities for Pb(II), Cu(II) and Cd(II). Hot water pretreatment was conducted on the lignin with both water and dilute acetic acid solution. Samples with both increased and decreased adsorption capacity were observed after the pretreatment, while samples with long duration of pretreatment encountered a substantial loss in the adsorption ability. Depolymerization and condensation lignin reaction schemes under acidic environment were summarized and applied to explain the capacity changes. NMR analysis was performed to quantify the functional groups in the lignin samples. Changes in the amount of functional groups were found in the samples after pretreatment.CONCLUSIONHot water pretreatment can either increase or decrease the adsorption capacity of lignin depending on the treatment duration. Lignin byproducts after treatment under acidic and high temperature environments with long duration is no longer suggested for use as a heavy metal adsorbent. © 2017 Society of Chemical Industry
  • Improved photocatalytic hydrogen production from methanol/water solution
           using CuO supported on fluorinated TiO2
    • Abstract: BACKGROUNDPhotocatalytic water splitting is an attractive alternative for hydrogen generation because it is considered a clean and environment‐friendly process. TiO2 semiconductor has been widely used in photocatalysis, however, its efficiency is limited due to the high recombination of the charge carriers. Many methods have been proposed to enhance TiO2 photoactivity, including modification with nonmetal ions and coupling with other semiconductor oxides. In this present work a series of CuO/TF photocatalysts with different CuO content were synthesized by impregnation of fluorinated TiO2 (TF) powder. These materials were characterized by several techniques and were studied in the hydrogen production reaction from a methanol/water solution under UV irradiation.RESULTSThe impregnation of the TF powder with Cu(NO3)2•H2O leads to the generation of crystalline and mesoporous materials and the existence of copper in the form of CuO. HRTEM results indicated the formation of heterojunctions between TiO2 and CuO phases. CuO(1.0)/TF photocatalyst was four times more active than TiO2 and fluorinated TiO2 support.CONCLUSIONSThe coexistence of fluoride and CuO species on TiO2 improves the photocatalytic properties of the semiconductor and the reduction of the H+ ions to H2 is considerably better than that achieved with TiO2, TF and CuO/TiO2 materials. © 2017 Society of Chemical Industry
  • A novel modeling approach for evaluating microbial mechanism and design of
           contact stabilization process
    • Abstract: BACKGROUNDThe paper offers a novel interpretation of microbial mechanisms and evaluates the assets of contact stabilization (CS) using multi‐component modelling. A model structure re‐defining microbial processes is adopted, where the function of the contact tank was limited to the utilization of soluble substrate fractions and that of the stabilization tank essentially involved endogenous decay and removal of the adsorbed particulate substrate.RESULTSThe model was used to simulate the microbial behaviour and performance of CS in comparison with a conventional activated sludge system (CAS), at an SRT range between 6 and 15 d. The results were confirmed by a stoichiometric description of the process using relevant mass balance relationships, which identified the role of major parameters in system behaviour and performance. A rational process design procedure was proposed based on modelling and process stoichiometry.CONCLUSIONThe CS process achieved effective carbon removal with a much smaller footprint and/or aeration volume with respect to CAS, due to its ability to work at significantly higher volumetric organic loadings; its flexibility to be operated at much higher SRT compared with CAS with the same HRT, allowed minimizing sludge production and sustaining a microbial composition also supporting nitrification. However, process stoichiometry reflected that the CS process, despite its significant advantages, should not be considered a suitable candidate for maximizing sludge harvest and energy recovery. © 2017 Society of Chemical Industry
  • Mined pyrite and chalcopyrite as catalysts for spontaneous acidic pH
           adjustment in Fenton and LED photo‐Fenton‐like processes
    • Abstract: BACKGROUNDThe Fenton‐based processes have been extensively studied for the treatment of pollutants contained in olive mill wastewater (OMW). These processes have some limitations, such as the need for acidic pH control, the generation of a sludge, and the separation of soluble iron species. Mined pyrite (FeS2) and chalcopyrite (CuFeS2) avoid the problem associated with sludge formation and the acidic pH adjustment. The catalytic activity of pyrite and chalcopyrite was investigated for the Fenton and LED (light emitting diode) photo‐Fenton‐like oxidation of tyrosol (TY) and in the treatment of aqueous mixtures containing phenolic compounds.RESULTSThe highest mineralization of TY (85%) and lowest Fe leaching (0.89 mg L‐1) was obtained by using chalcopyrite and the LED photo‐Fenton‐like process (0.50 mmol L‐1 of TY initial concentration and 19.0 mmol L‐1 of H2O2 stoichiometric dosage). Complete degradation of the phenolic pollutants and mineralization of 98% was also achieved.CONCLUSIONMined chalcopyrite can be an appropriate photo‐Fenton‐like catalyst in the degradation of phenolic compounds found in OMW because it can provide a high TOC removal, proper acidic pH conditions, low leaching of iron species and spontaneous formation of a small amount of H2O2. However, the catalyst stability must be improved to minimize the leaching of metals. © 2017 Society of Chemical Industry
  • Efficient adsorption/reduction of aqueous hexavalent chromium using
           oligoaniline hollow microspheres fabricated by a template‐free method
    • Abstract: BACKGROUNDUniform and well‐dispersed hollow microspheres of oligoaniline were synthesized by a facile and template‐free method in alkaline medium. The morphology of oligoanilines was controlled from hollow to hard microspheres, by simply changing the volumes of alkaline medium. SEM, TEM, XRD, FTIR and physical adsorption of nitrogen were used to characterize the products. Hexavalent chromium ion uptake experiments were run with these aniline oligomers.RESULTSAdsorption experiments showed that the removal of chromium ions was strongly dependent on the initial pH of the solution. The pseudo‐second‐order kinetic and Langmuir isotherm models were well correlated with the experimental data. The adsorption of Cr(VI) and synergistic reduction to Cr(III) were confirmed by analyzing remnant chromium in the liquid and XPS detection of the exhausted adsorbent. A redox/pseudo‐protonation process was suggested as the mechanism to explain the Cr(VI) removal. The adsorbed chromium ions could be desorbed by NaOH solution. The higher desorption efficiency of 96.2% was achieved by using 1.0 mol L‐1 NaOH as the desorption agent.CONCLUSIONSIt was observed that the hollow microsphere were the most effective adsorbent of the three adsorbents and its removal efficiency reached 99% to remove 60 mg L‐1 Cr(VI). The facile fabrication, efficient removal of Cr(VI) and simple regeneration offered an option to remove Cr(VI) contamination from natural water and industrial wastewater. © 2017 Society of Chemical Industry
  • Shaken flasks by resonant acoustic mixing in the biosynthesis of alginate
           by Azotobacter vinelandii with non‐Newtonian rheological characteristics
    • Abstract: BACKGROUNDOrbitally shaken flasks in polysaccharide‐producing bacterial cultures usually present oxygen limitations because of non‐Newtonian rheological characteristics of the resulting culture broth and bacterial respiration. Here, we present the production of alginate by Azotobacter vinelandii using a novel alternative mixing technology (resonant acoustic mixing, RAM) to increase oxygen transfer.RESULTSNo significant differences were observed in biomass growth (3.43 ± 0.61 g L‐1) with RAM frequencies between 5 and 20 g, but higher specific growth and sucrose consumption rates were found at higher frequencies (15 and 20 g). The highest alginate production (9.13 ± 0.63 g L‐1) was obtained in 20 g cultures, in which no oxygen limitation was detected, whereas intracellular reserve polymer poly‐β‐hydroxybutyrate (PHB) production was favored at low shaking frequencies (5 and 10 g), in which dissolved oxygen tension was zero for a long culture time. Cultures behave pseudoplastically, with an apparent viscosity that increases until the end of the exponential phase, and the alginate monomer ratio was approximately 1.0 in all cultures.CONCLUSIONRAM can maintain elevated oxygen transfer rates, even in non‐Newtonian high‐viscosity cultures, as in the case of alginate production by A. vinelandii. © 2017 Society of Chemical Industry
  • Influence of solvent additives on the aqueous extraction of tannins from
           pine bark: potential extracts for leather tanning
    • Abstract: BACKGROUNDPine bark, which represents approximately 10 to 20% in weight of the tree trunk, is an abundant and low cost agro‐industrial waste. In order to obtain condensed tannin‐rich pine bark extracts (for future application in leather tanning/retanning processes), conventional aqueous extractions were performed, varying the type and amount of the solvent additive: sodium hydroxide (0.5, 1.0 and 1.5%, w/v), formic acid (0.5, 1.0 and 1.5%, v/v) and ethanol (5, 10 and 15%, v/v). Extractions were performed with and without the addition of sodium sulfite (1.0%, w/v).RESULTSThe most favorable solvent additive in terms of total phenolics and condensed tannins was ethanol: extracts achieved 34.8% of gallic acid equivalents and 62.8% of catechin monohydrate equivalents. Moreover, the favorable pH values (∼3.5) of the resultant aqueous solutions and their relatively low viscosities are suitable for subsequent tanning applications.CONCLUSIONSThe results of this study suggest that the high added‐value aqueous extracts of Pinus pinaster bark, which were achieved with small amounts of ethanol, have appropriate characteristics for leather tanning, and therefore they may be used as eco‐friendly tanning agents to partially replace chromium salts, thus reducing some of the environmental impacts typically associated with the leather industry. © 2017 Society of Chemical Industry
