NITRILE HYDRATASE OF RHODOCOCCLIS RHODOCHROLIS NHB-2 : OPTIMISATION OF CONDITIONS FOR PRODUCTION OF ENZYME AND CONVERSION OF ACRYLONITRILE TO ACRYLAMIDEA DUTT SANKHIAN, HARISH KUMAR, DUNI CHAND, DINESH KUMAR AND TEK CHAND BHALLA
Culture conditions for the production of nitrile hydratase by Rhodococcus rhodochrous NHB-2 for the conversion of acrylonitrile to acrylamide were optimised. Medium containing 0.75% glucose, 0.5% yeast extract and 0.4% peptone (pH 9.5) was found most suitable for enzyme production at 30°C. Addition of 7 mg L-1 cobalt chloride in to the medium enhanced enzyme prodUCtion. Acetonitrile, isobutyronitrile, crotonamide, methacrylamide, and urea, which generally induce nitrile hydratases in other bacterial systems had inhibitory effect on the growth of Rhodococcus rhodochrous NHB-2 and production of this enyzme. Ammonium salts [NH4C1, NH4NO3, (NH4),SO4] used as nitrogen sources repressed growth and enzyme formation. Optimum enzyme production was in the early exponential phase at 22 h cultivation. Highest enzyme activity (conversion of acrylonitrile to acrylamide) was recorded in potassium phosphate buffer (100 mM) at pH 8.5 and temperature 50°C. AgNO3, iodoacetate, EDTA (ethylenediaminetetraacetic acid), phenanthroline, urea and glycine had strong inhibitory effect on the enzyme. These studies suggested this enzyme as constitutive cobalt containing metallonitrile hydratase.
Enter your contact information below to receive full paper.