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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 Biotechnology
  [SJR: 1.064]   [H-I: 118]   [68 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0168-1656
   Published by Elsevier Homepage  [3177 journals]
  • Extracellular biosynthesis of magnetic iron oxide nanoparticles by
           Bacillus cereus strain HMH1: characterization and In vitro cytotoxicity
           analysis on MCF-7 and 3T3 Cell Lines
    • Authors: Mohsen Fatemi; Nasrin Mollania; Majid Momeni-Moghaddam; Fatemeh Sadeghifar
      Pages: 1 - 11
      Abstract: Publication date: Available online 31 January 2018
      Source:Journal of Biotechnology
      Author(s): Mohsen Fatemi, Nasrin Mollania, Madjid Momeni-Moghaddam, Fatemeh Sadeghifar
      Discovery of new properties and special functionalities at the nanoscale materials caused nanotechnology to become one of the leading parts in all sciences namely biology and medicine. Magnetic iron oxide nanoparticles (MIONPs) are among interesting nanomaterials in biomedical arena, which have attracted the attention of many researchers owing to their extensive capabilities. Due to the simple, cost-effective and environmentally-friendly production processes, biosynthesis is of paramount importance between different methods of nanoparticles production. In the current study, we succeeded to synthesize MIONPs using a newly extracted bacteria supernatant. Produced nanoparticles were characterized using FE-SEM, DLS, VSM, UV-Vis, FT-IR and EDS spectroscopy. Analysis showed that the average particle size of very stable spherical MIONPs is about 29.3 nm. The bacteria protein profile obtained by SDS-PAGE analysis indicated induction of different proteins. In vitro cytotoxicity of nanoparticles on the viability of MCF7 and 3T3 cell lines was assessed by MTT assay. The results show that toxicity of the produced nanoparticles is very low (IC50, MCF-7>5mg/ml and IC50, 3T3>7.5mg/ml) and follows a concentration dependent manner.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.021
      Issue No: Vol. 270 (2018)
  • Metabolomic response of a marine bacterium to 3,6-anhydro-l-galactose,a
           rare sugar from red macroalgae, as a carbon source
    • Authors: Eun Ju Yun; Sora Yu; Sooah Kim; Kyoung Heon Kim
      Pages: 12 - 20
      Abstract: Publication date: Available online 31 January 2018
      Source:Journal of Biotechnology
      Author(s): Eun Ju Yun, Sora Yu, Sooah Kim, Kyoung Heon Kim
      Marine red macroalgae have received much attention as a sustainable resource for producing bio-based products. Therefore, understanding the metabolic pathways of carbohydrates from red macroalgae, in fermentative microorganisms, is crucial for efficient bioconversion of the carbohydrates into bio-based products. Recently, the novel catabolic pathway of 3,6-anhydro-l-galactose (AHG), the main component of red macroalgae, was discovered in a marine bacterium, Vibrio sp. strain EJY3. However, the global metabolic network in response to AHG remains unclear. Here, the intracellular metabolites of EJY3 grown on AHG, glucose, or galactose were comparatively profiled using gas chromatography/time-of-flight mass spectrometry. The global metabolite profiling results revealed that the metabolic profile for AHG significantly differed from those for other common sugars. Specifically, the metabolic intermediate of the AHG pathway, 3,6-anhydrogalactonate, was detected only during growth in the presence of AHG; thus, the recently discovered key steps in AHG catabolism may not occur in the catabolism of other common sugars. Moreover, the levels of metabolic intermediates related to glycerolipid metabolism and valine biosynthesis were higher with AHG than those with other sugars. These comprehensive metabolomic analytical results for AHG in this marine bacterium can be used for engineering fermentative microbial strains to efficiently utilize AHG.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.017
      Issue No: Vol. 270 (2018)
  • Validating a probe from GhSERK1 gene for selection of cotton genotypes
           with somatic embryogenic capacity
    • Authors: Taiza da Cunha Soares; Carliane Rebeca Coelho da Silva; Julita Maria Frota Chagas Carvalho; José Jaime Vasconcelos Cavalcanti; Liziane Maria de Lima; Péricles de Albuquerque Melo Filho; Liv Soares Severino; Roseane Cavalcanti dos Santos
      Pages: 44 - 50
      Abstract: Publication date: 20 March 2018
      Source:Journal of Biotechnology, Volume 270
      Author(s): Taiza da Cunha Soares, Carliane Rebeca Coelho da Silva, Julita Maria Frota Chagas Carvalho, José Jaime Vasconcelos Cavalcanti, Liziane Maria de Lima, Péricles de Albuquerque Melo Filho, Liv Soares Severino, Roseane Cavalcanti dos Santos
      Substantial progress is being reported in the techniques for plant transformation, but successful regeneration of some genotypes remains a challenging step in the attempts to transform some recalcitrant species. GhSERK1 gene is involved on embryo formation, and its overexpression enhances the embryogenic competence. In this study we validate a short GhSERK1 probe in order to identify embryogenic cotton genotypes using RT-qPCR and blotting assays. Cotton genotypes with contrasting somatic embryogenic capacity were tested using in vitro procedures. High expression of transcripts was found in embryogenic genotypes, and the results were confirmed by the RT-PCR-blotting using a non-radioactive probe. The regeneration ability was confirmed in embryogenic genotypes. We confirmed that GhSERK1 can be used as marker for estimating the somatic embryogenesis ability of cotton plants.

      PubDate: 2018-02-15T07:24:06Z
      DOI: 10.1016/j.jbiotec.2018.02.002
      Issue No: Vol. 270 (2018)
  • Comparative transcriptome analysis of a Trichoplusia ni cell line reveals
           distinct host responses to intracellular and secreted protein products
           expressed by recombinant baculoviruses
    • Authors: Krisztina Koczka; Philipp Peters; Wolfgang Ernst; Heinz Himmelbauer; Lisa Nika; Reingard Grabherr
      Pages: 61 - 69
      Abstract: Publication date: 20 March 2018
      Source:Journal of Biotechnology, Volume 270
      Author(s): Krisztina Koczka, Philipp Peters, Wolfgang Ernst, Heinz Himmelbauer, Lisa Nika, Reingard Grabherr
      The baculovirus insect cell expression system has become a firmly established production platform in biotechnology. Various complex proteins, multi-subunit particles including veterinary and human vaccines are manufactured with this system on a commercial scale. Apart from baculovirus infected Spodoptera frugiperda (Sf9) cells, the Trichoplusia ni (HighFive) cell line is alternatively used as host organism. In this study, we explored the protein production capabilities of Tnms42 insect cells, a new derivative of HighFive, which is free of latent nodavirus infection. As a model system, a cytosolic (mCherry) and a secreted (hemagglutinin) protein were overexpressed in Tnms42 cells. The response of the host cells was followed in a time course experiment over the infection cycle by comparative transcriptome analysis (RNA-seq). As expected, the baculovirus infection per se had a massive impact on the host cell transcriptome, which was observed by the huge total number of differentially expressed transcripts (>14,000). Despite this severe overall cellular reaction, a specific response could be clearly attributed to the overexpression of secreted hemagglutinin, revealing limits in the secretory capacity of the host cell. About 400 significantly regulated transcripts were identified and assigned to biochemical pathways and gene ontology (GO) categories, all related to protein processing, folding and response to unfolded protein. The identification of relevant target genes will serve to design specific virus engineering concepts for improving the yield of proteins that are dependent on the secretory pathway.

      PubDate: 2018-02-15T07:24:06Z
      DOI: 10.1016/j.jbiotec.2018.02.001
      Issue No: Vol. 270 (2018)
  • Of enzyme use in cost-effective high solid simultaneous saccharification
           and fermentation processes
    • Authors: Valentin Sóti; Silvia Lenaerts; Iris Cornet
      Pages: 70 - 76
      Abstract: Publication date: 20 March 2018
      Source:Journal of Biotechnology, Volume 270
      Author(s): Valentin Sóti, Silvia Lenaerts, Iris Cornet
      Enzyme cost is considered to be one of the most significant factors defining the final product price in lignocellulose hydrolysis and fermentation. Enzyme immobilization and recycling can be a tool to decrease costs. However, high solid loading is a key factor towards high product titers, and recovery of immobilized enzymes from this thick liquid is often overlooked. This paper aims to evaluate the economic feasibility of immobilized enzymes in simultaneous saccharification and fermentation (SSF) of lignocellulose biomass in general, as well as the recuperation of magnetic immobilized enzymes (m-CLEAs) during high solid loading in simultaneous saccharification, detoxification and fermentation processes (SSDF) of lignocellulose biomass. Enzyme prices were obtained from general cost estimations by Klein-Marcuschamer et al. [Klein-Marcuschamer et al. (2012) Biotechnol. Bioeng. 109, 1083–1087]. During enzyme cost analysis, the influence of inoculum recirculation as well as a shortened fermentation time was explored. Both resulted in 15% decrease of final enzyme product price. Enzyme recuperation was investigated experimentally and 99.5 m/m% of m-CLEAs was recovered from liquid medium in one step, while 88 m/m% could still be recycled from a thick liquid with high solid concentrations (SSF fermentation broth). A mathematical model was constructed to calculate the cost of immobilized and free enzyme utilization and showed that, with current process efficiencies and commercial enzyme prices, the cost reduction obtained by enzyme immobilization can reach around 60% compared to free enzyme utilization, while lower enzyme prices will result in a lower percentage of immobilization related savings, but overall enzyme costs will decrease significantly. These results are applied in a case study, estimating the viability of shifting from sugar to lignocellulose substrate for a 100 t lactic acid fermentation batch. It was concluded that it will only be economically feasible if the enzymes are produced at the most optimistic variable cost and either the activity of the immobilized catalyst or the recovery efficiency is further increased.

