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

The development of a biocatalytic process concept for epsilon-caprolactone, which directly converts cyclohexanol as an easily available industrial raw material into the desired epsilon-caprolactone in a one-pot fashion while only requiring air as sole reagent, is reported. The desired product epsilon-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 epsilon-caprolactone (in particular at higher concentrations) as well as an inhibition of the BVMO by cyclohexanol and cyclohexanone. (C) 2013 Elsevier Inc. All rights reserved.