Stereochemical applications of the expression of the L‐2,3‐butanediol dehydrogenase gene in Escherichia coli

S. UI, Y. TAKUSAGAWA, T. OHTSUKI, A. MIMURA, M. OHKUMA AND T. KUDO. 2001. The L‐2,3‐butanediol dehydrogenase (L‐BDH) gene of Brevibacterium saccharolyticum was strongly expressed in Escherichia coli using the tac promoter. However, the stereospecificity of the resulting L‐BDH was reduced. The region upstream of the meso‐BDH gene of Klebsiella pneumoniae was also involved in the expression of the B. saccharolyticum gene. However, in this case, the resulting L‐BDH exhibited more stable stereospecificity. A stereospecificity recognition region was located within the rear sequence (Hpa I site, carboxy terminal) of the BDH open reading frame. Using a transformed strain of E. coli, the conversion of L‐acetoin (L‐AC), in the commercially available racemic mixture of AC, to L‐2,3‐butanediol (L‐BD) was attempted. As a result, 0·37% L‐BD was formed from 1% AC added to the culture.