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.