| Summary: | The biocatalytic asymmetric reduction of prochiral ketones for the production of enantiopure alcohols is highly desirable due to its inherent advantages over chemical methods. In this study, a new bacterial strain capable of transforming ketones to corresponding alcohols with high activity and excellent enantioselectivity was discovered in a soil sample. The strain was subsequently identified as <i>Bacillus cereus</i> TQ-2 based on its physiological characteristics and 16S rDNA sequence analysis. Under optimized reaction conditions, the resting cells of <i>B. cereus</i> TQ-2 converted acetophenone to enantioenriched (<i>R</i>)-1-phenylethanol with 99% enantiometric excess following anti-Prelog’s rule, which is scarce in biocatalytic ketone reduction. The optimum temperature for the cells was 30 °C, and considerable catalytic activity was observed over a broad pH range from 5.0 to 9.0. The cells showed enhanced catalytic activity in the presence of 15% (<i>v/v</i>) glycerol as a co-substrate. The catalytic activity can also be substantially improved by adding Ca<sup>2+</sup> or K<sup>+</sup> ions. Moreover, the <i>B. cereus</i> TQ-2 cell was highly active in reducing several structurally diverse ketones and aldehydes to form corresponding alcohols with good to excellent conversion. Our study provides a versatile whole-cell biocatalyst that can be used in the asymmetric reduction of ketones for the production of chiral alcohol, thereby expanding the biocatalytic toolbox for potential practical applications.
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