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Asymmetric reduction of α, β-unsaturated ketone to (R) allylic alcohol by Candida chilensis

Pollard, D J; Telari, K; Lane, J; Humphrey, G; McWilliams, C; Nidositko, S; Salmon, P; Moore, J

Authors

D J Pollard

K Telari

J Lane

G Humphrey

C McWilliams

S Nidositko

P Salmon



Abstract

A pilot scale whole cell process was developed for the enantioselective 1,2‐reduction of prochiral α,β‐unsaturated ketone to (R) allylic alcohol using Candida chilensis. Initial development showed high enantiomeric excess (EE > 95%) but low product yield (10%). Process development, using a combination of statistically designed screening and optimization experiments, improved the desired alcohol yield to 90%. The fermentation growth stage, particularly medium composition and growth pH, had a significant impact on the bioconversion while process characterization identified diverse challenges including the presence of multiple enzymes, substrate/product toxicity, and biphasic cellular morphology. Manipulating the fermentation media allowed control of the whole cell morphology to a predominately unicellular broth, away from the viscous pseudohyphae, which were detrimental to the bioconversion. The activity of a competing enzyme, which produced the undesired saturated ketone and (R) saturated alcohol, was minimized to ≤5% by controlling the reaction pH, temperature, substrate concentration, and biomass level. Despite the toxicity effects limiting the volumetric productivity, a reproducible and scaleable process was demonstrated at pilot scale with high enantioselectivity (EE > 95%) and overall yield greater than 80%. This was the preferred route compared to a partially purified process using ultra centrifugation, which led to improved volumetric productivity but reduced yield (g/day). The whole cell approach proved to be a valuable alternative to chemical reduction routes, as an intermediate step for the asymmetric synthesis of an integrin receptor anatagonist for the inhibition of bone resorption and treatment of osteoporosis. © 2006 Wiley Periodicals, Inc.

Journal Article Type Article
Publication Date Mar 5, 2006
Journal Biotechnology and Bioengineering
Print ISSN 0006-3592
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 93
Issue 4
Pages 674-686
APA6 Citation Pollard, D. J., Telari, K., Lane, J., Humphrey, G., McWilliams, C., Nidositko, S., …Moore, J. (2006). Asymmetric reduction of α, β-unsaturated ketone to (R) allylic alcohol by Candida chilensis. Biotechnology and Bioengineering, 93(4), 674-686. https://doi.org/10.1002/bit.20751
DOI https://doi.org/10.1002/bit.20751
Publisher URL https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.20751
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