Aureobasidium subglaciale F134 is a Bifunctional whole-cell biocatalyst for Baeyer-Villiger oxidation or selective carbonyl reduction controllable by temperature

Abstract The microbial production of either ester/lactones or enantioenriched alcohols through Baeyer-Villiger oxidation or stereoselective reduction of ketones, respectively, is possible by using whole cells of A. subglaciale F134 as a bifunctional biocatalyst. The chemoselective pattern of acetophenone biotransformation catalyzed by these cells can be regulated through reaction temperature, directing the reaction either towards oxidation or reduction products. The Baeyer-Villiger oxidation activity of A. subglaciale F134 whole cells is particularly dependent on reaction temperature. Acetophenone was transformed efficiently to phenol via the primary Baeyer-Villiger product phenyl acetate at 20 °C after 48 h with 100% conversion. In contrast, at 35 °C, enantioenriched (S)-1-phenylethanol was obtained as the sole product with 64% conversion and 89% ee. In addition, A. subglaciale F134 cells also catalyze the selective reduction of various structurally different aldehydes and ketones to alcohols with 40% to 100% yield, indicating broad substrate spectrum and good enantioselectivity in relevant cases. Our study provides a bifunctional biocatalyst system that can be used in Baeyer-Villiger oxidation as well as in asymmetric carbonyl reduction, setting the stage for future work concerning the identification and isolation of the respective enzymes.