The production of D‐acetoin by a transgenic Escherichia coli

A 6 kbp SphI fragment encoding genes for the enzymes α‐acetolactate synthase (ALS), α‐acetolactate decarboxylase (ALDC) and meso‐2,3‐butanediol dehydrogenase (meso‐BDH), involved in the formation of meso‐2,3‐butanediol (meso‐BD) from pyruvic acid, was cloned into plasmid pUC118. When derivatives of this plasmid were introduced into Escherichia coli JM109, the transformants were able to produce D‐acetoin ( D‐AC) without contamination with L‐acetoin ( L‐AC).