Method for zymotic production of fine chemicals (metA) containing sulphur
The invention relates to methods for the fermentative production of sulfur-containing fine chemicals, in particular L-methionine, by using bacteria which express a nucleotide sequence coding for a methionine synthase (metA) gene.
1. A method for the fermentative production of L-methionine, which comprises the following steps:
a) fermenting in a medium cells of coryneform bacterium Corynebacterium glutamicum for producing L-methionine, said coryneform bacteria expressing at least one heterologous nucleotide sequence which encodes for a protein with homoserine O-acetyltransferase (metA) activity, wherein said heterologous nucleotide sequence comprises a nucleotide sequence encoding a metA protein derived from Corynebacterium diphteriae having an amino acid sequence as set forth in SEQ ID NO: 2;
b) concentrating L-methionine in the medium or in the bacterial cells, and
c) isolating L-methionine.
2. The method as claimed in claim 1 , wherein the metA-encoding nucleotide sequence comprises a coding sequence as set forth in SEQ ID NO:1.
3. The method as claimed in claim 1 , wherein the metA encoding sequence is a DNA or RNA which can be replicated in coryneform bacteria or is stably integrated into the chromosome.
4. The method as claimed in claim 3 , wherein
a) a bacteria strain transformed with a plasmid vector carrying at least one copy of the metA encoding sequence under the control of regulatory sequences is used, or
b) a strain in which the metA encoding sequence has been integrated into the bacteria chromosome is used.
5. The method as claimed in claim 1 , wherein the metA encoding sequence is overexpressed.
6. The method as claimed in claim 1 , wherein bacteria are fermented in which additionally at least one farther gene of the biosynthetic pathway of L-methionine has been over expressed.
7. The method of claim 1 , wherein coryneform bacteria are fermented in which, at the same time, a lysC gene derived from a coryneform bacterium, which encodes an aspartate kinase, is overexpressed.
8. A method for the production of L-methionine, which comprises the following steps:
a) fermenting in a medium cells of a coryneform bacterium for producing L-methionine, said coryneform bacteria expressing at least one heterologous nucleotide sequence which encodes for a protein with homoserine O-acetyltransferase (metA) activity, wherein the heterologous nucleotide sequence comprises a nucleotide sequence having 95% identity or more to the sequence as set forth in SEQ ID NO: 1;
b) concentrating L-methionine in the medium or in the bacterial cells; and
c) isolating L-methionine.
9. The method of claim 8 , wherein the coryneform bacterium is of the species Corynebacterium glutamicum.
10. The method of claim 8 , wherein the metA-encoding nucleotide sequence comprises a nucleotide sequence as set forth in SEQ ID NO:1.
11. The method of claim 8 , wherein the metA-encoding nucleotide sequence encodes a protein with metA activity, said protein comprising an amino acid sequence as set forth in SEQ ID NO: 2.
12. The method of claim 8 , wherein the metA encoding sequence is a DNA or RNA which can be replicated in coryneform bacteria or is stably integrated into the chromosome.
13. The method of claim 8 , wherein
a) a bacteria strain transformed with a plasmid vector carrying at least one copy of the metA encoding sequence under the control of regulatory sequences is used, or
b) a strain in which the metA encoding sequence has been integrated into the bacteria chromosome is used.
14. The method of claim 8 , wherein the metA encoding sequence is overexpressed.
15. The method of claim 8 , wherein bacteria are fermented in which additionally at least one further gene of the biosynthetic pathway of L-methionine has been overexpressed.
16. A method for the production of L-methionine, which comprises the following steps:
a) fermenting in a medium cells of a coryneform bacterium for producing of L-methionine, said coryneform bacteria expressing at least one heterologous nucleotide sequence which codes for a protein with homoserine O-acetyltransferase (metA) activity, wherein said heterologous nucleotide sequence comprises a nucleotide sequence encoding a metA protein having an amino acid sequence with 95% homology or more to the sequence as set forth in SEQ ID NO: 2 derived from Corynebacterium diphteriae;
b) concentrating L-methionine in the medium or in the bacterial cells; and
c) isolating L-methionine.
17. The method of claim 16 , wherein the metA encoding sequence is a DNA or RNA which can be replicated in coryneform bacteria or is stably integrated into the chromosome.
18. The method of claim 16 , wherein
a) a bacteria strain transformed with a plasmid vector carrying at least one copy of the metA encoding sequence under the control of regulatory sequences is used, or
b) a strain in which the metA encoding sequence has been integrated into the bacteria chromosome is used.
19. The method of claim 16 , wherein the metA encoding sequence is overexpressed.
20. The method of claim 16 , wherein bacteria are fermented in which additionally at least one further gene of the biosynthetic pathway of L-methionine has been overexpressed.
21. The method of claim 16 , wherein the coryneform bacterium is of the species Corynebacterium glutamicum.