The present invention provides a dehydrogenase mutant L283V/L286V, and a preparation method and use thereof, and relates to the field of biomedicine technologies. An amino acid sequence of the mutant L283V/L286V is as shown in SEQ ID NO: 1; and the mutant is prepared by simultaneously mutating 283.sup.rd and 286.sup.th leucine of a dehydrogenase with an amino acid sequence as shown in SEQ ID NO: 3 into valine. The dehydrogenase mutant L283V/L286V shows high selectivity in catalyzing myosmine reduction reaction in a whole cell system to produce S-nornicotine, and has relatively high dehydrogenase and imine reductase activities, a short enzyme reduction time, and a high transformation rate. The product S-nornicotine obtained through the reaction has extremely high optical purity, which reduces the operation difficulty of subsequent purification.

The present disclosure relates to a microorganism producing L-valine and a method for producing L-valine using the microorganism.

The present disclosure relates to a novel pyruvate dehydrogenase variant, a polynucleotide encoding the pyruvate dehydrogenase variant, a microorganism of the genus Corynebacterium producing L-amino acid, which includes the pyruvate dehydrogenase variant, and a method for producing an L-amino acid using the microorganism.

An engineered microorganism(s) with novel pathways for the conversion of short-chain hydrocarbons to fuels and chemicals (e.g. carboxylic acids, alcohols, hydrocarbons, and their alpha-, beta-, and omega-functionalized derivatives) is described. Key to this approach is the use of hydrocarbon activation enzymes able to overcome the high stability and low reactivity of hydrocarbon compounds through the cleavage of an inert CH bond. Oxygen-dependent or oxygen-independent activation enzymes can be exploited for this purpose, which when combined with appropriate pathways for the conversion of activated hydrocarbons to key metabolic intermediates, enables the generation of product precursors that can subsequently be converted to desired compounds through established pathways. These novel engineered microorganism(s) provide a route for the production of fuels and chemicals from short chain hydrocarbons such as methane, ethane, propane, butane, and pentane.

A method of treating a biofilm on a surface, comprising: providing a surface having a biofilm; and administering to the surface a treatment that reduces a concentration of pyruvate of the biofilm, comprising pyruvate produced by at least a portion the biofilm, under conditions effective reducing maintenance of the biofilm on the surface. A composition, comprising purified enzyme, within a particle, effective for reducing pyruvate concentration in an aqueous suspension of the composition.

A method for preparing glycine by using threonine relates to a fermentation process in which threonine is decomposed into glycine and acetaldehyde by aldolase. Glycine and acetyl coenzyme A can be produced in a fermentation process, in which acetaldehyde is reduced into acetyl coenzyme A or an acetyl coenzyme A derivative by acetylating acetaldehyde dehydrogenase; or threonine is dehydrogenated by threonine dehydrogenase to obtain 2-amino-3-ketobutyric acid, which is then ligated by 2-amino-3-ketobutyrate CoAligase to obtain acetyl coenzyme A. Coenzyme A can be converted into an acetyl coenzyme A derivative under different fermentation conditions.

The present disclosure relates to a novel pyruvate dehydrogenase variant, a polynucleotide encoding the pyruvate dehydrogenase variant, a microorganism of the genus Corynebacterium producing L-amino acid, which includes the pyruvate dehydrogenase variant, and a method for producing an L-amino acid using the microorganism.

The invention features compositions and methods for the increased production of mevalonate, isoprene, isoprenoid precursor molecules, and/or isoprenoids in microorganisms by engineering a microorganism for increased carbon flux towards mevalonate production in the following enzymatic pathways: (a) citrate synthase, (b) phosphotransacetylase, (c) acetate kinase, (d) lactate dehydrogenase, (e) malic enzyme, and (f) pyruvate dehydrogenase such that one of more of the enzyme activity is modulated. In addition, production of mevalonate, isoprene, isoprenoid precursor molecules, and/or isoprenoids can be further enhanced by the heterologous expression of the mvaE and mvaS genes (such as, but not limited to, mvaE and mvaS genes from the organisms Listeria grayi DSM 20601, Enterococcus faecium, Enterococcus gallinarum EG2, and Enterococcus casseliflavus).

This invention relates to metabolically engineered microorganism strains, such as bacterial strains, in which there is an increased utilization of malonyl-CoA for production of a chemical product, which includes 3-hydroxypropionic acid.

The present invention provides methods and compositions for reducing lactate production and increasing polypeptide production in cultured cells. In one aspect, the invention provides a method comprising culturing cells expressing a) a small interfering RNA (siRNA) specific for a lactate dehydrogenase (LDH) and b) an siRNA specific for a pyruvate dehydrogenase kinase (PDHK). In another aspect, the invention provides cultured cells or vectors comprising an siRNA specific for a LDH and an siRNA specific for a PDHK.