  • Dealginated seaweed waste for Zn(II) continuous removal from aqueous
           solution on fixed‐bed column
    • Abstract: BACKGROUNDThe alginate extraction residue from Brazilian Sargassum filipendula was employed as biosorbent for Zn(II) removal through a fixed‐bed column in order to explore its adsorptive properties and to establish a new use for this waste.RESULTSThe best operating conditions were 0.5 mL min‐1 and 1.0 mmol L‐1 (inlet concentration), providing lower mass transfer zone and higher uptake. Elution percentages of 52 and 73% were obtained for the first and second desorption cycles, respectively, using CaCl2 as eluent. The Yan et al. model was more representative of the experimental data. Characterization revealed that ion exchange is involved between zinc ions and light metals (Ca, Na, K and Mg). A decrease was observed in real and apparent densities of biomass, with an increase in particle porosity of the residue after process.CONCLUSIONThe study revealed that this biomass has potential for Zn removal from aqueous solution, encouraging its application as a biosorbent in future studies involving multicomponent systems. © 2017 Society of Chemical Industry
  • Hydrodynamic simulations and biological modelling of an Anammox reactor
    • Abstract: BACKGROUNDThe design of anammox process reactors should be addressed to obtain maximum sludge retention and maximum removal efficiency, and also prevent the inhibition of microorganisms. The conventional biological models (activated sludge models, ASM) are only focused to test the influence of operational parameters on the biological performance. This study integrated computational fluid dynamics (CFD) and biological modelling (ASM) for the description of a novel anammox reactor configuration.RESULTSA full description of the hydrodynamics, the mixing degree of the system and biological performance within the overall reactor domain was obtained. The strong recirculation of the system and the internal plates favoured correct mixing of the overall system, despite a particular point having a preferred flow in the inlet stream of the reactor. From the removal rates distributions calculated with the model, it was feasible to demonstrate that 45% of the domain had a zero reaction order with respect to the ammonium substrate (nitrite was in excess).CONCLUSIONSModel integration was demonstrated to be a powerful tool for the design of an anammox reactor. It was useful to obtain information about the overall mixing in the system, determine death zones of flow, and points of maximum and minimum removal efficiency. © 2017 Society of Chemical Industry
  • Improvement in lactone production from biotransformation of ricinoleic
           acid based on the porous starch delivery system
    • Abstract: BACKGROUNDThe natural gamma‐decalactone (GDL) produced by microbial fermentation is an essential lactone compound as a generally recognized as safe food additive. Effective control of the substrate ricinoleic acid (RA) concentration in the biotransformation medium is a bottleneck for the industrial manufacture of GDL. In this study, porous starch (P‐S) was utilized as a carrier of RA to control its distribution in the medium. The effect of P‐S on the biotransformation was evaluated and the mechanism was revealed.RESULTSScanning electron microscopy, Fourier‐transform infrared spectroscopy, and thermogravimetric analysis indicated that the RA layer was formed on the surface of P‐S, which increased the opportunity for interaction between microorganisms and the substrate. With P‐S‐embedded RA as a substrate, the yield of GDL increased to 3.36 g L‐1 which was 17.5% higher than in the control. In addition, the presence of P‐S in this system had no negative effect on the viability of the microorganism.CONCLUSIONThis study is a new attempt to apply P‐S as a delivery system in the biotransformation of GDL to increase its yield which indicates that the P‐S‐controlled release is a potential method of improving natural GDL production in industrial scale. © 2017 Society of Chemical Industry
  • Feasible microbial accumulation of triacylglycerides from crude glycerol
    • Abstract: BACKGROUNDCrude glycerol, a by‐product of the biodiesel production industry, was used to produce intracellular storage polymers for waste valorisation. The enrichment of a mixed microbial culture (MMC) in microorganisms with the ability to accumulate intracellular polymers was performed in a sequencing batch reactor (SBR) submitted to feast/famine conditions. The effect of different carbon sources in the accumulation of biopolymers was investigated.RESULTSA mixed microbial culture (MMC) enriched in yeast and bacteria was obtained using crude glycerol as feedstock. Accumulation experiments performed with crude glycerol, synthetic glycerol, and synthetic methanol, showed the feasibility of the MMC to produce different biopolymers. Triacylglycerides (TAGs) accumulation up to 46 wt.% in yeast cells was promoted by the presence of residual lipids in crude glycerol. However, bacteria from Betaproteobacteria class used glycerol mainly to accumulate 28 wt.% of polyglucose (PG) and methanol as carbon source for cell growth.CONCLUSIONSAs waste valorisation, a possible advantage which comes out of the present study is the use of open, non‐sterile and non‐defined systems to produce TAGs. These TAGs can potentially re‐enter the biodiesel production process helping on the maximisation of the feedstock used in this process.
  • Successful encapsulation of β‐glucosidase during the synthesis of
           siliceous mesostructured materials
    • Abstract: BACKGROUNDThe Biocatalysis field demands “universal supports” able to encapsulate enzymes with a straightforward methodology, and at the same time, being capable of keeping its catalytic activity. The employment of siliceous materials for such purpose is a big challenge because drastic synthesis conditions are required and besides, most of the times it is needed a functionalization to increase affinities towards the targeted enzyme. In this work, a compromise between the development of a well‐formed mesostructured support and an acceptable enzymatic activity was attempted via the in‐situ immobilization approach.RESULTSThe immobilization of β‐glucosidase (EC from Aspergillus niger was approached from different strategies. After trying immobilizing said enzyme with a post‐synthesis approach, both with a covalent linkage (using epoxy activated supports) and with a non‐covalent bonding (using amine‐functionalized materials), non‐high loadings were achieved (3.5 mgE/g and 7.6 mgE/g, respectively). Nevertheless, when the in‐situ approach was attempted, success in reaching the highest enzyme loading (close to 200 mgE/g) was achieved.CONCLUSIONIn this work, the in‐situ encapsulated enzyme within the support‐cages fully prevented it to be released through the narrow windows connecting cages, achieving a less than 5% release of the initially desorbed protein, as well as a further total absence of leaching. This enabled the biocatalyst to be reused at least eight times more without any loss in activity.
  • Direct conversion of cellulose to sorbitol via an enhanced pretreatment
           with ionic liquids
    • Abstract: BACKGROUNDDirect conversion of cellulose into platform chemicals, is regarded as one of the most promising aspects of biomass resource utilization. However, the development of direct conversion of cellulose to high value‐added chemicals such as sorbitol still remains a tremendous problem owing to the robust structure of cellulose to resist degradation.RESULTSIn this study, the ball‐milled microcrystalline cellulose was dissolved in ionic liquids, and finally converted to sorbitol smoothly through hydrolytic hydrogenation processes. Both ball‐milling and ionic liquids dissolution can effectively destroy the strong inter‐ and intra‐molecular hydrogen bonds network formed between hydroxyl groups within cellulose. Furthermore, water‐soluble ionic cellulose came into being due to the dissolution of cellulose in ionic liquids, which increased the contact of cellulose to catalyst remarkably. The crystalline index of cellulose can be reduced from 79.9% to 3.2% under an optimum ball‐milling time of 4 h, and the preferred cellulose dissolution solvent was selected to be [Amim]Cl. Finally, the final product, sorbitol was successfully synthesized over the catalysis of Nafion NR50 and Ru/AC (active carbon) with the sorbitol yield to be 34.3% at 150 °C for 1 hour.CONCLUSIONThis study proposed a novel approach about direct conversion of cellulose to sorbitol with ionic liquids as well as extended the application of ionic liquids in the field of conversion of renewable biomass to platform chemicals.
  • Comparison of ZnO nanofillers of different shapes on physical, thermal and
           gas transport properties of PEBA membrane: experimental testing and
           molecular simulation
    • Abstract: Molecular simulation and experimental approaches were done using PEBA 1657 mixed matrix membranes (MMMs) loaded with ZnO nanorod‐ and nanosphere‐shaped nanomaterials at 0.5% and 1% (wt) loading to investigate the gas separation properties of these MMMs. Structural characterization was carried out by FESEM, AFM, BET, FTIR on synthesized membranes and FFV and WAXD on the simulated membrane cells to study their structural properties. Thermal analysis was carried out by TGA, DMTA and calculation of the glass transition temperature to investigate the thermal properties of the MMMs. The results showed that the addition of ZnO filler significantly improved both the physical and thermal properties of the MMMs based on the characterization tests. The transport properties of the MMMs for three single light gas molecules (CO2, CH4, and N2) were investigated using experimental set‐up testing (permeability and selectivity) and also by molecular dynamic and Monte Carlo approaches in molecular simulation (diffusivity and solubility). The addition of ZnO nanomaterials in both shapes to the polymeric membrane significantly increased the transport properties, for instance: CO2 permeability increased from 120 for membrane without nanomaterial to 135 barrer for membrane with 0.5 wt.% of nanosphere ZnO and 157 barrer for membrane with 0.5 wt.% nanorod ZnO.
