Isolation and characterization of a bacterium possessing a novel aldoxime-dehydration activity and nitrile-degrading enzymes.

A bacterial strain capable of utilizing E-pyridine-3-aldoxime as a nitrogen source was isolated from soil after a 4-month acclimation period and was identified as Rhodococcus sp. The strain contained a novel aldoxime dehydration activity that catalyzed a stoichiometric dehydration of E-pyridine-3-aldoxime to form 3-cyanopyridine. The enzyme activity was induced by various aldoximes and nitriles. The strain metabolized the aldoxime as follows: E-pyridine-3-aldoxime was dehydrated to form 3-cyanopyridine, which was converted to nicotinamide by a nitrile hydratase, and the nicotinamide was successively hydrolyzed to nicotinic acid by an amidase.