Enzymatic resolution of 1-phenyl-1,2-ethanediol by enantioselective oxidation: Overcoming product inhibition by continuous extraction

• Published in: Biotechnology and bioengineering Vol. 51; no. 5; pp. 544 - 550
• Main Authors: Liese, Andreas, Karutz, Martin, Kamphuis, Johan, Wandrey, Christian, Kragl, Udo
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05.09.1996; Wiley
• Subjects: Bioconversions. Hemisynthesis; Biological and medical sciences; Biotechnology; chiral alcohol; continuous extraction; Fundamental and applied biological sciences. Psychology; membrane reactor; Methods. Procedures. Technologies; oxidoreductase; racemic resolution; Diol; Enantioselectivity; Product inhibition; Enzyme; Continuous process; Glycerol dehydrogenase; Membrane reactor; Bioreactor; Optical resolution; Racemate; Extraction; Oxidation; Oxidoreductases; Enzymatic reaction
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/(SICI)1097-0290(19960905)51:5<544::AID-BIT6>3.0.CO;2-C

Oxidations of alcohols by alcohol dehydrogenases often suffer from low conversions and slow reaction rates due to severe product inhibition. This can be overcome by continuous product extraction, because only the concentrations, but not the kinetic parameters, can be changed. As a consequence, it is favorable to apply a differential circulation reactor with continuous product extraction, where only a small amount of product is formed per cycle. The product is then directly extracted using a microporous hydrophobic hollow fiber membrane. This results in an increase of the relative activity of the dehydrogenase at a given conversion. The reaction investigated is the kinetic resolution of racemic 1‐phenyl‐1,2‐ethanediol by glycerol dehydrogenase (GDH). The resulting oxidation product, 2‐hydroxyacetophenone, causes a strong product inhibition. Additionally, it reacts in a chemical reaction with the cofactor lowering its active concentration. Because the GDH needs β‐nicotinamide adenine dinucleotide (NAD+) as a cofactor, lactate dehydrogenase is used to regenerate NAD+ from NADH by reducing pyruvate to (L)‐lactate. A conversion of 50% with respect to the racemate and an enantiomeric excess >99% of the (S)‐enantiomer was reached.