Showing papers on "2,3-Butanediol published in 2014"

Deletion of meso-2,3-butanediol dehydrogenase gene budC for enhanced D-2,3-butanediol production in Bacillus licheniformis

Abstract: D-2,3-butanediol has many industrial applications such as chiral reagents, solvents, anti-freeze agents, and low freezing point fuels. Traditional D-2,3-butanediol producing microorganisms, such as Klebsiella pneumonia and K. xoytoca, are pathogenic and not capable of producing D- 2,3-butanediol at high optical purity. Bacillus licheniformis is a potential 2,3-butanediol producer but the wild type strain (WX-02) produces a mix of D- and meso-type isomers. BudC in B. licheniformis is annotated as 2,3-butanediol dehydrogenase or acetoin reductase, but no pervious experiment was performed to verify this hypothesis. We developed a genetically modified strain of B. licheniformis (WX-02 Δbud C) as a D-2,3-butanediol producer with high optimal purity. A marker-less gene deletion protocol based on a temperature sensitive knock-out plasmid T2-Ori was used to knock out the bud C gene in B. licheniformis WX-02. The budC knock-out strain successfully abolished meso-2,3-butanediol production with enhanced D-2,3-butanediol production. No meso-BDH activity was detectable in cells of this strain. On the other hand, the complementary strain restored the characteristics of wild strain, and produced meso-2,3-butanediol and possessed meso-BDH activity. All of these data suggested that bud C encoded the major meso-BDH catalyzing the reversible reaction from acetoin to meso-2,3-butanediol in B. licheniformis. The bud C knock-out strain produced D- 2,3-butanediol isomer only with a high yield of 30.76 g/L and a productivity of 1.28 g/L-h. We confirmed the hypothesis that bud C gene is responsible to reversibly transfer acetoin to meso-2,3-butanediol in B. licheniformis. A mutant strain of B. licheniformis with depleted bud C gene was successfully developed and produced high level of the D-2,3-butanediol with high optimal purity.

NADH plays the vital role for chiral pure D-(-)-2,3-butanediol production in Bacillus subtilis under limited oxygen conditions.

Abstract: Compared with traditional pathogenic producers, Bacillus subtilis as a Class I microorganism offers many advantages for industrial-scale 2,3-butanediol production. Unlike previous reports in which two stereoisomers (with a ratio of 3:2) were produced, we first found that wild type B. subtilis 168 generates only D-(−)-2,3-butanediol (purity >99%) under low oxygen conditions. The total high yield of 2,3-butanediol and acetoin, and acetoin reductase enzyme assay indicate that it is the high level of NADH availability, instead of high acetoin reductase activity, contributes more to 2,3-butanediol production in B. subtilis. The strategy for increasing the pool of NADH availability, the key factor for 2,3-butanediol production, was designed through low dissolved oxygen control, adding reducing substrates and rationally metabolic engineering. A transhydrogenase encoded by udhA was introduced to provide more NADH from NADPH and allowed enhanced 2,3-butanediol production. Finally, BSF20 produced 49.29 g/L D(−)-2,3-butanediol. These results demonstrated that B. subtilis is a competitive producer for chiral 2,3-butanediol production. Biotechnol. Bioeng. 2014;111: 2126–2131. © 2014 Wiley Periodicals, Inc.

