Shanghai Jiaotong University

Fei Tao

Ping Xu

Hongzhi Tang

Cuiqing Ma

Yu Ying Wang

Chao Li

Bo Xin

Bo Zhao

Limin Wang

Geng Wu

Fei Su

Kunzhi Zhang

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, includingPDL-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.

Bacterium and obtaining method and application thereof

Provides an artificial enzyme obtained by improving upon a sequence of a natural nicotine dehydrogenase, wherein the improvement comprises replacing at least one amino acid hindering product release with an amino acid with smaller side chains, thereby improving a catalytic rate.

Enzyme and application thereof

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, 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 reconstructedcan 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.

D-lactate dehydrogenase, engineered strain containing D-lactate dehydrogenase and construction method and use of engineered strain

Provided herein is D-lactate dehydrogenase, an engineered strain containing the D-lactate dehydrogenase, and a construction method and use of the engineered strain. The D-lactate dehydrogenase has unique properties and is from, 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 reconstructedcan 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 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 method.

The invention is concerned with the strains offor lactic acid production and the related methods, in which the carbon sources are pentose or hexose or the agricultural or industrial wastes containing pentose or hexose or a mixture of both. According to the invention, the highest amount of-lactic acid produced from glucose is 173 g/L, the optical purity is over 99%, the yield is up to 0.98, and the productivity is up to 2.4 g/L per hour. The highest amount of-lactic acid produced from xylose is 195 g/L, the optical purity is over 99%, the yield is up to 0.98, and the productivity is up to 2.7 g/L per hour. The highest amount of-lactic acid produced from reducing sugars in xylitol byproducts is 106 g/L, the optical purity is over 99%, and the productivity is up to 2.08 g/L per hour. Thestrains XZL4 (DSM No. 23183) and XZL9 (DSM No. 23184) of the invention can directly utilize various reducing sugars in xylitol byproducts to produce high amounts of-lactic acid, which improves the production efficiency at low costs, and the strains are, thus, appropriate for industrial productions.

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Shanghai, China

Fei Tao