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  Subjects -> BIOLOGY (Total: 3134 journals)
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BIOTECHNOLOGY (236 journals)                  1 2 | Last

Showing 1 - 200 of 237 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 8)
Advanced Biomedical Research     Open Access  
Advances in Bioscience and Biotechnology     Open Access   (Followers: 14)
Advances in Genetic Engineering & Biotechnology     Hybrid Journal   (Followers: 8)
African Journal of Biotechnology     Open Access   (Followers: 6)
Algal Research     Partially Free   (Followers: 10)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 64)
American Journal of Bioinformatics Research     Open Access   (Followers: 7)
American Journal of Polymer Science     Open Access   (Followers: 31)
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 Bioenergy     Open Access  
Applied Biosafety     Hybrid Journal  
Applied Food Biotechnology     Open Access   (Followers: 3)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 63)
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: 8)
Asian Pacific Journal of Tropical Biomedicine     Open Access   (Followers: 2)
Australasian Biotechnology     Full-text available via subscription   (Followers: 1)
Banat's Journal of Biotechnology     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 5)
Bio-Algorithms and Med-Systems     Hybrid Journal   (Followers: 2)
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: 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)
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: 5)
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: 155)
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: 1)
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: 39)
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  
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)
Contributions to Tobacco Research     Open Access   (Followers: 2)
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)
Industrial Biotechnology     Hybrid Journal   (Followers: 18)
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: 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: 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: 68)
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  
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: 24)
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 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: 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: 4)
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: 13)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 3)
Nanobiomedicine     Open Access  
Nanobiotechnology     Hybrid Journal   (Followers: 2)
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: 535)

        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  [2350 journals]
  • Reprogramming Halomonas for industrial production of chemicals
    • Authors: Xiangbin Chen; Linping Yu; Guanqing Qiao; Guo-Qiang Chen
      Abstract: Halomonas spp. are able to grow under a high salt concentration at alkali pH, they are able to resist contamination by other microbes. Development of Halomonas spp. as platform production strains for the next-generation industrial biotechnology (NGIB) is intensively studied. Among Halomonas spp., Halomonas bluephagenesis is the best studied one with available engineering tools and methods to reprogram it for production of various polyhydroxyalkanoates, proteins, and chemicals. Due to its contamination resistance, H. bluephagenesis can be grown under open and continuous processes not just in the labs but also in at least 1000 L fermentor scale. It is expected that NGIB based on Halomonas spp. be able to engineer for production of increasing number of products in a competitive manner.
      PubDate: 2018-06-08
      DOI: 10.1007/s10295-018-2055-z
       
  • The increase of O-acetylation and N-deacetylation in cell wall promotes
           acid resistance and nisin production through improving cell wall integrity
           in Lactococcus lactis
    • Abstract: Cell wall is closely related to bacterial robustness and adsorption capacity, playing crucial roles in nisin production in Lactococcus lactis. Peptidoglycan (PG), the essential component of cell wall, is usually modified with MurNAc O-acetylation and GlcNAc N-deacetylation, catalyzed by YvhB and XynD, respectively. In this study, increasing the two modifications in L. lactis F44 improved autolysis resistance by decreasing the susceptibility to PG hydrolases. Furthermore, both modifications were positively associated with overall cross-linkage, contributing to cell wall integrity. The robust cell wall rendered the yvhB/xynD-overexpression strains more acid resistant, leading to the increase of nisin production in fed-batch fermentations by 63.7 and 62.9%, respectively. Importantly, the structural alterations also reduced nisin adsorption capacity, resulting in reduction of nisin loss. More strikingly, the co-overexpression strain displayed the highest nisin production (76.3% higher than F44). Our work provides a novel approach for achieving nisin overproduction via extensive cell wall remodeling.
      PubDate: 2018-06-06
      DOI: 10.1007/s10295-018-2052-2
       