      PubDate: 2018-02-15T07:24:06Z
      DOI: 10.1016/j.jbiotec.2018.01.020
      Issue No: Vol. 270 (2018)
  • Cryotherapy by encapsulation-dehydration is effective for in vitro
           eradication of latent viruses from ‘Marubakaido’ apple rootstock
    • Authors: Jean Carlos Bettoni; Murilo Dalla Costa; Juliana Aparecida Souza; Gayle M. Volk; Osmar Nickel; Fabio Nascimento da Silva; Aike Anneliese Kretzschmar
      Pages: 1 - 7
      Abstract: Publication date: 10 March 2018
      Source:Journal of Biotechnology, Volume 269
      Author(s): Jean Carlos Bettoni, Murilo Dalla Costa, Juliana Aparecida Souza, Gayle M. Volk, Osmar Nickel, Fabio Nascimento da Silva, Aike Anneliese Kretzschmar
      Apple stem pitting virus (ASPV), Apple chlorotic leaf spot virus (ACLSV) and Apple stem grooving virus (ASGV) are several major viral pathogens of apple trees, responsible for substantial damage to the world’s apple industry. This study aimed to evaluate the effectiveness of the encapsulation-dehydration cryopreservation technique to eradicate these viral pathogens from in vitro shoot tips excised from ‘Marubakaido’ apple rootstock cultures. Axillary shoot tips were excised from in vitro cultures, encapsulated in alginate beads, precultured in MS salts, dehydrated in a laminar flow hood, immersed in liquid nitrogen, then warmed and recovered on medium. After LN exposure, in vitro rooting and acclimatization, recovered ‘Marubakaido’ plants exhibited 52% survival and 35% regrowth without callus formation. After 8 months of regrowth, PCR analyses revealed that all the plants were free of ACLSV and ASPV, but 2 out of 20 recovered plants were still infected with ASGV. This is the first report in Brazil of the application of cryotherapy to eradicate viral complexes in Malus. Cryotherapy can facilitate the production of virus-free plants by producing high quality plant material.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.014
      Issue No: Vol. 269 (2018)
  • Laccase-mediated functionalization of chitosan with 4-hexyloxyphenol
           enhances antioxidant and hydrophobic properties of copolymer
    • Authors: Na Liu; Shuzhen Ni; Arthur J. Ragauskas; Xianzhi Meng; Naijia Hao; Yingjuan Fu
      Pages: 8 - 15
      Abstract: Publication date: 10 March 2018
      Source:Journal of Biotechnology, Volume 269
      Author(s): Na Liu, Shuzhen Ni, Arthur J. Ragauskas, Xianzhi Meng, Naijia Hao, Yingjuan Fu
      An effective method to functionalize chitosan with 4-hexyloxyphenol (HP) under homogeneous reaction conditions was developed using laccase as the catalyst. The resulting copolymer was characterized for chemical structure, grafted-HP content, surface morphology, thermal stability, antioxidant capacity, hydrophobic properties and tensile strength. Solid-state 13C NMR spectrum confirmed the incorporation of HP onto chitosan. X-ray diffraction (XRD) showed a decrease in the degree of crystallinity for laccase/HP treated chitosan compared to pure chitosan. The grafted-HP content in laccase/HP-treated chitosan first increased and then declined with increase of the initial HP/chitosan ratio. A heterogeneous surface with spherical particles on the laccase/HP treated chitosan was observed by environmental scanning electron microscopy (ESEM) and scanning probe microscopy (SPM). The laccase/HP treatment of chitosan improved the thermal stability of copolymer. More significantly, the HP functionalized chitosan showed greatly improved ABTS + and DPPH radicals scavenging capacity, compared with pure chitosan. The hydrophobicity property of the HP functionalized chitosan also significantly increased although its tensile strength decreased. This new type of composite with double functionalities (i.e., antioxidant and hydrophobic) could potentially be used as food packaging materials or coating agents.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.015
      Issue No: Vol. 269 (2018)
  • Bioreactors in solid state fermentation technology: Design, applications
           and engineering aspects
    • Authors: Sidharth Arora; Richa Rani; Sanjoy Ghosh
      Pages: 16 - 34
      Abstract: Publication date: 10 March 2018
      Source:Journal of Biotechnology, Volume 269
      Author(s): Sidharth Arora, Richa Rani, Sanjoy Ghosh
      In recent years, substantial credibility in employing Solid-State Fermentation (SSF) technique has been witnessed owing to its numerous advantages over submerged fermentation (SmF). In spite of enormous advantages, true potential of SSF technology has not been fully realized at industrial scale. The lack of rational and scalable bioreactor designs backed by mathematical models and automated control system that could successfully address heterogeneity with respect to heat and mass, and also operate aseptically, remains the prime reason for it. As a result, there still exists vast scope in SSF bioreactor research and development to facilitate broad spectrum of biotechnological applications. The present article reviews state-of-the-art in SSF technology with focus on bioreactors that have been employed for bioprocess applications, in particular, enzyme production. Based on the mode of operation, bioreactors are divided into four categories with emphasis on design features, effect of operating conditions on productivity, applications and limitations. Selected modeling studies developed over the years, have been revised and presented in problem specific manner in order to address the limitations. Some interesting designs including few recent ones that have been proposed and/or employed at pilot and industrial levels are discussed in more detail.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.010
      Issue No: Vol. 269 (2018)
  • Highly affine and selective aptamers against cholera toxin as capture
           elements in magnetic bead-based sandwich ELAA
    • Authors: Esther Frohnmeyer; Farina Frisch; Sven Falke; Christian Betzel; Markus Fischer
      Pages: 35 - 42
      Abstract: Publication date: 10 March 2018
      Source:Journal of Biotechnology, Volume 269
      Author(s): Esther Frohnmeyer, Farina Frisch, Sven Falke, Christian Betzel, Markus Fischer
      Aptamers are single-stranded DNA or RNA oligonucleotides, which have been emerging as recognition elements in disease diagnostics and food control, including the detection of bacterial toxins. In this study, we employed the semi-automated just in time-selection to identify aptamers that bind to cholera toxin (CT) with high affinity and specificity. CT is the main virulence factor of Vibrio cholerae and the causative agent of the eponymous disease. For the selected aptamers, dissociation constants in the low nanomolar range (23–56 nM) were determined by fluorescence-based affinity chromatography and cross-reactivity against related proteins was evaluated by direct enzyme-linked aptamer assay (ELAA). Aptamer CT916 has a dissociation constant of 48.5 ± 0.5 nM and shows negligible binding to Shiga-like toxin 1B, protein A and BSA. This aptamer was chosen to develop a sandwich ELAA for the detection of CT from binding buffer and local tap water. Amine-C6- or biotin-modified CT916 was coupled to magnetic beads to serve as the capture element. Using an anti-CT polyclonal antibody as the reporter, detection limits of 2.1 ng/ml in buffer and 2.4 ng/ml in tap water, with a wide log-linear dynamic range from 1 ng/ml to 1000 ng/ml and 500 ng/ml, respectively, were achieved.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.012
      Issue No: Vol. 269 (2018)
  • Complete genome sequence of Tsukamurella sp. MH1: A wide-chain length
           alkane-degrading actinomycete
    • Authors: Iulia Chiciudean; Yong Nie; Ana-Maria Tănase; Ileana Stoica; Xiao-Lei Wu
      Pages: 1 - 5
      Abstract: Publication date: 20 February 2018
      Source:Journal of Biotechnology, Volume 268
      Author(s): Iulia Chiciudean, Yong Nie, Ana-Maria Tănase, Ileana Stoica, Xiao-Lei Wu
      Tsukamurella sp. strain MH1, capable to use a wide range of n-alkanes as the only carbon source, was isolated from petroleum-contaminated soil (Pitești, Romania) and its complete genome was sequenced. The 4,922,396 bp genome contains only one circular chromosome with a G + C content of 71.12%, much higher than the type strains of this genus (68.4%). Based on the 16S rRNA genes sequence similarity, strain MH1 was taxonomically identified as Tsukamurella carboxydivorans. Genome analyses revealed that strain MH1 is harboring only one gene encoding for the alkB-like hydroxylase, arranged in a complete alkane monooxygenase operon. This is the first complete genome of the specie T. carboxydivorans, which will provide insights into the potential of Tsukamurella sp. MH1 and related strains for bioremediation of petroleum hydrocarbons-contaminated sites and into the environmental role of these bacteria.

      PubDate: 2018-01-26T10:30:30Z
      DOI: 10.1016/j.jbiotec.2017.12.013
      Issue No: Vol. 268 (2018)
  • Development of a whole-cell-based screening method for a carotenoid assay
           using aerial microalgae
    • Authors: Nobuhiro Aburai; Hiroaki Kazama; Atsushi Tsuruoka; Mizuki Goto; Katsuya Abe
      Pages: 6 - 11
      Abstract: Publication date: 20 February 2018
      Source:Journal of Biotechnology, Volume 268
      Author(s): Nobuhiro Aburai, Hiroaki Kazama, Atsushi Tsuruoka, Mizuki Goto, Katsuya Abe
      Non-destructive approaches based on the application of optical spectroscopy are important for monitoring carotenoid accumulation in a whole cell cultured under various conditions. A simple and rapid assay utilizing aerial microalgae helps to identify stress conditions that can efficiently enhance the carotenogenesis in photosynthetic organisms. The spectra of cell suspensions were characterized in the aerial microalga Coelastrella sp. KGU-Y002, which are unicellular and undifferentiated. Total carotenoid contents could be successfully estimated on the basis of the absorbance values of the cell suspensions and calibration data analyzed by HPLC (high-performance liquid chromatography). A novel screening method, the so-called “whole-cell-based screening method” for carotenoid assays (WCA), was developed based on this procedure. It was possible to investigate the effects of various stresses on carotenoid accumulation in the aerial microalga by adapting this bioassay to a 96-well microtiter plate. When bioactive compounds were screened from our library of plant extracts using this method, an active compound was identified from the plant extract.

