Kinetic profiles of the stereoselective reduction of acetophenone and its derivatives promoted by Galactomyces candidus GZ1. A mechanistic interpretation

DECARLINI, MARÍA F.; DEMMEL, GABRIELA I.; VÁZQUEZ, ANA M.; AIMAR, MARIO L.; BORDÓN, DANIELA L.; ROSSI, LAURA I.

Biocatalysis and Agricultural Biotechnology

Elsevier

Lugar: Amsterdam; Año: 2019 vol. 17 p. 7 - 14

1878-8181

A mechanistic interpretation of the kinetic profiles obtained for the stereoselective reduction ofacetophenone promoted by Galactomyces candidus GZ1 under aerobic and anaerobic conditions wasmade. Based on experimental and bibliographical data, a mechanism which may involve the participationof two alcohol dehydrogenases with opposite stereoselectivities and alcohol oxidase is discussed. Due tothe stereoselectivity of the reduction of acetophenone being changed when anaerobic conditions wereused, this microorganism also permitted (S)-1-phenylethanol to be obtained in the absence of oxygen.Moreover, the kinetic profiles of the reactions of a racemic mixture of (R,S)-1-phenylethanol and pure(S)-1-phenylethanol with Gal. candidus were analyzed, which corroborated that there existed a reactionstep where (S)-1-phenylethanol was oxidized to acetophenone. The results presented here show that notonly is it possible to resolve racemic mixtures of phenylethanols when Gal. candidus is used as abiocatalyst, but that this is also efficient in causing the complete stereoinversion of pure (S)-1-phenylethanol to (R)-1-phenylethanol.