Isolation and expression of a Bacillus cereus gene encoding benzil reductase

Benzil was reduced stereospecifically to (S)‐benzoin by Bacillus cereus strain Tim‐r01. To isolate the gene responsible for asymmetric reduction, we constructed a library consisting of Escherichia coli clones that harbored plasmids expressing Bacillus cereus genes. The library was screened using the halo formation assay, and one clone showed benzil reduction to ( S )‐benzoin. Thus, this clone seemed to carry a plasmid encoding a Bacillus cereus benzil reductase. The deduced amino acid sequence had marked homologies to the Bacillus subtilis yueD protein (41% identity), the yeast open reading frame YIR036C protein (31%), and the mammalian sepiapterin reductases (28% to 30%), suggesting that benzil reductase is a novel short‐chain de‐hydrogenases/ reductase. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 630–633, 2001.