      PubDate: 2018-01-26T10:30:30Z
      DOI: 10.1016/j.jbiotec.2017.12.025
      Issue No: Vol. 268 (2018)
  • Model of acetic acid-affected growth and poly(3-hydroxybutyrate)
           production by Cupriavidus necator DSM 545
    • Authors: Jaruwan Marudkla; Wen-Chien Lee; Siwaporn Wannawilai; Yusuf Chisti; Sarote Sirisansaneeyakul
      Pages: 12 - 20
      Abstract: Publication date: 20 February 2018
      Source:Journal of Biotechnology, Volume 268
      Author(s): Jaruwan Marudkla, Wen-Chien Lee, Siwaporn Wannawilai, Yusuf Chisti, Sarote Sirisansaneeyakul
      Acetic acid, a potential growth inhibitor, commonly occurs in lignocellulosic hydrolysates. The growth of Cupriavidus necator DSM 545 and production of poly(3-hydroxybutyrate) (PHB) by this bacterium in a glucose-based medium supplemented with various initial concentrations of acetic acid are reported. The bacterium could use both glucose and acetic acid to grow and produce PHB, but acetic acid inhibited growth once its initial concentration exceeded 0.5 g/L. As acetic acid is an unavoidable contaminant in hydrolysates used as sugar sources in commercial fermentations, a mathematical model was developed to describe its impact on growth and the production of PHB. The model was shown to satisfactorily apply to growth and PHB production data obtained in media made with acetic-acid-containing hydrolysates of Napier grass and oil palm trunk as carbon substrates.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.004
      Issue No: Vol. 268 (2018)
  • Lack of cations in flow cytometry buffers affect fluorescence signals by
           reducing membrane stability and viability of Escherichia coli strains
    • Authors: Kathrin Tomasek; Tobias Bergmiller; Călin C. Guet
      Pages: 40 - 52
      Abstract: Publication date: 20 February 2018
      Source:Journal of Biotechnology, Volume 268
      Author(s): Kathrin Tomasek, Tobias Bergmiller, Călin C. Guet
      Buffers are essential for diluting bacterial cultures for flow cytometry analysis in order to study bacterial physiology and gene expression parameters based on fluorescence signals. Using a variety of constitutively expressed fluorescent proteins in Escherichia coli K-12 strain MG1655, we found strong artifactual changes in fluorescence levels after dilution into the commonly used flow cytometry buffer phosphate-buffered saline (PBS) and two other buffer solutions, Tris-HCl and M9 salts. These changes appeared very rapidly after dilution, and were linked to increased membrane permeability and loss in cell viability. We observed buffer-related effects in several different E. coli strains, K-12, C and W, but not E. coli B, which can be partially explained by differences in lipopolysaccharide (LPS) and outer membrane composition. Supplementing the buffers with divalent cations responsible for outer membrane stability, Mg2+ and Ca2+, preserved fluorescence signals, membrane integrity and viability of E. coli. Thus, stabilizing the bacterial outer membrane is essential for precise and unbiased measurements of fluorescence parameters using flow cytometry.
      Graphical abstract image

      PubDate: 2018-01-26T10:30:30Z
      DOI: 10.1016/j.jbiotec.2018.01.008
      Issue No: Vol. 268 (2018)
  • Production, detection and application perspectives of quorum sensing
           autoinducer-2 in bacteria
    • Authors: Jing Zhao; Chunshan Quan; Liming Jin; Ming Chen
      Pages: 53 - 60
      Abstract: Publication date: 20 February 2018
      Source:Journal of Biotechnology, Volume 268
      Author(s): Jing Zhao, Chunshan Quan, Liming Jin, Ming Chen
      Autoinducer-2 (AI-2) is a major signal molecule in bacterial quorum sensing (QS) besides N-acyl homoserine lactones (AHLs or AI-1). AI-2 mediated QS pathways have been proved to regulate gene expression and physiological behaviors of bacteria in either intraspecies or interspecies communication. Recent reviews have mainly summarized AI-2 structures, AI-2 mediated QS pathways and the role of AI-2 in gene regulation, etc. In this article, we present a comprehensive review of AI-2 production, detection and applications. Firstly, intracellular AI-2 synthetic routes were outlined and environmental influences on AI-2 production were focused. Furthermore, recent advances in AI-2 detection and quantification were elucidated from an overall perspective. An in-depth understanding of mechanisms and features of various detection methods may facilitate development of new technologies aimed at signal molecule detection. Finally, utilization of AI-2 mediated QS in health improvement, water treatment and drug production indicate promising and extensive application perspectives of QS strategies.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.009
      Issue No: Vol. 268 (2018)
  • Mathematical model of the MenD-catalyzed 1,4-addition (Stetter reaction)
           of α-ketoglutaric acid to acrylonitrile
    • Authors: Martina Sudar; Đurđa Vasić-Rački; Michael Müller; Alexandra Walter; Zvjezdana Findrik Blažević
      Pages: 71 - 80
      Abstract: Publication date: 20 February 2018
      Source:Journal of Biotechnology, Volume 268
      Author(s): Martina Sudar, Đurđa Vasić-Rački, Michael Müller, Alexandra Walter, Zvjezdana Findrik Blažević
      The Stetter reaction, a conjugate umpolung reaction, is well known for cyanide-catalyzed transformations of mostly aromatic aldehydes. Enzymatic Stetter reactions, however, have been largely unexplored, especially with respect to preparative transformations. We have investigated the kinetics of the MenD-catalyzed 1,4-addition of α-ketoglutaric acid to acrylonitrile which has shown that acrylonitrile, while an interesting candidate, is a poor substrate for MenD due to low affinity of the enzyme for this substrate. The kinetic model of the reaction was simplified to double substrate Michaelis–Menten kinetics where the reaction rate linearly depends on acrylonitrile concentration. Experiments at different initial concentrations of acrylonitrile under batch, repetitive batch, and fed-batch reactor conditions were carried out to validate the developed mathematical model. Thiamine diphosphate dependent MenD proved to be quite a robust enzyme; nevertheless, enzyme operational stability decay occurs in the reactor. The spontaneous reactivity of acrylonitrile towards polymerization was also taken into account during mathematical modeling. Almost quantitative conversion of acrylonitrile was achieved in all batch reactor experiments, while the yield of the desired product was dependent on initial acrylonitrile concentration (i.e., the concentration of the stabilizer additive). Using the optimized reactor parameters, it was possible to synthesize the product, 6-cyano-4-oxohexanoic acid, in a concentration of 250 mM. The highest concentration of product was achieved in a repetitive batch reactor experiment. A fed-batch reactor experiment also delivered promising results, especially regarding the short reaction time needed to achieve a 200 mM concentration of product. Hence, the enzymatic Stetter reaction with a highly reactive acceptor substrate can be performed on a preparative scale, which should enable similar transformations with acrylate, methacrylate, and methyl vinyl ketone.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.013
      Issue No: Vol. 268 (2018)
  • Metabolic engineering of Escherichia coli for the production of indirubin
           from glucose
    • Authors: Jikun Du; Dongsoo Yang; Zi Wei Luo; Sang Yup Lee
      Pages: 19 - 28
      Abstract: Publication date: 10 February 2018
      Source:Journal of Biotechnology, Volume 267
      Author(s): Jikun Du, Dongsoo Yang, Zi Wei Luo, Sang Yup Lee
      Indirubin is an indole alkaloid that can be used to treat various diseases including granulocytic leukemia, cancer, and Alzheimer’s disease. Microbial production of indirubin has so far been achieved by supplementation of rather expensive substrates such as indole or tryptophan. Here, we report the development of metabolically engineered Escherichia coli strain capable of producing indirubin directly from glucose. First, the Methylophaga aminisulfidivorans flavin-containing monooxygenase (FMO) and E. coli tryptophanase (TnaA) were introduced into E. coli in order to complete the biosynthetic pathway from tryptophan to indirubin. Further engineering was performed through rational strategies including disruption of the regulatory repressor gene trpR and removal of feedback inhibitions on AroG and TrpE. Then, combinatorial approach was employed by systematically screening eight genes involved in the common aromatic amino acid pathway. Moreover, availability of the aromatic precursor substrates, phosphoenolpyruvate and erythrose-4-phosphate, was enhanced by inactivating the pykF (pyruvate kinase I) and pykA (pyruvate kinase II) genes, and by overexpressing the tktA gene (encoding transketolase), respectively. Fed-batch fermentation of the final engineered strain led to production of 0.056 g/L of indirubin directly from glucose. The metabolic engineering and synthetic biology strategies reported here thus allows microbial fermentative production of indirubin from glucose.

      PubDate: 2018-01-04T09:19:36Z
      DOI: 10.1016/j.jbiotec.2017.12.026
      Issue No: Vol. 267 (2018)
  • Evaluating the effect of in-process material on the binding mechanisms of
           surrogate viral particles to a multi-modal anion exchange resin
    • Authors: Matthew R. Brown; Michael S. Burnham; Sarah A. Johnson; Scott C. Lute; Kurt A. Brorson; David J. Roush
      Pages: 29 - 35
      Abstract: Publication date: 10 February 2018
      Source:Journal of Biotechnology, Volume 267
      Author(s): Matthew R. Brown, Michael S. Burnham, Sarah A. Johnson, Scott C. Lute, Kurt A. Brorson, David J. Roush
      Bacteriophage binding mechanisms to multi-modal anion exchange resin may include both anion exchange and hydrophobic interactions, or the mechanism can be dominated by a single moiety. However, previous studies have reported binding mechanisms defined for simple solutions containing only buffer and a surrogate viral spike (i.e. bacteriophage ΦX174, PR772, and PP7). We employed phage spiked in-process monoclonal antibody (mAb) pools to model binding under bioprocessing conditions. These experiments allow the individual contributions of the mAb, in-process impurities, and buffer composition on mechanistic removal of phages to be studied. PP7 and PR772 use synergetic binding by the positively charged quaternary amine and the hydrophobic aromatic phenyl group to bind multi-modal resin. ΦX174′s binding mechanism remains inconclusive due to operating conditions.

      PubDate: 2018-01-26T10:30:30Z
      DOI: 10.1016/j.jbiotec.2017.12.018
      Issue No: Vol. 267 (2018)
  • Polyhydroxyalkanoates (PHA) production from phenol in an acclimated
           consortium: Batch study and impacts of operational conditions
    • Authors: Yi Zhang; Apiredan Wusiman; Xiang Liu; Chunli Wan; Duu-Jong Lee; JooHwa Tay
      Pages: 36 - 44
      Abstract: Publication date: 10 February 2018
      Source:Journal of Biotechnology, Volume 267
      Author(s): Yi Zhang, Apiredan Wusiman, Xiang Liu, Chunli Wan, Duu-Jong Lee, JooHwa Tay
      Microbial intracellular biopolymer PHA was synthesized from toxic pollutant phenol by an acclimated consortium. Various operational conditions were experimented for their effects on biomass growth and PHA accumulation. Carbon to nitrogen ratios from 5 to 40 (w/w) showed little impact, as did the levels of Fe, Ca and Mg in a short term. Acidic pH inhibited both growth and PHA synthesis, and an optimal dissolved oxygen level of 1–4 mg L−1 was identified. Low temperature (7 °C) significantly slowed but did not totally repress microbial activities. A 2% NaCl shock retarded reactions and 4% NaCl caused irreversible damage. Various initial phenol (S0) and biomass concentrations (X0) were combined to study the effect of food to microbe (F/M) ratio. High S0 and F/M exerted toxicity, reducing reaction rates but generating higher ultimate PHA wt% in biomass. Increasing X0 alleviated phenol inhibition and improved productivity and carbon conversion from phenol. A pseudo-optimized F/M ratio of 0.2–0.4 and a maximum PHA% rate of 1.15% min−1 were identified under medium S0/high X0. This study is the first to systematically investigate the feasibility of toxic industrial waste as the carbon source for PHA production, and likely the only one indicating potential for scaling-up and industrialization.

