Comparison of cyclohexanone monooxygenase as an isolated enzyme and whole cell biocatalyst for the enantioselective oxidation of 1,3-dithiane

Abstract Both whole cells of recombinant Escherichia coli TOP10, overexpressing cyclohexanone monooxygenase (CHMO) and isolated cyclohexanone monooxygenase, were used to carry out the enantioselective oxidation of 1,3-dithiane ( 1 ) to ( R )-1,3-dithiane-1-oxide ( 2 ). The two biocatalysts were evaluated under various experimental conditions (e.g., shaken flask or bioreactor; non-bound or resin-adsorbed substrate; different substrate concentrations) in terms of volumetric productivity and enantioselectivity. While productivity was similar in the two cases (up to 0.58 g L −1  h −1 ), the optical purity of the product was much higher with the isolated enzyme (up to 98% e.e.) than with the whole cell biocatalyst (up to 85% e.e.).