  • Trichoderma harzianum based novel formulations: Potential Applications for
           Management of Next‐Gen agricultural challenges
    • Abstract: Fungi of the Trichoderma spp. genus, notably Trichoderma harzianum, are commonly used for biological management of deleterious seed and soil borne pathogens. The global biopesticides market is booming with a major share of various commercial formulations of T. harzianum. However, there are some major drawbacks associated with these commercial formulations including short shelf life, low on‐field stability, and irregular performance in different agro‐climatic regions. For effectively resolving these issues, new strategies are urgently required for efficient management of pathogens. The present review provides an overview of the use of Trichoderma spp., with special emphasis on T. harzianum, and discusses future trends for biological control. Technologies are described for the microencapsulation of fungi and for the biogenic synthesis of nanoparticles, with the aim of improving the biological control of pathogens and contributing to sustainable agricultural practices.
  • Metals in aqueous solutions and real effluents: Biosorption behavior onto
           a hemp‐based felt
    • Abstract: BACKGROUNDIn this study, a hemp‐based material in the form of a felt is used to adsorb metals in individual aqueous solutions and in polycontaminated effluents using the batch method. The factors affecting the biosorption process were initial metal concentration, biosorbent dosage, contact time and pH.RESULTSIn controlled conditions, results showed that: (i) the felt exhibited high adsorption capacities towards metals in the following order: Pb > Cd > Cu > Zn > Co ~ Fe ~ Ni ~ Cr ~ Al ~ Mn; (ii) no significant differences were observed for the three salts used (sulfate, chloride and nitrate); (iii) the process was rapid: 10 min were sufficient to attain equilibrium; iv) the biosorption efficiency increased considerably with the increase of the biosorbent dosage; and (v) the adsorption capacities were independent of pH between 4 ‐ 6. The maximum adsorption capacities for Cd, Cu, Zn, Co, Fe, Ni, Cr, Al and Mn were 27.47, 14.64, 10.59, 7.99, 7.85, 7.87, 6.53, 6.38 and 4.55 mg/g, respectively. Interesting results were also obtained for real polymetallic effluents. Ecotoxicological tests also confirmed the efficiency of the biosorption to radically decrease the effluent toxicity.CONCLUSIONSBased on these results, hemp‐based felt could serve as a novel and efficient biosorbent material for pollutant removal from industrial effluents.
  • Concentration of whey protein from cheese whey effluent using
           ultrafiltration by combination of hydrophilic metal oxides and hydrophobic
    • Abstract: BACKGROUNDIn this study, hydrophilic metal oxides such as TiO2, ZrO2 and ZnO were used as modifier for the preparation of polyethersulfone (PES) mixed matrix membranes (MMMs) for the filtration of cheese whey effluent. Nano metal oxides loading concentration is varied from 0.5 to 2.5 wt%.RESULTSCharacterization of metal oxides studies show that the particles are hydrophilic and nano scaled. ZnO nanoparticles are in the form of nano cluster and of size 14.28 ‐ 20.10 nm. Physio‐chemical characterization of PES MMMs indicated that the nano metal oxides dispersed well in the PES matrix. Contact angle decreased up to 59.88° for 1.5 wt% TiO2 embedded PES (TiO2ePES) MMMs. Also, 1.5 wt% TiO2ePES MMMs gives a higher water permeability of 4.62 x10‐7 m/s.kPa. Among membranes, 1.5 wt% TiO2ePES, 2.0 wt% ZrO2ePES and 1.5 wt% ZnOePES MMMs showed better flux, lesser percentage of fouling and better rejection for individual whey proteins.CONCLUSIONThe whey protein from cheese whey effluent was concentrated up to maximum of 43.9 mg/L using 2.0 wt% ZrO2ePES MMMs. It was found that 1.5 wt% TiO2ePES MMMs gives a higher average flux and lower flux reduction percentage of 25.09 L/m2h and 39% respectively.
  • Ozonation inactivation of Escherichia coli in aqueous solution over MgO
           nanocrystals: modelling and mechanism
    • Abstract: BACKGROUNDThis study aims to reveal a potential of using heterogeneous catalytic ozonation processes (HCOP) in water disinfection and provide a direction to tailor the catalytic activity by crystal facet engineering. Herein four kinds of MgO nanocrystals individually with exposure of (111), (200), (110) and (100) facets were prepared and used.RESULTSIt is found that MgO functions as a bactericide as well as a catalyst for ozonation. The catalytic activity of MgO nanocrystals decreases in the order of MgO(111) > MgO(200) > MgO(110) > MgO(100). The apparent first‐order inactivation rate (kap) fitted by Hom model of MgO(111)/O3 is 2.56 min‐1, which is 32.0 and 3.5 times that of single ozonation and classic MgO(100)/O3. It is confirmed by scavenger studies that •OH mainly works in MgO(111)/O3 while more direct ozonation occurs in other cases. Some O2•− are also detected in the presence of MgO. With the attack of those reactive oxidation species, cell membrane was damaged and intracellular components were released, leading to the death of Escherichia coli.CONCLUSIONThese results indicate that HCOP was a promising technology for water disinfection and crystal facet engineering is an effective strategy to enhance the catalytic performance.
  • Chronic impact of sulfamethoxazole: how does process kinetics relate to
           metabolic activity and composition of enriched nitrifying microbial
    • Abstract: BACKGROUNDThis study investigated utilization kinetics of ammonia‐nitrogen induced by chronic sulfamethoxazole (SMX) exposure on biomass with an enriched nitrifying community. A lab‐scale activated sludge system was supplied with 100 mg COD L‐1 of peptone mixture and 50 mg N L‐1 of ammonia nitrogen at a SRT of 15 days. At steady‐state, the reactor was operated with additional daily SMX dosing of 50 mg L‐1 for 35 days. Profiles of oxygen uptake rates and nitrogen fractions obtained in respirometric/batch experiments were used for estimation of nitrification kinetics.RESULTSAcute inhibitory impact of SMX was expressed with high levels of half saturation constants and endogenous decay rates. After 35 days, half saturation constants significantly increased while higher active biomass fractions and recovered endogenous decay rates were estimated. At the end of the acclimation phase, 92% nitrification was achieved with 10 mg L‐1 SMX utilization.CONCLUSIONInterpretation of modeling results with the outcomes of molecular analysis facilitated explanation of autotrophic/heterotrophic bacteria behavior in the course of SMX exposure. Removal of SMX may be attributed to co‐metabolism with ammonia oxidation and/or activity of SMX utilizing heterotrophic bacteria. © 2017 Society of Chemical Industry
  • Ni/γ‐Al2O3 catalyzed hydrogenation sequence of conjugated double bonds
           in 2‐ethyl‐2‐hexenal and reaction kinetics
    • Abstract: BACKGROUND2‐ethylhexanol (2EHO) is an important organic chemical, which is mainly used in the manufacture of plasticizers. At present, the industrial manufacture of 2EHO is generally carried out by gas‐phase hydrogenation of 2‐ethyl‐2‐hexenal, which has high energy consumption. So it is of significance to study liquid‐phase hydrogenation of 2‐ethyl‐2‐hexenal.RESULTSSeveral byproducts were found such as 3‐methylheptane, 2‐ethylhexyl butyrate, 2,4‐diethyloctanol, 2,4‐diethyloctanal, 5,7‐diethylundecane and 2‐ethylhexyl‐2‐ethylhexanoate in the reaction system of 2‐ethyl‐2‐hexenal liquid‐phase hydrogenation catalyzed by Ni/γ‐Al2O3 and a reaction network was proposed. The CC bond of 2‐ethyl‐2‐hexenal molecule was hydrogenated prior to the CO bond hydrogenation and furthermore the CO bond was hardly hydrogenated until the CC bond hydrogenation finished. The kinetics of liquid‐phase hydrogenation of 2‐ethyl‐2‐hexenal catalyzed by Ni/γ‐Al2O3 was studied and the result demonstrated that both 2‐ethyl‐2‐hexenal hydrogenation to 2‐ethylhexanal (CC bond hydrogenation) and 2‐ethylhexanal hydrogenation to 2‐ethylhexanol (CO bond hydrogenation) were first‐order irreversible reactions.CONCLUSIONSIt is made clear by means of online infrared analysis that the hydrogenation of CO bond is difficult to achieve before completion of the hydrogenation of CC bond. The 2‐ethylhexanal hydrogenation reaction, whose activation energy is higher, is the rate‐determining step in the entire hydrogenation process. © 2017 Society of Chemical Industry
  • Microbial production of glutaconic acid via extradiol ring cleavage of
    • Abstract: BACKGROUNDGlutaconic acid (GA), a potential precursor for nylons and biodegradable polyesters, can hardly be produced by microorganisms in nature. In this study, a metabolic engineering method was used to design a novel artificial pathway in Escherichia coli for GA production by connecting catechol biosynthesis and its extradiol cleavage degradation pathway.RESULTSResults of enzyme assays showed the kcat value of C23O (catechol 2, 3‐dioxygenase) toward catechol was 101.6 ± 2.0 s‐1, and the kcat value of DmpC (2‐hydroxymuconic semialdehyde dehydrogenase) toward 2‐hydroxymuconic semialdehyde was 11.1 ± 0.6 s‐1. The enzymes of full pathway were then split into four modules according to their various activities. After feeding experiments, the full pathway was introduced into E. coli strain BW25113, and the production of GA reached 18.1 ± 1.2 mg L‐1. After two genes of the pathway were incorporated into the chromosome, the resultant strain exhibited improved cell growth, and the titer of GA reached 35.3 ± 1.8 mg L‐1.CONCLUSIONSThe catalytic parameters of C23O and DmpC were tested and used for module assembling. Integration of genes in the pathway alleviated the metabolic burden of strain and resulted in higher production of GA. Moreover, this is the first report demonstrating the de novo biosynthesis of GA via extradiol ring cleavage of catechol from simple carbon sources in E. coli. © 2017 Society of Chemical Industry
  • A simple mathematical model capable of describing the microbial production
           of poly(hydroxyalkanoates) under carbon‐ and nitrogen‐limiting growth
    • Abstract: AIMSPoly(hydroxyalkanoates) (PHAs) are biodegradable polymers that can replace conventional plastics, but microbial production of PHAs must be optimized for commercial success. The aim of this study is to provide a simple mathematical model based on previous studies in the literature to represent the production of PHAs in chemostat and batch cultures by Pseudomonas putida GPo1 (ATCC 29347) and Cupriavidus necator (DSM 545) grown on octanoate and glucose, respectively.METHODS AND RESULTSKinetic and stoichiometric equations, dependent on the specific growth rate of residual biomass (μR), were developed for carbon‐ and nitrogen‐limiting growth conditions. The parameters have biochemical significance and are independent of the biomass concentration. The results revealed that the Luedeking‐Piret model is growth‐associated for both fermentations under carbon limitation. In addition, the PHA content increases with μR. Meanwhile, the PHA content is amplified under nitrogen limitation but decreases as μR increases. Also, the Luedeking‐Piret model exhibits a profile that depends on the synthesized polyhydroxyalkanoate.CONCLUSIONThis study demonstrates that strategies for the production of PHAs require an in‐depth understanding of the process kinetics. This model gives satisfactory predictions, may be extended to fed batch cultures and may be adapted to other fermentations.
