Isolation and characterization of Rhodococcus ruber CGMCC3090 that hydrolyzes aliphatic, aromatic and heterocyclic nitriles

Abstract

A bacterial strain was isolated from soil samples that had been polluted by nitrile compounds. This strain converts acrylonitrile to acrylamide with high activity. The nitrile hydrolysis activity was tested using eight substrates, including aliphatic, aromatic and heterocyclic (di)nitriles. All of the nitrile compounds were hydrolyzed by the resting cells. The main (cyano-)amide products demonstrated that nitrile hydratase was abundantly produced in this strain and that it mediated monohydrolysis. The specific conversion rate decreased in the following order: acrylonitrile > 3-cyanopyridine > valeronitrile > adiponitrile > 2,3,4,5,6-pentafluorobenzonitrile > -hydroxyphenylacetonitrile > 3-indoleaceto-nitrile > phthalonitrile, suggesting a higher conversion capability towards aliphatic nitriles. The strain that had broad substrate spectra was identified and named Rhodococcus ruber CGMCC3090 based on the 16S rDNA sequence.