  • Inactivation of the transcription factor mig1 ( YGL035C ) in Saccharomyces
           cerevisiae improves tolerance towards monocarboxylic weak acids: acetic,
           formic and levulinic acid
    • Abstract: Toxic concentrations of monocarboxylic weak acids present in lignocellulosic hydrolyzates affect cell integrity and fermentative performance of Saccharomyces cerevisiae. In this work, we report the deletion of the general catabolite repressor Mig1p as a strategy to improve the tolerance of S. cerevisiae towards inhibitory concentrations of acetic, formic or levulinic acid. In contrast with the wt yeast, where the growth and ethanol production were ceased in presence of acetic acid 5 g/L or formic acid 1.75 g/L (initial pH not adjusted), the m9 strain (Δmig1::kan) produced 4.06 ± 0.14 and 3.87 ± 0.06 g/L of ethanol, respectively. Also, m9 strain tolerated a higher concentration of 12.5 g/L acetic acid (initial pH adjusted to 4.5) without affecting its fermentative performance. Moreover, m9 strain produced 33% less acetic acid and 50–70% less glycerol in presence of weak acids, and consumed acetate and formate as carbon sources under aerobic conditions. Our results show that the deletion of Mig1p provides a single gene deletion target for improving the acid tolerance of yeast strains significantly.
      PubDate: 2018-06-06
      DOI: 10.1007/s10295-018-2053-1
       
  • Changes in biooxidation mechanism and transient biofilm characteristics by
           
    • Authors: Hugo Ramírez-Aldaba; Jorge Vázquez-Arenas; Fabiola S. Sosa-Rodríguez; Donato Valdez-Pérez; Estela Ruiz-Baca; Gabriel Trejo-Córdoba; Miguel A. Escobedo-Bretado; Luis Lartundo-Rojas; Patricia Ponce-Peña; René H. Lara
      Abstract: Chemical and surface analyses are carried out using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM–EDS), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), glow discharge spectroscopy (GDS) and extracellular surface protein quantification to thoroughly investigate the effect of supplementary As(V) during biooxidation of arsenopyrite by Acidithiobacillus thiooxidans. It is revealed that arsenic can enhance bacterial reactions during bioleaching, which can strongly influence its mobility. Biofilms occur as compact-flattened microcolonies, being progressively covered by a significant amount of secondary compounds (S n 2- , S0, pyrite-like). Biooxidation mechanism is modified in the presence of supplementary As(V), as indicated by spectroscopic and microscopic studies. GDS confirms significant variations between abiotic control and biooxidized arsenopyrite in terms of surface reactivity and amount of secondary compounds with and without As(V) (i.e. 6 μm depth). CLSM and protein analyses indicate a rapid modification in biofilm from hydrophilic to hydrophobic character (i.e. 1–12 h), in spite of the decrease in extracellular surface proteins in the presence of supplementary As(V) (i.e. stressed biofilms).
      PubDate: 2018-06-01
      DOI: 10.1007/s10295-018-2051-3
       
  • Corrections to: Enhanced lincomycin production by co‑overexpression of
           metK1 and metK2 in Streptomyces lincolnensis
    • Abstract: In the online published article, row value “pIB139-metK1-metK2” in table 1 has been processed incorrectly. The correct table is given below
      PubDate: 2018-05-30
      DOI: 10.1007/s10295-018-2036-2
       
