Objectives: To characterize a recombinant carbonyl reductase from Saccharomyces cerevisiae (SceCPR1) and explore its use in asymmetric synthesis of (R)-pantolactone [(R)-PL].
Results: The NADPH-dependent SceCPR1 exhibited strict (R)-enantioselectivity and high activity in the asymmetric reduction of ketopantolactone (KPL) to (R)-PL. Escherichia coli, coexpressing SceCPR1 and glucose dehydrogenase from Exiguobacterium sibiricum (EsGDH), was constructed to fulfill efficient NADPH regeneration. During the whole-cell catalyzed asymmetric reduction of KPL, the spontaneous hydrolysis of KPL significantly affected the yield of (R)-PL, which was effectively alleviated by the employment of the substrate constant-feeding strategy. The established whole-cell bioreduction for 6 h afforded 458 mM (R)-PL with the enantiomeric excess value of >99.9% and the yield of 91.6%.
Conclusions: Escherichia coli coexpressing SceCPR1 and EsGDH efficiently catalyzed the asymmetric synthesis of (R)-PL through the substrate constant-feeding strategy.
Keywords: (R)-Pantolactone; Asymmetric reduction; Carbonyl reductase; Coenzyme regeneration; Ketopantolactone; Saccharomyces cerevisiae; Spontaneous hydrolysis.