Anju Chadha

Candida parapsilosis ATCC 7330 grown using different culture conditions (inoculum size 4% (v/v), inoculum age 12 h, and harvest time 14 h) from those previously reported (inoculum size 2% (v/v), inoculum age 24 h, and harvest time 44 h) successfully deracemised racemic 1-arylethanols and 4-phenyl-2-butanol to the (R)-enantiomer (ee up to >99%). The deracemisation of racemic 1-aryl ethanol proceeds via (i) enantioselective oxidation of (S)-enantiomer followed by (ii) reduction of the ketone formed to give the racemic alcohol which gets kinetically resolved thus enriching for the (R)-enantiomer from the racemate. This is the first report on the deracemisation of 1-arylethanols using Candida parapsilosis ATTC 7330 via dynamic kinetic resolution. © 2011 Informa UK, Ltd.

Asymmetric reduction of ethyl-4-chloro-3-oxobutanoate to (S)-ethyl-4-chloro-3-hydroxybutanoate in aqueous medium by resting cells of Candida parapsilosis ATCC 7330 was optimized. The influence of culture parameters (inoculum size, inoculum age and biocatalyst harvest time) and reaction parameters (co-substrate, resting cell, pH and substrate concentrations) on the asymmetric reduction were studied. It was found that these parameters significantly influenced the rate of the asymmetric reduction. Under the optimum conditions, the final concentration of (S)-ethyl-4-chloro-3- hydroxybutanoate, enantiomeric excess and the isolated yield of (S)-ethyl-4-chloro-3-hydroxybutanoate were 1.38 M (230 g/l), >99 and 95%, respectively. The space time yield was 115 mmol/lh, which is significantly higher than other whole cell biocatalysts reported so far. © 2009 Society for Industrial Microbiology.