Microbial biotransformations to obtain (R)- and (S)-2-octanol

Microbial obtainment of (R)- and (S)-2-octanol was studied. Two strategies were developed: kinetic resolution of 2-octanol racemic mixture through selective oxidation and enantioselective reduction of 2-octanone. Two strains of acetic acid bacteria were found to preferentially oxidize (R)-2-octanol with moderate discrimination between the enantiomers. Various microorganisms belonging to different genera gave 2-octanone reduction with general preference for (S)-2-octanol formation. Lactobacillus fermentum ILC G18D, Acetobacter sp. CH MIM, Candida boidinii CBS 2428 and Pichia fermentans DPVPG 2770 afforded (S)-2-octanol with an enantiomeric excess (e.e.) greater than 97%. Reduction of shorter chain methyl ketones with Candida boidinii and Pichia fermentans showed that the ketone structure was extremely important to the transformation stereobias.