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-11746345-B2
Application number	US-201615165606-A
Country	US
Kind code	B2
Filing date	May 26, 2016
Priority date	May 28, 2015
Publication date	Sep 5, 2023
Grant date	Sep 5, 2023

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

The invention claimed is:

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, and wherein said L-amino acid is a branched-chain L-amino acid.

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;
(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; and
(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 branched-chain L-amino acid is selected from the group consisting of L-isoleucine, L-leucine, and L-valine.

10. The method according to claim 9 , wherein said L-amino acid is L-valine.

11. The method according to claim 1 , wherein said bacterium is Escherichia coli and said gshA gene is deleted.

Assignees

• Ajinomoto Kk

Inventors

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

Classifications

• C12P13/04 Primary

  Alpha- or beta- amino acids {(other amino acids C12P13/005)} · CPC title

• C12N9/93 Primary

  Ligases (6) · CPC title

• C12N15/52

  Genes encoding for enzymes or proenzymes · CPC title

• C12P13/06

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

• C12P13/08

  Lysine; Diaminopimelic acid; Threonine; Valine · CPC title