Asymmetric reduction of ?, ?-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

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.

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

• Journal Article Type: Article
• Acceptance Date: Sep 14, 2005
• Online Publication Date: Jan 4, 2006
• Publication Date: Mar 5, 2006
• Deposit Date: Apr 22, 2020
• Journal: Biotechnology and Bioengineering
• Print ISSN: 0006-3592
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 93
• Issue: 4
• Pages: 674-686
• DOI: https://doi.org/10.1002/bit.20751
• Public URL: http://doi.wiley.com/10.1002/bit.20751
• Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.20751