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  Subjects -> BIOLOGY (Total: 3126 journals)
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BIOTECHNOLOGY (236 journals)                  1 2 | Last

Showing 1 - 200 of 239 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 8)
Advanced Biomedical Research     Open Access  
Advances in Bioscience and Biotechnology     Open Access   (Followers: 16)
Advances in Genetic Engineering & Biotechnology     Hybrid Journal   (Followers: 7)
Advances in Regenerative Medicine     Open Access   (Followers: 2)
African Journal of Biotechnology     Open Access   (Followers: 6)
Algal Research     Partially Free   (Followers: 11)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Bioinformatics Research     Open Access   (Followers: 7)
American Journal of Polymer Science     Open Access   (Followers: 32)
Anadolu University Journal of Science and Technology : C Life Sciences and Biotechnology     Open Access  
Animal Biotechnology     Hybrid Journal   (Followers: 8)
Annales des Sciences Agronomiques     Full-text available via subscription  
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 43)
Applied Biosafety     Hybrid Journal  
Applied Food Biotechnology     Open Access   (Followers: 3)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 64)
Applied Mycology and Biotechnology     Full-text available via subscription   (Followers: 4)
Arthroplasty Today     Open Access   (Followers: 1)
Artificial Cells, Nanomedicine and Biotechnology     Hybrid Journal   (Followers: 1)
Asia Pacific Biotech News     Hybrid Journal   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 9)
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: 5)
Beitr?ge zur Tabakforschung International/Contributions to Tobacco Research     Open Access   (Followers: 2)
Bio-Algorithms and Med-Systems     Hybrid Journal   (Followers: 2)
Bio-Research     Full-text available via subscription   (Followers: 3)
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   (Followers: 1)
Biofuels     Hybrid Journal   (Followers: 11)
Biofuels Engineering     Open Access   (Followers: 1)
Biological & Pharmaceutical Bulletin     Full-text available via subscription   (Followers: 4)
Biological Cybernetics     Hybrid Journal   (Followers: 10)
Biomarkers and Genomic Medicine     Open Access   (Followers: 3)
Biomarkers in Drug Development     Partially Free   (Followers: 1)
Biomaterials Research     Open Access   (Followers: 4)
BioMed Research International     Open Access   (Followers: 4)
Biomédica     Open Access  
Biomedical and Biotechnology Research Journal     Open Access  
Biomedical Engineering Research     Open Access   (Followers: 6)
Biomedical Glasses     Open Access  
Biomedical Reports     Full-text available via subscription  
BioMedicine     Open Access  
Biomedika     Open Access  
Bioprinting     Hybrid Journal   (Followers: 1)
Bioresource Technology Reports     Hybrid Journal   (Followers: 1)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 21)
Biosensors Journal     Open Access  
Biosimilars     Open Access   (Followers: 1)
Biosurface and Biotribology     Open Access  
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
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: 4)
Biotechnology Advances     Hybrid Journal   (Followers: 33)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 44)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 153)
Biotechnology and Bioprocess Engineering     Hybrid Journal   (Followers: 5)
Biotechnology and Genetic Engineering Reviews     Hybrid Journal   (Followers: 13)
Biotechnology and Health Sciences     Open Access   (Followers: 1)
Biotechnology and Molecular Biology Reviews     Open Access   (Followers: 2)
Biotechnology Annual Review     Full-text available via subscription   (Followers: 5)
Biotechnology for Biofuels     Open Access   (Followers: 10)
Biotechnology Frontier     Open Access   (Followers: 2)
Biotechnology Journal     Hybrid Journal   (Followers: 16)
Biotechnology Law Report     Hybrid Journal   (Followers: 4)
Biotechnology Letters     Hybrid Journal   (Followers: 34)
Biotechnology Progress     Hybrid Journal   (Followers: 40)
Biotechnology Reports     Open Access  
Biotechnology Research International     Open Access   (Followers: 1)
Biotechnology Techniques     Hybrid Journal   (Followers: 10)
Biotecnología Aplicada     Open Access  
Bioteknologi (Biotechnological Studies)     Open Access  
BIOTIK : Jurnal Ilmiah Biologi Teknologi dan Kependidikan     Open Access  
Biotribology     Hybrid Journal   (Followers: 1)
BMC Biotechnology     Open Access   (Followers: 16)
Cell Biology and Development     Open Access  
Chinese Journal of Agricultural Biotechnology     Full-text available via subscription   (Followers: 4)
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)
Copernican Letters     Open Access   (Followers: 1)
Critical Reviews in Biotechnology     Hybrid Journal   (Followers: 20)
Crop Breeding and Applied Biotechnology     Open Access   (Followers: 3)
Current Bionanotechnology     Hybrid Journal  
Current Biotechnology     Hybrid Journal   (Followers: 4)
Current Opinion in Biomedical Engineering     Hybrid Journal   (Followers: 1)
Current Opinion in Biotechnology     Hybrid Journal   (Followers: 56)
Current Pharmaceutical Biotechnology     Hybrid Journal   (Followers: 9)
Current Research in Bioinformatics     Open Access   (Followers: 12)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 3)
Current trends in Biotechnology and Pharmacy     Open Access   (Followers: 8)
EBioMedicine     Open Access  
Electronic Journal of Biotechnology     Open Access  
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: 9)
Food Science and Biotechnology     Hybrid Journal   (Followers: 8)
Frontiers in Bioengineering and Biotechnology     Open Access   (Followers: 6)
Frontiers in Systems Biology     Open Access   (Followers: 2)
Fungal Biology and Biotechnology     Open Access   (Followers: 2)
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: 2)
Indonesian Journal of Biotechnology     Open Access   (Followers: 1)
Indonesian Journal of Medicine     Open Access  
Industrial Biotechnology     Hybrid Journal   (Followers: 17)
International Biomechanics     Open Access  
International Journal of Bioinformatics Research and Applications     Hybrid Journal   (Followers: 13)
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: 3)
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)
JMIR Biomedical Engineering     Open Access  
Journal of Biometrics & Biostatistics     Open Access   (Followers: 3)
Journal of Bioterrorism & Biodefense     Open Access   (Followers: 6)
Journal of Petroleum & Environmental Biotechnology     Open Access   (Followers: 1)
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: 4)
Journal of Applied Biomedicine     Open Access   (Followers: 2)
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: 64)
Journal of Biotechnology and Strategic Health Research     Open Access  
Journal of Chemical and Biological Interfaces     Full-text available via subscription   (Followers: 1)
Journal of Chemical Technology & Biotechnology     Hybrid Journal   (Followers: 9)
Journal of Chitin and Chitosan Science     Full-text available via subscription   (Followers: 1)
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: 3)
Journal of Essential Oil Research     Hybrid Journal   (Followers: 2)
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: 17)
Journal of Integrative Bioinformatics     Open Access  
Journal of Medical Imaging and Health Informatics     Full-text available via subscription  
Journal of Molecular Biology and Biotechnology     Open Access  
Journal of Molecular Microbiology and Biotechnology     Full-text available via subscription   (Followers: 11)
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: 1)
Journal of Organic and Biomolecular Simulations     Open Access  
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 4)
Journal of Science and Applications : Biomedicine     Open Access  
Journal of the Mechanical Behavior of Biomedical Materials     Hybrid Journal   (Followers: 12)
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: 4)
Meat Technology     Open Access  
Messenger     Full-text available via subscription  
Metabolic Engineering Communications     Open Access   (Followers: 4)
Metalloproteinases In Medicine     Open Access  
Microbial Biotechnology     Open Access   (Followers: 9)
MicroMedicine     Open Access   (Followers: 3)
Molecular and Cellular Biomedical Sciences     Open Access   (Followers: 1)
Molecular Biotechnology     Hybrid Journal   (Followers: 13)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 3)
Nanobiomedicine     Open Access  
Nanobiotechnology     Hybrid Journal   (Followers: 2)
Nanomaterials and Nanotechnology     Open Access  
Nanomedicine and Nanobiology     Full-text available via subscription  
Nanomedicine Research Journal     Open Access  

