Process for the enzymatic reduction of enoates

A process for the enzymatic reduction of a compound (1), wherein the C═C bond of the compound (1) according to formula (1) is stereoselectively hydrogenated in the presence of an enoate-reductase and an oxidizable co-substrate which is a compound having a chemical structure according to formula (1) in a system which is free of NAD(P)H,

• in which
• A is a ketone radical (—CRO), an aldehyde radical (—CHO), a carboxyl radical (—COOR), with R =H or optionally substituted C1-C6-alkyl radical, R1, R2 and R3 are independently of one another H, —O—C1-C6-alkyl, C1-C6-alkyl, which can be substituted, C2-C6-alkenyl, carboxyl, or an optionally substituted carbo- or heterocyclic, aromatic or nonaromatic radical, or Rl is linked to R3 so as to become part of a 4-8-membered cycle, or Rl is linked to R so as to become part of a 4-8-membered cycle, with the proviso that R1, R2 and R3 may not be identical;
• wherein the enoate reductase is selected from:
• (i) an enoate reductase comprising at least one of the polypeptide sequences SEQ ID NO:
• 3 or 4;
• or
• (ii) an enoate reductase comprising a polypeptide sequence which has at least 95% sequence identity with SEQ ID NO:
• 3.