Application of a promiscuous Arthrobacter sp from Antarctic in aerobic (R)-selective deracemization and anaerobic (S)-selective reduction

Inspired by enzyme-catalyzed reactions with microorganisms found in harsh marine environments, in which the amount of oxygen is restrict, we have shown that Arthrobacter sp. can perform different chemical transformations by switching from anaerobic to aerobic reaction conditions. Depending on the presence or absence of oxygen, either alcohol deracemization or ketone reduction with enantiocomplementary selectivities can be performed by the same microorganism. For example, reactions performed in the presence of oxygen favored the deracemization process, in which a racemic mixture of 1-(4-methylphenyl) ethanol was enriched to the (R)-alcohol in high conversion (94%) and high enantiomeric excess (94%). On the other hand, reaction in the absence of oxygen favored the reduction process, in which 4-methyl-acetophenone was converted to the (S)-alcohol in good conversion (58%) and excellent enantiomeric excess (> 99%). These concepts were applied for both deracemization and enantio selective reduction of heteroatom-containing (silicon, phosphorus, tin and boron) molecules. Moreover, preparative scale reactions were also performed for both chemical processes. (C) 2014 Elsevier B.V. All rights reserved. (AU)