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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: 15)
Advances in Genetic Engineering & Biotechnology     Hybrid Journal   (Followers: 8)
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: 10)
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: 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: 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: 7)
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: 11)
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: 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: 16)
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)
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: 4)
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: 13)
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 Industrial Microbiology and Biotechnology
  [SJR: 0.966]   [H-I: 80]   [16 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1476-5535 - ISSN (Online) 1367-5435
   Published by Springer-Verlag Homepage  [2351 journals]
  • Safety, security, and serving the public interest in synthetic biology
    • Abstract: This article describes what may be done by scientists and by the biotechnology industry, generally, to address the safety and security challenges in synthetic biology. Given the technical expertise requirements for developing sound policy options, as well as the importance of these issues to the future of the industry, scientists who work in synthetic biology should be informed about these challenges and get involved in shaping policies relevant to the field.
      PubDate: 2018-03-21
  • Bottom-up approaches in synthetic biology and biomaterials for tissue
           engineering applications
    • Abstract: Synthetic biologists use engineering principles to design and construct genetic circuits for programming cells with novel functions. A bottom-up approach is commonly used to design and construct genetic circuits by piecing together functional modules that are capable of reprogramming cells with novel behavior. While genetic circuits control cell operations through the tight regulation of gene expression, a diverse array of environmental factors within the extracellular space also has a significant impact on cell behavior. This extracellular space offers an addition route for synthetic biologists to apply their engineering principles to program cell-responsive modules within the extracellular space using biomaterials. In this review, we discuss how taking a bottom-up approach to build genetic circuits using DNA modules can be applied to biomaterials for controlling cell behavior from the extracellular milieu. We suggest that, by collectively controlling intrinsic and extrinsic signals in synthetic biology and biomaterials, tissue engineering outcomes can be improved.
      PubDate: 2018-03-19
  • An integrated workflow for phenazine-modifying enzyme characterization
    • Abstract: Increasing availability of new genomes and putative biosynthetic gene clusters (BGCs) has extended the opportunity to access novel chemical diversity for agriculture, medicine, environmental and industrial purposes. However, functional characterization of BGCs through heterologous expression is limited because expression may require complex regulatory mechanisms, specific folding or activation. We developed an integrated workflow for BGC characterization that integrates pathway identification, modular design, DNA synthesis, assembly and characterization. This workflow was applied to characterize multiple phenazine-modifying enzymes. Phenazine pathways are useful for this workflow because all phenazines are derived from a core scaffold for modification by diverse modifying enzymes (PhzM, PhzS, PhzH, and PhzO) that produce characterized compounds. We expressed refactored synthetic modules of previously uncharacterized phenazine BGCs heterologously in Escherichia coli and were able to identify metabolic intermediates they produced, including a previously unidentified metabolite. These results demonstrate how this approach can accelerate functional characterization of BGCs.
      PubDate: 2018-03-15
  • Production of pikromycin using branched chain amino acid catabolism in
           Streptomyces venezuelae ATCC 15439
    • Authors: Jeong Sang Yi; Minsuk Kim; Eun-Jung Kim; Byung-Gee Kim
      Abstract: Branched chain amino acids (BCAA) are catabolized into various acyl-CoA compounds, which are key precursors used in polyketide productions. Because of that, BCAA catabolism needs fine tuning of flux balances for enhancing the production of polyketide antibiotics. To enhance BCAA catabolism for pikromycin production in Streptomyces venezuelae ATCC 15439, three key enzymes of BCAA catabolism, 3-ketoacyl acyl carrier protein synthase III, acyl-CoA dehydrogenase, and branched chain α-keto acid dehydrogenase (BCDH) were manipulated. BCDH overexpression in the wild type strain resulted in 1.3 fold increase in pikromycin production compared to that of WT, resulting in total 25 mg/L of pikromycin. To further increase pikromycin production, methylmalonyl-CoA mutase linked to succinyl-CoA production was overexpressed along with BCDH. Overexpression of the two enzymes resulted in the highest titer of total macrolide production of 43 mg/L, which was about 2.2 fold increase compared to that of the WT. However, it accumulated and produced dehydroxylated forms of pikromycin and methymycin, including their derivatives as well. It indicated that activities of pikC, P450 monooxygenase, newly became a bottleneck in pikromycin synthesis.
