Microbial Metabolism of Nitriles and Its Biotechnological Potential

925-947Biocatalysts display a remarkable capability to function under normal temperature and pressure with high specificity and are potentially very economical. Bioconversion of nitrile compounds to a number of economically important compounds is described. A wide variety of microorganisms having the ability to metabolize different nitriles and discovered during the last two decades are described. It is pointed out that the microbial degradation of nitriles proceeds through two distinct enzymatic pathways: nitrilase catalyzes the direct hydrolysis of nitriles to the corresponding carboxylic acids and ammonia, while nitrile hydratase catalyzes the hydration of nitriles to  the corresponding amides, followed by their conversion to the corresponding carboxylic acids plus ammonia by amidase. It is mentioned that the versatile biocatalytic nature and applications of these enzymes are being increasingly recognised for the selective hydrolysis of various types of nitriles for the production of several fine chemicals, pharmaceuticals and optically active nitriles, amides and carboxylic acids, which are not generally feasible by chemical routes. A commercial process involving the multi-kiloton scale synthesis of acrylamide using Rhodococcus rhodochrous J 1 nitrile hydratase is described, which is the best example of a fully developed industrial application of this biotechnology. Though, recent developments broadened the potential application of these versatile biocatalysts in chemical synthesis and bioremediation, further studies are required to fully harness their biotechnological potential