Advances in cloning, structural and bioremediation aspects of nitrile hydratases

Nitrile hydratase (NHase) is a prominent enzyme in many microorganisms for its nitrile metabolism. The potentiality in the bioconversion of nitriles to its high-value amides has been extensively used in industries for the production of acrylamide and nicotinamide which are essential chemicals. Enzymologists are still considering NHases for its potential biotechnological applications including biotransformations and bioremediations. But most of the nitrile hydratases have limitations like the low expression, low thermostability and enantioselectivity. Though considerable data has been generated in the area of gene configuration, crystal structure, kinetic mechanism and photoreactivity of NHases, there is a need for constant improvement to develop a robust biocatalyst for bioremediation of toxic nitriles. With these considerations, in the present review, we report advances with the main focus to structure, catalytic mechanism, cloning strategy, gene expression, bioinformatic tools, metagenomics, thermostability and current bioremediation applications of NHases.