  • Catalytic wet peroxide oxidation of m‐cresol over novel Fe2O3 loaded
           microfibrous entrapped CNT composite catalyst in a fixed bed reactor
    • Abstract: BACKGROUNDA novel iron loaded microfibrous entrapped carbon‐nanotubes catalyst (Fe2O3‐MF‐CNT) was synthesized by wet lay‐up papermaking process, sintering process and metal organic chemical vapor deposition (MOCVD) process. The catalysts were characterized by N2 adsorption‐desorption isotherm, Mercury porosimetry, FE‐SEM, EDS and NH3‐TPD, and the performance of catalyst was tested by catalytic wet peroxide oxidation (CWPO) of m‐cresol in a fixed bed reactor. Finally, the probable multistep reaction pathway for CWPO degradation of m‐cresol over Fe2O3‐MF‐CNT catalyst in a fixed bed reactor is presented.RESULTSCharacterization results conclude that the prepared catalysts are acid catalysts containing macropores and mesopores. Active components Fe2O3 are evenly loaded on supports by MOCVD method. CWPO results show that higher temperature and higher space time promote the catalyst performance. Meanwhile, the Fe2O3‐MF‐CNT catalyst shows perfect reusability with nearly no iron leaching concentration and high m‐cresol conversion (above 95.0%) after four successive runs (24 hours). Two possible pathways during degradation of m‐cresol are presented. The hydroxyl radicals turn m‐cresols into aromatic by‐products such as p‐Toluquinone, 4‐Methylpyrocatechol and Methylhydroquinone, followed by evolution to organic acids and finally to carbon dioxide and water. During the reaction, more m‐cresols are degraded through the pathway which m‐cresols are first converted into 4‐Methylpyrocatechol.CONCLUSIONThe novel Fe2O3‐MF‐CNT catalyst we prepared owns both the advantages of CNTs as well as stainless steel fibers and it shows promising performance in CWPO of m‐cresol.
  • Enzymatic detoxification: A sustainable means of degrading toxic
           organophosphate pesticides and chemical warfare nerve agents
    • Abstract: Organophosphorus (OP) compounds are highly toxic molecules mainly used as pesticides. OP compounds also include nerve gasses used in the past as chemical warfare agents and collectively we refer to OP pesticides and nerve gasses as nerve agents (NA). An intensive, widespread use of pesticides since the 20th century has resulted in the emergence of an urgent global issue concerning both environment and human health. In addition, past terroristic acts and the recent dramatic events in Syria highlighted more than ever the need to explore applicable strategies for the sensing, decontamination and detoxification of these compounds in stored bulks, on critical surfaces and media (food, water and air) and for in vivo prophylaxes and therapies.OP compounds, act as covalent inhibitors of acetylcholinesterase (AChE) in nerve system of vertebrates, thus posing a substantial threat to the ecosystem. In order to address a strong demand for the establishment of environmental monitoring system and remediation process for NA , an increasing number of studies have been focused on the enzymatic degradation in vitro . Use of enzymes for detoxification and decontamination of toxic NA could provide a long‐term benefit as it is environmentally friendly compared to conventional methods such as chemical treatments and incineration. This review presents an overview of current state of enzymatic detoxification research against NA. This includes the detailed characterization and protein engineering for the improvement in NA‐degrading activities of such enzymes. Research on biosensors for NA detection and identification yet important in the field has not be treated in this review. Instead a special attention has been paid to the Phosphotriesterase‐Like‐Lactonase (PLL) enzyme family. Several PLL enzymes have been isolated from hyperthermophilic Archaea or thermophilic/extremophilic Bacteria, and exhibit exceptional thermal stability. Extremophilic PLLs therefore hold promise for the potential industrial application towards NA detoxification.
  • Microbial decontamination of stainless steel and polyethylene surfaces
           using glidarc plasma activated water without chemical additives
    • Abstract: BACKGROUNDThe gliding electric discharge (Glidarc) in humid air produces a non‐thermal plasma, which is efficient for the cleaning up of the contaminated media. However, beyond decontamination, plasma can have significant impacts on the surface of the contaminated material. It has been shown that even distilled water exposed to plasma glidarc (plasma‐activated water) also has antimicrobial properties. This study reports on the performance of Glidarc plasma‐activated water for the decontamination of solid surfaces.RESULTSWater activated for 5 min with plasma glidarc contains reactive nitrogen and oxygenated species (Nitrites, Hydrogen peroxide, peroxynitrite). The Scanning Electron Microscopy images showed strong cell damage on four types of microorganisms adhering to stainless steel and polyethylene surfaces, two materials widely used in food industry and hospital environments. The level of cell damage correlates with the quantitative lethal study. The Atomic Force Microscopy images showed that the materials do not exhibit a considerable change (< 2%) on their surface topography after treatment in contrast to effect of Bleach (41%), a conventional disinfecting solution.CONCLUSIONThe study confirmed the potential of plasma‐activated water as a means of microbial decontamination without affecting the surface of the materials previously contaminated.
  • Enhancing the removal of pollutants from coke wastewater by
           bioaugmentation: A scoping study
    • Abstract: BACKGROUNDBioaugmentation and biostimulation were investigated for their ability to improve the removal of thiocyanate (SCN‐), polycyclic aromatic hydrocarbons (PAHs), phenol and trace metals in coke wastewater. Additionally, the ability of the microorganisms supplemented with the bioaugmentation product to survive in a simulated river water discharge was evaluated.RESULTSA commercially available bioaugmentation product composed mainly of Bacillus sp. was mixed with activated sludge biomass. A dose of 0.5 g/L increased the removal of Ʃ6PAHs (sum of fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3‐cd]pyrene and benzo[g,h,i]perylene) by 51% and reduced SCN‐ below 4 mg/L enabling compliance with the EU Industrial Emissions Directive (IED). Biostimulation (supplementing micronutrients and alkalinity) allowed compliance for both SCN‐ and phenol (
  • A mechanistic analysis of the influence of iron‐oxidizing bacteria on
           antimony (V) removal from water by microscale zero‐valent iron
    • Abstract: BACKGROUNDMicroscale zero‐valent iron (mZVI) is an efficient material for removing heavy metals from water, and iron‐oxidizing bacteria are the primary microorganisms responsible for iron corrosion. We investigated the effects of Sphaerotilus natans on antimony [Sb(V)] removal by mZVI using batch experiments.RESULTSAt an initial Fe0 dose of 0.1g·L‐1, 40 mg·L‐1 Sb(V) was almost completely removed in an abiotic system. Although Sphaerotilus natans exhibited significant tolerance to Sb(V), its ability to adsorb Sb(V) was poor. Most importantly, the presence of Sphaerotilus natans reduced the removal rate of aqueous Sb(V) by mZVI by up to 39%. The value of the redox potential in the biologically mediated system was lower than that in the abiotic control, indicating oxygen consumption by Sphaerotilus natans. In the presence of Sphaerotilus natans, the main reaction products were FeOOH and FeSb2O6, compared to Fe2O3 in the abiotic system. Biomineralization of Fe3+ ions by Sphaerotilus natans may have occurred during the experiment, but it did not play a significant role in Sb(V) removal.CONCLUSIONmZVI can be efficiently used to remove Sb(V) from water. However, the presence of Sphaerotilus natans may inhibit its removal ability, likely due to the decreased mass transfer and lower corrosion of iron.
