Metabolism of acetonitrile and propionitrile by Nocardia rhodochrous LL100-21

Abstract

Six nitrile compounds and two amide derivatives were degraded by Nocardia rhodochrous LL100-21. Acetonitrile, hydroacrylonitrile, and propionitrile were the best sources of carbon and nitrogen for growth, whereas butenenitrile, succinonitrile, and acetamide supported less growth. Acrylonitrile and acrylamide supported growth but only as a source of nitrogen. Gas chromatography of the culture medium revealed a decrease in acetonitrile with the sequential formation of acetamide and acetic acid. Ammonia was also detected by colorimetric procedures. The enzyme system responsible for the hydrolysis of acetonitrile was shown to be intracellular and inducible. The breakdown of acetonitrile by a crude bacterial extract was a two-step enzymatic hydrolysis with acetamide as the intermediate product and acetic acid and ammonia as the final products. Product formation was stoichiometric with substrate disappearance. When propionitrile was the growth substrate, there was complete conversion of the nitrile to propionic acid and ammonia as the major products. The enzymatic breakdown of the propionitrile, although slower than acetonitrile, yielded the corresponding carboxylic acid and ammonia. Propionamide was produced in very small amounts as an intermediate product.