        1 2 | Last

Journal Cover
Electronic Journal of Biotechnology
Journal Prestige (SJR): 0.537
Citation Impact (citeScore): 2
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Print) 0717-3458
Published by Elsevier Homepage  [3161 journals]
  • Type C feruloyl esterase from Aspergillus ochraceus: A butanol specific
           biocatalyst for the synthesis of hydroxycinnamates in a ternary solvent
           system

    • Abstract: Publication date: Available online 3 July 2018Source: Electronic Journal of BiotechnologyAuthor(s): Evelyn Romero Borbón, Daniel Grajales Hernández, Mariana Armendáriz Ruiz, Lorena Ramírez Velasco, Jorge Alberto Rodríguez-González, Luis Alberto Cira-Chávez, María Isabel Estrada-Alvarado, Juan Carlos Mateos-Díaz BackgroundAspergillus ochraceus was isolated from coffee pulp and selected as an interesting hydroxycinnamoyl esterase strain producer, using an activity microplate high-throughput screening method. In this work, we purified and characterized a new type C A. ochraceus feruloyl esterase (AocFaeC), which synthesized specifically butyl hydroxycinnamates in a ternary solvent system.ResultsAocFaeC was produced by solid state fermentation (SSF), reaching its maximal activity (1.1 U/g) after 48 h of culture. After purification, the monomeric protein (34 kDa) showed a specific activity of 57.9 U/mg towards methyl ferulate. AocFaeC biochemical characterization confirmed its identity as a type C feruloyl esterase and suggested the presence of a catalytic serine in the active site. Its maximum hydrolytic activity was achieved at 40°C and pH 6.5 and increased by 109 and 77% with Ca2 + and Mg2 +, but decreased by 90 and 45% with Hg2 + and Cu2 +, respectively. The initial butyl ferulate synthesis rate increased from 0.8 to 23.7 nmol/min after transesterification condition improvement, using an isooctane:butanol:water ternary solvent system, surprisingly the synthesis activity using other alcohols was negligible. At these conditions, the synthesis specific activities for butyl p-coumarate, sinapinate, ferulate, and caffeate were 87.3, 97.6, 168.2, and 234 U/μmol, respectively. Remarkably, AocFaeC showed 5 folds higher butyl caffeate synthesis rate compared to type B Aspergillus niger feruloyl esterase, a well-known enzyme for its elevated activity towards caffeic acid esters.ConclusionsType C feruloyl esterase from A. ochraceus is a butanol specific biocatalyst for the synthesis of hydroxycinnamates in a ternary solvent system.
       
  • Recombinant production, biochemical and in silico characterization of
           lactate dehydrogenase from Geobacillus thermodenitrificans DSM-465

    • Abstract: Publication date: Available online 3 July 2018Source: Electronic Journal of BiotechnologyAuthor(s): Muhammad Shahid Nadeem, Maryam A. Al-Ghamdi, Jalaluddin Azam Khan, Saida Sadath, Abdulaziz Al-Malki BackgroundLactate Dehydrogenase (LDH) is an enzyme of glycolytic pathway, ubiquitously found in living organisms. Increased glycolysis and LDH activity are associated with many pathogenic conditions including inflammation and cancer, making the enzyme a suitable drug target. Studies on the conserved structural and functional domains of LDH from various species can reveal novel inhibitory molecules. Our study describes, Escherichia coli production and characterization of a moderately thermostable LDH (LDH-GT) from Geobacillus thermodenitrificans DSM-465. In silico 3D model of recombinant enzyme and molecular docking with a set of potential inhibitors are also described.ResultsThe recombinant enzyme was overexpressed in E. coli and purified to electrophoretic homogeneity. The molecular weight of enzyme determined by MALDI-TOF was 34,798.96 Da. It exhibited maximum activity at 65°C and pH 7.5 with KM value for pyruvate as 45 μM. LDH-GT and human LDH-A have only 35.6% identity in the amino acid sequence. Contrary to that, a comparison by in silico structural alignment reveals that LDH-GT monomer has about 80% identity to that of truncated LDH-A. The amino acids ‘GEHGD’ as well as the active site His179 and His193 are conserved. Docking studies have shown the binding free energy changes of potential inhibitors with LDH-A and LDH-GT ranging − 407.11 kJ mole− 1 to − 127.31 kJ mole− 1.ConclusionsHighlighting the conserved structural and functional domains of LDH from two entirely different species, study has graded potential inhibitory molecules on the basis of their binding affinities that can be applied for in vivo anticancer studies.
       
