Production and immobilization of alkaline protease from Bacillus mycoides

The production of alkaline protease was investigated in submerged culture of Bacillus mycoides. The optimal conditions for enzyme production were pH 9•0, 3% (w/v) dextrin as carbon source, (NH4)2SO4 (0•1%, w/v) and peptone (0•1%, w/v) as nitrogen sources and KH2PO4 at 1•0 g/l. The enzyme was immobilized on various carriers by different methods of immobilization including physical adsorption, ionic binding, covalent binding, and entrapment. The enzymes prepared by physical adsorption on chitosan, ionic binding on Amberlite IR-120, covalent binding on chitin, and entrapment in 2% crosslinked polyacrylamide had the highest activites. The optimal reaction temperature of the immobilized enzymes was shifted from 50 to 55°C. The thermal and storage stabilities of the free enzyme were significantly improved by the immobilization process.