  • Metabolomic and proteomic analysis of d -lactate-producing Lactobacillus
           delbrueckii under various fermentation conditions
    • Abstract: As an important feedstock monomer for the production of biodegradable stereo-complex poly-lactic acid polymer, d-lactate has attracted much attention. To improve d-lactate production by microorganisms such as Lactobacillus delbrueckii, various fermentation conditions were performed, such as the employment of anaerobic fermentation, the utilization of more suitable neutralizing agents, and exploitation of alternative nitrogen sources. The highest d-lactate titer could reach 133 g/L under the optimally combined fermentation condition, increased by 70.5% compared with the control. To decipher the potential mechanisms of d-lactate overproduction, the time-series response of intracellular metabolism to different fermentation conditions was investigated by GC–MS and LC–MS/MS-based metabolomic analysis. Then the metabolomic datasets were subjected to weighted correlation network analysis (WGCNA), and nine distinct metabolic modules and eight hub metabolites were identified to be specifically associated with d-lactate production. Moreover, a quantitative iTRAQ–LC–MS/MS proteomic approach was employed to further analyze the change of intracellular metabolism under the combined fermentation condition, identifying 97 up-regulated and 42 down-regulated proteins compared with the control. The in-depth analysis elucidated how the key factors exerted influence on d-lactate biosynthesis. The results revealed that glycolysis and pentose phosphate pathways, transport of glucose, amino acids and peptides, amino acid metabolism, peptide hydrolysis, synthesis of nucleotides and proteins, and cell division were all strengthened, while ATP consumption for exporting proton, cell damage, metabolic burden caused by stress response, and bypass of pyruvate were decreased under the combined condition. These might be the main reasons for significantly improved d-lactate production. These findings provide the first omics view of cell growth and d-lactate overproduction in L. delbrueckii, which can be a theoretical basis for further improving the production of d-lactate.
      PubDate: 2018-05-28
      DOI: 10.1007/s10295-018-2048-y
       
  • Corn steep liquor as a nutritional source for biocementation and its
           impact on concrete structural properties
    • Abstract: Microbial-induced carbonate precipitation (MICP) has a potential to improve the durability properties and remediate cracks in concrete. In the present study, the main emphasis is placed upon replacing the expensive laboratory nutrient broth (NB) with corn steep liquor (CSL), an industrial by-product, as an alternate nutrient medium during biocementation. The influence of organic nutrients (carbon and nitrogen content) of CSL and NB on the chemical and structural properties of concrete structures is studied. It has been observed that cement-setting properties were unaffected by CSL organic content, while NB medium influenced it. Carbon and nitrogen content in concrete structures was significantly lower in CSL-treated specimens than in NB-treated specimens. Decreased permeability and increased compressive strength were reported when NB is replaced with CSL in bacteria-treated specimens. The present study results suggest that CSL can be used as a replacement growth medium for MICP technology at commercial scale.
      PubDate: 2018-05-28
      DOI: 10.1007/s10295-018-2050-4
       
  • Deletion of the Clostridium thermocellum recA gene reveals that it is
           required for thermophilic plasmid replication but not plasmid integration
           at homologous DNA sequences
    • Abstract: A limitation to the engineering of cellulolytic thermophiles is the availability of functional, thermostable (≥ 60 °C) replicating plasmid vectors for rapid expression and testing of genes that provide improved or novel fuel molecule production pathways. A series of plasmid vectors for genetic manipulation of the cellulolytic thermophile Caldicellulosiruptor bescii has recently been extended to Clostridium thermocellum, another cellulolytic thermophile that very efficiently solubilizes plant biomass and produces ethanol. While the C. bescii pBAS2 replicon on these plasmids is thermostable, the use of homologous promoters, signal sequences and genes led to undesired integration into the bacterial chromosome, a result also observed with less thermostable replicating vectors. In an attempt to overcome undesired plasmid integration in C. thermocellum, a deletion of recA was constructed. As expected, C. thermocellum ∆recA showed impaired growth in chemically defined medium and an increased susceptibility to UV damage. Interestingly, we also found that recA is required for replication of the C. bescii thermophilic plasmid pBAS2 in C. thermocellum, but it is not required for replication of plasmid pNW33N. In addition, the C. thermocellum recA mutant retained the ability to integrate homologous DNA into the C. thermocellum chromosome. These data indicate that recA can be required for replication of certain plasmids, and that a recA-independent mechanism exists for the integration of homologous DNA into the C. thermocellum chromosome. Understanding thermophilic plasmid replication is not only important for engineering of these cellulolytic thermophiles, but also for developing genetic systems in similar new potentially useful non-model organisms.
      PubDate: 2018-05-28
      DOI: 10.1007/s10295-018-2049-x
       