  • JcZFP8, a C2H2 zinc finger protein gene from Jatropha curcas, influences
           plant development in transgenic tobacco

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Xiaodong Shi, Yan Wu, Tingwei Dai, Yuxi Gu, Linghui Wang, Xiaobo Qin, Ying Xu, Fang Chen BackgroundJatropha curcas L., as an important strategic biofuel resource with considerable economic potential, has attracted worldwide attention. However, J. curcas has yet to be domesticated. Plant height, an important agronomic trait of J. curcas, has not been sufficiently improved, and the genetic regulation of this trait in J. curcas is not fully understood. Zinc finger proteins (ZFPs), a class of transcription factors, have previously been shown to play critical roles in regulating multiple aspects of plant growth and development and may accordingly be implicated in the genetic regulation of plant height in J. curcas.ResultsIn this study, we cloned JcZFP8, a C2H2 ZFP gene in J. curcas. We found that the JcZFP8 protein was localized in the nucleus and contained a conserved QALGGH motif in its C2H2 structure. Furthermore, ectopic expression of JcZFP8 under the control of the 35S promoter in transgenic tobacco resulted in dwarf plants with malformed leaves. However, when JcZFP8 was knocked out, the transgenic tobacco did not show the dwarf phenotype. After treatment with the gibberellic acid (GA) biosynthesis inhibitor paclobutrazol (PAC), the dwarf phenotype was more severe than plants that did not receive the PAC treatment, whereas application of exogenous gibberellin3 (GA3) reduced the dwarf phenotype in transgenic plants.ConclusionsThe results of this study indicate that JcZFP8 may play a role in J. curcas plant phenotype through GA-related pathways. Our findings may help us to understand the genetic regulation of plant development in J. curcas and to accelerate breeding progress through engineering of the GA metabolic pathway in this plant.How to cite: Shi X, Wu Y, Dai T, et al. JcZFP8, a C2H2 zinc-finger protein gene from Jatropha curcas, influences plant development in transgenic tobacco. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.05.008.
       
  • Genomic comparisons of Rhizobium species using in silico AFLP-PCR,
           endonuclease restriction, and AMPylating enzymes

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): M. Amjad Qureshi, Muhammad. Tariq Pervez, Masroor Ellahi Babar, Tanveer Hussain, Muhammad Shoaib, Syed Shah Mohammad BackgroundThe whole-genome sequences of nine Rhizobium species were evaluated using different in silico molecular techniques such as AFLP-PCR, restriction digest, and AMPylating enzymes. The entire genome sequences were aligned with progressiveMauve and visualized by reconstructing phylogenetic tree using NTSYS pc 2.11X. The “insilico.ehu.es” was used to carry out in silico AFLP-PCR and in silico restriction digest of the selected genomes. Post-translational modification (PTM) and AMPylating enzyme diversity between the proteome of Rhizobium species were determined by novPTMenzy.ResultsSlight variations were observed in the phylogeny based on AFLP-PCR and PFGE and the tree based on whole genome. Results clearly demonstrated the presence of PTMs, i.e., AMPylation with the GS-ATasE (GlnE), Hydroxylation, Sulfation with their domain, and Deamidation with their specific domains (AMPylating enzymes) GS-ATasE (GlnE), Fic, and Doc (Phosphorylation); Asparagine_hydroxylase and Collagen_prolyl_lysyl_hydroxylase; Sulfotransferase; and CNF (Cytotoxic Necrotizing Factors), respectively. The results pertaining to PTMs are discussed with regard to functional diversities reported in these species.ConclusionsThe phylogenetic tree based on AFLP-PCR was slightly different from restriction endonuclease- and PFGE-based trees. Different PTMs were observed in the Rhizobium species, and the most prevailing type of PTM was AMPylation with the domain GS-ATasE (GlnE). Another type of PTM was also observed, i.e., Hydroxylation and Sulfation, with the domains Asparagine_hydroxylase and Collagen_prolyl_lysyl_hydroxylase and Sulfotransferase, respectively. The deamidation type of PTM was present only in Rhizobium sp. NGR234.How to cite: Qureshi MA, Pervez MT, Babar ME, et al. Genomic comparisons of Rhizobium species using in silico AFLP-PCR, endonuclease restrictions and ampylating enzymes. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.05.006.
       
  • Poly(3-hydroxybutyrate) graft copolymer dense membranes for human
           mesenchymal stem cell growth

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Maykel González-Torres, Roberto Sánchez-Sánchez, Silvia G. Solís-Rosales, Witold Brostow, Eric Reyes-Cervantes, Janet Alejandra Gutiérrez-Uribe, Phaedra Silva-Bermúdez, María de los Angeles Moyaho-Bernal, María Cristina Velasquillo-Martínez BackgroundThe use of novel materials as an artificial extracellular matrix for stem cell growth is a current strategy of increasing interest for regenerative medicine. Here, we prepare thermal-remolded membrane scaffolds from poly(3-hydroxybutyrate) grafted with 2-amino-ethyl methacrylate hydrochloride. However, it is unclear whether these membranes are useful for tissue engineering.ResultsThe mechanical properties, tribology, and morphology of the dense membranes were assessed. The results show that tensile strain at break and roughness of the compressed membrane decrease with increasing graft degree. Moreover, graft copolymer membranes showed lower resistance to scratching, greater degree of swelling and higher brittleness than un-grafted P(3HB) films. Thus, it effectively supports the growth of dermal fibroblast, as demonstrated by epifluorescence microscopy.ConclusionsIt is concluded that the developed membrane can be properly used in is the restoration of skin tissue.How to cite: González-Torres M, Sánchez-Sánchez R, Solís-Rosales SG, et al. Poly(3-hydroxybutyrate) graft copolymer dense membranes for human mesenchymal stem cell growth. Electron J Biotechnol 2018, 34; https://doi.org/10.1016/j.ejbt.2018.05.007.
       
  • Development of a direct transformation method by GFP screening and in
           vitro whole plant regeneration of Capsicum frutescens L.

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Marcus Jenn Yang Chee, Grantley W. Lycett, Chiew Foan Chin BackgroundCapsicum is a genus of an important spice crop that belongs to the chili lineage. However, many Capsicum species (family Solanaceae) are known to be recalcitrant to genetic transformation and in vitro regeneration, thus hampering the effort in using Capsicum species for detailed biological investigation. In this study, we have developed an optimized protocol for the direct transformation of Capsicum frutescens L. cv. Hot Lava using a biolistic particle delivery system. In addition, a procedure for in vitro whole plant regeneration from the hypocotyl explants of C. frutescens was established.ResultsIn this study on the biolistic system, explant target distance, bombardment helium (He) pressure, and the size of the microcarrier were the key parameters to be investigated. The optimized parameters based on the screening of GFP expression were determined to have a target distance of 6 cm, helium pressure of 1350 psi, and gold particle (microcarrier) size of 1.6 μm. The greatest number of shoots was obtained from hypocotyls as explants using Murashige and Skoog medium supplemented with 5.0-mg/L 6-benzylaminopurine and 0.1-mg/L 1-naphthaleneacetic acid. On an average, five shoots per explant were formed, and of them, one shoot managed to form the root and developed into a whole plant.ConclusionsWe obtained an optimized protocol for the biolistic transformation of chili and in vitro regeneration of chili plantlets. The establishment of the protocols will provide a platform for molecular breeding and biological studies of chili plants.How to cite: Chee MYY, Lycett GW, Chin CF. Development of a direct transformation method by GFP screening and in vitro whole plant regeneration of Capsicum frutescens L. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.05.005.
       
