Process for the fermentative preparation of sulphur-containing amino acids

A process for the fermentative preparation of sulphur-containing amino acids selected from the group consisting 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 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 and/or addition of from 1 to 45 amino acid residues with respect to the amino acid sequence shown in SEQ ID NO:
• 2;
• b) fermentation of the microorganism from a) in a medium which contains an inorganic source of sulphur from the group of salt of thiosulphuric acid or a mixture of a salt of thiosulphuric 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).