Taking Corynebacterium glutamicum YP97158 as the starting bacterium, introducing site-directed mutation and/or expression enhancement in the coding region of its NCgl1089 gene, the coding region of NCgl0761 gene, and/or the coding region of ptsS gene, the obtained mutant gene and the recombination comprising said gene has high-efficiency L-amino acids production capacity, which greatly increases the output of L-amino acids, and the strain has good stability, which reduces the production cost as an L-amino acids production strain.

Taking Corynebacterium glutamicum YP97158 as the starting bacterium, introducing site-directed mutation and/or expression enhancement in the coding region of its NCgl1089 gene, the coding region of NCgl0761 gene, and/or the coding region of ptsS gene, the obtained mutant gene and the recombination comprising said gene has high-efficiency L-amino acids production capacity, which greatly increases the output of L-amino acids, and the strain has good stability, which reduces the production cost as an L-amino acids production strain.

A bacterium for producing L-amino acid has improved expression of a polynucleotide encoding a protein represented by SEQ ID NO:3 and improved expression of a polynucleotide encoding a protein represented by SEQ ID NO:31, and/or has mutations in bases at positions −45 bp and −47 bp of a promotor region represented by SEQ ID NO:57. A polynucleotide, encodes proteins and can be included in a recombinant vector, which can be included in a recombinant strain. These are useful in a method for producing L-amino acid. The polynucleotide encodes a protein which is represented by SEQ ID NO:3 and has arginine at position 334 substituted by a terminator or encodes a protein which is represented by SEQ ID NO:31 and has tyrosine at position 592 substituted by phenylalanine, or is formed by mutations in bases at positions −45 bp and −47 bp of a promotor region represented by SEQ ID NO:57.

The present invention provides a method for producing an L-amino acid such as a branched-chain L-amino acid by fermentation using a bacterium of the family Enterobacteriaceae, particularly a bacterium belonging to the genus Escherichia, which has been modified to attenuate expression of the gshA gene.

The present invention provides a method for producing an L-amino acid such as a branched-chain L-amino acid by fermentation using a bacterium of the family Enterobacteriaceae, particularly a bacterium belonging to the genus Escherichia, which has been modified to attenuate expression of the gshA gene.

Described are methods for increasing the production of small molecules in a submerged Corynebacterium culture by supplementing Corynebacterium growth medium with the non-enzymatic fraction of spent Trichoderma fermentation broth.

Described are methods for increasing the production of small molecules in a submerged Corynebacterium culture by supplementing Corynebacterium growth medium with the non-enzymatic fraction of spent Trichoderma fermentation broth.

The present disclosure describes the engineering of microbial cells for fermentative production of 3-amino-4-hydroxybenzoic acid and provides novel engineered microbial cells and cultures, as well as related 3-amino-4-hydroxybenzoic acid production methods. Embodiments 1: An engineered microbial cell that produces 3-amino-4-hydroxybenzoic acid, wherein the engineered microbial cell expresses: (a) a non-native 2-amino-4,5-dihydroxy-6-oxo-7-(phosphooxy) heptanoate synthase; and (b) a non-native 3-amino-4-benzoic acid synthase.

The present disclosure describes the engineering of microbial cells for fermentative production of 3-amino-4-hydroxybenzoic acid and provides novel engineered microbial cells and cultures, as well as related 3-amino-4-hydroxybenzoic acid production methods. Embodiments 1: An engineered microbial cell that produces 3-amino-4-hydroxybenzoic acid, wherein the engineered microbial cell expresses: (a) a non-native 2-amino-4,5-dihydroxy-6-oxo-7-(phosphooxy) heptanoate synthase; and (b) a non-native 3-amino-4-benzoic acid synthase.

The present invention belongs to the bioengineering field, and relates to a method for fermentation production of L-theanine by using an Escherichia coli genetically engineered bacterium. The engineered bacterium is obtained by serving a strain as an original strain, wherein the strain is obtained after performing a single copy of T7RNAP, a dual copy of gmas, xylR knockout, and sucCD knockout on an Escherichia coli W3110 genome, and by integrating genes xfp, pta, acs, gltA, and ppc, and knocking out ackA on the genome. The present invention has a high yield, and stable production performance; after 20-25 h, L-theanine has a titer of 75-80 g/L, and the yield is up to 52-55%. The fermentation broth is purified by membrane separation in combination with a cation-anion resin series technique. Moreover, the one-step crystallization yield is 72.3% and the L-theanine final product has a purity of 99%.