2,3-Butanediol

About: 2,3-Butanediol is a research topic. Over the lifetime, 299 publications have been published within this topic receiving 6016 citations. The topic is also known as: Pseudobutylene glycol & Dimethylene glycol.

Bacterial 2,3-butanediol dehydrogenases.

Abstract: Enterobacter aerogenes, Aeromonas hydrophila, Serratia marcescens and Staphylococcus aureus possessing L(+)-butanediol dehydrogenase produced mainly meso-butanediol and small amounts of optically active butanediol; Acetobacter suboxydans, Bacillus polymyxa and Erwinia carotovora containing D(-)-butanediol dehydrogenase produced more optically active butanediol than meso-butanediol. Resting and growing cells of these organisms oxidezed only one enantiomer of racemic butanediol. The D(-)-butanediol dehydrogenase from Bacillus polymyxa was partially purified (30-fold) with a specific activity of 24.5. Except NAD and NADH no other cofactors were required. Optimum pH-values for oxidation and reduction were pH 9 and pH 7, respectively. The optimum temperature was about 60 degrees C. The molecular weight was 100000 to 107000. The Km-values were 3.3 mM for D(-)butanediol, 6.25 mM for meso-butanediol, 0.53 mM for acetoin, 0.2 mM for NAD, 0.1 mM for NADH, 87 mM for diacetyl, 38 mM for 1,2-propanediol; 2,3-pentanedion was not a substrate for this enzyme. The L(+)butanediol dehydrogenase from Serratia marcescens was purified 57-fold (specific activity 22.3). Besides NAD or NADH no cofactors were required. The optimum value for oxidation was about pH9 and for reduction pH 4.5. The optimum temperature was 32-36 degrees C. The molecular weight was 100000 to 107000. The Km-values were 5 mM for meso-butanediol, 10 mM for racemic butanediol, 6.45 for acetoin, 1 mM for NAD, 0.25 mM for NADH, 2.08 mM for diacetyl, 16.7 mM for 2,3-pentanedion and 11.8 mM for 1,2-propanediol.

Enhanced 2,3-Butanediol Production by Optimizing Fermentation Conditions and Engineering Klebsiella oxytoca M1 through Overexpression of Acetoin Reductase

Abstract: Microbial production of 2,3-butanediol (2,3-BDO) has been attracting increasing interest because of its high value and various industrial applications. In this study, high production of 2,3-BDO using a previously isolated bacterium Klebsiella oxytoca M1 was carried out by optimizing fermentation conditions and overexpressing acetoin reductase (AR). Supplying complex nitrogen sources and using NaOH as a neutralizing agent were found to enhance specific production and yield of 2,3-BDO. In fed-batch fermentations, 2,3-BDO production increased with the agitation speed (109.6 g/L at 300 rpm vs. 118.5 g/L at 400 rpm) along with significantly reduced formation of by-product, but the yield at 400 rpm was lower than that at 300 rpm (0.40 g/g vs. 0.34 g/g) due to acetoin accumulation at 400 rpm. Because AR catalyzing both acetoin reduction and 2,3-BDO oxidation in K. oxytoca M1 revealed more than 8-fold higher reduction activity than oxidation activity, the engineered K. oxytoca M1 overexpressing the budC encoding AR was used in fed-batch fermentation. Finally, acetoin accumulation was significantly reduced by 43% and enhancement of 2,3-BDO concentration (142.5 g/L), yield (0.42 g/g) and productivity (1.47 g/L/h) was achieved compared to performance with the parent strain. This is by far the highest titer of 2,3-BDO achieved by K. oxytoca strains. This notable result could be obtained by finding favorable fermentation conditions for 2,3-BDO production as well as by utilizing the distinct characteristic of AR in K. oxytoca M1 revealing the nature of reductase.

Microbial production of meso-2,3-butanediol by metabolically engineered Escherichia coli under low oxygen condition.

Abstract: A metabolically engineered Escherichia coli has been constructed for the production of meso-2,3-butanediol (2,3-BD) under low oxygen condition. Genes responsible for 2,3-BD formation from pyruvate were assembled together to generate a high-copy plasmid pEnBD, in which each gene was transcribed with a constitutive promoter. To eliminate by-product formation under low oxygen condition, genes including ldhA, pta, adhE, and poxB which functioned for the mixed acid fermentation pathways were deleted in E. coli JM109. Compared with the wild type, the quadruple gene deletion mutant produced smaller amounts of acetate, succinate, and ethanol from glucose when cultivated in LB medium in shake flasks under low-aeration. When 2,3-BD producing pathway was introduced via pEnBD into the mutant, higher glucose consumption and faster 2,3-BD production rate compared with that of the wild-type control were observed under aerobic condition in shake flasks. In a 6-L fermentor supplied with only 3% dissolved oxygen (DO), the mutant harboring pEnBD converted glucose to 2,3-BD much faster than the control did. When DO supply was further lowered to 1% DO, the recombinant mutant grew much slower but produced 2,3-BD as a major fermentation metabolic product. In addition, the 2,3-BD yield showed an increase from 0.20 g BD/g glucose for the control to 0.43 g BD/g glucose for the mixed acid pathway deleted mutant grown in fermentors under 1% DO. These results reveals the potential of production of enantiomerically pure 2,3-BD isomer by recombinant E. coli under low oxygen condition.