      PubDate: 2018-03-10
      DOI: 10.1007/s10295-018-2024-6
  • Correction to: Synthetic biology, genome mining, and combinatorial
           biosynthesis of NRPS‑derived antibiotics: a perspective
    • Authors: Richard H. Baltz
      Abstract: The original article can be found online at .
      PubDate: 2018-02-26
      DOI: 10.1007/s10295-018-2022-8
  • Rational design and analysis of an Escherichia coli strain for
           high-efficiency tryptophan production
    • Authors: Yuanye Chen; Yongfei Liu; Dongqin Ding; Lina Cong; Dawei Zhang
      Abstract: l-tryptophan (l-trp) is a precursor of various bioactive components and has great pharmaceutical interest. However, due to the requirement of several precursors and complex regulation of the pathways involved, the development of an efficient l-trp production strain is challenging. In this study, Escherichia coli (E. coli) strain KW001 was designed to overexpress the l-trp operator sequences (trpEDCBA) and 3-deoxy-D-arabinoheptulosonate-7-phosphate synthase (aroG fbr ). To further improve the production of l-trp, pyruvate kinase (pykF) and the phosphotransferase system HPr (ptsH) were deleted after inactivation of repression (trpR) and attenuation (attenuator) to produce strain KW006. To overcome the relatively slow growth and to increase the transport rate of glucose, strain KW018 was generated by combinatorial regulation of glucokinase (galP) and galactose permease (glk) expression. To reduce the production of acetic acid, strain KW023 was created by repressive regulation of phosphate acetyltransferase (pta) expression. In conclusion, strain KW023 efficiently produced 39.7 g/L of l-trp with a conversion rate of 16.7% and a productivity of 1.6 g/L/h in a 5 L fed-batch fermentation system.
      PubDate: 2018-02-20
      DOI: 10.1007/s10295-018-2020-x
  • Potential of biogenic methane for pilot-scale fermentation ex situ with
           lump anthracite and the changes of methanogenic consortia
    • Authors: Xiuqing Yang; Yanmei Chen; Ruiwei Wu; Zhiqiang Nie; Zuoying Han; Kaili Tan; Linyong Chen
      Abstract: Pilot-scale fermentation is one of the important processes for achieving industrialization of biogenic coalbed methane (CBM), although the mechanism of biogenic CBM remains unknown. In this study, 16 samples of formation water from CBM production wells were collected and enriched for methane production, and the methane content was between 3.1 and 21.4%. The formation water of maximum methane production was used as inoculum source for pilot-scale fermentation. The maximum methane yield of the pilot-scale fermentation with lump anthracite amendment reached 13.66 μmol CH4/mL, suggesting that indigenous microorganisms from formation water degraded coal to produce methane. Illumina high-throughput sequencing analysis revealed that the bacterial and archaeal communities in the formation water sample differed greatly from the methanogic water enrichment culture. The hydrogenotrophic methanogen Methanocalculus dominated the formation water. Acetoclastic methanogens, from the order Methanosarcinales, dominated coal bioconversion. Thus, the biogenic methanogenic pathway ex situ cannot be simply identified according to methanogenic archaea in the original inoculum. Importantly, this study was the first time to successfully simulate methanogenesis in large-capacity fermentors (160 L) with lump anthracite amendment, and the result was also a realistic case for methane generation in pilot-scale ex situ.