  • Metabolic engineering of lipid pathways in Saccharomyces cerevisiae and
           staged bioprocess for enhanced lipid production and cellular physiology
    • Abstract: Microbially produced lipids have attracted attention for their environmental benefits and commercial value. We have combined lipid pathway engineering in Saccharomyces cerevisiae yeast with bioprocess design to improve productivity and explore barriers to enhanced lipid production. Initially, individual gene expression was tested for impact on yeast growth and lipid production. Then, two base strains were prepared for enhanced lipid accumulation and stabilization steps by combining DGAT1, ΔTgl3 with or without Atclo1, which increased lipid content ~ 1.8-fold but reduced cell viability. Next, fatty acid (FA) biosynthesis genes Ald6-SEACS L641P alone or with ACC1** were co-expressed in base strains, which significantly improved lipid content (8.0% DCW, 2.6-fold than control), but severely reduced yeast growth and cell viability. Finally, a designed two-stage process convincingly ameliorated the negative effects, resulting in normal cell growth, very high lipid productivity (307 mg/L, 4.6-fold above control) and improved cell viability.
      PubDate: 2018-05-26
      DOI: 10.1007/s10295-018-2046-0
       
  • Construction of an alternative glycerol-utilization pathway for improved
           β-carotene production in Escherichia coli
    • Authors: Jin-Ying Guo; Kun-Le Hu; Chang-Hao Bi; Qing-Yan Li; Xue-Li Zhang
      Abstract: Glycerol, which is an inevitable by-product of biodiesel production, is an ideal carbon source for the production of carotenoids due to its low price, good availability and chemically reduced status, which results in a low requirement for additional reducing equivalents. In this study, an alternative carbon-utilization pathway was constructed in Escherichia coli to enable more efficient β-carotene production from glycerol. An aldehyde reductase gene (alrd) and an aldehyde dehydrogenase gene (aldH) from Ralstonia eutropha H16 were integrated into the E. coli chromosome to form a novel glycerol-utilization pathway. The β-carotene specific production value was increased by 50% after the introduction of alrd and aldH. It was found that the glycerol kinase gene (garK), alrd and aldH were the bottleneck of the alternative glycerol metabolic pathway, and modulation of garK gene with an mRS library further increased the β-carotene specific production value by 13%. Finally, co-modulation of genes in the introduced aldH–alrd operon led to 86% more of β-carotene specific production value than that of the strain without the alternative glycerol-utilization pathway and the glycerol-utilization rate was also increased. In this work, β-carotene production of E. coli was significantly improved by constructing and optimizing an alternative glycerol-utilization pathway. This strategy can potentially be used to improve the production of other isoprenoids using glycerol as a cheap and abundant substrate, and therefore has industrial relevance.
      PubDate: 2018-05-11
      DOI: 10.1007/s10295-018-2045-1
       
  • An economically and environmentally acceptable synthesis of chiral drug
           intermediate l -pipecolic acid from biomass-derived lysine via
           artificially engineered microbes
    • Authors: Jie Cheng; Yuding Huang; Le Mi; Wujiu Chen; Dan Wang; Qinhong Wang
      Abstract: Deficiency in petroleum resources and increasing environmental concerns have pushed a bio-based economy to be built, employing a highly reproducible, metal contaminant free, sustainable and green biomanufacturing method. Here, a chiral drug intermediate l-pipecolic acid has been synthesized from biomass-derived lysine. This artificial bioconversion system involves the coexpression of four functional genes, which encode l-lysine α-oxidase from Scomber japonicus, glucose dehydrogenase from Bacillus subtilis, Δ1-piperideine-2-carboxylase reductase from Pseudomonas putida, and lysine permease from Escherichia coli. Besides, a lysine degradation enzyme has been knocked out to strengthen the process in this microbe. The overexpression of LysP improved the l-pipecolic acid titer about 1.6-folds compared to the control. This engineered microbial factory showed the highest l-pipecolic acid production of 46.7 g/L reported to date and a higher productivity of 2.41 g/L h and a yield of 0.89 g/g. This biotechnological l-pipecolic acid production is a simple, economic, and green technology to replace the presently used chemical synthesis.
      PubDate: 2018-05-10
      DOI: 10.1007/s10295-018-2044-2
       
