Application of glutamate dehydrogenase GdhA of Peptostreptococcus asaccharolyticus in increasing the yield of poly-γ-glutamic acid from Bacillus licheniformis. The glutamate dehydrogenase GdhA of the Bacillus licheniformis WX-02 per se is replaced with the glutamate dehydrogenase derived from the Peptostreptococcus asaccharolyticus by means of homologous recombination, which significantly increases the level of synthesizing the poly-γ-glutamic acid for the Bacillus licheniformis, and the yield of the obtained poly-γ-glutamic acid from strains is increased at least by more than 20% compared with control strains.

The present invention relates to glutamate dehydrogenase mutants and their application in preparation of L-phosphinothricin. The amino acid sequences of the glutamate dehydrogenase mutants are as shown in SEQ ID NO. 1-9, 11, 13, 15, 17-19 and 22. By means of molecular engineering, mutating the specific alanine in glutamate dehydrogenase substrate-binding pocket into glycine and/or mutating the specific valine in glutamate dehydrogenase substrate-binding pocket into alanine, the present invention has obtained NADPH-specific glutamate dehydrogenase mutants with high enzyme activity in catalyzing the substrate 2-oxo-4-[(hydroxy)(methyl)phosphinoyl]butyric acid or its salt for L-phosphinothricin preparation or NADH-specific glutamate dehydrogenase mutants with catalytic activity toward PPO; this has significantly improved substrate conversion, and increased the product concentration of the L-phosphinothricin preparation process.

The disclosure relates to host cells having altered NADPH availability, allowing for increased production of compounds produced using NADPH, and methods of use thereof. NADPH availability is altered by one or more of: expressing an altered GAPDH, expressing a variant glutamate dehydrogenase (gdh), aspartate semialdehyde dehydrogenase (asd), dihydropicolinate reductase (dapB), and meso-diaminopimelate dehydrogenase (ddh), expressing a novel nicotinamide nucleotide transhydrogenase, expressing a novel threonine aldolase, and expressing or modulating the expression of a pyruvate carboxylase in the host cells.

The present invention relates to glutamate dehydrogenase mutants and their application in preparation of L-phosphinothricin. The amino acid sequences of the glutamate dehydrogenase mutants are as shown in SEQ ID NO. 19, 11, 13, 15, 1719 and 22. By means of molecular engineering, mutating the specific alanine in glutamate dehydrogenase substrate-binding pocket into glycine and/or mutating the specific valine in glutamate dehydrogenase substrate-binding pocket into alanine, the present invention has obtained NADPH-specific glutamate dehydrogenase mutants with high enzyme activity in catalyzing the substrate 2-oxo-4-[(hydroxy)(methyl)phosphinoyl]butyric acid or its salt for L-phosphinothricin preparation or NADH-specific glutamate dehydrogenase mutants with catalytic activity toward PPO; this has significantly improved substrate conversion, and increased the product concentration of the L-phosphinothricin preparation process.

Disclosed are a gene mining method combining functional sequence and structure simulation, an NADH-preferring phosphinothricin dehydrogenase mutant and an application thereof. The gene mining method comprises the following steps: (1) analyzing a characteristic sequence which an NADH-type glutamate dehydrogenase should have; (2) searching a gene library based on the characteristic sequence; (3) performing clustering analysis and protein structure simulation on genes obtained by the searching; (4) selecting genes that feature high gene aggregation and a protein structure similar to that of the known phosphinothricin dehydrogenase as candidate genes. A wild-type phosphinothricin dehydrogenase with an amino acid sequence as set forth in SEQ ID No.2 derived from Lysinibacillus composti is obtained through the gene mining, and then mutated, and an NADH-preferring phosphinothricin dehydrogenase mutant is screened out, which has a mutation site selected from one of the following: (1) A144G-V375F-M91A; (2) A144G-V345A-M91A; (3) A144G. This mutant enzyme can be used for catalytic reaction with an inexpensive coenzyme NAD.

The disclosure relates to host cells having altered NADPH availability, allowing for increased production of compounds produced using NADPH, and methods of use thereof. NADPH availability is altered by one or more of: expressing an altered GAPDH, expressing a variant glutamate dehydrogenase (gdh), aspartate semialdehyde dehydrogenase (asd), dihydropicolinate reductase (dapB), and meso-diaminopimelate dehydrogenase (ddh), expressing a novel nicotinamide nucleotide transhydrogenase, expressing a novel threonine aldolase, and expressing or modulating the expression of a pyruvate carboxylase in the host cells.

Methods for increasing carbon-based chemical product yield in an organism by genetically modifying one or more genes involved in a stringent response and/or in a regulatory network, nonnaturally occurring organisms having increased carbon-based chemical product yield, and methods for use in production of carbon-based chemical products are provided.

Application of glutamate dehydrogenase GdhA of Peptostreptococcus asaccharolyticus in increasing the yield of poly-?-glutamic acid from Bacillus licheniformis. The glutamate dehydrogenase GdhA of the Bacillus licheniformis WX-02 per se is replaced with the glutamate dehydrogenase derived from the Peptostreptococcus asaccharolyticus by means of homologous recombination, which significantly increases the level of synthesizing the poly-?-glutamic acid for the Bacillus licheniformis, and the yield of the obtained poly-?-glutamic acid from strains is increased at least by more than 20% compared with control strains.

The present invention concerns a method for the production of derivatives of 4-hydroxy-2-ketobutyrate chosen among 1,3-propanediol or 2,4-dihydroxybutyrate by culturing a genetically modified microorganism for the production of the desired derivative of 4-hydroxy-2-ketobutyrate, the microorganism further comprising a gene coding for a mutant glutamate dehydrogenase converting by deamination L-homoserine into 4-hydroxy-2-ketobutyrate. The invention also concerns said genetically modified microorganism.

The present disclosure relates to relates to promoter variants and Corynebacterium mutant strain, and methods of use thereof.