      PubDate: 2018-02-20
      DOI: 10.1007/s10295-018-2023-7
  • The role of acyl-CoA thioesterase ACOT8I in mediating intracellular lipid
           metabolism in oleaginous fungus Mortierella alpina
    • Authors: Jing Guo; Haiqin Chen; Bo Yang; Hao Zhang; Wei Chen; Yong Q. Chen
      Abstract: Thioesterases (TEs) play an essential role in the metabolism of fatty acids (FAs). To explore the role of TEs in mediating intracellular lipid metabolism in the oleaginous fungus Mortierella alpina, the acyl-CoA thioesterase ACOT8I was overexpressed. The contents of total fatty acids (TFAs) were the same in the recombinant strains as in the wild-type M. alpina, whilst the production of free fatty acids (FFAs) was enhanced from about 0.9% (wild-type) to 2.8% (recombinant), a roughly threefold increase. Linoleic acid content in FFA form constituted about 9% of the TFAs in the FFA fraction in the recombinant strains but only about 1.3% in the wild-type M. alpina. The gamma-linolenic acid and arachidonic acid contents in FFA form accounted for about 4 and 25%, respectively, of the TFAs in the FFA fraction in the recombinant strains, whilst neither of them in FFA form were detected in the wild-type M. alpina. Overexpression of the TE ACOT8I in the oleaginous fungus M. alpina reinforced the flux from acyl-CoAs to FFAs, improved the production of FFAs and tailored the FA profiles of the lipid species.
      PubDate: 2018-02-13
      DOI: 10.1007/s10295-018-2006-8
  • Synthetic biology of polyketide synthases
    • Authors: Satoshi Yuzawa; Tyler W. H. Backman; Jay D. Keasling; Leonard Katz
      Abstract: Complex reduced polyketides represent the largest class of natural products that have applications in medicine, agriculture, and animal health. This structurally diverse class of compounds shares a common methodology of biosynthesis employing modular enzyme systems called polyketide synthases (PKSs). The modules are composed of enzymatic domains that share sequence and functional similarity across all known PKSs. We have used the nomenclature of synthetic biology to classify the enzymatic domains and modules as parts and devices, respectively, and have generated detailed lists of both. In addition, we describe the chassis (hosts) that are used to assemble, express, and engineer the parts and devices to produce polyketides. We describe a recently developed software tool to design PKS system and provide an example of its use. Finally, we provide perspectives of what needs to be accomplished to fully realize the potential that synthetic biology approaches bring to this class of molecules.
      PubDate: 2018-02-09
      DOI: 10.1007/s10295-018-2021-9
  • Regulatory and biosynthetic effects of the bkd gene clusters on the
           production of daptomycin and its analogs A21978C 1–3
    • Authors: Shuai Luo; Xin-Ai Chen; Xu-Ming Mao; Yong-Quan Li
      Abstract: Daptomycin is a cyclic lipopeptide antibiotic produced by Streptomyces roseosporus in an acidic peptide complex A21978C. In this complex, A21978C1–3 is most abundant and contains branched-chain fatty acyl groups, while daptomycin has a straight decanoic acyl group. The branched-chain α-keto acid dehydrogenase complex (BCDH complex), encoded by bkd gene clusters in Streptomyces, is responsible for the early step of converting branched-chain amino acids into branched-chain fatty acids. In a daptomycin industrial producer S. roseosporus L30, two alleles of bkd gene clusters, bkdA1B1C1/bkdA2B2C2, and a regulatory gene bkdR located upstream of bkdA2B2C2 are identified. We show that BkdR positively regulated bkdA2B2C2 expression and was negatively auto-regulated, but is not directly involved in regulation of daptomycin gene cluster expression. However, BkdR is required for both daptomycin and A21978C1–3 production. Furthermore, deletion of bkdA2B2C2 only led to partial reduction of A21978C1–3 production, while the ΔbkdA1B1C1 mutant shows very weak production of A21978C1–3, and the double bkd mutant has a similar production profile as the single ΔbkdA1B1C1 mutant, suggesting that bkdA1B1C1 gene cluster plays a dominant role in branched-chain fatty acid biosynthesis. So we reveal a unique regulatory function of BkdR and genetic engineered a bkd null strain for daptomycin production with reduced impurities.