  • Optimization of on‐site cellulase preparation for efficient hydrolysis
           of atmospheric glycerol organosolv pretreated wheat straw
    • Abstract: BACKGROUNDThe cost of using cellulase to effectively release fermentable sugars from lignocellulosic substrates is still a major impediment to the development of the enzyme‐based “biorefinery” industry. This study attempted to optimize a cellulase preparation from on‐site fermentation to efficiently hydrolyse atmospheric glycerol organosolv (AGO)‐pretreated wheat straw.RESULTSAddition of Cu2+, PEG10000, L‐ascorbic acid and trehalose in the fermentation medium significantly improved the cellulase production. All of the additives enabled the cellulase to enhance 45.5% of filter paper cellulase (FPA), 14.7% of β‐glucosidase (BG) and 32.4% of carboxymethyl cellulase (CMCase). With the on‐site production of crude cellulase, accessory enzymes (β‐glucosidase (BG), xylanase and lysozyme) and additives (tea saponin (TS) and cationic polyacrylamide (c‐PAM)) were found to facilitate the hydrolysis of AGO‐pretreated substrates effectively. The optimized cellulase mixture allowed 96% of enzymatic hydrolysis at 5 FPU/g for 48 hr upon addition of 11.5 U/g BG, 180 U/g xylanase, 45 U/g lysozyme, 10 mg/g TS and 2 mg/g C‐PAM, which was twice that of the crude cellulase broth.CONCLUSIONThe cellulase customization for specific substrate hydrolysis with on‐site produced broth produced an efficient pathway to lower the enzyme cost in the ongoing lignocellulosic biorefining industry.
  • Protective effects of Lactococcus lactis expressing alcohol dehydrogenase
           and acetaldehyde dehydrogenase on acute alcoholic liver injury in mice
    • Abstract: BACKGROUNDAlcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) play important roles in alcohol metabolism. Therefore, a possible effective way to attenuate alcoholic liver damage is the exogenous supply of these two enzymes to the stomach as they might accelerate the oxidation of ethanol into nontoxic acetate.RESULTSADH and ALDH were coexpressed in Lactococcus lactis NZ3900 and used as treatments for acute alcoholic liver injury in mice. Intragastric ethanol administration was carried out at 5.6 g kg‐1 body weight per day in mice for 15 consecutive days and different doses of recombinant ADH‐ALDH L. lactis treatment were administrated together with ethanol. A high dose of L. lactis recombinant ADH‐ALDH treatment (ADH activity of 2000 U kg‐1 BW and ALDH activity of 1000 U kg‐1 BW) reduced the serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase levels by 38.1%, 54.8% and 23.2%, respectively, in ethanol‐treated mice. Moreover, it also helped maintaining serum lipid levels and liver oxidative stress parameters against ethanol. Histopathological examination of mice livers revealed that L. lactis recombinant ADH‐ALDH at a high dose (ADH activity of 2000 U kg‐1 BW and ALDH activity of 1000 U kg‐1 BW) protected liver tissue from the damage induced by ethanol.CONCLUSIONResults demonstrate that L. lactis with ADH and ALDH activity exhibit a dose‐dependent protective effect on alcohol‐induced liver damage in mice. © 2017 Society of Chemical Industry
  • Gallic acid mediated oxidation of pentachlorophenol by the Fenton reaction
           under mild oxidative conditions
    • Abstract: BACKGROUNDThe present study demonstrates the decomposition of pentachlorophenol (PCP) by the Fenton reaction in the presence of gallic acid (GA). Unlike other studies, catalytic Fe2+ concentrations were used with respect to PCP in an effort to evaluate an environmentally benign Fenton system, studying the effect of phenolic‐type compounds widely found in the environment. The effect of operating variables was evaluated.RESULTSAt initial reaction times or at low H2O2 and Fe concentrations, GA enhanced PCP removal. At high H2O2 and Fe concentrations GA enhanced PCP removal only at initial reaction times. GA was the determinant factor controlling activity acting both as a chelating agent and reducer of Fe3+. Electron paramagnetic resonance (EPR) spectroscopy was applied to shed light on mechanistic aspects, verifying the interaction of GA with Fe ions. GA accelerated significantly the Fe3+/Fe2+ redox cycling. This enhanced the formation of hydroxyl radicals (HO·) as confirmed by in situ EPR spin trap experiments. A reaction mechanism was proposed including the redox cycle of GA quinoide forms.CONCLUSIONThe operational variables of a GA modified Fenton system are provided and mechanistic steps are discussed including PCP degradation, GA/Fe interaction, Fe3+/Fe2+ redox cycling and HO· formation. GA concentration controls the catalytic degradation of PCP. © 2017 Society of Chemical Industry
  • Solubilization of inclusion body proteins using low and very low
           concentrations of chemicals: implications of novel combined chemical
           treatment designs in enhancement of post‐solubilization target protein
           purity and biological activity
    • Abstract: BACKGROUNDSolubilization of inclusion body (IB) proteins by conventional methods (i.e. high concentrations of denaturants such as chaotropes) is a challenging process due to denaturation of the native‐like secondary structures and subsequently low recovery into bioactive forms. The main objective of this work was to study the effect of a range of chemicals at low and very low concentrations on the solubilization of IB proteins produced in Escherichia coli and the enhancement of the target protein biological activity subsequent to refolding.RESULTSPerformance of chemical combinations at low and very low concentrations through the solubilization process of recombinant streptokinase (rSK) from IBs isolated from E. coli was appraised based on values pertinent to three parameters including target protein solubilization yield, purity and biological activity. In comparison with the conventional IBs' solubilization method (i.e. 4 mol L‐1 urea), combinations of 0.5–1 mol L‐1 urea with very low to low concentrations (0.05–1%) of detergents resulted in considerable target protein solubilization (by 100%), very high post‐solubilization target protein purities (up to 100%) and biological activities (up by 360%).CONCLUSIONOwing to the improvements in the abovementioned integral parameters, these chemical treatments are good candidates to be considered for more efficient and cost‐effective recovery of recombinant target proteins from IBs. © 2017 Society of Chemical Industry
  • Effect of organic loading rate on the performance of a submerged anaerobic
           membrane bioreactor (SAnMBR) for malting wastewater treatment and biogas
    • Abstract: BACKGROUNDMost malting plants discharge their wastewater to the sewer system and have to pay high discharge fees. Malting wastewater is rich in nutrients and contains high soluble COD (mostly sugars and organic acids). Hence, it is suited for anaerobic treatment without nutrients addition and can produce biogas simultaneously. The main objective of this study was to investigate the treatability of malting wastewater in a submerged anaerobic membrane bioreactor (SAnMBR) and biogas production under mesophilic temperature conditions (36 ± 1 °C) and variable organic loading rates (OLRs).RESULTSAs the OLR was increased from 1.36 to 3.18 kg COD m‐3 d‐1, the COD removal efficiency decreased from 94.1 ± 2.5% to 90.2 ± 1.4%, the effluent COD increased from 283 ± 121 mg L‐1 to 506 ± 68 mg L‐1, and the biogas production yield decreased from 0.345 ± 0.007 to 0.308 ± 0.025 L g‐1 CODremoved. The BOD5 removal efficiency was consistently above 99%. Methane accounted for 70.9 ± 2.0% of the biogas. Membrane permeability measurements, scanning electron microscopy (SEM), and energy dispersive X‐ray (EDX) spectrometry indicated that the membrane fouling that occurred during operation of the SAnMBR could be removed by a series of physical and chemical cleaning steps.CONCLUSIONSMalting wastewater was successfully treated using a SAnMBR for the first time. The SAnMBR adapted quickly to both gradual and sudden changes in OLR. © 2017 Society of Chemical Industry
  • Anaerobic re‐digestion of digested sludge post‐treated by ultrasound:
           Effect of the adding linear alkylbenzene sulfonate
    • Abstract: BACKGROUNDIncreasing the degradation ratio of organic matter is one of the key challenges for sludge anaerobic digestion. Conventional solution is by directly treating the raw sludge so as to enhance the sludge degradation. In contrast, the target of the present study focused on the digested sludge enriching in refractory organic matter. The method to improve the organic degradation of digested sludge was proposed by using ultrasound combined with linear alkylbenzene sulfonate (LAS) to control flocs re‐flocculation.RESULTSThe gas production of the sludge treated with the highest ultrasound energy (360 W, 20 min) was only 57.7 ± 0.3 mL‐CH4/g‐VSadded, and the sludge treated with lower ultrasound energy (120 W, 20 min) with LAS had the highest gas production, up to 92.5 ± 8.5 mL‐CH4/g‐VSadded. Meanwhile, the total VS degradation of 120 W, 20 min with LAS was up to 69.6 ± 5.2%. And the gas production of 360 W, 5 min with LAS was 27.1% higher than that of 360 W, 5 min without LAS.CONCLUSIONThese results revealed that digested sludge treated by ultrasonication could be further degraded, and the addition of LAS could largely improve the re‐digestion performance with less energy.
