Methods for producing L-amino acids

• US 20030166174A1
• Filed: 12/04/2002
• Published: 09/04/2003
• Est. Priority Date: 08/17/1999
• Status: Active Grant

• Current Assignee: Ajinomoto Co., Inc.
• Original Assignee: Ajinomoto Co., Inc.
• Inventors: Ono, Yukiko, Sugimoto, Shinichi, Yasueda, Hisashi, Kawahara, Yoshio
• Granted Patent: US 7,192,747 B2
• Time in Patent Office: Days
• US Class Current: 435/106
• CPC Class Codes: C12N 1/205 Bacterial isolates
• CPC Class Codes: C12P 13/04 Alpha- or beta- amino acids other amino acids C12P13/005
• CPC Class Codes: C12P 13/08 Lysine; Diaminopimelic acid; Threonine; Valine
• CPC Class Codes: C12P 13/12 Methionine; Cysteine; Cystine
• CPC Class Codes: C12R 2001/01 Bacteria or Actinomycetales ; using bacteria or Actinomycetales
• CPC Class Codes: C12R 2001/26 Methylomonas

Abstract

A methane-utilizing microorganism capable of producing L-amino acid, for example, bacteria belonging to type I, type X or type II in the taxonomic categorization methane-utilizing bacteria such as Methylomonas albus, Methylococcus capsulatus and Methylosinus trichosporium, is cultivated in a culture medium in contact with gas containing methane which is the main source of carbon, to allow the L-amino acid to be produced and accumulated in the medium, and the L-amino acid is collected from the medium.

Claims

1. A method for production of an L-amino acid, comprising the steps of:

cultivating a methane-utilizing microorganism capable of producing L-amino acid in a culture medium which is in contact with gas containing methane which is the main source of carbon, to allow said L-amino acid to be produced and accumulated in said medium, and collecting said L-amino acid from said medium.

2. A method according to claim 1, wherein said microorganism belongs to type I, type X or type II in the taxonomic categorization of methane-utilizing bacteria.

3. A method according to claim 2, wherein said microorganism belonging to type I, type X or type II belongs to the genus Methylomonas, Methylococcus or Methylosinus, respectively.

4. A method according to claim 1, wherein said L-amino acid is selected from the group consisting of L-aspartic acid, L-threonine, L-serine, L-glutamic acid, L-proline, L-glycine, L-alanine, L-cysteine, L-valine, L-methionine, L-isoleucine, L-leucine, L-tyrosine, L-phenylalanine, L-lysine, L-histidine, L-arginine and L-tryptophan.

5. A method according to claim 1, wherein said methane-utilizing microorganism capable of producing L-amino acid is a wild type strain.

6. A method according to claim 1, wherein said methane-utilizing microorganism capable of producing L-amino acid is resistant to an L-amino acid or an analog thereof.

7. A method according to claim 6, wherein the L-amino acid is L-lysine and the analog thereof is S-(2-aminoethyl)-cysteine.

8. A method according to claim 1, wherein said methane-utilizing microorganism capable of producing L-amino acid is a mutant strain or a recombinant strain in which activity of at least one enzyme involved in biosynthesis of L-amino acid is enhanced.

9. A method according to claim 8, wherein the microorganism is a transformant strain which harbors a vector capable of encoding at least one enzyme involved in biosynthesis of L-amino acid.

10. A method according to claim 8 or 9, wherein the enzyme involved in L-amino acid biosynthesis is one or more enzymes selected from the group consisting of mutant dihydrodipicolinate synthase which is desensitized to the feedback inhibition by L-lysine, mutatant aspartokinase which is desensitized to the feedback inhibition by L-lysine, dihydrodipicolinate reductase and diaminopimelate dehydrogenase.

11. A mutant strain of a methane-utilizing microorganism capable of producing L-amino acid and resistant to the an L-amino acid or an analog thereof.

12. A transformant of a mthane-utilizing microorganism capable of producing L-amino acid which harbors a vector capable of encoding at least one enzyme involved in biosynthesis of L-amino acid.