      PubDate: 2018-02-07
      DOI: 10.1007/s10295-018-2011-y
  • Characterization of a novel lytic bacteriophage from an industrial
           Escherichia coli fermentation process and elimination of virulence using a
           heterologous CRISPR–Cas9 system
    • Authors: Mathew C. Halter; James A. Zahn
      Abstract: Bacterial–bacteriophage interactions are a well-studied and ecologically-important aspect of microbiology. Many commercial fermentation processes are susceptible to bacteriophage infections due to the use of high-density, clonal cell populations. Lytic infections of bacterial cells in these fermentations are especially problematic due to their negative impacts on product quality, asset utilization, and fouling of downstream equipment. Here, we report the isolation and characterization of a novel lytic bacteriophage, referred to as bacteriophage DTL that is capable of rapid lytic infections of an Escherichia coli K12 strain used for commercial production of 1,3-propanediol (PDO). The bacteriophage genome was sequenced and annotated, which identified 67 potential open-reading frames (ORF). The tail fiber ORF, the largest in the genome, was most closely related to bacteriophage RTP, a T1-like bacteriophage reported from a commercial E. coli fermentation process in Germany. To eliminate virulence, both a fully functional Streptococcus thermophilus CRISPR3 plasmid and a customized S. thermophilus CRISPR3 plasmid with disabled spacer acquisition elements and seven spacers targeting the bacteriophage DTL genome were constructed. Both plasmids were separately integrated into a PDO production strain, which was subsequently infected with bacteriophage DTL. The native S. thermophilus CRISPR3 operon was shown to decrease phage susceptibility by approximately 96%, while the customized CRISPR3 operon provided complete resistance to bacteriophage DTL. The results indicate that the heterologous bacteriophage-resistance system described herein is useful in eliminating lytic infections of bacteriophage DTL, which was prevalent in environment surrounding the manufacturing facility.
      PubDate: 2018-02-07
      DOI: 10.1007/s10295-018-2015-7
  • A novel riboregulator switch system of gene expression for enhanced
           microbial production of succinic acid
    • Authors: Jing Wang; Haoyuan Wang; Le Yang; Liping Lv; Zhe Zhang; Bin Ren; Lichun Dong; Ning Li
      Abstract: In this paper, a novel riboregulator Switch System of Gene Expression including an OFF-TO-ON switch and an ON-TO-OFF switch was designed to regulate the expression state of target genes between “ON” and “OFF” by switching the identifiability of ribosome recognition site (RBS) based on the thermodynamic stability of different RNA–RNA hybridizations between RBS and small noncoding RNAs. The proposed riboregulator switch system was employed for the fermentative production of succinic acid using an engineered strain of E. coli JW1021, during which the expression of mgtC gene was controlled at “ON” state and that of pepc and ecaA genes were controlled at the “OFF” state in the lag phase and switched to the “OFF” and “ON” state once the strain enters the logarithmic phase. The results showed that using the strain of JW1021, the yield and productivity of succinic acid can reach 0.91 g g−1 and 3.25 g L−1 h−1, respectively, much higher than those using the strains without harboring the riboregulator switch system.
      PubDate: 2018-02-05
      DOI: 10.1007/s10295-018-2019-3
  • Ribosome engineering and fermentation optimization leads to overproduction
           of tiancimycin A, a new enediyne natural product from Streptomyces sp.