  • A highly glucose-tolerant GH1 β-glucosidase with greater conversion rate
           of soybean isoflavones in monogastric animals
    • Authors: Huifang Cao; Yueqi Zhang; Pengjun Shi; Rui Ma; Hong Yang; Wei Xia; Ying Cui; Huiying Luo; Yingguo Bai; Bin Yao
      Abstract: In the feed industry, β-glucosidase has been widely used in the conversion of inactive and bounded soybean isoflavones into active aglycones. However, the conversion is frequently inhibited by the high concentration of intestinal glucose in monogastric animals. In this study, a GH1 β-glucosidase (AsBG1) with high specific activity, thermostability and glucose tolerance (IC 50  = 800 mM) was identified. It showed great glucose tolerance against substrates with hydrophobic aryl ligands (such as pNPG and soy isoflavones). Using soybean meal as the substrate, AsBG1 exhibited higher hydrolysis efficiency than the GH3 counterpart Bgl3A with or without the presence of glucose in the reaction system. Furthermore, it is the first time to find that the endogenous β-glucosidase of soybean meal, mostly belonging to GH3, plays a role in the hydrolysis of soybean isoflavones and is highly sensitive to glucose. These findings lead to a conclusion that the GH1 rather than GH3 β-glucosidase has prosperous application advantages in the conversion of soybean isoflavones in the feed industry.
      PubDate: 2018-05-09
      DOI: 10.1007/s10295-018-2040-6
       
  • A light-controlled cell lysis system in bacteria
    • Authors: Geyi Wang; Xin Lu; Yisha Zhu; Wei Zhang; Jiahui Liu; Yankang Wu; Liyang Yu; Dongchang Sun; Feng Cheng
      Abstract: Intracellular products (e.g., insulin), which are obtained through cell lysis, take up a big share of the biotech industry. It is often time-consuming, laborious, and environment-unfriendly to disrupt bacterial cells with traditional methods. In this study, we developed a molecular device for controlling cell lysis with light. We showed that intracellular expression of a single lysin protein was sufficient for efficient bacterial cell lysis. By placing the lysin-encoding gene under the control of an improved light-controlled system, we successfully controlled cell lysis by switching on/off light: OD600 of the Escherichia coli cell culture was decreased by twofold when the light-controlled system was activated under dark condition. We anticipate that our work would not only pave the way for cell lysis through a convenient biological way in fermentation industry, but also provide a paradigm for applying the light-controlled system in other fields of biotech industry.
      PubDate: 2018-05-08
      DOI: 10.1007/s10295-018-2034-4
       
  • Construction of a plasmid interspecific transfer system in Bacillus
           species with the counter-selectable marker mazF
    • Authors: XingYa Zhao; JianYong Xu; Ming Tan; ZhenXiao Yu; ShiBin Yang; HongChen Zheng; Hui Song
      Abstract: Bacillus sp. strains as attractive hosts for the production of heterologous secretory proteins usually play important roles in bio-industry. However, low transformation efficiency of exogenous plasmids limited the application of Bacillus species. Here, a novel plasmid interspecific transfer system, with high transformation efficiency, high positive rate, and convenient manipulation, has been successfully constructed. A high electrotransformation efficiency strain Bacillus subtilis F-168 containing the counter-selectable marker mazF was used as the plasmid donor strain in this transfer method. A shuttled plasmid pBE980 and its recombinant plasmids pBE980::pulA and pBE980::HSPA were successfully transferred into the recipient Bacillus strains (Bacillus amyloliquefaciens 66, Bacillus licheniformis 124 and Bacillus megaterium 258) by this method. After co-culturing the donor cells (OD600nm = 1.3–1.7) and the recipient cells (OD600nm = 0.5–0.9) for 24 h in 22 °C, more than 1.0 × 105 positive transformants were obtained and a interspecific transformation efficiency of 1.0 × 10−3. It would provide a new approach for genetic manipulation in Bacillus strains and accelerate the research progress of the wild Bacillus strains in bio-industry.
      PubDate: 2018-05-08
      DOI: 10.1007/s10295-018-2038-0
       
