Method for producing mercaptans by disulfide enzyme hydrogenolysis

A process for the preparation of a mercaptan of formula R—SH, comprising:

• (a) preparing a mixture, comprising:
• (1) a disulfide of formula R—S—S—R′,
• wherein R and R′, independently, represent a linear, branched or cyclic hydrocarbon-based radical comprising from 1 to 20 carbon atoms, wherein the hydrocarbon-based radical is saturated or contains one or more unsaturations in the form of double or triple bond(s), or R and R′ form together, with the sulfur atoms bearing them, a cyclic group comprising from 4 to 22 atoms,
• (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 an enzyme catalyzing the reduction of a disulfide bridge created between two equivalents of the amino acid bearing a thiol group or the thiol-group-containing peptide,
• (4) a catalytic amount of an enzyme catalyzing the dehydrogenation of the organic reducing compound in (b),
• (5) a catalytic amount of a cofactor common to the two enzymes catalyzing the reduction and the dehydrogenation,
• (b) adding an organic reducing compound in a stoichiometric amount relative to the disulfide of formula R—S—S—R′,
• (c) carrying out the enzymatic reaction,
• (d) recovering the mercaptan of formula R—SH and the mercaptan of formula R′—SH,
• (e) optionally, separating and, optionally, purifying the mercaptan of formula R—SH and/or the mercaptan of formula R′—SH.

A mixture, comprising:

• a disulfide of formula R S S R′,
• wherein R and R′, independently, represent a linear, branched or cyclic hydrocarbon-based radical comprising from 1 to 20 carbon atoms, wherein the hydrocarbon-based radical is saturated or contains one or more unsaturations in the form of double or triple bond(s), or R and R′ form together, and with the sulfur atoms bearing them, a cyclic group comprising from 4 to 22 atoms,
• a catalytic amount of 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,
• a catalytic amount of an enzyme catalyzing the reduction of a disulfide bridge created between two equivalents of the amino acid bearing a thiol group or the thiol-group-containing peptide,
• optionally, a catalytic amount of an enzyme catalyzing the dehydrogenation of an organic reducing compound, and
• a catalytic amount of a cofactor common to the two enzymes catalyzing the reduction and the dehydrogenation.