P450 BM3 Monooxygenase as an Efficient NAD(P)H-Oxidase for Regeneration of Nicotinamide Cofactors in ADH-Catalysed Preparative Scale Biotransformations

Enzymatic oxidations of primary and secondary alcohols catalysed by nicotinamide dependent alcohol dehydrogenases on the preparative scale require cofactor regeneration systems. Of critical value from an economic and ecological perspective is the application of NAD(P)H-oxidases, which utilise molecular oxygen as a cost-effective, atom-efficient and environmentally benign oxidant to regenerate the cofactor NAD(P)+. Herein, the P450 BM3 monooxygenase from Bacillus megaterium is presented as an NAD(P)H-oxidase for the successful regeneration of both NADP+ and NAD+ on the preparative scale. This enzyme was exemplarily applied for ADH-catalysed oxidative kinetic resolutions of racemic secondary alcohols and the desymmetrisation of a meso-diol leading to enantiomerically enriched secondary alcohols in both cases. Furthermore, the ADH-catalysed oxidation of a primary alcohol targeting the corresponding aldehyde was performed. The obtained results significantly broaden the scope of feasible oxidative biotransformations, thereby increasing the number of synthetic reactions complying with key challenges of a modern and sustainable chemistry such as mild reaction conditions, environmentally benign solvents, and biodegradable non-toxic catalysts.