Bacillus subtilis produces acetoin as a major extracellular product. However, the by-products of 2,3-butanediol, lactic acid and ethanol were accompanied in the NADH-dependent pathways. In this work, metabolic engineering strategies were proposed to redistribute the carbon flux to acetoin by manipulation the NADH levels. We first knocked out the acetoin reductase gene bdhA to block the main flux from acetoin to 2,3-butanediol. Then, among four putative candidates, we successfully screened an active water-forming NADH oxidase, YODC. Moderate-expression of YODC in the bdhA disrupted B. subtilis weakened the NADH-linked pathways to by-product pools of acetoin. Through these strategies, acetoin production was improved to 56.7g/l with an increase of 35.3%, while the production of 2,3-butanediol, lactic acid and ethanol were decreased by 92.3%, 70.1% and 75.0%, respectively, simultaneously the fermentation duration was decreased 1.7-fold. Acetoin productivity by B. subtilis was improved to 0.639g/(lh).
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http://dx.doi.org/10.1016/j.ymben.2014.02.002 | DOI Listing |
Front Microbiol
January 2025
Research Institute of International Agriculture, Technology and Information, Hankyong National University, Anseong-si, Republic of Korea.
Volatile organic compounds (VOCs) produced by potential plant growth-promoting rhizobacteria (PGPR) play an important role in plant interactions. However, the mechanisms underlying this phenomenon are not well understood. Our findings show that the influence of VOCs from the PGPR strain (EXTN-1) on tobacco plant growth is dependent on the culture media used.
View Article and Find Full Text PDFFood Chem X
January 2025
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education. Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control. School of Biological Engineering, Tianjin University of Science and Technology, Tianjin 300457, China.
Traditional cereal vinegars are fermented by microorganisms that are spontaneously enriched, leading to uncertainty in regulating the fermentation process and flavor. The objective of this study was to elucidate the impact of the predominant microorganisms, provenly and , on the solid-state fermentation (SSF) and flavor profile of cereal vinegar by several bioaugmentation strategies. The results indicated that the sequential bioaugmentation of predominant microorganisms improved the utilization of raw material and most key flavor compounds.
View Article and Find Full Text PDFFood Res Int
February 2025
State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 PR China. Electronic address:
In this work, the functional activities including α-glucosidase, α-amylase, angiotensin converting enzyme (ACE) inhibitory activity, and antioxidant activity of mixed grains (mung beans, cowpeas, and quinoa) fermented with Bacillus amyloliquefaciens SY07 were investigated. The volatile flavor of the mixed grains collected every 12 h during 72 h-fermentation were further detected as well. The inhibition on α-glucosidase and α-amylase reached up to 89.
View Article and Find Full Text PDFJ Chem Ecol
January 2025
Centre des Sciences du Goût et de l'Alimentation, UMR-CNRS 6265, INRAe, Université de Bourgogne, Dijon, France.
Geographical, ethological, temporal and ecological barriers can affect interbreeding between populations deriving from an ancestral population, this progressively leading to speciation. A rare case of incipient speciation currently occurs between Drosophila melanogaster populations sampled in Zimbabwe (Z) and all other populations (M). This phenomenon was initially characterized by Z females refusing to mate with M males.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
School of Life Science, Shanxi University, Taiyuan 030006, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China. Electronic address:
Acetoin (AC) and 2,3-butanediol (2,3-BDO) are metabolites produced by lactic acid bacteria using glucose as a carbon source. These two metabolites act as carbon reserves and can be reutilised by the cells. In this study, we investigated the enzymatic characteristics of acetoin reductase (ButA) and 2,3-butanediol dehydrogenase (ButB).
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