    • Authors: Ling Liu; Jian Pan; Zilong Wang; Xiaohui Yan; Dong Yang; Xiangcheng Zhu; Ben Shen; Yanwen Duan; Yong Huang
      Abstract: Tiancimycin (TNM) A, a recently discovered enediyne natural product from Streptomyces sp. CB03234, showed rapid and complete killing of cancer cells and could be used as a payload in antibody drug conjugates. The low yield of TNM A in the wild-type strain promoted us to use ribosome engineering and fermentation optimization for its yield improvement. The Streptomyces sp. CB03234-R-16 mutant strain with a L422P mutation in RpoB, the RNA polymerase β-subunit, was obtained from the rifamycin-resistant screening. After fermentation optimization, the titers of TNM A in Streptomyces sp. CB03234-R-16 reached to 22.5 ± 3.1 mg L−1 in shaking flasks, and 13 ± 1 mg L−1 in 15 L fermentors, which were at least 40-fold higher than that in the wild-type strain (~ 0.3 mg L−1). Quantitative real-time RT-PCR revealed markedly enhanced expression of key genes encoding TNM A biosynthetic enzymes and regulators in Streptomyces sp. CB03234-R-16. Our study should greatly facilitate the future efforts to develop TNM A into a clinical anticancer drug.
      PubDate: 2018-02-02
      DOI: 10.1007/s10295-018-2014-8
  • High-level recombinant production of squalene using selected Saccharomyces
           cerevisiae strains
    • Authors: Jong Yun Han; Sung Hwa Seo; Jae Myeong Song; Hongweon Lee; Eui-Sung Choi
      Abstract: For recombinant production of squalene, which is a triterpenoid compound with increasing industrial applications, in microorganisms generally recognized as safe, we screened Saccharomyces cerevisiae strains to determine their suitability. A strong strain dependence was observed in squalene productivity among Saccharomyces cerevisiae strains upon overexpression of genes important for isoprenoid biosynthesis. In particular, a high level of squalene production (400 ± 45 mg/L) was obtained in shake flasks with the Y2805 strain overexpressing genes encoding a bacterial farnesyl diphosphate synthase (ispA) and a truncated form of hydroxyl-3-methylglutaryl-CoA reductase (tHMG1). Partial inhibition of squalene epoxidase by terbinafine further increased squalene production by up to 1.9-fold (756 ± 36 mg/L). Furthermore, squalene production of 2011 ± 75 or 1026 ± 37 mg/L was obtained from 5-L fed-batch fermentations in the presence or absence of terbinafine supplementation, respectively. These results suggest that the Y2805 strain has potential as a new alternative source of squalene production.
      PubDate: 2018-02-02
      DOI: 10.1007/s10295-018-2018-4
  • Rational design of a synthetic Entner–Doudoroff pathway for enhancing
           glucose transformation to isobutanol in Escherichia coli
    • Authors: Shaoxiong Liang; Hong Chen; Jiao Liu; Jianping Wen
      Abstract: Isobutanol as a more desirable biofuel has attracted much attention. In our previous work, an isobutanol-producing strain Escherichia coli LA09 had been obtained by rational redox status improvement under guidance of the genome-scale metabolic model. However, the low transformation from sugar to isobutanol is a limiting factor for isobutanol production by E. coli LA09. In this study, the intracellular metabolic profiles of the isobutanol-producing E. coli LA09 with different initial glucose concentrations were investigated and the metabolic reaction of fructose 6-phosphate to 1, 6-diphosphate fructose in glycolytic pathway was identified as the rate-limiting step of glucose transformation. Thus, redesigned carbon catabolism was implemented by altering flux of sugar metabolism. Here, the heterologous Entner–Doudoroff (ED) pathway from Zymomonas mobilis was constructed, and the adaptation of upper and lower parts of ED pathway was further improved with artificial promoters to alleviate the accumulation of toxic intermediate metabolite 2-keto-3-deoxy-6-phospho-gluconate (KDPG). Finally, the best isobutanol-producing E. coli ED02 with higher glucose transformation and isobutanol production was obtained. In the fermentation of strain E. coli ED02 with 45 g/L initial glucose, the isobutanol titer, yield and average producing rate were, respectively, increased by 56.8, 47.4 and 88.1% to 13.67 g/L, 0.50 C-mol/C-mol and 0.456 g/(L × h) in a shorter time of 30 h, compared with that of the starting strain E. coli LA09.