  • Prospects for engineering dynamic CRISPR–Cas transcriptional
           circuits to improve bioproduction
    • Authors: Jason Fontana; William E. Voje; Jesse G. Zalatan; James M. Carothers
      Abstract: Dynamic control of gene expression is emerging as an important strategy for controlling flux in metabolic pathways and improving bioproduction of valuable compounds. Integrating dynamic genetic control tools with CRISPR–Cas transcriptional regulation could significantly improve our ability to fine-tune the expression of multiple endogenous and heterologous genes according to the state of the cell. In this mini-review, we combine an analysis of recent literature with examples from our own work to discuss the prospects and challenges of developing dynamically regulated CRISPR–Cas transcriptional control systems for applications in synthetic biology and metabolic engineering.
      PubDate: 2018-05-08
      DOI: 10.1007/s10295-018-2039-z
       
  • Transcriptome remodeling of Pseudomonas putida KT2440 during mcl-PHAs
           synthesis: effect of different carbon sources and response to nitrogen
           stress
    • Authors: Justyna Mozejko-Ciesielska; Tomasz Pokoj; Slawomir Ciesielski
      Abstract: Bacterial response to environmental stimuli is essential for survival. In response to fluctuating environmental conditions, the physiological status of bacteria can change due to the actions of transcriptional regulatory machinery. The synthesis and accumulation of polyhydroxyalkanoates (PHAs) are one of the survival strategies in harsh environments. In this study, we used transcriptome analysis of Pseudomonas putida KT2440 to gain a genome-wide view of the mechanisms of environmental-friendly biopolymers accumulation under nitrogen-limiting conditions during conversion of metabolically different carbon sources (sodium gluconate and oleic acid). Transcriptomic data revealed that phaG expression is associated with medium-chain-length-PHAs’ synthesis not only on sodium gluconate but also on oleic acid, suggesting that PhaG may play a role in this process, as well. Moreover, genes involved in the β-oxidation pathway were induced in the PHAs production phase when sodium gluconate was supplied as the only carbon and energy source. The transition from exponential growth to stationary phase caused a significant expression of genes involved in nitrogen metabolism, energy supply, and transport system. In this study, several molecular mechanisms, which drive mcl-PHAs synthesis, have been investigated. The identified genes may provide valuable information to improve the efficiency of this bioprocess and make it more economically feasible.
      PubDate: 2018-05-07
      DOI: 10.1007/s10295-018-2042-4
       
  • Improved l -ornithine production in Corynebacterium crenatum by
           introducing an artificial linear transacetylation pathway
    • Authors: Qunfeng Shu; Meijuan Xu; Jing Li; Taowei Yang; Xian Zhang; Zhenghong Xu; Zhiming Rao
      Abstract: l-Ornithine is a non-protein amino acid with extensive applications in the food and pharmaceutical industries. In this study, we performed metabolic pathway engineering of an l-arginine hyper-producing strain of Corynebacterium crenatum for L-ornithine production. First, we amplified the L-ornithine biosynthetic pathway flux by blocking the competing branch of the pathway. To enhance L-ornithine synthesis, we performed site-directed mutagenesis of the ornithine-binding sites to solve the problem of l-ornithine feedback inhibition for ornithine acetyltransferase. Alternatively, the genes argA from Escherichia coli and argE from Serratia marcescens, encoding the enzymes N-acetyl glutamate synthase and N-acetyl-l-ornithine deacetylase, respectively, were introduced into Corynebacterium crenatum to mimic the linear pathway of L-ornithine biosynthesis. Fermentation of the resulting strain in a 5-L bioreactor allowed a dramatically increased production of L-ornithine, 40.4 g/L, with an overall productivity of 0.673 g/L/h over 60 h. This demonstrates that an increased level of transacetylation is beneficial for L-ornithine biosynthesis.
      PubDate: 2018-05-04
      DOI: 10.1007/s10295-018-2037-1
       
