Enzymatic reduction to produce optically active alcohols.

Method for preparing optically active alkanols of the formula I wherein n represents an integer value from 0 to 5; Cyc represents a carbocyclic or heterocyclic, saturated or unsaturated, mono- or polycyclic ring, optionally substituted, and R 1 is halogen, SH, OH, NO2, NR 2 R 3 or NR 2 R 3 R 4+ X -, where R 2 , R 3 and R 4, independently of one another, represent H or a lower alkyl of C1-C8 alkyl or lower alkoxy of C1-C8 alkyl and X - represents a counterion, in which case in a medium containing an alkanone of formula II in which n, Cyc and R 1 are as defined above, an enzyme is incubated with a polypeptide sequence (i) SEQ ID NO: 1 or (ii) (ii) in which up to 25% of amino acid residues have been altered compared to SEQ ID NO: 1 by deletion, insertion, substitution or a combination thereof and still has at least 50% of the enzymatic activity of SEQ ID NO: 1, in which case the compound of formula II is reduced enzymatically to the compound of formula I and the product formed is isolated.