Biotransformation of nitriles to amides using soluble and immobilized nitrile hydratase from Rhodococcus erythropolis A4

A semi-purified nitrile hydratase from Rhodococcus erythropolis A4 was applied to biotransformations of 3-oxonitriles 1a-4a, 3-hydroxy-2-methylenenitriles 5a-7a, 4-hydroxy-2-methylenenitriles 8a-9a, 3-hydroxynitriles 10a-12a and 3-acyloxynitrile 13a into amides 1b-13b. Crosslinked enzyme aggregates (CLEAs) with nitrile hydratase and amidase activities (88% and 77% of the initial activities, respectively) were prepared from cell-free extract of this microorganism and used for nitrile hydration in presence of ammonium sulfate, which selectively inhibited amidase activity. The genes nhal and nha2 coding for alpha and beta subunits of nitrile hydratase were cloned and sequenced. (c) 2007 Elsevier B.V. All rights reserved.