      PubDate: 2018-01-26T10:30:30Z
      DOI: 10.1016/j.jbiotec.2018.01.001
      Issue No: Vol. 267 (2018)
  • Complete genome sequence of Streptomyces peucetius ATCC 27952, the
           producer of anticancer anthracyclines and diverse secondary metabolites
    • Authors: Dipesh Dhakal; Si-Kyu Lim; Dae Hee Kim; Byung-Gee Kim; Tokutaro Yamaguchi; Jae Kyung Sohng
      Pages: 50 - 54
      Abstract: Publication date: 10 February 2018
      Source:Journal of Biotechnology, Volume 267
      Author(s): Dipesh Dhakal, Si-Kyu Lim, Dae Hee Kim, Byung-Gee Kim, Tokutaro Yamaguchi, Jae Kyung Sohng
      Streptomyces peucetius ATCC 27952 is a filamentous soil bacterium with potential to produce anthracyclines such as doxorubicin (DXR) and daunorubicin (DNR), which are potent chemotherapeutic agents for the treatment of cancer. Here we present the complete genome sequence of S. peucetius ATCC 27952, which consists of 8,023,114 bp with a linear chromosome, 7187 protein-coding genes, 18 rRNA operons and 66 tRNAs. Bioinformatic analysis of the genome sequence revealed ∼68 putative gene clusters involved in the biosynthesis of secondary metabolites, including diverse classes of natural products. Diverse secondary metabolites of PKS (polyketide synthase) type II (doxorubicin and daunorubicin), NRPS (non-ribosomal peptide synthase) (T1-pks), terpene (hopene) etc. have already been reported for this strain. In addition, in silico analysis suggests the potential to produce diverse compound classes such as lantipeptides, lassopeptides, NRPS and polyketides. Furthermore, many catalytically-efficient enzymes involved in hydroxylation, methylation etc. have been characterized in this strain. The availability of genomic information provides valuable insight for devising rational strategies for the production and isolation of diverse bioactive compounds as well as for the industrial application of efficient enzymes.

      PubDate: 2018-01-14T22:13:04Z
      DOI: 10.1016/j.jbiotec.2017.12.024
      Issue No: Vol. 267 (2018)
  • Administration of co-expressed Penaeus stylirostris densovirus-like
           particles and dsRNA-YHV-Pro provide protection against yellow head virus
           in shrimp
    • Authors: Rapee Sinnuengnong; Pongsopee Attasart; Duncan R. Smith; Sakol Panyim; Wanchai Assavalapsakul
      Pages: 63 - 70
      Abstract: Publication date: 10 February 2018
      Source:Journal of Biotechnology, Volume 267
      Author(s): Rapee Sinnuengnong, Pongsopee Attasart, Duncan R. Smith, Sakol Panyim, Wanchai Assavalapsakul
      The activation of the innate RNA interference pathway through double-stranded RNAs (dsRNAs) is one of the approaches to protecting shrimp from viruses. Previous studies have shown that injection of specific dsRNAs can successfully inhibit viral infection in shrimp. However, inhibition requires high levels of dsRNA and dsRNA stability in shrimp is limited. Virus-like particles (VLPs) have been applied to deliver nucleic acids into host cells because of the protection of dsRNAs from host endonucleases as well as the target specificity provided by VLPs. Therefore, this study aimed to develop Penaeus stylirostris densovirus (PstDNV) VLPs for dsRNA deliver to shrimp. The PstDNV capsid protein was expressed and can be self-assembled to form PstDNV VLPs. Co-expression of dsRNA-YHV-Pro and PstDNV capsid protein was achieved in the same bacterial cells, whose structure was displayed as the aggregation of VLPs by TEM. Tested for their inhibiting yellow head virus (YHV) from infecting shrimp, the dsRNA-YHV-Pro-PstDNV VLPs gave higher levels of YHV suppression and a greater reduction in shrimp mortality than the delivery of naked dsRNA-YHV-Pro. Therefore, PstDNV-VLPs are a promising vehicle for dsRNA delivery that maintains the anti-virus activity of dsRNA in shrimp over a longer period of time as compared to native dsRNAs.

      PubDate: 2018-01-14T22:13:04Z
      DOI: 10.1016/j.jbiotec.2018.01.002
      Issue No: Vol. 267 (2018)
  • Ohmic heating pretreatment of algal slurry for production of biodiesel
    • Authors: Natthawut Yodsuwan; Pitiya Kamonpatana; Yusuf Chisti; Sarote Sirisansaneeyakul
      Pages: 71 - 78
      Abstract: Publication date: 10 February 2018
      Source:Journal of Biotechnology, Volume 267
      Author(s): Natthawut Yodsuwan, Pitiya Kamonpatana, Yusuf Chisti, Sarote Sirisansaneeyakul
      Suspensions of the model microalga Chlorella sp. TISTR 8990 were pretreated by ohmic heating to facilitate release of lipids from the cells in subsequent extraction and lipase-mediated transesterification to biodiesel. After ohmic pretreatment, the moist biomass was suspended in a system of water, hexane, methanol and immobilized lipase for extraction of lipids and simultaneous conversion to biodiesel. The ohmic pretreatment was optimized using an experimental design based on Taguchi method to provide treated biomass that maximized the biodiesel yield in subsequent extraction–transesterification operation. The experimental factors were the frequency of electric current (5–105 Hz), the processing temperature (50–70 °C), the algal biomass concentration in the slurry (algal fresh weight to water mass ratio of 1–3) and the incubation time (1–3 min). Extraction–transesterification of the pretreated biomass was carried out at 40 °C for 24 h using a reaction systems of a fixed composition (i.e. biomass, hexane, methanol, water and immobilized enzyme). Compared to control (i.e. untreated biomass), the ohmic pretreatment under optimal conditions (5 Hz current frequency, 70 °C, 1:2 mass ratio of biomass to water, incubation time of 2-min) increased the rate of subsequent transesterification by nearly 2-fold.

      PubDate: 2018-01-26T10:30:30Z
      DOI: 10.1016/j.jbiotec.2017.12.022
      Issue No: Vol. 267 (2018)
  • Visualisation of intracellular production bottlenecks in
           suspension-adapted CHO cells producing complex biopharmaceuticals using
           fluorescence microscopy
    • Abstract: Publication date: 10 April 2018
      Source:Journal of Biotechnology, Volume 271
      Author(s): Sven Mathias, Simon Fischer, René Handrick, Jürgen Fieder, Patrick Schulz, Harald Bradl, Ingo Gorr, Martin Gamer, Kerstin Otte
      With the advance of complex biological formats such as bispecific antibodies or fusion proteins, mammalian expression systems often show low performance. Described determining factors may be accumulation or haltering of heterologous proteins within the different cellular compartments disturbing transport or secretion. In case of the investigated bispecific antibody (bsAb)-producing Chinese hamster ovary (CHO) cell line neither impaired transcription nor decreased translation processes were identified and thus satisfactorily explained its low production capacity. Hence, we established a streamlined confocal microscopy-based methodology for CHO production cells investigating the distribution of the recombinant protein within the respective organelles of the secretory pathway and visualised the structure of the endoplasmic reticulum (ER) to be affected pinpointing towards an intra-ER bottleneck putatively hampering or limiting efficient secretion. The ER displayed not only a heavily altered morphology in comparison to a high immunoglobulin G (IgG)-producing cell line with a possibly inflated or overloaded structure, but the recombinant protein was also completely absent in the Golgi apparatus. Notably, the results obtained using an automated microscopy approach suggest the possible application of this methodology in cell line development and engineering.
      Graphical abstract image

      PubDate: 2018-03-07T14:09:39Z
  • Enhanced butyric acid production in Clostridium tyrobutyricum by
           overexpression of rate-limiting enzymes in the Embden-Meyerhof-Parnas
    • Abstract: Publication date: Available online 6 March 2018
      Source:Journal of Biotechnology
      Author(s): Yukai Suo, Hongxin Fu, Mengmeng Ren, Zhengping Liao, Yi Ma, Jufang Wang
      Clostridium tyrobutyricum is an excellent microorganism for bio-based butyric acid production. However, the main obstacles for its industrialization are low butyric acid concentration and productivity. This study indicated that overexpression of rate-limiting enzymes in the Embden-Meyerhof-Parnas pathway, including 6-phosphofructokinase (pfkA) and pyruvate kinase (pykA), in C. tyrobutyricum ATCC 25755 could enhance its intracellular NADH and ATP levels and resistance to butyric acid and glucose. The results of fed-batch fermentation by ATCC 25755/pfkA+pykA showed that the butyrate concentration and productivity reached 48.2 g/L and 0.50 g/L·h, which increased 38.1% and 38.9% as compared with the wild-type, respectively. The increased butyric acid tolerance and production could be due to the higher intracellular NADH and ATP levels by overexpression of pfkA and pykA in C. tyrobutyricum ATCC 25755. Furthermore, ATCC 25755/pfkA+pykA exhibited higher glucose tolerance. Consequently, the productivity of butyrate was further increased by 64.0% in batch fermentation using high concentration of glucose (120 g/L).

