Patent ID: 9279137
Filing Date: 2016-03-08
CPC Classification: C12N,C12P,C12Y,Y02P

Claim Text:
1. A method for producing a branched-chain L-amino acid comprising cultivating a recombinant microorganism from the Enterobacteriaceae family in a culture medium, and collecting the branched-chain L-amino acids from the culture medium, wherein said recombinant microorganism has been transformed with a vector comprising an isolated DNA coding for a mutant small subunit of bacterial acetolactate synthase (AHAS I) or the isolated DNA has been introduced into the chromosome of said recombinant microorganism, wherein the amino acid sequence of said mutant small subunit comprises the amino acid sequence shown in SEQ ID NO: 2, and also comprises a mutation selected from the group consisting of: A) replacing the L-amino acid at position 17 in the amino acid sequence of SEQ ID NO: 2 with a lysine residue, B) replacing the L-amino acid at position 30 in the amino acid sequence of SEQ ID NO: 2 with another L-amino acid, C) replacing the sequence from the L-amino acid at position 44 to the C-terminus in the amino acid sequence of SEQ ID NO: 2 with 1 to 10 L-amino acids, and D) combinations thereof; and wherein said bacterial acetolactate synthase comprising said mutant small subunit is expressed, and is desensitized to feedback inhibition by valine.