METHOD FOR PRODUCING AN L-AMINO ACID USING A BACTERIUM OF THE FAMILY ENTEROBACTERIACEAE HAVING AN ATTENUATED EXPRESSION OF A gshA GENE

Patent metadata

Field	Value
Publication number	US-2016348089-A1
Application number	US-201615165606-A
Country	US
Kind code	A1
Filing date	May 26, 2016
Priority date	May 28, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

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.

First claim

1 . A method for producing an L-amino acid comprising:
(i) cultivating an L-amino acid-producing bacterium of the family Enterobacteriaceae in a culture medium to produce the L-amino acid in the culture medium, the bacterium, or both; and (ii) collecting said L-amino acid from the culture medium, the bacterium, or both, wherein said bacterium has been modified to attenuate expression of a gshA gene.

2 . The method according to claim 1 , wherein said bacterium belongs to the genus Escherichia.

3 . The method according to claim 2 , wherein said bacterium is Escherichia coli.

4 . The method according to claim 1 , wherein said bacterium belongs to the genus Pantoea.

5 . The method according to claim 4 , wherein said bacterium is Pantoea ananatis.

6 . The method according to claim 1 , wherein said expression of the gshA gene is attenuated by inactivation of the gshA gene.

7 . The method according to claim 6 , wherein said gshA gene is deleted.

8 . The method according to claim 1 , wherein said gshA gene is selected from the group consisting of:
(A) a DNA comprising the nucleotide sequence of SEQ ID NO: 1; (B) a DNA comprising a variant nucleotide sequence of SEQ ID NO: 1 due to the degeneracy of the genetic code; (C) a DNA having an identity of not less than 60% with respect to the entire nucleotide sequence of SEQ ID NO: 1, and wherein said DNA encodes a protein having an activity of γ-glutamate-cysteine ligase; (D) a DNA encoding a protein comprising the amino acid sequence of SEQ ID NO: 2; and (E) a DNA encoding a protein comprising the amino acid sequence of SEQ ID NO: 2, but which includes one or more mutations comprising substitution, deletion, insertion, or addition of one or several amino acid residues, and wherein said protein has the activity of γ-glutamate-cysteine ligase. (F) a DNA encoding a protein having an identity of not less than 65% with respect to the entire amino acid sequence of SEQ ID NO: 2, wherein said protein has the activity of γ-glutamate-cysteine ligase.

9 . The method according to claim 1 , wherein said L-amino acid is selected from the group consisting of an aromatic L-amino acid and a non-aromatic L-amino acid.

10 . The method according to claim 9 , wherein said aromatic L-amino acid is selected from the group consisting of L-phenylalanine, L-tryptophan, and L-tyrosine.

11 . The method according to claim 9 , wherein said non-aromatic L-amino acid is selected from the group consisting of L-alanine, L-arginine, L-asparagine, L-aspartic acid, L-citrulline, L-cysteine, L-glutamic acid, L-glutamine, glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-ornithine, L-proline, L-serine, L-threonine, and L-valine.

12 . The method according to claim 1 , wherein said L-amino acid is a branched-chain L-amino acid.

13 . The method according to claim 12 , wherein said branched-chain L-amino acid is selected from the group consisting of L-isoleucine, L-leucine, and L-valine.

14 . The method according to claim 13 , wherein said L-amino acid is L-valine.

Assignees

• Ajinomoto Kk

Inventors

• Samsonov Valery Vasilievich
• Eremina Natalia Sergeevna
• Stoynova Natalia Viktorovna

Classifications

• C12P13/06

  Alanine; Leucine; Isoleucine; Serine; Homoserine · CPC title

• C12N15/52

  Genes encoding for enzymes or proenzymes · CPC title

• C12Y603/02002

  Glutamate-cysteine ligase (6.3.2.2) · CPC title

• C12P13/12

  Methionine; Cysteine; Cystine · CPC title

• C12P13/08

  Lysine; Diaminopimelic acid; Threonine; Valine · CPC title