  • Controlling microbubbles in alcohol solutions by using a multi‐channel
           ceramic membrane distributor
    • Abstract: BACKGROUNDMicrobubbles are gaining more attention in environmental, medical, agricultural and industrial processes. The alcohol addition plays an important role in controlling microbubble generation. The effect of n‐butanol concentration on microbubble characteristics is still not studied. Experimental effort is made to efficiently control the microbubbles in the alcohol solutions.RESULTSMicrobubbles are successfully generated by using a 19‐channel ceramic membrane. The bubble Sauter diameter is found to decrease with increasing the n‐butanol concentration. Increasing cross flow velocity and decreasing superficial gas velocity results in smaller bubbles. Gas holdup and specific interfacial area is found to increase with increasing the n‐butanol concentration. The volumetric mass transfer coefficient Kla is found to increase with increasing the n‐butanol concentration, which follows the trends of specific interfacial area. Increasing cross flow velocity and superficial gas velocity results in the increase in Kla.CONCLUSIONSThe bubble characteristics in the solutions with different n‐butanol concentrations are very different. The alcohol addition is an important way to generate the smaller bubbles and larger gas holdup.
  • Removal of copper ions by few‐layered graphene oxide nanosheets from
           aqueous solutions: External influences and adsorption mechanisms
    • Abstract: BACKGROUDIn this article, we synthesize graphene oxide (GO) followed by a modified Hummers method and several characterization techniques were provided. Its adsorptive activity was evaluated based on the removal of Cu(II) from an aqueous solution. External influences were taken account to further study the adsorption mechanism.RESULTCharacterisation results revealed that GO was well prepared and a large amount of oxygen‐containing functional groups were introduced. The Cu(II) adsorption increased with increasing the solution pH and precipitate at alkaline condition had been considered. NaCl concentration improved copper adsorption at low pH. Formate reduced copper adsorption while benzoate improved the adsorption under low pH conditions.CONCLUSIONSHere, GO performed well adsorption ability to Cu(II). The external conditions represent different influences on the adsorption process. Experimental results demonstrate that GO is a promising alternative material for pollutants removal.
  • Viscosity reduction of pretreated softwood by endoglucanases
    • Abstract: BACKGROUNDCost‐effective processing of lignocellulosic biomass into sugar derived products, such as biofuels or biochemicals, needs to be performed at high water insoluble solid (WIS) loading. However, the difficult rheology of such materials presents significant challenges. The aim of this study was to investigate if a Cel5A endoglucanase can be used to reduce the viscosity of two types of pretreated softwood: steam pretreated Scots pine and sulfite pretreated Norway spruce.RESULTSThe viscosity of steam pretreated pine increased (by more than 60%) during the first 20 minutes of enzymatic hydrolysis, followed by a gradual decrease. A slightly lower viscosity during prolonged hydrolysis could be obtained by replacing 25% of the protein in Cellic CTec3 with the Cel5A endoglucanase. Very different results were obtained with sulfite pretreated spruce. The viscosity of this material was rapidly reduced by either CTec3 or the Cel5A endoglucanase, without a transient initial increase in viscosity. Even very low doses of Cel5A (0.1 mg protein per g glucan) decreased the viscosity of sulfite pretreated spruce 30‐fold within 6 h.CONCLUSIONLow endoglucanase doses can be used to reduce the viscosity of sulfite pretreated softwood, whereas the viscosity of steam pretreated softwood is less affected by endoglucanase activity.
  • Magnetic hydrophobic‐charge induction adsorbents for the recovery of
           immunoglobulins from antiserum feedstocks by high‐gradient magnetic
    • Abstract: BACKGROUNDThe extraction of biopharmaceuticals from plasma and serum often employs overly complicated antiquated procedures, that can inflict serious damage on especially prone protein targets and which afford low purification power and overall yields. Here we describe systematic development of a high‐gradient magnetic fishing process for recovery of immunoglobulins from unclarified antiserum.RESULTSNon‐porous superparamagnetic particles were transformed into hydrophobic‐charge induction adsorbents and then used to recover immunoglobulins from rabbit antiserum feedstocks. Comprehensive characterisation tests conducted with variously diluted clarified antiserum on a magnetic rack revealed that immunoglobulin binding was rapid (equilibrium reached in 3‐fold purified form.CONCLUSIONSFast magnetic particle based capture of antibodies from an unclarified high‐titre feed has been demonstrated. Efficient product recovery from ultra‐high titre bioprocess liquors by high‐gradient magnetic fishing requires that improved magnetic adsorbents displaying high selectivity, ultra‐high capacity and operational robustness are used with 'state‐of‐the‐art’ rotor‐stator magnetic separators.
  • Performance and bacterial community structure in three autotrophic
           submerged biofilters operated under different conditions
    • Abstract: BACKGROUNDAutotrophic nitrogen removal was evaluated in three bench‐scale bioreactors filled with Filtralite. This configuration is an alternative to the conventional technologies for nitrogen removal. One of the main problems associated with these new technologies, based on anammox (anaerobic ammonium oxidation) processes, is the stability of biomass. In this research the bioreactors performance and the stability of bacterial community were studied under the following conditions: dissolved oxygen (0.3‐1.5 mg O2/L), influent N‐NH4+ concentration 246 mg/L, and different NO2‐‐N concentrations (106.5, 30 and 0 mg NO2‐‐N/L).RESULTSTotal nitrogen removal efficiencies were 80.78% and 92.00% for bioreactors operated under microaerobic conditions (less than 1.5 mg O2/L) and 30 and 0 mg NO2‐‐N /L respectively. Bioreactors attained maximum efficiency after about 80 days. In contrast, the total nitrogen removal efficiency was only 69.57% for the bioreactor operated under anoxic conditions and 106.5 mg NO2‐‐N/L, but maximum efficiency was achieved after approximately 30 days. The presence of oxygen increased the relative abundance of AOB, which reached 6% in bioreactors with a low dissolved oxygen concentration. The relative abundance of Candidatus Brocadia remained stable in all bioreactors.CONCLUSIONSThe results showed that nitrite and anoxic conditions led to a quicker start‐up of a single reactor process during the initial days of operation. The combination of quantitative real‐time PCR (qPCR) and Illumina sequencing revealed that the operational conditions changed the bacterial community structure. The relative abundance of Candidatus Brocadia remained stable in all bioreactors, whereas significant differences were detected for Nitrosomonas.
  • Elevated production of the aromatic fragrance molecule, 2‐phenylethanol,
           using Metschnikowia pulcherrima through both de novo and ex novo
           conversion in batch and continuous modes
    • Abstract: BACKGROUND2‐phenylethanol (2PE) is a fragrance molecule predominantly used in perfumes and the food industry. It can be made from petrochemicals inexpensively, however, this is unsuitable for most food applications. Currently, the main method of production for the bio‐derived compound is to extract the trace amounts found in rose petals, which is extremely costly. Potentially fermentation could provide an inexpensive, naturally sourced, alternative.RESULTSIn this investigation, 2PE was produced from the yeast Metschnikowia pulcherrima, optimised in flasks before scaling to 2L batch and continuous operation. 2PE can be produced in high titres under de novo process conditions with up to 1,500 mg/L achieved in a 2L stirred bioreactor. This is the highest reported de novo titre to date, and achieved through high sugar loadings coupled with low nitrogen conditions. The process successfully ran in continuous mode also, with a concentration of 650 mg/L of 2PE being maintained. The 2PE production was further increased by the ex‐novo conversion of phenylalanine and semi‐continuous solid phase extraction from the supernatant. Under optimal conditions 14,000 mg/L of 2PE was produced.CONCLUSIONSThe work presented here offers a novel route to naturally sourced 2PE through a scalable fermentation with a robust yeast highly suited to industrial biotechnology.
  • Utilization of phosphogypsum for the preparation of α‐calcium sulfate
           hemihydrate in chloride‐free solution under atmospheric pressure
    • Abstract: BACKGROUNDThis work aims to investigate the possibility of recycling by‐product phosphogypsum (PG) as raw material for preparing α‐calcium sulfate hemihydrate (α‐CSH) in chloride‐free salt solution under mild conditions. The dehydration of PG in a concentrated Ca(NO3)2 solution at 97 oC under atmospheric pressure was analyzed. The effect of Al2(SO4)3 on the phase‐transition kinetics as well as succinic acid concentration on the crystal morphology of α‐CSH were investigated in detail.RESULTSα‐CSH was successfully prepared from PG in 3.7 M Ca(NO3)2 solution at 97 oC under atmospheric pressure. Addition of Al2(SO4)3 accelerates dehydration rate of PG and decreases crystal size of α‐CSH. Moreover, succinic acid is an effective morphology modifier for α‐CSH. When the reaction is carried out with 5.84 mM Al2(SO4)3 and 0.15 wt.% succinic acid, the obtained α‐CSH has aspect ratio of 1.2, and the corresponding paste shows enhanced 3 d bending/compressive strengths of 11.3/41.7 MPa which are comparable to those of commercial α‐CSH.CONCLUSIONSThis chloride‐free system provides an improved alternative for preparing high quality α‐CSH, and helps to push forward value‐added utilization of PG.
