Patent ID: 7829324

Claim:
A method for the microbiological isomerization of alpha-hydroxycarboxylic acids of the formula I where R is straight-chain or branched C 2 -C 8 alkyl or C 2 -C 8 alkenyl or —(CH 2 ) n -Cyc, where n is an integer of 0 to 4, and Cyc is an unsubstituted or mono- or polysubstituted, mono- or binuclear carbo- or heterocyclic ring, wherein said method comprises isomerizing a substrate consisting essentially of a first stereoisomer of an alpha-hydroxycarboxylic acid of the formula (I) with an enzyme in a reaction medium to obtain a second stereoisomer or an isomer mixture comprising the first stereoisomer and the second stereoisomer, wherein the enzyme is contained in an extract of a microorganism or present in intact cells of a microorganism which express the enzyme, wherein said microorganism is selected from the group consisting of the strains L. paracasei DSM 15755, L. paracasei DSM 15751 , L. delbrueckii DSM 15754 , L. sakei DSM 15753 and L. oris DSM 15752, and wherein said microorganism is capable of racemizing at least one compound selected from the group consisting of (R) and/or (S) form of phenyl lactate, 4-fluorophenyl lactate, 2-hydroxy-4-phenylbutyric acid, 2-hydroxy-4-methylpentanecarboxylic acid and 2-hydroxy-3-methylbutyric acid.