Biodegradation of butyronitrile and demonstration of its mineralization by Rhodococcus sp. MTB5

A nitrile utilizing bacterium Rhodococcus sp. MTB5 was previously isolated in our laboratory by the enrichment culture technique. It is able to utilize butyronitrile as sole carbon, nitrogen, and energy source. Maximum butyronitrile degrading property of this strain has been investigated. Results reveal that 100, 98, and 88 % degradation was achieved for 2, 2.5, and 3 % butyronitrile, respectively. The strain is capable of growing in as high as 5 % butyronitrile concentration. A two-step pathway involving nitrile hydratase (NHase) and amidase was observed for the biodegradation of butyronitrile. Complete degradation (mineralization) of butyronitrile with the help of metabolite feeding experiment was reported. The significance of this investigation was the capability of the strain to completely degrade and its ability to grow on higher concentrations of butyronitrile. These potential features make it a suitable candidate for practical field application for effective in situ bioremediation of butyronitrile contaminated sites.