  • Improvement of bacterial methane elimination using porous ceramsite as
    • Abstract: BACKGROUNDMethane is a greenhouse gas (GHG) which contributes to climate change. Biofiltration with immobilized methane‐oxidizing bacteria (MOB) is a promising option to eliminate methane. In order to achieve high methane removal efficiency (RE), the appropriate carrier material with favorable characters, which could perform excellently in MOB immobilization and methane elimination, was needed to be selected out.RESULTSThe MOB consortium was enriched from landfill soil and immobilized on porous materials to eliminate methane at high (~20% (v/v)) and low (~1% (v/v)) concentrations. The methane elimination capacities of immobilized MOB were evaluated and the microbial immobilization abilities of materials were compared. Results showed that the MOB inoculated in black ceramsite (BC) permitted the highest elimination capacity (EC) of 5.36±0.29μmol h‐1 cm‐3 at methane concentration of ~20% (v/v), which was almost 3.6 times of suspended cell. At methane concentration of ~1% (v/v), the MOB incorporated with red ceramsite (RC) exhibited the optimal EC of 1.48±0.03μmol h‐1 cm‐3, which was 64.0% higher than the control. The biophosphorus tests showed that, the BC and RC could immobilize more MOB cells than active carbon (AC), and the SEM images, MB adsorption tests, BET and FTIR indicated that their large pore and surface properties might favor the MOB immobilization.CONCLUSIONThe ceramsite with desirable porosity and surface property could promote the MOB immobilization, and further improve the methane elimination capacity, which might be a favorable biocarrier for MOB biofilter.
  • Μelanoidin removal from aqueous systems by a hybrid
           flotation‐filtration technique
    • Abstract: BACKGROUNDMelanoidins are brown colored polymers found in wastewater produced by the fermentation industry. Melanoidins are recalcitrant compounds that cause several toxic effects to living systems, therefore, must be treated before disposal. The aim of the present study is the removal of melanoidins from simulated effluents by a hybrid flotation‐filtration process, which combines filtration and flotation. Coagulation‐flocculation or adsorption processes were evaluated as pre‐treatment stages.RESULTSIn the coagulation hybrid flotation/filtration process, coagulation is realized by ferric ions and a cationic flocculant, flotation by sodium dodecyl sulfate and filtration by a 250 μm filter. In the adsorption hybrid flotation/filtration process, adsorption is performed by powdered activated carbon, flotation by sodium dodecyl sulfate and filtration by a 16‐40 μm filter.CONCLUSIONThe results show effective melanoidin removal (about 90%) for both processes and limited filter fouling in the second process, which was corrected by air back‐flushing.
  • Ethylene epoxidation over supported silver catalysts – influence of
           catalyst pretreatment on conversion and selectivity
    • Abstract: BACKGROUNDEthylene oxide is a key intermediate in the chemical industry. It is produced through catalytic epoxidation of ethylene. Significant economic benefits can be achieved by small improvements on catalyst activity and selectivity. The aim of this work was to study how different preparation methods and pretreatments affects the catalyst performance under industrially relevant reaction conditions. The influence of pretreatment strategy on the selectivity and reaction temperature was for the first time investigated at a constant ethylene conversion of 7%.RESULTSEpoxidation of ethylene to ethylene oxide was studied over a range of silver catalysts which were prepared with different thermal treatment. The influence of catalyst preparation method and catalyst pretreatment strategy on the catalytic performance was investigated. It was found that calcination resulted in lower ethylene conversion compared to pre‐drying. In the latter case an induction period was observed, absent for the calcined catalyst. This induction period can be eliminated by oxidative or reductive pretreatment of the catalyst.CONCLUSIONSThe most promising pretreatment strategy was carried out by first treating the catalyst with 1 ppm of DCE for 5 h at 230 °C followed by overnight pre‐treatment in 20% ethylene at 250 °C. With this pretreatment it was possible to achieve a target ethylene conversion of 7% at 232.6 °C with a selectivity to ethylene oxide of 82.1%.
  • Separation of immunoglobulin G using aqueous biphasic systems composed of
           cholinium‐based ionic liquids and poly(propylene glycol)
    • Abstract: BACKGROUNDThe use of antibodies, such as immunoglobulin G (IgG), has faced a significant growth in the past decades for biomedical and research purposes. However, antibodies are high cost biopharmaceuticals, for which the development of alternative and cost‐effective purification strategies is still in high demand.RESULTSAqueous biphasic systems (ABS) composed of poly(propylene glycol) (PPG) and cholinium‐based ionic liquids (ILs) were investigated for the separation of IgG. The ABS phase diagrams were determined whenever required. Initial studies with commercial IgG were carried out, followed by the IgG separation from rabbit serum. In all ABS, IgG preferentially partitions to the IL‐rich phase, unveiling preferential interactions between IgG and ILs. Extraction efficiencies ranging between 93% and 100%, and recovery yields ranging between 20% and 100%, were obtained for commercial IgG. Two of the best and two of the worst identified ABS were then evaluated in what concerns their performance to separate IgG from rabbit serum, where extraction efficiencies of 100% and recovery yields > 80% were obtained. Under the best conditions studied, IgG with a purity level of 49% was obtained in a single‐step. After an ultracentrifugation step applied to the best ABS, allowing the IgG recovery from the IL‐rich phase, the IgG purity level increased up to 66%. This purity level of IgG is higher than those previously reported using other IL‐polymer ABS.CONCLUSIONIgG preferentially migrates to the IL‐rich phase in ABS formed by ILs and polymers, allowing the design of effective separation systems for its recovery from serum samples.
  • Biological nitrification in the presence of sulfide and organic matter:
           Effect of zeolite on the process in a batch system
    • Abstract: BackgroundEven though the nitrification process is inhibited in the presence of sulfide and organic matter, few efforts have been reported to overcome this weakness. The present work has the goal of determining the effect of zeolite (2.5, 5, 10 and 15 g/L) as an improver of the nitrification process in the presence of sulfide and organic matter in a batch system.ResultsThe inhibitory effect of both sulfide and organic matter on the nitrification process was decreased up to 53% by the use of zeolite, with the best results at zeolite concentration of 15 g/L. No Total Ammonia Nitrogen (TAN) adsorption on the zeolite was observed under these conditions, with TAN removal taking place mainly by biological oxidation. Specific nitrate production rate increased up to 37.73% compared to the control. Sulfide was oxidized chemically in all the assays, with sulfate as the main product, while COD reduction and VSS production were not affected by zeolite.ConclusionsZeolite can be used to improve nitrification in batch systems in the presence of sulfur and organic matter, obtaining a faster TAN removal rate and higher specific nitrate production compared to the controls.
  • Enzymatic ethanolysis of fish oil for selective concentration of
           polyunsaturated fatty acids (PUFAs) with flexible production of
           corresponding glycerides and ethyl esters
    • Abstract: BACKGROUNDProduct with higher concentration of polyunsaturated fatty acids (PUFAs) is now in high demand for health care and medicine. In this work, a novel lipase‐catalyzed ethanolysis of low‐grade fish oil was developed with combined use of two commercial free and immobilized lipases (triacylglycerol acylhydrolase, EC, namely Novozyme NS81006 and 435, to flexibly produce fatty acid ethyl esters (FAEEs) and concentrated PUFAs.RESULTSIn the first‐step, most of fatty acid glycerides (FAGCs) were converted to ethyl esters with conversion ratios of 70‐80% but just a minor part of docosahexaenoic fatty acids (DHA) was converted (
  • Extraction of recombinant proteins from Escherichia coli by cell
           disruption with aqueous solutions of surface‐active compounds
    • Abstract: BACKGROUNDGreen fluorescent protein (GFP) is extensively used as biomarker due to its unique spectral and fluorescence characteristics. GFP is usually obtained from recombinant strains of Escherichia coli (E. coli) producing the protein intracellularly. However, the common methods of extraction are cumbersome leading to an increase in the downstream process costs and complexity, sometimes leading to a higher risk of biomolecule degradation.RESULTSThis work proposes a new method to extract recombinant intracellular GFP from E. coli BL21 by using aqueous solutions of surface‐active compounds.CONCLUSIONBy comparing the fluorescence intensity of the extracted GFP, it was concluded that some of these compounds, namely ILs with an alkyl chain of 10 or more carbons (best solvent being the tributyl‐1‐tetradecylphosphonium, [P4,4,4,14]Cl) are more effective than an ultrasonic‐assisted extraction, even at low concentrations, being able to extract the whole GFP content from the cells.