      PubDate: 2018-03-07T14:09:39Z
  • Degradation of cationic surfactants using immobilized bacteria: its effect
           on adsorption to activated sludge
    • Abstract: Publication date: Available online 5 March 2018
      Source:Journal of Biotechnology
      Author(s): María F. Bergero, Gloria I. Lucchesi
      Adsorption of cationic surfactants (QACs) Br-tetradecyltrimethylammonium (TTAB), Cl-tetradecylbenzyldimethylammonium (C14BDMA) and Cl-hexadecylbenzyldimethylammonium (C16BDMA) to activated sludge from a wastewater treatment plant was tested. Adsorption equilibrium was reached after 2 h, and for initial 200 mg L−1 81%, 90% and 98% of TTAB, C14BDMA and C16BDMA were respectively adsorbed. After six successive desorption cycles, 21% of TTAB and 12.7% of C14BDMA were desorbed from the sludge. In agreement with the percentage of QACs pre-adsorbed, the more hydrophobic the compound, the lesser the extent of desorption. Wastewater samples with activated sludge were supplemented with TTAB 200 mg L-1 and Ca-alginate beads containing the QACs-degrading microorganisms Pseudomonas putida A (ATCC 12633) and Aeromonas hydrophila MFB03. After 24 h, 10 mg L-1 of TTAB were detected in the liquid phase and 6–8 mg L-1 adsorbed to the sludge. Since without Ca-alginate beads or with empty beads total TTAB amount (phase solid and liquid) did not change, the 90% reduction of the initial 200 mg L-1 after treatment with immobilized cells was attributed to the bacterial consortium's capacity to biodegrade QACs. The results show the advantages of using immobilized bacteria to achieve complete QACs elimination from wastewater systems, thus preventing them from reaching the environment.

      PubDate: 2018-03-07T14:09:39Z
  • Sensitive and Specific Detection of Ligands Using Engineered Riboswitches
    • Abstract: Publication date: Available online 5 March 2018
      Source:Journal of Biotechnology
      Author(s): Daniel P. Morse, Colin E. Nevins, Joana Aggrey-Fynn, Rick J. Bravo, Herman O.I. Pfaeffle, Jess E. Laney
      Riboswitches are RNA elements found in non-coding regions of messenger RNAs that regulate gene expression through a ligand-triggered conformational change. Riboswitches typically bind tightly and specifically to their ligands, so they have the potential to serve as highly effective sensors in vitro. In B. subtilis and other gram-positive bacteria, purine nucleotide synthesis is regulated by riboswitches that bind to guanine. We modified the xpt-pbuX guanine riboswitch for use in a fluorescence quenching assay that allowed us to specifically detect and quantify guanine in vitro. Using this assay, we reproducibly detected as little as 5 nM guanine. We then produced sensors for 2’-deoxyguanosine and cyclic diguanylate (c-diGMP) by appending the P1 stem of the guanine riboswitch to the ligand- binding domains of a 2’-deoxyguanosine riboswitch and a c-diGMP riboswitch. These hybrid sensors could detect 15 nM 2’-deoxyguanosine and 3 nM c-diGMP, respectively. Each sensor retained the ligand specificity of its corresponding natural riboswitch. In order to extend the utility of our approach, we developed a strategy for the in vitro selection of sensors with novel ligand specificity. Here we report a proof-of-principle experiment that demonstrated the feasibility of our selection strategy.

      PubDate: 2018-03-07T14:09:39Z
  • Exploring the aglycone subsite of a GH11 xylanase for the synthesis of
           xylosides by transglycosylation reactions
    • Abstract: Publication date: Available online 1 March 2018
      Source:Journal of Biotechnology
      Author(s): C. Brusa, N. Belloy, D. Gérard, M. Muzard, M. Dauchez, R. Plantier-Royon, C. Rémond
      Xylanases Tx-xyn10 and Tx-xyn11 were compared for their transxylosylation abilities in the presence of various acceptors. Tx-xyn10 exhibited a broad specificity for various acceptors, whereas xylanase Tx-xyn11 catalysed transxylosylation reactions only in presence of polyphenolic acceptors. A modelling approach was developed to study the molecular bottlenecks into the active site of the enzyme that could be responsible for this restricted specificity. The glycosyl-enzyme intermediate of Tx-xyn11 was modelled, and a rotamer of the Y78 residue was integrated. In silico mutations of some residues from the (+1) and (+2) subsites were tested for the deglycosylation step in the presence of non-polyphenolic acceptors. The results indicated that the mutant W126A was able to use aliphatic alcohols and benzyl alcohol as acceptors for transxylosylation. Experimental validation was tested by mutating the xylanase Tx-xyn11 at position W126 into alanine. The specific activity and catalytic efficiency of the W126A mutant during the hydrolysis of xylans decreased by 2-fold and 4-fold, respectively, compared to wild-type xylanase. Among tested acceptors, transxylosylation catalysed by mutant W126A was improved with benzyl alcohol leading to a 2-fold higher concentration of benzyl xylobioside, as predicted by in silico mutation. This improved transxylosylation in the presence of benzyl alcohol leading to higher synthesis of benzyl xylobioside could likely be explained by lowest steric hindrance in the aglycone subsite of the mutated xylanase. No secondary hydrolysis of benzyl xylobioside occurred for both wild-type and mutant xylanases. Finally, our results demonstrated that the modelling approach was limited and that accounting for protein dynamics can lead to improved models.

      PubDate: 2018-03-07T14:09:39Z
  • Metabolomic elucidation of the effects of media and carbon sources on
           fatty acid production by Yarrowia lipolytica
    • Abstract: Publication date: Available online 27 February 2018
      Source:Journal of Biotechnology
      Author(s): Eun Ju Yun, James Lee, Do Hyoung Kim, Jungyeon Kim, Sooah Kim, Yong-Su Jin, Kyoung Heon Kim
      Lipid production by oleaginous Yarrowia lipolytica depends highly on culture environments, such as carbon sources, carbon/nitrogen (C/N) ratios, types of media, and cellular growth phases. In this study, the effects of media and carbon sources on lipid and metabolite production were investigated by profiling fatty acids and intracellular metabolites of Y. lipolytica grown in various media. The highest total fatty acid yield 114.04 ± 6.23 mg/g dry cell weight was achieved by Y. lipolytica grown in minimal medium with glycerol (SCG) in the exponential phase. The high lipid production by Y. lipolytica in SCG was presumed to be due to the higher C/N ratio in SCG than in the complex media. Moreover, glycerol promoted lipid production better than glucose in both complex and minimal media because glycerol can easily incorporate into the core of triglycerides. Metabolite profiling revealed that levels of long-chain fatty acids, such as stearic acid, palmitic acid, and arachidic acid, increased in SCG medium. Meanwhile, in complex media supplemented with either glucose or glycerol, levels of amino acids, such as cysteine, methionine, and glycine, highly increased. This metabolomic approach could be applied to modulate the global metabolic network of Y. lipolytica for producing lipids and other valuable products.

      PubDate: 2018-03-07T14:09:39Z
  • Chicken feather peptone: A new alternative nitrogen source for pigment
           production by Monascus purpureus
    • Abstract: Publication date: Available online 21 February 2018
      Source:Journal of Biotechnology
      Author(s): Tugba Orak, Ozge Caglar, Serkan Ortucu, Hakan Ozkan, Mesut Taskin
      Peptones are accepted as one of the most favourable nitrogen sources supporting pigment synthesis in Monascus purpureus. The present study was performed to test the feasibility of chicken feather peptone (CFP) as nitrogen source for pigment production from M. purpureus ATCC16365. CFP was compared with fish peptone (FP) and protease peptone (PP) in order to elucidate its effectiveness on pigment production. CFP was prepared from waste feathers using hydrolysis (KOH) and neutralization (H2SO4) methods. The protein content of CFP was determined as 67.2 g/100 g. Optimal concentrations of CFP and glucose for pigment production were determined as 3 and 20 g/L, respectively. A medium pH of 5.5 and an incubation period of 7-days were found to be more favourable for pigment production. In CFP, PP and FP media, yellow pigment absorbances were 2.819, 2.870 and 2.831, red pigment absorbances were 2.709, 2.304 and 2.748, and orange pigment absorbances were 2.643, 2.132 and 2.743, respectively. Sugar consumption and mycelia growth showed the similar trends in CFP, FP and PP media. This study indicates that the peptone from chicken feathers may be a good nutritional substrate for pigment production from M. purpureus.

      PubDate: 2018-02-26T07:41:04Z
  • An RNA-seq based transcriptomic investigation into the productivity and
           growth variants with Chinese Hamster Ovary cells
    • Abstract: Publication date: Available online 21 February 2018
      Source:Journal of Biotechnology
      Author(s): Sha Sha, Hemlata Bhatia, Seongkyu Yoon
      Chinese hamster ovary (CHO) cells are widely used to produce monoclonal antibodies (mAbs), however, these cell lines can show significant variants associated with productivity and growth. Fundamental understanding of cellular mechanisms can benefit high mAbs production while maintaining robust cell growth. In this study, RNA sequencing (RNA-seq) based approach was used to study the transcriptomic space among three mAb-producing CHO cell lines. A phenotypic contrast of higher productivity but lower growth was found with one cell line versus the other two cell lines. The messenger RNAs from those cells at two different time points in culture were sequenced to seek the gene functions possibly associated with the phenotypic differences. It was found that the mAb transcripts from each cell line were correlated with the mAb production level, indicating a strong determination of production by the expression level of gene of interest (GOI). Further exploration in the global transcriptome showed that the high producers had more expression with genes related with secretion and protein transportation. In the meantime, the slower growth of the high producers was linked to higher regulation to cell growth as well as lower gene expression on biosynthesis, central metabolism and nutrient transport.

      PubDate: 2018-02-26T07:41:04Z
  • Identification of branched-chain amino acid aminotransferases active
           towards (R)-(+)-1-phenylethylamine among PLP fold type IV transaminases
    • Authors: Ekaterina Yu. Bezsudnova; Daria V. Dibrova; Alena Yu. Nikolaeva; Tatiana V. Rakitina; Vladimir O. Popov
      Abstract: Publication date: Available online 14 February 2018
      Source:Journal of Biotechnology
      Author(s): Ekaterina Yu. Bezsudnova, Daria V. Dibrova, Alena Yu. Nikolaeva, Tatiana V. Rakitina, Vladimir O. Popov
      New class IV transaminases with activity towards L-Leu, which is typical of branched-chain amino acid aminotransferases (BCAT), and with activity towards (R)-(+)-1-phenylethylamine ((R)-PEA), which is typical of (R)-selective (R)-amine:pyruvate transaminases, were identified by bioinformatics analysis, obtained in recombinant form, and analyzed. The values of catalytic activities in the reaction with L-Leu and (R)-PEA are comparable to those measured for characteristic transaminases with the corresponding specificity. Earlier, (R)-selective class IV transaminases were found to be active, apart from (R)-PEA, only with some other (R)-primary amines and D-amino acids. Sequences encoding new transaminases with mixed type of activity were found by searching for changes in the conserved motifs of sequences of BCAT by different bioinformatics tools.