Mechanism of 2,3-butanediol stereoisomer formation in Klebsiella pneumoniae

Abstract: Klebsiella pneumoniae is known to produce meso-2,3-butanediol and 2S,3S-butanediol, whereas 2R,3R-butanediol was detected in the culture broth of K. pneumoniae CGMCC 1.6366. The ratio of 2R,3R-butanediol to all isomers obtained using glycerol as the carbon source was higher than that obtained using glucose as the carbon source. Therefore, enzymes involved in glycerol metabolism are likely related to 2R,3R-butanediol formation. In vitro reactions show that glycerol dehydrogenase catalyzes the stereospecific conversion of R-acetoin to 2R,3R-butanediol and S-acetoin to meso-2,3-butanediol. Butanediol dehydrogenase exhibits high (S)-enantioselectivity in ketone reduction. Genes encoding glycerol dehydrogenase, α-acetolactate decarboxylase, and butanediol dehydrogenase were individually disrupted in K. pneumoniae CGMCC 1.6366, and the 2,3-butanediol synthesis characteristics of these mutants were investigated. K. pneumoniae ΔdhaD lost the ability to synthesize 2R,3R-butanediol. K. pneumoniae ΔbudA showed reduced 2R,3R-butanediol synthesis. However, K. pneumoniae ΔbudC produced a high level of 2R,3R-butanediol, and R-acetoin was accumulated in the broth. The metabolic characteristics of these mutants and in vitro experiment results demonstrated the mechanism of the 2,3-butanediol stereoisomer synthesis pathway. Glycerol dehydrogenase, encoded by dhaD, exhibited 2R,3R-butanediol dehydrogenase activity and was responsible for 2R,3R-butanediol synthesis from R-acetoin. This enzyme also contributed to meso-2,3-butanediol synthesis from S-acetoin. Butanediol dehydrogenase, encoded by budC, was the only enzyme that catalyzed the conversion of diacetyl to S-acetoin and further to 2S,3S-butanediol.

Microbial production of 2,3-butanediol by a newly-isolated strain of Serratia marcescens

Abstract: A newly-isolated strain of Serratia marcescens, G12, was characterized for 2,3-butanediol (2,3-BD) production. In shake-flask and batch fermentations, 2,3-BD reached 48.5 and 51 g l−1, respectively. Low amounts of (~8 g l−1) of acetoin were also formed. In fed-batch fermentations, strain G12 produced 72.8 g 2,3-BD l−1 with glucose initially at 130 g l−1. When aeration rate was increased to 2.5 vvm for the fermentation process, 2,3-BD reached 87.8 g l−1 and the highest productivity was 1.6 g l−1 h−1. Acetoin was at 6.2 g l−1. G12 therefore may be a suitable candidate strain for large-scale production of 2,3-BD.

Production of 2-butanol through meso-2,3-butanediol consumption in lactic acid bacteria.

Abstract: 2-Butanol has been an issue of industries in many areas, for example, biofuel production (as an advanced alternate fuel), fermented beverages, and food (as taste-altering component). Thus, its source of production, the biological pathway, and the enzymes involved are of high interest. In this study, 42 different isolates of lactic acid bacteria from nine different species were screened for their capability to consume meso-2,3-butanediol and produce 2-butanol. Lactobacillus brevis was the only species that showed any production of 2-butanol. Five of ten tested isolates of L.brevis were able to convert meso-2,3-butanediol to 2-butanol in a synthetic medium (SM2). However, none of them showed the same capability in a complex medium such as MRS indicating that the ability to produce 2-butanol is subject to some kind of repression mechanism. Furthermore, by evaluating the performance of the enzymes required to convert meso-2,3-butanediol to 2-butanol, that is, the secondary alcohol dehydrogenase and the diol dehydratase, it was shown that the latter needed the presence of a substrate to be expressed.

2,3-butanediol production from starch by engineered Klebsiella pneumoniae G31-A.

