Method for producing L-methionine

A process for the preparation of L-methionine, comprising:

• (a) preparing a mixture, comprising:
• (1) dimethyl disulfide (DMDS),
• (2) a catalytic amount of an amino acid bearing a thiol group or of a thiol-group-containing peptide, wherein the amino acid bearing a thiol group or the thiol-group-containing peptide may optionally be in the form of the corresponding disulfide,
• (3) a catalytic amount of a reductase enzyme catalyzing the reduction reaction of a disulfide bridge of the amino acid bearing a thiol group or of the thiol-group-containing peptide,
• (4) an organic reducing compound in a stoichiometric amount relative to the dimethyl disulfide,
• (5) a catalytic amount of a dehydrogenase enzyme catalyzing the reaction for the dehydrogenation of the organic reducing compound,
• (6) a catalytic amount of a cofactor common to the reductase enzyme and the dehydrogenase enzyme,
• (b) carrying out an enzymatic reaction to form methyl mercaptan (CH3—SH),
• (c) adding a precursor of L-methionine and converting the precursor by reacting with the methyl mercaptan formed in (b) to produce L-methionine, and
• (d) recovering and optionally purifying the L-methionine.