Domestication of a Nitrile Hydratase Producing Strain

A bacterial strain having higher nitrile hydratase activity and acrylonitrile concentration tolerance,numbered Nocardia sp.LNSY0611XH,was developed by repeated subculturing of Nocardia sp.LNSY0611 in the broth containing acrylonitrile with slightly increased acrylonitrile concentration.The specific nitrile hydratase activity of Nocardia sp.LNSY0611XH increased up to 72.5 U·mg~(-1) of dry cells,15 times higher than that of Nocardia sp.LNSY0611.The results showed that the factors influencing nitrile hydratase activity mostly were glucose,urea,acrylamide,Co~(2 +)and pH,and the optimum conditions were as following:glucose 20 g·L~(-1),urea 0.06 g·L~(-1),acrylamide 10%,Co~(2+) 0.3 g·L~(-1),pH 7 and temperature 30℃.