Synthesis of chiral epsilon-lactones in a two-enzyme system of cyclohexanone mono-oxygenase and formate dehydrogenase with integrated bubble-free aeration

A two-enzyme system consisting of a cyclohexanone mono-oxygenase from Acinetobacter NCIMB 9871 and a protein-engineered formate dehydrogenase for the regeneration of the cofactor NADPH was used for the synthesis of chiral epsilon-lactones. 4-Methylcyclohexanone was used as the model substrate yielding (S)-(-)-5-methyl-oxepane-2-one with high chemical and enantiomeric purity. Syntheses were carried out in a repetitive-batch reactor with integrated bubble-free aeration by means of a thin-walled silicon tube. (C) 1997 Elsevier Science Ltd.