      PubDate: 2018-01-30
      DOI: 10.1007/s10295-018-2017-5
  • Engineering co-culture system for production of apigetrin in Escherichia
    • Authors: Nguyen Huy Thuan; Amit Kumar Chaudhary; Duong Van Cuong; Nguyen Xuan Cuong
      Abstract: Microbial cells have extensively been utilized to produce value-added bioactive compounds. Based on advancement in protein engineering, DNA recombinant technology, genome engineering, and metabolic remodeling, the microbes can be re-engineered to produce industrially and medicinally important platform chemicals. The emergence of co-culture system which reduces the metabolic burden and allows parallel optimization of the engineered pathway in a modular fashion restricting the formation of undesired byproducts has become an alternative way to synthesize and produce bioactive compounds. In this study, we present genetically engineered E. coli-based co-culture system to the de novo synthesis of apigetrin (APG), an apigenin-7-O-β-d-glucopyranoside of apigenin. The culture system consists of an upstream module including 4-coumarate: CoA ligase (4CL), chalcone synthase, chalcone flavanone isomerase (CHS, CHI), and flavone synthase I (FNSI) to synthesize apigenin (API) from p-coumaric acid (PCA). Whereas, the downstream system contains a metabolizing module to enhance the production of UDP-glucose and expression of glycosyltransferase (PaGT3) to convert API into APG. To accomplish this improvement in titer, the initial inoculum ratio of strains for making the co-culture system, temperature, and media component was optimized. Following large-scale production, a yield of 38.5 µM (16.6 mg/L) of APG was achieved. In overall, this study provided an efficient tool to synthesize bioactive compounds in microbial cells.
      PubDate: 2018-01-24
      DOI: 10.1007/s10295-018-2012-x
  • xylA and xylB overexpression as a successful strategy for improving xylose
           utilization and poly-3-hydroxybutyrate production in Burkholderia sacchari
    • Authors: Linda P. Guamán; Edmar R. Oliveira-Filho; Carlos Barba-Ostria; José G. C. Gomez; Marilda K. Taciro; Luiziana Ferreira da Silva
      Abstract: Despite the versatility and many advantages of polyhydroxyalkanoates as petroleum-based plastic substitutes, their higher production cost compared to petroleum-based polymers has historically limited their large-scale production. One appealing approach to reducing production costs is to employ less expensive, renewable feedstocks. Xylose, for example is an abundant and inexpensive carbon source derived from hemicellulosic residues abundant in agro-industrial waste (sugarcane bagasse hemicellulosic hydrolysates). In this work, the production of poly-3-hydroxybutyrate P(3HB) from xylose was studied to develop technologies for conversion of agro-industrial waste into high-value chemicals and biopolymers. Specifically, this work elucidates the organization of the xylose assimilation operon of Burkholderia sacchari, a non-model bacterium with high capacity for P(3HB) accumulation. Overexpression of endogenous xylose isomerase and xylulokinase genes was successfully assessed, improving both specific growth rate and P(3HB) production. Compared to control strain (harboring pBBR1MCS-2), xylose utilization in the engineered strain was substantially improved with 25% increase in specific growth rate, 34% increase in P(3HB) production, and the highest P(3HB) yield from xylose reported to date for B. sacchari (YP3HB/Xil = 0.35 g/g). This study highlights that xylA and xylB overexpression is an effective strategy to improve xylose utilization and P(3HB) production in B. sacchari.