  • Effects of all-trans retinoic acid on goat dermal papilla cells
           cultured in vitro

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Sen Ma, Guangxian Zhou, Yulin Chen BackgroundAll-trans retinoic acid (ATRA), a vitamin A-derived active metabolite, exerts important functions in hair biology. Previous studies indicated that excess ATRA hampered hair follicle morphogenesis and cyclic regeneration in adulthood, but other studies stated that ATRA promoted hair growth. Dermal papilla (DP), a cluster of specialized fibroblasts, plays pivotal roles in controlling development and regeneration of hair follicle. Several lines of evidence indicated that DP might be the target cells of ATRA in the hair follicle. To confirm this hypothesis, the present study was performed to explore the biological effects of ATRA on goat dermal papilla cells (DPCs) and clarify the roles of ATRA in hair biology.ResultsOur experimental results indicated that key signaling transducers of ATRA were dynamically expressed in distinct stages of goat cashmere growth cycle, and high-dose ATRA treatment (10-5 M) significantly impaired the viability of goat DPCs and lowered the ratio of proliferating cells. Otherwise, goat DPCs were stimulated to enter apoptosis and their cell cycle progression was severely blocked by ATRA. Moreover, the expression of fibroblast growth factor 7 (Fgf7), one of the potent hair growth stimulators secreted by DPCs, was transcriptionally repressed following ATRA treatment.ConclusionDPCs are the targets of ATRA in the hair follicle, and ATRA negatively regulates hair growth by the targeted suppression of cell viability and growth factor expression of goat DPCs. Through these observations, we offer a new mechanistic insight into the roles of ATRA in hair biology.How to cite: Ma S, Zhou G, Chen Y. Effects of all-trans retinoic acid on goat dermal papilla cells cultured in vitro. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.05.004.
       
  • Cloning and characterisation of four catA genes located on the chromosome
           and large plasmid of Pseudomonas putida ND6

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Shanshan Li, Kun Qin, Huaying Li, Jin Guo, Dejin Li, Fang Liu, Zhilei Tan, Wei Yan, Shuling Qu, Huabing Zhao BackgroundAlthough the functional redundancy of catechol 1,2-dioxygenase (C12O) genes has been reported in several microorganisms, limited enzymes were characterised, let alone the advantage of the coexistence of the multiple copies of C12O genes.ResultsIn this study, four novel C12O genes, designated catA, catAI, catAII and catAIII, in the naphthalene-degrading strain Pseudomonas putida ND6, were cloned and characterised. Phylogenetic analysis of their deduced amino acid sequences revealed that the four C12O isozymes each formed independent subtrees, together with homologues from other organisms. All four enzymes exhibited maximum activity at pH 7.4 and higher activity in alkaline than in acidic conditions. Furthermore, CatA, CatAI and CatAIII were maximally active at a temperature of 45°C, whereas a higher optimum temperature was observed for CatAII at a temperature of 50°C. CatAI exhibited superior temperature stability compared with the other three C12O isozymes, and kinetic analysis indicated similar enzyme activities for CatA, CatAI and CatAII, whereas that of CatAIII was lower. Significantly, among metal ions tested, only Cu2 + substantially inhibited the activity of these C12O isozymes, thus indicating that they have potential to facilitate bioremediation in environments polluted with aromatics in the presence of metals. Moreover, gene expression analysis at the mRNA level and determination of enzyme activity clearly indicated that the redundancy of the catA genes has increased the levels of C12O.ConclusionThe results clearly imply that the redundancy of catA genes increases the available amount of C12O in P. putida ND6, which would be beneficial for survival in challenging environments.How to cite: Li S, Qin K, Li H, et al. Cloning and characterisation of four catA genes located on the chromosome and large plasmid of Pseudomonas putida ND6. Electron J Biotechnol 2018;34.
       
  • Heterologous expression and enhanced production of β-1,4-glucanase of
           Bacillus halodurans C-125 in Escherichia coli

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Nadia Zeeshan, Saher Naz, Shumaila Naz, Amber Afroz, Muzna Zahur, Safia Zia BackgroundRecombinant DNA technology enables us to produce proteins with desired properties and insubstantial amount for industrial applications. Endo-1, 4-β-glucanases (Egl) is one of the major enzyme involved in degradation of cellulose, an important component of plant cell wall. The present study was aimed at enhancing the production of endo-1, 4-β-glucanases (Egl) of Bacillus halodurans in Escherichia coli.ResultsA putative Egl gene of Bacillus Halodurans was expressed in E. coli by cloning in pET 22b (+). On induction with isopropyl-b-d-1-thiogalactopyranoside, the enzyme expression reached upto ~ 20% of the cell protein producing 29.2 mg/liter culture. An increase in cell density to 12 in auto-inducing LB medium (absorbance at 600 nm) enhanced β-glucanase production up to 5.4 fold. The molecular mass of the enzyme was determined to be 39 KDa, which is nearly the same as the calculated value. Protein sequence was analyzed by CDD, Pfam, I TASSER, COACH, PROCHECK Servers and putative amino acids involved in the formation of catalytic, substrate and metal binding domains were identified. Phylogenetic analysis of the β-glucanases of B. halodurans was performed and position of Egl among other members of the genus Bacillus producing endo-glucanases was determined. Temperature and pH optima of the enzyme were found to be 60°C and 8.0, respectively, under the assay conditions.ConclusionProduction of endo-1, 4 β-glucanase enzymes from B. halodurans increased several folds when cloned in pET vector and expressed in E. coli. To our knowledge, this is the first report of high-level expression and characterization of an endo-1, 4 β-glucanases from B. halodurans.How to cite: Zeeshan N, Naz S, Naz S et al. Heterologous expression and enhanced production of β-1,4-glucanase of Bacillus halodurans C-125 in E. coli. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.05.001.
       
  • Comparison of the phenolic contents and epigenetic and genetic variability
           of wild and cultivated watercress (Rorippa nasturtium var. aquaticum L.)