Abstract: 2,3-Butanediol (2,3-BD) is an organic compound, which is widely used as a fuel and fuel additive and applied in chemical, food, and pharmaceutical industries. Contemporary strategies for its economic synthesis include the development of microbial technologies that use starch as cheap and renewable feedstock. The present work encompasses the metabolic engineering of the excellent 2,3-BD producer Klebsiella pneumoniae G31. In order to perform direct starch conversion into 2,3-BD, the amyL gene encoding quite active, liquefying α-amylase in Bacillus licheniformis was cloned under lac promoter control in the recombinant K. pneumoniae G31-A. The enhanced extracellular over-expression of amyL led to the highest extracellular amylase activity (68 U/ml) ever detected in Klebsiella. The recombinant strain was capable of simultaneous saccharification and fermentation (SSF) of potato starch to 2,3-BD. In SSF batch process by the use of 200 g/l starch, the amount of total diols produced was 60.9 g/l (53.8 g/l 2,3-BD and 7.1 g/l acetoin), corresponding to 0.31 g/g conversion rate. The presented results are the first to show successful starch conversion to 2,3-BD by K. pneumoniae in a one-step process.

Recombinant microorganism having enhanced 2,3-butanediol producing ability and method for producing 2,3-butanediol using the same

Abstract: The present invention relates to a recombinant microorganism with increased productivity of 2,3-butanediol, wherein a pathway for converting pyruvate to acetyl-CoA, a pathway for converting pyruvate to formic acid, or a pathway for converting pyruvate to lactate is inhibited in a microorganism having acetyl-CoA and lactate biosynthetic pathways.

Method for increasing yield of paenibacillus polymyxa 2,3-butanediol by using vitamin C

Abstract: The invention discloses a method for increasing the yield of paenibacillus polymyxa 2,3-butanediol by using vitamin C. The method comprises the following steps: (1) seed culture; (2) fermentation culture: inoculating secondary seeds into a fermentation culture medium, performing fermentation under the conditions that the ventilatory capacity is 0.1-0.8vvm, the stirring rotating speed is 300-500rpm and the temperature is 32-42 DEG C for 12-24 hours, and adding 80-160g/L vitamin C solution when the concentration of glucose in the fermentation culture medium is reduced to 2-10g/L. By the adoption of a method for continuously adding a reducing agent, the method disclosed by the invention is favorable for maintenance of a redox situation of an external environment in which bionts exist in the whole fermentation process, so that consumption of the glucose in fermentation liquid and conversion of acetoin are finally promoted, and the accumulation of (R,R)-2,2- butanediol is improved.

Method for producing 2,3-butanediol

Abstract: Disclosed is a method for producing 2,3-butanediol by microbial fermentation using biologically safe bacteria. This method for producing 2,3-butanediol includes a step in which Zymobacter bacteria are cultured in a fermentation raw material including a carbon source (step A), and a step in which the culture medium obtained in this step is refined into 2,3-butanediol (step B). In this method, the carbon source includes pentose, and the Zymobacter bacteria has a function of assimilating pentose.

Method for selectively producing 3-hydroxyl-2-butanone and 2, 3-butanediol through microbial fermentation

Abstract: The invention discloses a method for selectively producing 3-hydroxyl-2-butanone and 2, 3-butanediol by using an environmental safety bacterial strain Bacillus amyloliquefaciens with the CCTCC NO. M2012349 and changing the content of corn steep liquor in a medium, the stirring speed and the ventilation capacity, and belongs to the field of a fermentation technology in biological engineering. The method is characterized in that when the 3-hydroxyl-2-butanone is mainly synthesized, the concentration of the corn steep liquor in the fermentation medium can be reduced to be more than or equal to 5g/L, and the relatively high dissolved oxygen level (the air mass flow is 240m /h.m medium, and the stirring rotating speed is 450r/min) is maintained in a fermentation process; and when the 2, 3-butanediol is synthesized, the concentration of the corn steep liquor in the fermentation medium can be increased to be more than or equal to 40g/l, the relatively low dissolved oxygen level (the air mass flow is 120m /h.m medium, and the stirring rotating speed is 350r/min) is maintained in a fermentation process.

