Process for the fermentative preparation of sulphur-containing amino acids
View Patent ↗Disclosed herein is a process for the fermentative preparation of sulphur-containing amino acids chosen from the group of L-methionine, L-cysteine, L-cystine, L-homocysteine and L-homocystine, comprising the steps: a) provision of a microorganism of the family Enterobacteriaceae or of a microorganism of the family Corynebacteriaceae which has an increased thiosulphate sulphurtransferase activity compared with the particular starting strain; b) fermentation of the microorganism from a) in a medium which contains an inorganic source of sulphur chosen from the group of salt of dithiosulphuric acid or a mixture of a salt of dithiosulphuric acid and a salt of sulphuric acid, a fermentation broth being obtained, and c) concentration of the sulphur-containing amino acid in the fermentation broth from b).
1. A recombinant microorganism selected from the group consisting of
Corynebacterium glutamicum with increased activity and/or expression of aspartate kinase and attenuation or deletion of the regulator protein McbR compared with the starting strain; and
Escherichia coli with increased activity and/or expression of aspartate kinase and attenuation or deletion of the regulator protein MetJ compared with the starting strain;
wherein the recombinant microorganism secretes or produces L-methionine, and wherein the recombinant microorganism overexpresses a gene coding for a polypeptide with the activity of a thiosulphate sulphurtransferase comprising the amino acid sequence shown in SEQ ID NO: 2 or an amino acid sequence containing a deletion, substitution, insertion, addition, or combinations thereof, of from 1 to 45 amino acid residues with respect to the amino acid sequence shown in SEQ ID NO: 2, and
wherein the recombinant microorganism has an increased thiosulfate sulfurtransferase activity compared with the starting strain.
2. The recombinant microorganism according to claim 1 , wherein the starting strain is derived from a microorganism selected from the group consisting of Escherichia coli MG1655, Escherichia coli W 3110, Escherichia coli DHSa, Escherichia coli DH10B, Escherichia coli BW 2952, Escherichia coli REL 606, Corynebacterium glutamicum ATCC 13032, Corynebacterium glutamicum R, Corynebacterium glutamicum DSM 20411 (former name Brevibacterium flavum ), Corynebacterium glutamicum DSM 20412 (former name Brevibacterium lactofermentum ), Corynebacterium glutamicum DSM 1412 (former name Brevibacterium lactofermentum ), Corynebacterium efficiens YS- 314 T (=DSM 44549 ), Corynebacterium glutamicum ATCC 21608, and Corynebacterium glutamicum DSM 17322.