  • Mathematical modelling of Expanded Bed Adsorption – a perspective on
           in silico process design
    • Abstract: Expanded bed adsorption (EBA) emerged in the early 1990’s in an attempt to integrate the clarification, capture and initial product concentration/purification process. Several mathematical models have been put forward to describe its operation. However, none of the models developed specifically for EBA allow simultaneous prediction of bed hydrodynamics, mass transfer/adsorption and (unwanted) interactions and fouling. This currently limits the development and early optimization of EBA‐based separation processes. In multiphase reactor engineering, the use of multiphase computational fluid dynamics has been shown to improve fundamental understanding of fluidized beds. To advance EBA technology, a combination of particle, equipment and process scale models should be used. By employing a cascade of multiscale simulations, the various challenges EBA currently faces can be addressed. This allows for optimal design and selection of equipment, materials and process conditions, and reduces risks and development times of downstream processes involving EBA.
  • High cell‐density cultivation of phenolic acid
           decarboxylase‐expressing Escherichia coli and 4‐vinylguaiacol
           bioproduction from ferulic acid by whole‐cell catalysis
    • Abstract: Background4‐Vinyl guaiacol (4‐VG) is a high value‐added product widely used in the cosmetic, pharmaceutical, and chemical industries. The practical bioproduction of 4‐VG using phenolic acid decarboxylases has been limited by its relatively high biocatalyst cost and low yield and product concentration.ResultsIn the present study, high‐cell density cultivation was employed to improve the activity and production of phenolic acid decarboxylase from Bacillus licheniformis (BLPAD) in recombinant Escherichia coli. The factors influencing enzyme production in E. coli such as the induction point and temperature for induction and feeding strategies were optimized. The highest BLPAD activity (531 U/mL) and productivity (20.4 U/mL/h), respectively, were achieved in a 5‐L bioreactor using a glucose exponential feeding strategy with isopropyl β‐D‐thiogalactoside (IPTG) as inducer. Furthermore, we achieved a high BLPAD production level (512 U/mL) using lactose as an inducer and continuous lactose feeding. Using a biphasic emulsion system with an equal volume (1 L) of cyclohexane as the organic solvent and a substrate fed‐batch strategy, the concentration and conversion yield of 4‐VG reached 129.9 g/L (85.6%) in a 5‐L bioreactor by whole‐cell biocatalysis, which is the highest reported to date.ConclusionThis study describes a strategy for large‐scale 4‐VG bioproduction using the biocatalytic method.
  • Selenate removal in biofilm systems: effect of nitrate and sulfate on
           selenium removal efficiency, biofilm structure and microbial community
    • Abstract: BACKGROUNDSelenium (Se) discharged into natural waterbodies can accumulate over time and have negative impacts on the environment. Se‐laden wastewater streams can be treated using biological processes. However, the presence of other electron acceptors in wastewater, such as nitrate (NO3‐) and sulfate (SO42‐), can influence selenate (SeO42‐) reduction and impact the efficiency of biological treatment systems.RESULTSSeO42‐ removal by biofilms formed from an anaerobic sludge inoculum was investigated in the presence of NO3‐ and SO42‐ using drip flow reactors operated continuously for 10 days at pH 7.0 and 30°C. The highest total Se (~60%) and SeO42‐ (~80%) removal efficiencies were observed when the artificial wastewater contained SO42‐. A maximum amount of 68 μmol Se/cm2 was recovered from the biofilm matrix in SO42‐+SeO42‐ exposed biofilms and biofilm mass was 2.7 fold increased for biofilms grown in the presence of SO42‐. When SeO42‐ was the only electron acceptor, biofilms were thin and compact. In the simultaneous presence of NO3‐ or SO42‐, biofilms were thicker (> 0.6 mm), less compact and exhibited gas pockets.CONCLUSIONThe presence of SO42‐ had a beneficial effect on biofilm growth and the SeO42‐ removal efficiency, while the presence of NO3‐ did not have a significant effect on SeO42‐ removal by the biofilms.
  • Operator Training Simulators for Biorefineries: Current Position and
           Future Directions
    • Abstract: Recent technological advances in the development of alternative energy sources, including biofuels, for transportation and energy requirements have demonstrated the need for highly skilled engineers and operators in the biotechnological industries. Although Operator Training Simulators (OTS) used in the traditional chemical process industries may be used to train biorefinery operators and engineers, several distinct aspects of bioprocess operations make their direct application limited. The development and deployment of OTSs for use in biotechnological processes is therefore beginning to gain increasing attention. This review paper will examine the present status of OTS development and use in biorefineries, including future considerations on how an OTS may be used to improve operator competence, maximise biorefinery operational efficiencies and protect people and the environment.The general premise of an OTS is that model‐based operator training simulators can be used to verifiably enhance the training of industrial operators to run complex biorefineries. Only a few examples of the design and application of OTSs in large‐scale biorefineries have so far been reported. A discussion of the mathematical models used for OTS development is briefly presented, as well as available OTS design frameworks and vendors, including their benefits and drawbacks. The review concludes by looking at possible future directions of OTS development and use in biorefineries and their contribution in facilitating the transition to a bio‐based economy.
  • Production of butyric acid by Clostridium tyrobutyricum coated with
           carboxyl functioned magnetic nanoparticles
    • Abstract: BACKGROUNDMagnetic nanomaterial has been considered as the promising carriers for cell immobilization, because of its low mass transfer resistance, high load rate, high specific surface and facility of reusability. In this study, carboxyl functioned magnetic nanoparticles (CMNPs) were prepared by chemical co‐precipitation and oleate modification methods, and then immobilized with Clostridium tyrobutyricum for the production of butyric acid.RESULTSThe immobilization conditions were systematically optimized to achieve the maximal efficiency and the highest cell relative activity, in which the mass ratio, immobilization temperature and time were determined as 0.72 g/g, 35 °C and 30 min, respectively. The endurance of CMNPs‐cells was also evaluated in a repeated‐batch mode of 8 continuous batches. A stable and reliable production of butyric acid was obtained in each batch with an average butyrate titer and yield of ~11.02 g/L and ~0.43 g/g utilized sugar. Comparing to the free‐cell fermentation, higher butyrate yield and concentration were obtained with immobilized cells of C. tyrobutyricum in repeated‐batch fermentation, suggesting that the coated cells did not experience a mass transfer problem.CONCLUSIONConsidering about the convenient separation of CMNPs‐cells from fermentation broth via external magnetic force, as well as its excellent long term performance overcoming the possible accumulation of dead cells and culture degeneration, the developed usage of CMNPs‐cells could be very benign for industrial application.
  • Heavy gas oil biodesulfurization using a low‐cost bacterial
    • Abstract: BACKGROUNDPetroleum and its derivatives usually containing great amounts of sulfur. During the combustion of fossil fuels, sulfur it is liberated to the atmosphere as one of the most noxious pollutant form: the sulfur dioxide (SOx). The removal of sulfur content to the ultralow levels demanded by the worldwide legislation has been a challenge to the refinery industry. Principally, due to the inefficiency of conventional processes, such as hydrodesulfurization, which are not capable of removing the recalcitrant sulfur compounds. Biodesulfurization is a biological process that removes these recalcitrant pollutants from hydrocarbons. However, there are several unsolved technological difficulties associated with this procedure, e.g., the development of a stable and efficient biocatalyst and a low‐cost culture medium. Thus, the use of a bacterial consortium as a substitute for both the biocatalyst and the nutritional medium in order to improve the biodesulfurization process was studied.RESULTSThe desulfurization activity was determined applying different temperatures and bacterial consortium (BC) concentrations. An efficient desulfurization capacity (71.2%) was observed using only 5% (w/w) of BC at 45 °C. At this temperature, the total time required for the biodesulfurization was substantially reduced, with only 2 h needed to achieve the highest desulfurization capacity.CONCLUSIONThe BC can be used as a substitute of biocatalysts and nutritional media for the heavy gas oil desulfurization. The desulfurization capacity using BC was similar to that achieved with other pure bacterial strains and culture medium. Moreover, the time process was diminished, which represents an important improvement in the biodesulfurization technology.
  • NIR‐responsive Nanomaterials and Their Applications : Upconversion
           nanoparticles and Carbon dots : A Perspective
    • Abstract: Near‐infrared (NIR) light responsive materials have drawn much attention for diverse applications due to its excellent optical properties. This type of material exhibits upconverted luminescence, a non‐linear optical process where two or more low energy photons, usually from NIR light irradiation are transformed to high energy photons emission through energy transfer upconversion, excited state absorption, photon avalanche or multiphoton absorption. NIR range of excitation source is favorable for biological imaging and cancer theranostic applications due to their high penetration depth, low autofluorescence, minimal light scattering, reduced photodamage, and negligible phototoxicity. Having these properties, NIR responsive materials such as upconversion nanoparticles (UCNPs) and carbon dots (CDs) which perform upconversion luminescence are actively exploited in a wide variety of applications such as display and sensory technology. While CDs are well known for its versatility in using different chemicals and green precursors to achieve tunable optical properties, UCNPs also has its own merit where a continuous‐wave NIR laser can be used as the excitation source. In this article, we review the properties of these two materials in the aspects of luminescence mechanisms and their recent developments in cancer theranostics, display technology, biosensing and metal ions sensing applications.
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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Fax: +00 44 (0)131 4513327
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