      PubDate: 2018-01-19
      DOI: 10.1007/s10295-018-2007-7
  • Immobilization of Methylosinus trichosporium OB3b for methanol production
    • Authors: Anne Taylor; Paige Molzahn; Tanner Bushnell; Clint Cheney; Monique LaJeunesse; Mohamad Azizian; Lewis Semprini
      Abstract: Due to the natural gas boom in North America, there is renewed interest in the production of other chemical products from methane. We investigated the feasibility of immobilizing the obligate methanotrophic bacterium Methylosinus trichosporium OB3b in alginate beads, and selectively inactivating methanol dehydrogenase (MDH) with cyclopropane to produce methanol. In batch cultures and in semi-continuous flow columns, the exposure of alginate-immobilized cells to cyclopropane or cyclopropanol resulted in the loss of the majority of MDH activity (> 80%), allowing methanol to accumulate to significant concentrations while retaining all of M. trichosporium OB3b’s methane monooxygenase capacity. Thereafter, the efficiency of methanol production fell due to recovery of most of the MDH activity; however, subsequent inhibition periods resulted in renewed methanol production efficiency, and immobilized cells retained methane-oxidizing activity for at least 14 days.
      PubDate: 2018-01-19
      DOI: 10.1007/s10295-018-2010-z
  • Class III bacteriocin Helveticin-M causes sublethal damage on target cells
           through impairment of cell wall and membrane
    • Authors: Zhilan Sun; Xiaomeng Wang; Xinxiao Zhang; Haihong Wu; Ye Zou; Pengpeng Li; Chong Sun; Weimin Xu; Fang Liu; Daoying Wang
      Abstract: Helveticin-M, a novel Class III bacteriocin produced by Lactobacillus crispatus exhibited an antimicrobial activity against Staphylococcus aureus, S. saprophyticus, and Enterobacter cloacae. To understand how Helveticin-M injured target cells, Helveticin-M was cloned and heterologously expressed in Escherichia coli. Subsequently, the cell wall organization and cell membrane integrity of target cells were determined. The mechanism of cellular damage differed according to bacterial species. Based on morphology analysis, Helveticin-M disrupted the cell wall of Gram-positive bacteria and disorganized the outer membrane of Gram-negative bacteria, therefore, altering surface structure. Helveticin-M also disrupted the inner membrane, as confirmed by leakage of intracellular ATP from cells and depolarization of membrane potential of target bacteria. Based on cell population analysis, Helveticin-M treatment caused the increase of cell membrane permeability, but the cytosolic enzymes were not influenced, indicating that it was the sublethal injury. Therefore, the mode of Helveticin-M action is bacteriostatic rather than bactericidal.
      PubDate: 2018-01-18
      DOI: 10.1007/s10295-018-2008-6
  • Effect of impaired twitching motility and biofilm dispersion on
           performance of Pseudomonas aeruginosa -powered microbial fuel cells
    • Authors: Devesh D. Shreeram; Warunya Panmanee; Cameron T. McDaniel; Susan Daniel; Dale W. Schaefer; Daniel J. Hassett
      Abstract: Pseudomonas aeruginosa is a metabolically voracious bacterium that is easily manipulated genetically. We have previously shown that the organism is also highly electrogenic in microbial fuel cells (MFCs). Polarization studies were performed in MFCs with wild-type strain PAO1 and three mutant strains (pilT, bdlA and pilT bdlA). The pilT mutant was hyperpiliated, while the bdlA mutant was suppressed in biofilm dispersion chemotaxis. The double pilT bdlA mutant was expected to have properties of both mutations. Polarization data indicate that the pilT mutant showed 5.0- and 3.2-fold increases in peak power compared to the wild type and the pilT bdlA mutant, respectively. The performance of the bdlA mutant was surprisingly the lowest, while the pilT bdlA electrogenic performance fell between the pilT mutant and wild-type bacteria. Measurements of biofilm thickness and bacterial viability showed equal viability among the different strains. The thickness of the bdlA mutant, however, was twice that of wild-type strain PAO1. This observation implicates the presence of dead or dormant bacteria in the bdlA mutant MFCs, which increases biofilm internal resistance as confirmed by electrochemical measurements.
      PubDate: 2017-12-29
      DOI: 10.1007/s10295-017-1995-z
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