  • Rapid and stable production of 2,3-butanediol by an engineered
           Saccharomyces cerevisiae strain in a continuous airlift bioreactor
    • Authors: Ryosuke Yamada; Riru Nishikawa; Kazuki Wakita; Hiroyasu Ogino
      Abstract: Utilization of renewable feedstocks for the production of bio-based bulk chemicals, such as 2,3-butanediol (2,3-BDO), by engineered strains of the non-pathogenic yeast, Saccharomyces cerevisiae, has recently become an attractive option. In this study, to realize rapid production of 2,3-BDO, a flocculent, 2,3-BDO-producing S. cerevisiae strain YPH499/dPdAdG/BDN6-10/FLO1 was constructed from a previously developed 2,3-BDO-producing strain. Continuous 2,3-BDO fermentation was carried out by the flocculent strain in an airlift bioreactor. The strain consumed more than 90 g/L of glucose, which corresponded to 90% of the input, and stably produced more than 30 g/L of 2,3-BDO over 380 h. The maximum 2,3-BDO productivity was 7.64 g/L/h at a dilution rate of 0.200/h, which was higher than the values achieved by continuous fermentation using pathogenic bacteria in the previous reports. These results demonstrate that continuous 2,3-BDO fermentation with flocculent 2,3-BDO-producing S. cerevisiae is a promising strategy for practical 2,3-BDO production.
      PubDate: 2018-03-31
      DOI: 10.1007/s10295-018-2033-5
       
  • The influence of fatty acid supply and aldehyde reductase deletion on
           cyanobacteria alkane generating pathway in Escherichia coli
    • Authors: Juli Wang; Haiying Yu; Xuejiao Song; Kun Zhu
      Abstract: Cyanobacteria alkane synthetic pathway has been heterologously constructed in many microbial hosts. It is by far the most studied and reliable alkane generating pathway. Aldehyde deformylating oxygenase (i.e., ADO, key enzyme in this pathway) obtained from different cyanobacteria species showed diverse catalytic abilities. This work indicated that single aldehyde reductase deletions were beneficial to Nostoc punctiforme ADO-depended alkane production in Escherichia coli even better than double deletions. Fatty acid metabolism regulator (FadR) overexpression and low temperature increased C18:1 fatty acid supply, and in turn stimulated C18:1-derived heptadecene production, suggesting that supplying ADO with preferred substrate was important to overall alkane yield improvement. Using combinational methods, 1 g/L alkane was obtained in fed-batch fermentation with heptadecene accounting for nearly 84% of total alkane.
      PubDate: 2018-03-29
      DOI: 10.1007/s10295-018-2032-6
       
  • Substrate selection of adenylation domains for nonribosomal peptide
           synthetase (NRPS) in bacillamide C biosynthesis by marine Bacillus
           atrophaeus C89
    • Authors: Fengli Zhang; Yukun Wang; Qun Jiang; Qihua Chen; Loganathan Karthik; Yi-Lei Zhao; Zhiyong Li
      Abstract: Nonribosomal peptide synthetases (NRPSs) are multi-modular enzymes involved in the biosynthesis of natural products. Bacillamide C was synthesized by Bacillus atrophaeus C89. A nonribosomal peptide synthetase (NRPS) cluster found in the genome of B. atrophaeus C89 was hypothesized to be responsible for the biosynthesis of bacillamide C using alanine and cysteine as substrates. Here, the structure analysis of adenylation domains based on homologous proteins with known crystal structures indicated locations of the substrate-binding pockets. Molecular docking suggested alanine and cysteine as the potential substrates for the two adenylation domains in the NRPS cluster. Furthermore, biochemical characterization of the purified recombinant adenylation domains proved that alanine and cysteine were the optimum substrates for the two adenylation domains. The results provided the in vitro evidence for the hypothesis that the two adenylation domains in the NRPS of B. atrophaeus C89 preferentially select alanine and cysteine, respectively, as a substrate to synthesize bacillamide C. Furthermore, this study on substrates selectivity of adenylation domains provided basis for rational design of bacillamide analogs.
      PubDate: 2018-03-24
      DOI: 10.1007/s10295-018-2028-2
       
 
 
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