MICROBIAL BIOTRANSFORMATIONS IN WATER ORGANIC SOLVENT SYSTEM - ENANTIOSELECTIVE REDUCTION OF AROMATIC BETA-NITROKETONE AND GAMMA-NITROKETONE/

The production of single enantiomers of gamma- and beta-nitroalcohols by microbial bioreduction has been studied. A restricted screening amo ng 14 yeasts was performed using 1-phenyl-4-nitro-1-butanone 1 as subs trate. Pichia minuta (CBS 1708) and Pichia etchellsii (CBS 2011) gave the highest enantiopreference for (S)-alcohol 3 formation (e.e. 85% an d 80%, respectively), while Kluyveromyces marxianus (CBS 397) was the only strain able to preferentially furnish the (R) enantiomer (e.e. 70 %). These three microorganisms, along with baker's yeast, were then em ployed in reactions performed in water/organic solvent systems using d ifferent solvents (hexane, benzene and dibutyl ether) affording alcoho l 3 in high enantiomeric excesses (>95-97%). These strains were also e mployed to reduce 1-phenyl-3-nitro-1-propanone 2, maintaning the same stereobias observed with gamma-nitroketone 1 and showing high enantios electivity in both simple aqueous (>85-97%) and biphasic media (>97%). (C) 1998 Elsevier Science Ltd. All rights reserved.