2,3-butanediol ester and preparation method thereof

Abstract: The invention relates to a 2,3- butanediol ester and a preparation method thereof, and belongs to the technical field of organic synthesis. A chemical structural formula of the 2,3- butanediol ester is as shown in the specification, wherein n is 1,2,3 or 4. The preparation for the 2,3- butanediol ester has two ways: one way is that the 2,3- butanediol ester is prepared by reaction of 2,3-epoxybutane and acid CnH2nO2; and the other way is that the 2,3- butanediol ester is prepared by reaction of 2,3- butanediol and acid CnH2nO2. The 2,3- butanediol ester disclosed by the invention has characteristics of being simple in preparation process, low in cost and wide in application field. And the preparation method is simple and easy to implement, and easy to realize.

Recombinant microorganism with increased productivity of 2,3-butanediol, and method for producing 2,3-butanediol using same

Abstract: Disclosed herein is a recombinant microorganism having enhanced 2,3-butanediol producing ability, wherein a pathway for converting pyruvate to acetyl-CoA, a pathway for converting pyruvate to formic acid, or a pathway for converting pyruvate to lactate is inhibited in a microorganism having acetyl-CoA and lactate biosynthetic pathways.

The production method of 2,3-butanediol

Abstract: PROBLEM TO BE SOLVED: To obtain 2,3-butanediol efficiently in a high yield from 3-hydroxy-2-butanone, especially by hydrogenation of an acetoin in a fermentation product obtained by biological fermentation.SOLUTION: A production method of 2,3-butanediol comprises subjecting a raw material containing 2-hydroxy-3-butanone to a reductive reaction in a hydrogen gas atmosphere in the presence an inhomogeneous metal catalyst to convert 2-hydroxy-3-butanone to 2,3-butanediol. The method especially improves the efficiency of the fermentation production of 2,3-butanediol by microorganisms.

Recombinant microorganism with increased productivity of 2,3-butanediol, and method for producing 2,3-butanediol using same

Abstract: The present invention relates to a recombinant microorganism with increased productivity of 2,3-butanediol, wherein a pathway for converting pyruvate to acetyl-CoA, a pathway for converting pyruvate to formic acid, or a pathway for converting pyruvate to lactate is inhibited in a microorganism having acetyl-CoA and lactate biosynthetic pathways.

Characterization of a 2,3-Butanediol Producing Bacterial Strain and Optimization of Fermentation Medium

Abstract: A bacterial strain G12 capable of producing high content of 2,3- butanediol (2,3-BD, BD) was isolated from raw milk samples. With the analysis of its 16S rRNA gene sequence, strain G12 was identified as Serratia marcescens. Carbon source evaluation experiments showed that with glycerol as carbon source, strain G12 produced relatively high amount of 2,3-BD and the lowest amount of byproduct acetoin among the tested carbon sources. Furthermore, the optimal fermentation medium was determined by single factor experiments and orthogonal experimental design, and it was composed of glycerin 130 g/L, peptone 16 g/L, yeast extract 5 g/L, K2HPO4 1 g/L, and MnSO4·7H2O 0.025 g/L. Confirmation experiments were also performed. The final yield of 2,3-BD in the shaking-flask was up to 37.400 g/L, and the substrate conversion rate was 79.62 % of the theoretical value.

Recombinant microorganism with increased productivity of 2,3-butanediol, and method for producing 2,3-butanediol using same

Abstract: The present invention relates to a recombinant microorganism with increased productivity of 2,3-butanediol, wherein a pathway for converting pyruvate to acetyl-CoA, a pathway for converting pyruvate to formic acid, or a pathway for converting pyruvate to lactate is inhibited in a microorganism having acetyl-CoA and lactate biosynthetic pathways.

Recombinant microorganism having enhanced ability to produce 2,3-butanediol, and method for producing 2,3-butanediol using same

Abstract: The present invention relates to a gene which codes an enzyme having conversion activity between acetoin and 2,3-butanediol and has a nucleotide sequence of SEQ ID NO: 12. Further, the present invention relates to a protein coded by the gene. Further, the present invention relates to a recombinant microorganism having suppressed activity of the protein.