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Marcela Verónica Gutiérrez-Velázquez, Norma Almaraz-Abarca, Yolanda Herrera-Arrieta, José Antonio Ávila-Reyes, Laura Silvia González-Valdez, Rene Torres-Ricario, José Natividad Uribe-Soto, Hugo Manuel Monreal-García BackgroundEpigenetic modifications are key factors modulating the expression of genes involved in the synthesis of phytochemicals. The knowledge of plant epigenetic and genetic variations can contribute to enhance the production of bioactive compounds. These issues have been little explored thus far in Rorippa nasturtium var. aquaticum L. (watercress), an edible and medicinal plant. The aim of the current study was to determine and compare the phenolic composition and epigenetic and genetic variations between wild and cultivated watercress.ResultsSignificant differences were found in the quantitative phenolic composition between wild and cultivated watercress. The eight primer combinations used in the methylation-sensitive amplification polymorphism (MSAP) method revealed different epigenetic status for each watercress type, the cultivated one being the most epigenetically variable. The genetic variability revealed by the EcoRI/MspI amplification profile and also by eight inter-simple sequence repeat (ISSR) primers was different between the two types of watercress. The results of the Mantel test showed that the correlation between genetic and epigenetic variations has diminished in the cultivated type. Cluster analyses showed that the epigenetic and genetic characterizations clearly discriminated between wild and cultivated watercress.ConclusionsRelevant chemical, epigenetic, and genetic differences have emerged between wild and cultivated watercress. These differences can contribute to fingerprint and develop quality control tools for the integral and safety use and the commercialization of watercress. The richness of epialleles could support the development of tools to manipulate the watercress epigenome to develop high bioproduct–producing cultivars.How to cite: Gutiérrez-Velázquez MV, Almaraz-Abarca N, Herrera-Arrieta Y, et al. Comparison of the phenolic contents and the epigenetic and genetic variability of wild and cultivated watercress (Rorippa nasturtium var. aquaticum L.). Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.04.005.
       
  • Kinetic modeling of the simultaneous production of ethanol and fructose by
           Saccharomyces cerevisiae

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Ashraf K. Sulieman, Meilana Dharma Putra, Ahmed E. Abasaeed, Mohamed H. Gaily, Saeed M. Al-Zahrani, Mohamed A. Zeinelabdeen BackgroundEthanol and fructose are two important industrial products that enjoy many uses. In this contribution, their production via selective fermentation of date extract using Saccharomyces cerevisiae was studied. Scaling up the process for possible commercialization was investigated in three fermentors with working volume ratio of 1:40:400.ResultsHigher ethanol concentration was obtained in the larger fermentor due to conversion of fructose. Fructose yields in the 0.5-L, 7.5-L and 80-L fermentors were 99, 92 and 90%, respectively. Good fitting was obtained with the modified Monod kinetics; however, a better fit of cell mass was obtained with the modified Ghose–Tyagi model which accounts for ethanol inhibition.ConclusionsThe modified Gompertz model was expanded to facilitate prediction of products' formation and fructose fractions in all three fermentors. Such expansion will be beneficial in industrial applications.How to cite: Sulieman AK, Putra MD, Abasaeed AE, et al. Kinetic modeling of the simultaneous production of ethanol and fructose by Saccharomyces cerevisiae. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.04.006.
       
  • The genetic diversity of wild and cultivated Manila clam (Ruditapes
           philippinarum) revealed by 29 novel microsatellite markers

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Liwen Jiang, Hongtao Nie, Chen Li, Dongdong Li, Zhongming Huo, Xiwu Yan BackgroundMicrosatellite loci often used as a genetic tool for estimating genetic diversity population variation in a wide variety of different species. The application of microsatellite markers in genetics and breeding includes investigating the genetic differentiation of wild and cultured populations, assessing and determining the genetic relationship of different populations. The aim of this work is to develop several microsatellite markers via high-throughput sequencing and characterize these markers in commercially important bivalve Ruditapes philippinarum.ResultsAmong the two populations of R. philippinarum studied, 110 alleles were detected. The number of alleles at the cultured population ranged from 3 to 17 (mean NA = 6.897) and wild population ranged from 2 to 15 (mean NA = 6.793). The observed and expected heterozygosities of cultured population ranged from 0.182 to 0.964, and from 0.286 to 0.900, with an average of 0.647 and 0.692, respectively. The observed and expected heterozygosities of wild population ranged from 0.138 to 1.000, and from 0.439 to 0.906, with an average of 0.674 and 0.693, respectively. The polymorphism information content ranged from 0.341 to 0.910 with an average of 0.687. Sixteen and thirteen microsatellite loci deviated significantly from Hardy–Weinberg equilibrium after correction for multiple tests in cultured and wild population, respectively.ConclusionsTwenty-nine novel microsatellite loci were developed using Illumina paired-end shotgun sequencing and characterized in two population of R. philippinarum.How to cite: Jiang L, Nie H, Li C, et al. The genetic diversity of wild and cultivated Manila clam (Ruditapes philippinarum) revealed by 29 novel microsatellite markers. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.05.003.
       
  • Melanoma transplants in “green” mice: Fluorescent cells in tumors are
           not equivalent to host-derived cells

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Dolores C. García-Olmo, María G. Picazo, Damián García-Olmo BackgroundTo examine the usefulness of green fluorescent protein (GFP) mice for studying the interactions between normal cells and tumor cells in a host, we used a melanoma model in such “green” mice [C57BL/6-Tg(CAG-EGFP)1Osb mice]. Mice were given a subcutaneous injection of B16-F10 cells, and the resultant primary tumors were removed. Then cells from individual tumors were cultured.ResultsThe proportion of EFGP + cells was determined by fluorescence-activated cell sorting (FACS) and was 6.8% ± 3.2% (mean ± s.d.) on day 1 of culture, 0.6% ± 0.3% on day 2, and 0.02% ± 0.01% at day 7. In all cases, isolated cells grew at a constant rate, but fluorescence decreased over time and became undetectable on day 14. Cells were tested using PCR for the presence of an EGFP-specific sequence, and results were negative in all cases, thus indicating that the cells did not harbor the host's reporter gene. Cells were also tested for the presence of EGFP mRNA, which was consistently detected for 22 days after the start of culture. The tumorogenicity of the cultured cells was confirmed in GFP mice injected with cells from a selection of cultures.ConclusionsIn a melanoma model in GFP mice, the detection of “green” cells in tumors was not equivalent to the detection of host-derived cells. Such “masking” was caused by a transient, but lasting, transfer of EGFP mRNA from the host's normal cells to tumor cells. Thus, an analysis of tumors postmortem by techniques that yield only a single snapshot can lead to incorrect interpretations and erroneous conclusions.How to cite: Garcia-Olmo D, Picazo MG, García-Olmo D. Melanoma transplants in “green” mice: fluorescent cells in tumors are not equivalent to host-derived cells. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.04.007.
       
