A process for producing butanol is provided, involving: A) mixing water, lactate, an enzyme mixture comprising at least one enzyme, at least one cofactor and at least one coenzyme, to prepare a reaction mixture; B) catalytically reacting the reaction mixture for an amount of time sufficient to cause conversion of lactate into butanol; and wherein the conversion of lactate into butanol in B) is associated with a regeneration system of NAD (P).sup.+/NAD (P) H and/or acetyl-CoA/CoA.

A method for the preparation of 2,4-dihydroxybutyric acid from homoserine includes a first step of conversion of the primary amino group of homoserine to a carbonyl group to obtain 2-oxo-4-hydroxybutyrate, and a second step of reduction of the obtained 2-oxo-4-hydroxybutyrate (OHB) to 2,4-dihydroxybutyrate.

Industrial fermentation for the production of lactic acid from organic waste combined with chemical recycling of polylactic acid are provided, to obtain lactic acid at high yields.

Disclosed is a method of producing lactic acid using a recombinant acid-resistant yeast with inhibited lactate metabolism and alcohol production. More specifically, disclosed are a recombinant acid-resistant yeast in which lactate consumption reaction is reduced and which is imparted with lactic-acid-producing ability to thereby exhibit improved lactic-acid-producing ability and reduced ethanol production, and a method of producing lactic acid using the same.

The present invention relates to a process of producing isobutanol, including: mixing water, lactate, an enzyme mixture including at least one enzyme, at least one cofactor, and at least one coenzyme, to prepare a reaction mixture; allowing catalytic conversions of lactate in the reaction mixture for a sufficient amount of time to produce isobutanol; and separating the isobutanol from a reactant obtained by the catalytic conversions, in which the conversion of lactate into isobutanol is in association with a NADH.sup.+/NADH and/or NADP.sup.+/NADPH regenerating system.

Disclosed is a method of producing lactic acid using a recombinant acid-resistant yeast with inhibited lactate metabolism and alcohol production. More specifically, disclosed are a recombinant acid-resistant yeast in which lactate consumption reaction is reduced and which is imparted with lactic-acid-producing ability to thereby exhibit improved lactic-acid-producing ability and reduced ethanol production, and a method of producing lactic acid using the same.

The invention relates to a genetically engineered thermophilic bacterial cell that is facultative anaerobic comprising: a) inactivation or deletion of the endogenous (S)-lactate dehydrogenase gene; b) introduction of a (R)-lactate dehydrogenase gene; c) inactivation or deletion of the endogenous pyruvate formate lyase A and/or B gene.

The present invention discloses a bacterium and an obtaining method and application thereof. The bacterium has a property of coproducing 1,3-propanediol and D-lactic acid. Further, the bacterium is Klebsiella oxytoca, including Klebsiella oxytoca PDL-5 CCTCC M 2016185. The obtaining method of the bacterium may be to obtain the bacterium by directly screening wild bacteria that satisfy conditions from the environment or performing gene engineering modification to wild bacteria. The present invention has the advantages that the bacteria can coproduce 1,3-propanediol and D-lactic acid through fermentation, the molar conversion rate and the concentration of the two products are very high, the types of byproducts are few, the concentration is low, the product extraction process is simplified, the high-efficiency biological production of 1,3-propanediol and D-lactic acid can be realized, and the industrial application prospect is very great.

The present invention discloses a bacterium and an obtaining method and application thereof. The bacterium has a property of coproducing 1,3-propanediol and D-lactic acid. Further, the bacterium is Klebsiella oxytoca, including Klebsiella oxytoca PDL-5 CCTCC M 2016185. The obtaining method of the bacterium may be to obtain the bacterium by directly screening wild bacteria that satisfy conditions from the environment or performing gene engineering modification to wild bacteria. The present invention has the advantages that the bacteria can coproduce 1,3-propanediol and D-lactic acid through fermentation, the molar conversion rate and the concentration of the two products are very high, the types of byproducts are few, the concentration is low, the product extraction process is simplified, the high-efficiency biological production of 1,3-propanediol and D-lactic acid can be realized, and the industrial application prospect is very great.

The present invention provides D-lactate dehydrogenase, an engineered strain containing the D-lactate dehydrogenase and a construction method and use of the engineered strain. The present invention discloses a D-lactate dehydrogenase which has unique properties and is from Thermodesulfatator indicus, and the D-lactate dehydrogenase has good thermophily and heat stability. By using the D-lactate dehydrogenase and the gene engineering reconstruction method, a fermentation product of the reconstructed Bacillus licheniformis can be redirected to optically-pure D-lactic acid with a high yield from naturally produced 2,3-butanediol, and the optical purity of the produced D-lactic acid reaches 99.9%; and raw materials for fermentation are low-cost, and a fermentation state is between an anaerobic fermentation state and a microaerobic fermentation state. By using the inventive method for producing D-lactic acid through fermentation at high temperature, the production cost can be reduced, the production efficiency can be improved and there is a wide industrial application prospect for the inventive method.