ISOLATION, IDENTIFICATION AND SUBSTRATE SPECIFICITY OF A NITRILASE PRODUCING BACTERIA, Acidovorax sp. SK1

The process of biocatalysis or biotransformation remains the core of industrial biotechnology owing to its importance in the synthesis of high-value products in a cost effective manner. Nitrile biotransformation has also achieved considerable attention in last few decades due to its widespread biotechnological and industrial applications. In the present study, a versatile, potent nitrile-degrading bacterium, Acidovorax sp. SK1 was isolated from the cracker waste dumping site of Sivakasi, Tamilnadu and characterized for its biocatalytic potential, nitrilase production and enzyme activity. A pH sensitive indicator-based assay was performed to identify the nitrile degrading ability of the isolated samples. Semi quantitative High performance thin layer chromatographic (HPTLC) method was performed for quantitative measurement of mandelic acid produced from degradation of nitrile compound, mandelonitrile. The optimization of medium and nutritional parameters were studied for the improvement of nitrilase activity, which indicated that maximum nitrilase activity was observed at an optimum pH of 7.0, agitation at 100 rpm, glucose as best carbon source (10 g/L) and yeast extract (0.1 g/L) as principal nitrogen source. Biomass is also a critical parameter in the biocatalysis of mandelonitrile to mandelic acid and at a biomass of 100 mg/L, maximum nitrilase activity of 0.026 I.U was observed. The versatility of Acidovorax sp. in the hydrolysis of mandelonitrile to pharmaceutically valuable mandelic acid makes it a potential biocatalyst in organic synthesis. The present work demonstrates the production of nitrilase and the biotransformation of mandelonitrile to mandelic acid using the newly isolated strain of Acidovorax sp. SK1 and also suggests that this strain open avenues for biotechnological application as an effective green catalyst.