  • Hydrolytic efficiency and isomerization during de-esterification of
           natural astaxanthin esters by saponification and enzymolysis

    • Abstract: Publication date: July 2018Source: Electronic Journal of Biotechnology, Volume 34Author(s): Fang Su, Huarong Xu, Na Yang, Wei Liu, Jianguo Liu BackgroundAstaxanthin from natural sources is typically esterified with fatty acids; hence, it must be hydrolyzed to remove esters before identification and quantification by conventional HPLC. Alkaline-catalyzed saponification and enzyme-catalyzed enzymolysis are the most commonly used de-esterification methods. However, information on the efficiency and isomerization during de-esterification of natural astaxanthin esters by these two methods remains scarce. Therefore, we conducted two HPLC-based experiments to determine which method is better for hydrolyzing astaxanthin esters.ResultsTo assess the effect of enzymolysis (0.67 U/mL cholesterol esterase, at 37°C) and saponification (0.021 M NaOH, at 5°C) conditions on free astaxanthin recovery and destruction or structural transformation of astaxanthin, we varied the total treatment time across a range of 195 min. The results showed that enzymolysis and saponification were complete in 60 min and 90 min, respectively. After complete hydrolysis, the maximum free astaxanthin recovery obtained by enzymolysis was 42.6% more than that obtained by saponification. The identification of by-products, semi-astacene and astacene, during the process of saponification also indicated that a more severe degradation of astaxanthin occurred during saponification. Moreover, the composition of astaxanthin isomers during saponification was similar to that of the isomers during enzymolysis between 30 min and 75 min (all-trans:9-cis:13-cis = 21:3:1, approximately) but dramatically changed after 90 min, whereas the composition in the enzymolysis treatment remained relatively stable throughout.ConclusionCompared with saponification, enzymolysis with cholesterol esterase was recommended as a more accurate method for de-esterification of natural astaxanthin esters for further qualitative and quantitative HPLC analysis.How to cite: Su F, Xu H, Yang N, et al. Hydrolytic efficiency and isomerization during the process of de-esterifying natural astaxanthin esters using saponification and enzymolysis. Electron J Biotechnol 2018;34. https://doi.org/10.1016/j.ejbt.2018.05.002.
       
  • Alanine mother liquor as a nitrogen source for docosahexaenoic acid
           production by Schizochytrium sp. B4D1

    • Abstract: Publication date: Available online 30 June 2018Source: Electronic Journal of BiotechnologyAuthor(s): Jian Xu, Yujing Zhu, Hanchen Li, Limei Chen, Wuxi Chen, Min Cui, Lina Han, Wenbo Hou, Demao Li Alanine mother liquor, a type of industrial waste from alanine fermentation, was used as a nitrogen source to produce docosahexaenoic acid (DHA) by Schizochytrium sp. B4D1. The results indicated that yeast extract could trigger the utilization of the alanine mother liquor. Additionally, the alanine can be quenched during the culture, which aids in DHA accumulation. The medium components were optimized via response surface methodology as follows: 99.98 g/L glucose, 0.05 g/L yeast extract and a 183.17 dilution factor of the alanine mother liquid (v/v, with an alanine content of 0.72 g/L) and 17.98% inoculum concentration (v/v). Finally, in a 50 mL shake-flask fermentation, the DHA yield was 2.29 g/L.
       
  • Biofiltration of trimethylamine in biotrickling filter inoculated with
           Aminobacter aminovorans

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Alberto Aguirre, Pamela Bernal, Daniela Maureira, Nicolás Ramos, Javier Vásquez, Homero Urrutia, Juan Carlos Gentina, Germán Aroca BackgroundTrimethylamine (TMA) is the main responsible for the odor associated with rotting fish and other annoying odors generated in many industrial activities. Biofiltration has proved to be efficient for treating odorous gaseous emissions. The main objective of this work was to determine the removal capacity of TMA of a biotrickling filter inoculated with Aminobacter aminovorans and to evaluate the effect of H2S on its performance.ResultsThe maximum specific growth rate of A. aminovorans in a liquid culture was 0.15 h-1, with a TMA to biomass yield of 0.10 (g g-1) and a specific consumption rate of 0.062 g·g-1·h-1. The initial specific consumption rate of TMA was highly influenced by the presence of H2S in liquid culture at concentrations of 20 and 69 ppm in heading space of the flasks. A BTF inoculated with A. aminovorans showed removal efficiencies higher than 98% in a range of loading rate of 0.2 to 8 g·m-3·h-1 at empty bed residence time (EBRT) of 85 and 180 s. No effect on the elimination capacity and efficiency was detected when H2S was added at 20 and 50 ppm to the inlet gaseous emission, though the fraction of A. aminovorans measured by qPCR in the biofilm decreased.ConclusionsA biotrickling filter inoculated with A. aminovorans can remove efficiently the TMA in a gaseous stream. The elimination capacity of TMA can be negatively affected by H2S, but its effect is not notorious when it is forming part of a biofilm, due to its high specific consumption rate of TMA.How to cite: Aguirre A, Bernal P, Maureira D, et al. Biofiltration of trimethylamine in biotrickling filter inoculated with Aminobacter aminovorans. Electron J Biotechnol 2018;33. https://doi.org/10.1016/j.ejbt.2018.04.004.
       
  • l-tryptophan+broth+by+vacuum+thin+film+evaporation+during+l-tryptophan+production&rft.title=Electronic+Journal+of+Biotechnology&rft.issn=0717-3458&rft.date=&rft.volume=">Removing the by-products acetic acid and NH4 + from the l-tryptophan broth
           by vacuum thin film evaporation during l-tryptophan production

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Qingyang Xu, Fang Bai, Ning Chen, Gang Bai BackgroundDuring l-tryptophan production by Escherichia coli, the by-products, acetic acid and NH4+, accumulate in the fermentation broth, resulting in inhibited cell growth and activity and decreased l-tryptophan production. To improve the l-tryptophan yield and glucose conversion rate, acetic acid and NH4+ were removed under low-temperature vacuum conditions by vacuum scraper concentrator evaporation; the fermentation broth after evaporation was pressed into another fermenter to continue fermentation. To increase the volatilisation rate of acetic acid and NH4+ and reduce damage to bacteria during evaporation, different vacuum evaporation conditions were studied.ResultsThe optimum operating conditions were as follows: vacuum degree, 720 mm Hg; concentration ratio, 10%; temperature, 60°C; and feeding rate, 300 mL/min. The biomass yield of the control fermentation (CF) and fermentation by vacuum evaporation (VEF) broths was 55.1 g/L and 58.3 g/L at 38 h, respectively, (an increase of 5.8%); the living biomass yield increased from 8.9 (CF) to 10.2 pF (VEF; an increase of 14.6%). l-tryptophan production increased from 50.2 g/L (CF) to 60.2 g/L (VEF) (an increase of 19.9%), and glucose conversion increased from 18.2% (CF) to 19.5% (VEF; an increase of 7.1%). The acetic acid concentrations were 2.74 g/L and 6.70 g/L, and the NH4+ concentrations were 85.3 mmol/L and 130.9 mmol/L in VEF and CF broths, respectively.ConclusionsThe acetic acid and NH4+ in the fermentation broth were quickly removed using the vacuum scraper concentrator, which reduced bacterial inhibition, enhanced bacterial activity, and improved the production of l-tryptophan and glucose conversion rate.How to cite: Xu Q, Bai F, Chen N, et al. Removing the by-products acetic acid and NH4+ from the l-tryptophan broth by vacuum thin film evaporation during l-tryptophan production. Electron J Biotechnol 2018; 33. https://doi.org/10.1016/j.ejbt.2018.04.003.
       
