ISOLATION AND PHYSICO-CHEMICAL CHARACTERIZATION OF EXTRACELLULAR LIGNO-CELLULOLYTIC ENZYMES OF PLEUROTUS PULMONARIUS IN SUBMERGED FERMENTATION

摘要

Pleurotus pulmonarius, a member of oyster mushroom can produced lignocellulosic enzymes laccase, peroxidise and cellulase in liquid potato-dextrose medium in submerged stationary condition. The lignocellulolytic activities were assayed using the extracellular culture filtrate which was partially purified using 0- 80% ammonium sulphate saturation. Different physico-chemical studies were performed using the partially purified culture filtrate. The fungus produced more laccase and peroxidase than the cellulase. The optimum laccase production was found on 17 th day whereas cellulase & peroxidase productions were found on 9 th & 10 th day, respectively. K m of laccase is 4.1mM against guaiacol and 1.25 mM against o-dianisidine whereas K m of peroxidase was 0.72mM and cellulase was 0.06 mM. Optimum pH of laccase was 6.0 but for peroxidase and cellulase it was 7.0. The temperature optima of cellulase (50 . C) was more than laccase (40 . C) and peroxidase (30 . C). All the lignocellulosic enzymes showed a wide range of temperature and pH stabilities. Laccase and peroxidase were fully inhibited by NaCl but it was not so effective against cellulase. P. pulmonarius showed higher ligninolytic (Laccase and peroxidase) activity than cellulolytic (cellulase) activity. The lignocellulosic enzymes isolated from submerged fermentation of P. pulmonarius might be industrially significant as they showed a wide range of temperature and pH stabilities.