      PubDate: 2018-02-15T07:24:06Z
      DOI: 10.1016/j.jbiotec.2018.02.005
  • Magnetic combined cross-linked enzyme aggregates (Combi-CLEAs) for
           cofactor regeneration in the synthesis of chiral alcohol
    • Authors: Erzheng Su; Yang Meng; Chenxi Ning; Xiaoqiang Ma; Senwen Deng
      Abstract: Publication date: Available online 13 February 2018
      Source:Journal of Biotechnology
      Author(s): Erzheng Su, Yang Meng, Chenxi Ning, Xiaoqiang Ma, Senwen Deng
      Magnetic Fe3O4 nanoparticles were prepared and embedded into the Combi-CLEAs to produce the magnetic Combi-CLEAs in this work. The process for magnetic Combi-CLEAs preparation was optimized, and its properties were investigated. The optimum temperature, thermal stability and optimum pH of magnetic Combi-CLEAs were similar to those of Combi-CLEAs. The catalytic performance of magnetic Combi-CLEAs was tested with the biosynthesis of (S)-ethyl 4-chloro-3-hydroxybutyrate ((S)-CHBE). Magnetic Combi-CLEAs could tolerate higher substrate concentration in the biphasic system. The catalytic efficiency and long-term operational stability of magnetic Combi-CLEAs were obviously superior to those of Combi-CLEAs in both aqueous and biphasic systems. Embedding of magnetic Fe3O4 nanoparticles endowing rigidity contributed to these improvements. Furthermore, the preparation of magnetic Combi-CLEAs was easy, and its recovery during multiple batches of reactions could be fulfilled by magnetic field. Aforementioned advantages make the magnetic Combi-CLEAs hold obvious potential for industrial application.

      PubDate: 2018-02-15T07:24:06Z
      DOI: 10.1016/j.jbiotec.2018.02.007
  • Novel antibody-cytokine fusion proteins featuring granulocyte-colony
           stimulating factor, interleukin-3 and interleukin-4 as payloads
    • Authors: Anja Sophie Schmid; Diana Tintor; Dario Neri
      Abstract: Publication date: Available online 10 February 2018
      Source:Journal of Biotechnology
      Author(s): Anja Sophie Schmid, Diana Tintor, Dario Neri
      Neutrophils can strongly influence disease activity in cancer and in chronic inflammation. Here, we report for the first time the construction and characterization of antibody-fusion proteins featuring granulocyte-colony stimulating factor and interleukin-3 as payloads capable of enhancing neutrophil activity and a novel antibody-interleukin-4 fusion protein with neutrophil inhibitory potential. We used the F8 antibody specific to the alternatively-spliced extra domain A (EDA) of fibronectin as a targeting agent, since the cognate antigen is strongly upregulated in diseases characterized by angiogenesis. The fusion proteins GCSF-F8, F8-IL3 and F8-IL4-F8, were cloned, expressed, and their targeting ability assessed, exhibiting preferential tumor uptake with tumor:blood ratios at 24 hours after injection of 3.3, 18.2 and 27.3, respectively. In F9 tumor bearing-mice GCSF-F8 and F8-IL3 did not provide a therapeutic benefit, while F8-IL4-F8 showed a potent tumor growth retardation. In the collagen-induced model of arthritis, GCSF-F8 and F8-IL3 induced a worsening of the disease, while F8-IL4-F8 slowed arthritis progression but, surprisingly, exhibited substantial toxicity when used in combination with dexamethasone. Collectively, the results indicate that the novel fusion proteins could be expressed and efficiently delivered to the site of disease. However, they were not superior to other antibody-cytokine fusions previously described by our laboratory.

      PubDate: 2018-02-15T07:24:06Z
      DOI: 10.1016/j.jbiotec.2018.02.004
  • Construction of a high-efficiency cloning system using the Golden Gate
           method and I-SceI endonuclease for targeted gene replacement in Bacillus
    • Authors: Tiantian Wang; Dongshu Wang; Yufei Lyu; Erling Feng; Zhu Li; Chunjie Liu; Yanchun Wang; Xiankai Liu; Hengliang Wang
      Abstract: Publication date: Available online 10 February 2018
      Source:Journal of Biotechnology
      Author(s): Tiantian Wang, Dongshu Wang, Yufei Lyu, Erling Feng, Zhu Li, Chunjie Liu, Yanchun Wang, Xiankai Liu, Hengliang Wang
      To investigate gene function in Bacillus anthracis, a high-efficiency cloning system is required with an increased rate of allelic exchange. Golden Gate cloning is a molecular cloning strategy allowing researchers to simultaneously and directionally assemble multiple DNA fragments to construct target plasmids using type IIs restriction enzymes and T4 DNA ligase in the same reaction system. Here, a B. anthracis S-layer protein EA1 allelic exchange vector was successfully constructed using the Golden Gate method. No new restriction sites were introduced into this knockout vector, and seamless assembly of the DNA fragments was achieved. To elevate the efficiency of homologous recombination between the allelic exchange vector and chromosomal DNA, we introduced an I-SceI site into the allelic exchange vector. The eag gene was successfully knocked out in B. anthracis using this vector. Simultaneously, the allelic exchange vector construction method was developed into a system for generating B. anthracis allelic exchange vectors. To verify the effectiveness of this system, some other allelic exchange vectors were constructed and gene replacements were performed in B. anthracis. It is speculated that this gene knockout vector construction system and high-efficiency targeted gene replacement using I-SceI endonuclease can be applied to other Bacillus spp.

      PubDate: 2018-02-15T07:24:06Z
      DOI: 10.1016/j.jbiotec.2018.02.006
  • Low-molecular weight keratins with anti-skin aging activity produced by
           anaerobic digestion of poultry feathers with Fervidobacterium islandicum
    • Authors: Inhyuk Yeo; Yong-Jik Lee; Kyeongseop Song; Hyeon-Su Jin; Jae-Eun Lee; Dajeong Kim; Dong-Woo Lee; Nam Joo Kang
      Abstract: Publication date: Available online 10 February 2018
      Source:Journal of Biotechnology
      Author(s): Inhyuk Yeo, Yong-Jik Lee, Kyeongseop Song, Hyeon-Su Jin, Jae-Eun Lee, Dajeong Kim, Dong-Woo Lee, Nam Joo Kang
      Bioactive peptides contribute to various cellular processes including improved skin physiology. Hence, bioactive keratins have attracted considerable attention as active cosmetic ingredients for skin health. Here, we obtained low molecular weight (LMW) keratins from native chicken feathers by anaerobic digestion with an extremely thermophilic bacterium Fervidobacterium islandicum AW-1, followed by stepwise fractionation through ultrafiltration. To assess the effects of the feather keratins on skin health, we performed in vitro and ex vivo assays to investigate their inhibitory effects on matrix metalloproteinases (MMPs). As results, LMW feather keratins marginally inhibited collagenase, elastase, and radical scavenging activities. On the other hand, LMW feather keratins significantly suppressed the expression of ultraviolet B (UVB)-induced MMP-1 and MMP-13 in human dermal fibroblasts. Furthermore, phospho-kinase antibody array revealed that LMW feather keratins suppressed UVB-induced phosphorylation of Akts, c-Jun N-terminal kinases 1, p38 beta, and RSK2, but not ERKs in human dermal fibroblast. Overall, these results suggest that LMW feather keratins are potential candidates as cosmeceutical peptides for anti-skin aging.
      Graphical abstract image