  • Agroindustrial biomass for xylanase production by Penicillium chrysogenum:
           Purification, biochemical properties and hydrolysis of hemicelluloses

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Cárol Cabral Terrone, Caroline de Freitas, César Rafael Fanchini Terrasan, Alex Fernando de Almeida, Eleonora Cano Carmona BackgroundIn this work, the xylanase production by Penicillium chrysogenum F-15 strain was investigated using agroindustrial biomass as substrate. The xylanase was purified, characterized and applied in hemicellulose hydrolysis.ResultsThe highest xylanase production was obtained when cultivation was carried out with sugar cane bagasse as carbon source, at pH 6.0 and 20°C, under static condition for 8 d. The enzyme was purified by a sequence of ion exchange and size exclusion chromatography, presenting final specific activity of 834.2 U·mg·prot-1. The molecular mass of the purified enzyme estimated by SDS-PAGE was 22.1 kDa. The optimum activity was at pH 6.5 and 45°C. The enzyme was stable at 40°C with half-life of 35 min, and in the pH range from 4.5 to 10.0. The activity was increased in the presence of Mg+2 and Mn+ 2 and reducing agents such as DTT and β-mercaptoethanol, but it was reduced by Cu+2 and Pb+2. The xylanase presented Km of 2.3 mM and Vmax of 731.8 U·mg·prot-1 with birchwood xylan as substrate. This xylanase presented differences in its properties when it was compared to the xylanases from other P. chrysogenum strains.ConclusionThe xylanase from P. chrysogenum F-15 showed lower enzymatic activity on commercial xylan than on hemicellulose from agroindustry biomass and its biochemistry characteristics, such as stability at 40°C and pH from 4.0 to 10.0, shows the potential of this enzyme for application in food, feed, pulp and paper industries and for bioethanol production.How to cite: Terrone CC, Freitas C, Terrasan CRF, et al. Agroindustrial biomass for xylanase production by Penicillium chrysogenum: purification, biochemical properties and hydrolysis of hemicelluloses. Electron J Biotechnol 2018;33. https://doi.org/10.1016/j.ejbt.2018.04.001.
       
  • Scaling-up fermentation of Escherichia coli for production of recombinant
           P64k protein from Neisseria meningitidis

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Raúl Espinosa Pérez, José García Suárez, Emilio Narciandi Diaz, Ricardo Silva Rodríguez, Evelin Caballero Menéndez, Héctor Díaz Balaguer, Alexis Musacchio Lasa BackgroundP64k is a Neisseria meningitidis high molecular weight protein present in meningococcal vaccine preparations. The lpdA gene, which encodes for this protein, was cloned in Escherichia coli and the P64k recombinant protein was expressed in E. coli K12 GC366 cells under the control of a tryptophan promoter. P64k was expressed as an intracellular soluble protein about 28% of the total cellular protein. Several scale-up criteria of fermentation processes were studied to obtain the recombinant P64k protein at the pilot production scale.ResultsThe best operational conditions at a larger scale production of P64k recombinant protein were studied and compared using the four following criteria: Constant Reynold's number (Re constant), Constant impeller tip speed (n di constant), Constant power consumption per unit liquid volume (P/V constant) and Constant volumetric oxygen transfer coefficients (KLa/k constant). The highest production of the recombinant protein was achieved based on the constant KLa/k scale-up fermentation criterion, calculating the aeration rate (Q) and the impeller agitation speed (n) by iterative process, keeping constant the KLa/k value from bench scale. The P64k protein total production at the 50 l culture scale was 546 mg l-1 in comparison with the 284 mg l-1 obtained at 1.5 l bench scale.ConclusionsThe methodology described herein, for the KLa/k scale-up fermentation criterion, allowed us to obtain the P64k protein at 50 l scale. A fermentation process for the production of P64k protein from N. meningitidis was established, a protein to be used in future vaccine formulations in humans.How to cite: Espinosa R, García J, Narciandi E, et al. Scaling-up fermentation of Escherichia coli for production of recombinant P64k protein from Neisseria meningitidis. Electron J Biotechnol 2018;33. https://doi.org/10.1016/j.ejbt.2018.03.004.
       
  • Increasing pinosylvin production in Escherichia coli by reducing the
           expression level of the gene fabI-encoded enoyl-acyl carrier protein
           reductase

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Caheri Salas-Navarrete, Georgina Hernández-Chávez, Noemí Flores, Luz María Martínez, Alfredo Martinez, Francisco Bolívar, Francisco Barona-Gomez, Guillermo Gosset BackgroundThe plant secondary metabolite pinosylvin is a polyphenol from the stilbene family, which have positive effects on human health. Biotechnological production is an attractive alternative for obtaining this stilbene. In Escherichia coli, malonyl-CoA is the precursor for both stilbene and fatty acid syntheses. In this study, with the aim of increasing pinosylvin production, we evaluated a novel approach that is based on reducing the expression of the gene fabI, which encodes the enzyme enoyl-acyl carrier protein reductase that is involved in fatty acid synthesis.ResultsA recombineering method was employed to eliminate the chromosomal -35 promoter sequence and the upstream region of the gene fabI in E. coli strain W3110. Analysis, employing RT-qPCR, showed that such modification caused a 60% reduction in the fabI transcript level in the mutant strain W3110Δ-35fabI::Cm compared to the wild type W3110. Synthetic genes encoding a mutant version of 4-coumaroyl-CoA ligase from Streptomyces coelicolor A3 with improved catalytic activity employing cinnamic acid as substrate and a stilbene synthase from Vitis vinifera were cloned to generate the plasmid pTrc-Sc4CL(M)-VvSTS. The production performance of strains W3110Δ-35fabI::Cm/pTrc-Sc4CL(M)-VvSTS and W3110/pTrc-Sc4CL(M)-VvSTS was determined in shake flask cultures with Luria-Bertani medium supplemented with 10 g/L glycerol and 3 mM cinnamic acid. Under these conditions, the strain W3110Δ-35fabI::Cm/pTrc-Sc4CL(M)-VvSTS produced 52.67 mg/L pinosylvin, a level 1.5-fold higher than that observed with W3110/pTrc-Sc4CL(M)-VvSTS.ConclusionA reduction in the transcript level of fabI caused by the elimination of the -35 and upstream promoter sequences is a successful strategy to improve pinosylvin production in E. coli.How to cite: Salas-Navarrete, C., Hernández-Chávez, G., Flores, N., et al. Increasing pinosylvin production in Escherichia coli by reducing expression level of gene fabI-encoded enoyl-acyl carrier protein reductase. Electron J Biotechnol 2018;33. https://doi.org/10.1016/j.ejbt.2018.03.001.
       
