1.4.1 Hydrolysis of Nitriles to Amides

Abstract Nitrile hydratase (NHase; EC 4.2.1.84) catalyzes the hydration of nitriles to form amides. The reaction catalyzed by nitrile hydratase is strikingly fast and versatile and a wide range of nitriles, including aromatic and arylalkyl nitriles, α- and β-substituted nitriles, and aminonitriles can be hydrated to the corresponding amides. Although nitrile hydratase generally has low stereoselectivity, its use in conjunction with highly stereospecific amidases provides a valuable route for the stereoselective synthesis of carboxylic acids. The powerful nature of nitrile hydratase has had a huge impact on the progress of applied microbiology, enzyme engineering, and enzyme-catalyzed organic synthesis. The best-known applications of nitrile hydratase on an industrial scale are the production of acrylamide and nicotinamide from acrylonitrile and pyridine-3-carbonitrile, respectively. This chapter provides an overview of the current scope of nitrile hydratase mediated reactions and focuses on whole-cell biotransformations.