Applied Microbiology and Biotechnology

, Volume 34, Issue 1, pp 15–19 | Cite as

Reduction of acetophenone to R(+)-phenylethanol by a new alcohol dehydrogenase from Lactobacillus kefir

  • Werner Hummel


A new alcohol dehydrogenase catalysing the enantioselective reduction of acetophenone to R(+)-phenylethanol was found in a strain of Lactobacillus kefir. A 70-fold enrichment of the enzyme with an overall yield of 76% was obtained in two steps. The addition of Mg2+ ions was found to be necessary to prevent rapid deactivation. The enzyme depends essentially on NADPH and was inactive when supplied with NADH as the coenzyme. Important enzymological data of the dehydrogenase are: Km (acetophenone) 0.6 mM, Km (NADPH) 0.14 mM, and a pH optimum for acetophenone reduction at 7.0. Addition of EDTA leads to complete deactivation of the enzyme activity. Added iodoacetamide or p-hydroxymercuribenzoate cause only slight inhibition, revealing that the active centre of the enzyme contains no essential SH-group. Besides acetophenone several other aromatic and long-chain aliphatic secondary ketones are substrates for this enzyme. Batch production of phenylethanol was examined using three different methods for the regeneration of NADPH: glucose/glucose dehydrogenase, glucose-6-phosphate/glucose-6-phosphate dehydrogenase, and isopropanol.


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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Werner Hummel
    • 1
  1. 1.Forschungszentrum Jülich (KFA)Institut für Enzymtechnologie der Heinrich-Heine-UniversitätJülichFederal Republic of Germany

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