      PubDate: 2018-02-15T07:24:06Z
      DOI: 10.1016/j.jbiotec.2018.02.003
  • Soil metagenome-derived 3-hydroxypalmitic acid methyl ester hydrolases
           suppress extracellular polysaccharide production in Ralstonia solanacearum
    • Authors: Myung Hwan Lee; Raees Khan; Weixin Tao; Kihyuck Choi; Seung Yeup Lee; Jae Wook Lee; Eul Chul Hwang; Seon-Woo Lee
      Abstract: Publication date: Available online 3 February 2018
      Source:Journal of Biotechnology
      Author(s): Myung Hwan Lee, Raees Khan, Weixin Tao, Kihyuck Choi, Seung Yeup Lee, Jae Wook Lee, Eul Chul Hwang, Seon-Woo Lee
      Autoinducers are indispensable for bacterial cell–cell communication. However, due to the reliance on culture-based techniques, few autoinducer-hydrolyzing enzymes are known. In this study, we characterized soil metagenome-derived unique enzymes capable of hydrolyzing 3-hydroxypalmitic acid methyl ester (3-OH PAME), an autoinducer of the plant pathogenic bacterium Ralstonia solanacearum. Among 146 candidate lipolytic clones from a soil metagenome library, 4 unique enzymes capable of hydrolyzing the autoinducer 3-OH PAME, termed ELP86, ELP96, ELP104, and EstDL33, were selected and characterized. Phylogenetic analysis revealed that metagenomic enzymes were novel esterase/lipase candidates as they clustered as novel subfamilies of family I, V, X, and family XI. The purified enzymes displayed various levels of hydrolytic activities towards 3-OH PAME with optimum activity at 40-50°C and pH 7-10. Interestingly, ELP104 also displayed N-(3-oxohexanoyl)-L-homoserine lactone hydrolysis activity. Heterologous expression of the gene encoding 3-OH PAME hydrolase in R. solanacearum significantly decreased exopolysaccharide production without affecting bacterial growth. mRNA transcription analysis revealed that genes regulated by quorum-sensing, such as phcA and xpsR, were significantly down-regulated in the stationary growth phase of R. solanacearum. Therefore, metagenomic enzymes are capable of quorum-quenching by hydrolyzing the autoinducer 3-OH PAME, which could be used as a biocontrol strategy against bacterial wilt.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.023
  • Methane oxidation in industrial biogas plants – insights in a novel
           methanotrophic environment evidenced by pmoA gene analyses and stable
           isotope labelling studies
    • Authors: Tobias May; Daniela Polag; Frank Keppler; Markus Greule; Liane Müller; Helmut König
      Abstract: Publication date: Available online 3 February 2018
      Source:Journal of Biotechnology
      Author(s): Tobias May, Daniela Polag, Frank Keppler, Markus Greule, Liane Müller, Helmut König
      A broad methanotrophic community consisting of 16 different operational taxonomic units (OTUs) was detected by particulate methane monooxygenase A (pmoA) gene analyses of reactor sludge samples obtained from an industrial biogas plant. Using a cloning-sequencing approach, 75% of the OTUs were affiliated to the group of type I methanotrophs (γ-Proteobacteria) and 25 % to type II methanotrophs (α-Proteobacteria) with a distinct predominance of the genus Methylobacter. By database matching, half of the total OTUs may constitute entirely novel species. For evaluation of process conditions that support growth of methanotrophic bacteria, qPCR analyses of pmoA gene copy numbers were performed during a sampling period of 70 days at varying reactor feeding scenarios. During the investigation period, methanotrophic cell counts estimated by qPCR fluctuated between 3.4 × 104 and 2 × 105 cells/mL with no distinct correlation to the organic loading rate, the amount of CH4, O2 and NH4-N. Methanotrophic activity was proofed even at low O2 levels (1 %) by using stable carbon isotope labelling experiments of CH4 in batch experiments inoculated with reactor sludge. Supplementation of 13C labelled CH4 in the headspace of the reaction vials unambiguously confirmed the formation of 13C labelled CO2. Thus, industrial biogas reactors can be considered as a further methanotrophic habitat that exhibits a unique methanotrophic community which is specifically adapted to high CH4 and low O2 concentrations. To the best of our knowledge, our study is the first accurate detection and quantification of methanotrophic bacteria in industrial biogas reactors.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.022
  • Construction of genetically engineered Candida tropicalis for conversion
           of L-arabinose to L-ribulose
    • Authors: In-Seok Yeo; Woo-Yong Shim; Jung Hoe Kim
      Abstract: Publication date: Available online 31 January 2018
      Source:Journal of Biotechnology
      Author(s): In-Seok Yeo, Woo-Yong Shim, Jung Hoe Kim
      For the biological production of L-ribulose, conversion by enzymes or resting cells has been investigated. However, expensive or concentrated substrates, an additional purification step to remove borate and the requirement for cell cultivation and harvest steps before utilization of resting cells make the production process complex and unfavorable. Microbial fermentation may help overcome these limitations. In this study, we constructed a genetically engineered Candida tropicalis strain to produce L-ribulose by fermentation with a glucose/L-arabinose mixture. For the uptake of L-arabinose as a substrate and conversion of L-arabinose to L-ribulose, two heterologous genes coding for L-arabinose transporter and L-arabinose isomerase, were constitutively expressed in C. tropicalis under the GAPDH promoter. The Arabidopsis thaliana-originated L-arabinose transporter gene (STP2)-expressing strain exhibited a high L-arabinose uptake rate of 0.103 g/g cell/h and the expression of L-arabinose isomerase from Lactobacillus sakei 23K showed 30% of conversion (9 g/L) from 30 g/L of L-arabinose. This genetically engineered strain can be used for L-ribulose production by fermentation using mixed sugars of glucose and L-arabinose.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.019
  • Development of a high efficient biocatalyst by oriented covalent
           immobilization of a novel recombinant 2′-N-deoxyribosyltransferase from
           Lactobacillus animalis
    • Authors: Mariana B. Méndez; Cintia W. Rivero; Fernando López-Gallego; José M. Guisán; Jorge A. Trelles
      Abstract: Publication date: Available online 31 January 2018
      Source:Journal of Biotechnology
      Author(s): Mariana B. Méndez, Cintia W. Rivero, Fernando López-Gallego, José M. Guisán, Jorge A. Trelles
      The 2′-N-deoxyribosyltransferases [NDT; EC] are a group of enzymes widely used as biocatalysts for nucleoside biosynthesis. In this work, the molecular cloning, expression and purification of a novel NDT from Lactobacillus animalis (LaNDT) have been reported. On the other hand, biocatalyst stability has been significantly enhanced by multipoint covalent immobilization using a hetero-functional support activated with nickel-chelates and glyoxyl groups. The immobilized enzyme could be reused for more than 300 h and stored during almost 3 months without activity loss. Besides, the obtained derivative (Ni2+-Gx-LaNDT) was able to biosynthesize 88 mg floxuridine/g biocatalyst after 1 h of reaction. In this work, a green bioprocess by employing an environmentally friendly methodology was developed, which allowed the obtaining of a compound with proven anti-tumor activity. Therefore, the obtained enzymatic biocatalyst meets the requirements of high activity, stability, and short reaction times needed for low-cost production in a future preparative application.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.011
  • The construction of recombinant Lactobacillus casei expressing BVDV E2
           protein and its immune response in mice
    • Authors: Anjuman Ara Bhuyan; Atta Muhammad Memon; Ali Akbar Bhuiyan; Li Zhonghua; Bingzhou Zhang; Shiyi Ye; Li Mengying; Qi-Gai He
      Abstract: Publication date: Available online 31 January 2018
      Source:Journal of Biotechnology
      Author(s): Anjuman Ara Bhuyan, Atta Muhammad Memon, Ali Akbar Bhuiyan, Li Zhonghua, Bingzhou Zhang, Shiyi Ye, Li Mengying, Qi-Gai He
      Bovine viral diarrhea virus (BVDV) is the etiological agent of BVD causes substantial economic losses and endemic in world-wide cattle population. Mucosal immunity plays an important role in protection against BVDV infection and Lactobacillus casei is believed as an excellent live vaccine vector for expressing foreign genes. In this study, we have constructed a novel recombinant L. casei/pELX1-E2 strain expressing the most immunogenic E2 antigen of BVDV; using growth phage dependent surface expression system pELX1. The expression of E2 protein was verified by SDS-PAGE, Western blotting, and Immunofluorescence microscopic analysis. The immune responses triggered by the E2 producing recombinant L. casei were evaluated in BALB/c mice revealed that oral and intranasal (IN) administration of the recombinant strain was able to induce a significantly higher level of specific anti-E2 mucosal IgA and serum IgG as well as the greater level of cellular response by IFN-γ and IL-12 than those of intramuscular (IM) and control groups of mice. However, IN inoculation was found the most potent route of immunization. The ability of the recombinant strain to induce serum neutralizing antibody against BVDV and reduced viral load after viral challenge indicated better protection of BVDV infection. Therefore, this recombinant L. casei expressing E2 could be a safe and promising mucosal vaccine candidate against BVD.

      PubDate: 2018-02-05T02:13:06Z
      DOI: 10.1016/j.jbiotec.2018.01.016
  • Aerobic and anaerobic cellulose utilization by Paenibacillus sp. CAA11 and
           enhancement of its cellulolytic ability by expressing a heterologous
    • Authors: Eun Sook Kim; Byeong-Soo Kim; Ki-Yeon Kim; Han-Min Woo; Sun-Mi Lee; Youngsoon Um
      Abstract: Publication date: Available online 12 January 2018
      Source:Journal of Biotechnology
      Author(s): Eun Sook Kim, Byeong-Soo Kim, Ki-Yeon Kim, Han-Min Woo, Sun-Mi Lee, Youngsoon Um
      For cost-effective lignocellulosic biofuel/chemical production, consolidated bioprocessing (CBP)-enabling microorganisms utilizing cellulose as well as producing biofuel/chemical are required. A novel strain Paenibacillus sp. CAA11 isolated from sediment was found to be not only as a cellulose degrader under both aerobic and strict anaerobic conditions but also as a producer of cellulosic biofuel/chemicals. Paenibacillus sp. CAA11 secreted cellulolytic enzymes by its own secretion system and produced ethanol as well as short-chain organic acids (formic acid, acetic acid, lactic acid) from cellulose. Cellulolytic activity of the strain was significantly enhanced by expressing a heterologous endoglucanase 168Cel5 from Bacillus subtilis under both aerobic and anaerobic conditions. The strain harboring the 168cel5 gene revealed 2-fold bigger halo zone on Congo-red plate and 1.75-fold more aerobic cellulose utilization in liquid medium compared with the negative control. Notably, under anaerobic conditions, the recombinant strain expressing 168Cel5 consumed 1.83-fold more cellulose (5.10 g/L) and produced 5-fold more ethanol (0.65 g/L) along with 5-fold more total acids (1.6 g/L) compared with the control, resulting 2.73-fold higher yields. This result demonstrates the potential of Paenibacillus sp. CAA11 as a suitable aerobic and anaerobic CBP-enabling microbe with cellulolytic production of ethanol and short-chain organic acids.

      PubDate: 2018-01-14T22:13:04Z
      DOI: 10.1016/j.jbiotec.2018.01.007
  • Valorization of Brewer’s spent grain to prebiotic oligosaccharide:
           production, xylanase catalyzed hydrolysis, in-vitro evaluation with
           probiotic strains and in a batch human fecal fermentation model
    • Authors: Mursalin Sajib; Peter Falck; Roya R.R. Sardari; Sindhu Mathew; Carl Grey; Eva Nordberg Karlsson; Patrick Adlercreutz
      Abstract: Publication date: Available online 12 January 2018
      Source:Journal of Biotechnology
      Author(s): Mursalin Sajib, Peter Falck, Roya R.R. Sardari, Sindhu Mathew, Carl Grey, Eva Nordberg Karlsson, Patrick Adlercreutz
      Brewer’s spent grain (BSG) accounts for around 85% of the solid by-products from beer production. BSG was first extracted to obtain water-soluble arabinoxylan (AX). Using subsequent alkali extraction (0.5 M KOH) it was possible to dissolve additional AX. In total, about 57% of the AX in BSG was extracted with the purity of 45-55%. After comparison of nine xylanases, Pentopan mono BG, a GH11 enzyme, was selected for hydrolysis of the extracts to oligosaccharides with minimal formation of monosaccharides. Growth of Bifidobacterium adolescentis (ATCC 15703) was promoted by the enzymatic hydrolysis to arabinoxylooligosaccharides, while Lactobacillus brevis (DSMZ 1264) utilized only unsubstituted xylooligosaccharides. Furthermore, utilization of the hydrolysates by human gut microbiota was also assessed in a batch human fecal fermentation model. Results revealed that the rates of fermentation of the BSG hydrolysates by human gut microbiota were similar to that of commercial prebiotic fructooligosaccharides, while inulin was fermented at a slower rate. In summary, a sustainable process to valorize BSG to functional food ingredients has been proposed.

