Direct biocatalytic one-pot-transformation of cyclohexanol with molecular oxygen into ɛ-caprolactone

Abstract

The development of a biocatalytic process concept for ɛ-caprolactone, which directly converts cyclohexanol as an easily available industrial raw material into the desired ɛ-caprolactone in a one-pot fashion while only requiring air as sole reagent, is reported. The desired product ɛ-caprolactone was obtained with 94-97% conversion when operating at a substrate concentration in the range of 20-60 mM. At higher substrate concentrations, however, a significant drop of conversion was found. Subsequent detailed studies on the impact of the starting material, intermediate and product components revealed a significant inhibition and partial deactivation of the BVMO by the product ɛ-caprolactone (in particular at higher concentrations) as well as an inhibition of the BVMO by cyclohexanol and cyclohexanone.

Keywords: ADH; Alcohol dehydrogenase; BVMO; Baeyer–Villiger monooxygenase; Cyclohexanol; Cyclohexanone; LK-ADH; Oxidation; UCC; Union Carbide Corporation; alcohol dehydrogenase; alcohol dehydrogenase from Lactobacillus kefir; ɛ-Caprolactone.