  • Inhibition of Nitzschia ovalis biofilm settlement by a bacterial bioactive
           compound through alteration of EPS and epiphytic bacteria

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Claudia D. Infante, Francisca Castillo, Vilma Pérez, Carlos Riquelme BackgroundMarine ecosystems contain benthic microalgae and bacterial species that are capable of secreting extracellular polymeric substances (EPS), suggesting that settlement of these microorganisms can occur on submerged surfaces, a key part of the first stage of biofouling. Currently, anti-fouling treatments that help control this phenomenon involve the use of biocides or antifouling paints that contain heavy metals, which over a long period of exposure can spread to the environment. The bacterium Alteromonas sp. Ni1-LEM has an inhibitory effect on the adhesion of Nitzschia ovalis, an abundant diatom found on submerged surfaces.ResultsWe evaluated the effect of the bioactive compound secreted by this bacterium on the EPS of biofilms and associated epiphytic bacteria. Three methods of EPS extraction were evaluated to determine the most appropriate and efficient methodology based on the presence of soluble EPS and the total protein and carbohydrate concentrations. Microalgae were cultured with the bacterial compound to evaluate its effect on EPS secretion and variations in its protein and carbohydrate concentrations. An effect of the bacterial supernatant on EPS was observed by assessing biofilm formation and changes in the concentration of proteins and carbohydrates present in the biofilm.ConclusionsThese results indicate that a possible mechanism for regulating biofouling could be through alteration of biofilm EPS and alteration of the epiphytic bacterial community associated with the microalga.How to cite: Infante, C.D., Castillo, F., Pérez, V., et al. Inhibition of Nitzschia ovalis biofilm settlement by a bacterial bioactive compound through alteration of EPS and epiphytic bacteria. Electron J Biotechnol 2018;33 https://doi.org/10.1016/j.ejbt.2018.03.002.
       
  • Draft genomes and reference transcriptomes extend the coding potential of
           the fish pathogen Piscirickettsia salmonis

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Angela D. Millar, Paz Tapia, Fernando A. Gómez, Sergio H. Marshall, Derie E. Fuentes, Jorge H. Valdes BackgroundDraft and complete genome sequences from bacteria are key tools to understand genetic determinants involved in pathogenesis in several disease models. Piscirickettsia salmonis is a Gram-negative bacterium responsible for the Salmon Rickettsial Syndrome (SRS), a bacterial disease that threatens the sustainability of the Chilean salmon industry. In previous reports, complete and draft genome sequences have been generated and annotated. However, the lack of transcriptome data underestimates the genetic potential, does not provide information about transcriptional units and contributes to disseminate annotation errors.ResultsHere we present the draft genome and transcriptome sequences of four P. salmonis strains. We have identified the transcriptional architecture of previously characterized virulence factors and trait-specific genes associated to cation uptake, metal efflux, antibiotic resistance, secretion systems and other virulence factors.ConclusionsThis data has provided a refined genome annotation and also new insights on the transcriptional structures and coding potential of this fish pathogen.How to cite: Millar AD, Tapia P, Gomez FA, et al. Draft genomes and reference transcriptomes extend the coding potential of the fish pathogen Piscirickettsia salmonis. Electron J Biotechnol 2018;33. https://doi.org/10.1016/j.ejbt.2018.04.002.
       
  • Methods for the genetic manipulation of marine bacteria

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Zahraa Zeaiter, Francesca Mapelli, Elena Crotti, Sara Borin Genetic manipulation of bacteria is a procedure necessary to obtain new strains that express peculiar and defined genetic determinants or to introduce genetic variants responsible for phenotypic modifications. This procedure can be applied to explore the biotechnological potential associated with environmental bacteria and to utilize the functional properties of specific genes when inserted into an appropriate host. In the past years, marine bacteria have received increasing attention because they represent a fascinating reservoir of genetic and functional diversity that can be utilized to fuel the bioeconomy sector. However, there is an urgent need for an in-depth investigation and improvement of the genetic manipulation tools applicable to marine strains because of the paucity of knowledge regarding this. This review aims to describe the genetic manipulation methods hitherto used in marine bacteria, thus highlighting the limiting factors of the different techniques available today to increase manipulation efficiency. In particular, we focus on methods of natural and artificial transformations (especially electroporation) and conjugation because they have been successfully applied to several marine strains. Finally, we emphasize that, to avoid failure, future work should be carried out to establish tailored methodologies for marine bacteria.How to cite: Zeaiter Z, Mapelli F, Crotti E, et al. Methods for the genetic manipulation of marine bacteria. Electron J Biotechnol 2018;33. https://doi.org/10.1016/j.ejbt.2018.03.003.
       
  • Evaluation of biogas and syngas as energy vectors for heat and power
           generation using lignocellulosic biomass as raw material

    • Abstract: Publication date: May 2018Source: Electronic Journal of Biotechnology, Volume 33Author(s): Juan Camilo Solarte-Toro, Yessica Chacón-Pérez, Carlos Ariel Cardona-Alzate The use of nonrenewable energy sources to provide the worldwide energy needs has caused different problems such as global warming, water pollution, and smog production. In this sense, lignocellulosic biomass has been postulated as a renewable energy source able to produce energy carriers that can cover this energy demand. Biogas and syngas are two energy vectors that have been suggested to generate heat and power through their use in cogeneration systems. Therefore, the aim of this review is to develop a comparison between these energy vectors considering their main features based on literature reports. In addition, a techno-economic and energy assessment of the heat and power generation using these vectors as energy sources is performed. If lignocellulosic biomass is used as raw material, biogas is more commonly used for cogeneration purposes than syngas. However, syngas from biomass gasification has a great potential to be employed as a chemical platform in the production of value-added products. Moreover, the investment costs to generate heat and power from lignocellulosic materials using the anaerobic digestion technology are higher than those using the gasification technology. As a conclusion, it was evidenced that upgraded biogas has a higher potential to produce heat and power than syngas. Nevertheless, the implementation of both energy vectors into the energy market is important to cover the increasing worldwide energy demand.How to cite: Solarte-Toro JC, Chacón-Pérez Y, Cardona-Alzate CA. Evaluation of biogas and syngas as energy vectors for heat and power generation using lignocellulosic biomass as raw material. Electron J Biotechnol 2018:33. https://doi.org/10.1016/j.ejbt.2018.03.005
       
 
 
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