      PubDate: 2018-01-14T22:13:04Z
      DOI: 10.1016/j.jbiotec.2018.01.005
  • Expression, activation and processing of a novel plant milk-clotting
           aspartic protease in Pichia pastoris
    • Authors: Lucía Feijoo-Siota; José Luis R. Rama; Angeles Sánchez-Pérez; Tomás G. Villa
      Abstract: Publication date: Available online 12 January 2018
      Source:Journal of Biotechnology
      Author(s): Lucía Feijoo-Siota, José Luis R. Rama, Angeles Sánchez-Pérez, Tomás G. Villa
      Galium verum, also known as Lady's Bedstraw or Cheese Rennet, is a herbaceous perennial plant traditionally used in cheese-making. We used RACE PCR to isolate novel enzymes from Galium verum with the ability to clot milk. This approach generated two cDNA sequences (named preprogaline A and B) encoding proteins displaying the typical plant aspartic protease primary structure. Preprogaline B was expressed in the yeast Pichia pastoris, after deleting and replacing its original signal peptide with the yeast α-factor signal peptide from Saccharomyces cerevisiae. The secreted recombinant protein was obtained by growing P. pastoris in YPD medium and had the ability to clot milk. The mature form of progaline B is a heterodimeric glycosylated enzyme, with a molecular weight of approximately 48 kDa, that contains a heavy (30.7 kDa) and a light (13.5 kDa) polypeptide chains linked by disulfide bonds. Western blot analysis revealed that progaline B is activated by the acidification of the yeast culture medium and that enzymatic activation requires two steps. First the precursor protein is cleaved into two polypeptide chains by partial removal of the plant-specific insert (PSI) present in plant aspartic proteases; this is later followed by propeptide removal. By altering the pH of the P. pastoris culture medium, we were able to obtain either active or inactive forms of the enzyme. Recombinant progaline B displayed a κ-casein hydrolysis pattern analogous to those produced by the animal and microbial coagulants currently used in the dairy industry, but it exhibited a different digestion profile on α- and β-caseins. The plant protease progaline B displays milk-clotting activities suitable for the production of novel dairy products.

      PubDate: 2018-01-14T22:13:04Z
      DOI: 10.1016/j.jbiotec.2018.01.006
  • Corrigendum to “Novel approaches to microbial enhancement of oil
           recovery” [J. Biotechnol. 266 (2018) 118–123]
    • Authors: Yuriy Kryachko
      Abstract: Publication date: Available online 8 January 2018
      Source:Journal of Biotechnology
      Author(s): Yuriy Kryachko

      PubDate: 2018-01-14T22:13:04Z
      DOI: 10.1016/j.jbiotec.2018.01.003
  • Smelling Pseudomonas aeruginosa infections using a whole-cell biosensor
           − an alternative for the gold-standard culturing assay
    • Authors: Igor Kviatkovsk; Sagit Shushan Yahav Oron Idan Frumin Daniel Amir
      Abstract: Publication date: Available online 29 December 2017
      Source:Journal of Biotechnology
      Author(s): Igor Kviatkovsk, Sagit Shushan, Yahav Oron, Idan Frumin, Daniel Amir, Lavi Secundo, Eitan Livne, Aharon Weissbrod, Noam Sobel, Yael Helman
      Improved easy-to-use diagnostic tools for infections are in strong demand worldwide. Yet, despite dramatic advances in diagnostic technologies, the gold-standard remains culturing. Here we offer an alternative tool demonstrating that a bacterial biosensor can efficiently detect Pseudomonas aeruginosa infections in patients suffering from otitis externa. Detection was based on specific binding between the biosensor and 2-aminoacetophenone (2-AA), a volatile produced by P. aeruginosa in high amounts. We collected pus samples from ears of 26 subjects exhibiting symptoms of otitis externa. Detection of P. aeruginosa using the biosensor was compared to detection using gold-standard culturing assay and to gas-chromatograph-mass-spectrometry (GC-MS) analyses of 2-AA. The biosensor strain test matched the culture assay in 24 samples (92%) and the GC-MS analyses in 25 samples (96%). With this result in hand, we designed a device containing a whole-cell luminescent biosensor combined with a photo-multiplier tube. This device allowed detection of 2-AA at levels as low as 2 nmol, on par with detection level of GC-MS. The results of the described study demonstrate that the volatile 2-AA serves as an effective biomarker for P. aeruginosa in ear infections, and that activation of the biosensor strain by 2-AA provides a unique opportunity to design an easy-to-use device that can specifically detect P. aeruginosa infections.

      PubDate: 2018-01-04T09:19:36Z
  • Isolation, taxonomic analysis, and phenotypic characterization of
           bacterial endophytes present in alfalfa (Medicago sativa) seeds
    • Authors: José Luis López; Florencia Alvarez; Analía Príncipe; María Eugenia Salas; Mauricio Javier Lozano; Walter Omar Draghi; Edgardo Jofré; Antonio Lagares
      Abstract: Publication date: Available online 29 December 2017
      Source:Journal of Biotechnology
      Author(s): José Luis López, Florencia Alvarez, Analía Príncipe, María Eugenia Salas, Mauricio Javier Lozano, Walter Omar Draghi, Edgardo Jofré, Antonio Lagares
      A growing body of evidence has reinforced the central role of microbiomes in the life of sound multicellular eukaryotes, thus more properly described as true holobionts. Though soil was considered a main source of plant microbiomes, seeds have been shown to be endophytically colonized by microorganisms thus representing natural carriers of a selected microbial inoculum to the young seedlings. In this work we have investigated the type of culturable endophytic bacteria that are carried within surface-sterilized alfalfa seeds. MALDI-TOF analysis revealed the presence of bacteria that belonged to 40 separate genera, distributed within four taxa (Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes). Nonsymbiotic members of the Rhizobiaceae family were also found. The evaluation of nine different in-vitro biochemical activities demonstrated isolates with complex combinations of traits that, upon a Principal-Component-Analysis, could be classified into four phenotypic groups. That isolates from nearly half of the genera identified had been able to colonize alfalfa plants grown under axenic conditions was remarkable. Further analyses should be addressed to investigating the colonization mechanisms of the alfalfa seeds, the evolutionary significance of the alfalfa-seed endophytes, and also how after germination the seed microbiome competes with spermospheric and rhizospheric soil bacteria to colonize newly emerging seedlings.

      PubDate: 2018-01-04T09:19:36Z
      DOI: 10.1016/j.jbiotec.2017.12.020
  • Application of CFD in Bioprocessing: Separation of mammalian cells using
           disc stack centrifuge during production of biotherapeutics
    • Authors: Lalita Kanwar Shekhawat; Jayati Sarkar; Rachit Gupta; Sandeep Hadpe; Anurag S Rathore
      Abstract: Publication date: Available online 24 December 2017
      Source:Journal of Biotechnology
      Author(s): Lalita Kanwar Shekhawat, Jayati Sarkar, Rachit Gupta, Sandeep Hadpe, Anurag S Rathore
      Centrifugation continues to be one of the most commonly used unit operations for achieving efficient harvest of the product from the mammalian cell culture broth during production of therapeutic monoclonal antibodies (mAbs). Since the mammalian cells are known to be shear sensitive, optimal performance of the centrifuge requires a balance between productivity and shear. In this study, Computational Fluid Dynamics (CFD) has been successfully used as a tool to facilitate efficient optimization. Multiphase Eulerian-Eulerian model coupled with Gidaspow drag model along with k-ε mixture turbulence model have been used to quantify the complex hydrodynamics of the centrifuge and thus evaluate the turbulent stresses generated by the centrifugal forces. An empirical model has been developed by statistical analysis of experimentally observed cell lysis data as a function of turbulent stresses. An operating window that offers the optimal balance between high productivity, high separation efficiency, and low cell damage has been identified by use of CFD modeling.

      PubDate: 2017-12-24T14:45:26Z
      DOI: 10.1016/j.jbiotec.2017.12.016
  • Assembly of the Lactuca sativa, L. cv. Tizian draft genome sequence
           reveals differences within Major Resistance Complex 1 as compared to the
           cv. Salinas reference genome
    • Authors: Bart Verwaaijen; Daniel Wibberg; Johanna Nelkner; Miriam Gordin; Oliver Rupp; Anika Winkler; Andreas Bremges; Jochen Blom; Rita Grosch; Alfred Pühler; Andreas Schlüter
      Abstract: Publication date: Available online 24 December 2017
      Source:Journal of Biotechnology
      Author(s): Bart Verwaaijen, Daniel Wibberg, Johanna Nelkner, Miriam Gordin, Oliver Rupp, Anika Winkler, Andreas Bremges, Jochen Blom, Rita Grosch, Alfred Pühler, Andreas Schlüter
      Lettuce (Lactuca sativa, L.) is an important annual plant of the family Asteraceae (Compositae). The commercial lettuce cultivar Tizian has been used in various scientific studies investigating the interaction of the plant with phytopathogens or biological control agents. Here, we present the de novo draft genome sequencing and gene prediction for this specific cultivar derived from transcriptome sequence data. The assembled scaffolds amount to a size of 2.22 Gb. Based on RNAseq data, 31,112 transcript isoforms were identified. Functional predictions for these transcripts were determined within the GenDBE annotation platform. Comparison with the cv. Salinas reference genome revealed a high degree of sequence similarity on genome and transcriptome levels, with an average amino acid identity of 99%. Furthermore, it was observed that two large regions are either missing or are highly divergent within the cv. Tizian genome compared to cv. Salinas. One of these regions covers the major resistance complex 1 region of cv. Salinas. The cv. Tizian draft genome sequence provides a valuable resource for future functional and transcriptome analyses focused on this lettuce cultivar.

      PubDate: 2017-12-24T14:45:26Z
      DOI: 10.1016/j.jbiotec.2017.12.021
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