Purification and characterization of intracellular nitrilases from rhodococcus sp. - potential role of periplasmic nitrilase

摘要

Two bacterial species?Rhodococcus rhodochrous?and?Rhodococcus?fascianswere evaluated for the production of nitrilase enzyme?(EC 3.5.5.2)?from benzonitrile. This is the first time report on comparative analyses of intracellular nitrilases in two different?Rhodococcus?species which showed the involvement of periplasmic nitrilases towards nitrile degradation rather than cytoplasmic nitrilases.?The periplasmic nitrilases of?R. rhodochrous?showed nearly 50% more activity as compared to?R. fascians. In comparison to?R. fascians,?R. rhodochrous?was?found to be better towards nitrile production and degradation as observed under different physiological conditions. The optimum nitrile degradation was recorded at 40?C and at pH 8.0. The nitrilase enzyme produced by?R. rhodochrous?was found to be fairly thermostable, as an incubation temperature of 45?C did not affect the activity of nitrilase enzyme produced by it adversely. The pre-incubation temperature resulted in a decrease of nitrilase activity. The substrate concentration of 40 mM was found to be optimum for hydrolyzing benzonitrile. These findings may prove beneficial from enzymology and industrial biotechnology point of view so as to render both the environment free from harmful nitrile compounds.