Production, purification and characterization of an acid/alkali and thermo tolerant cellulase from Schizophyllum commune NAIMCC-F-03379 and its application in hydrolysis of lignocellulosic wastes

A cellulase producing fungus Schizophyllum commune NAIMCC-F-03379 was isolated from decomposed leaf sample of Lantana camera. The nutritional components (wheat bran, magnesium sulphate and calcium chloride concentrations) and physical parameters (temperature and pH) were optimised by response surface methodology for enhanced cellulase production by S. commune NAIMCC-F-03379. The optimized medium contained: 1% (w/v) wheat bran, 0.3g/L MgSO4, 0.8-1.0g/L CaCl2, optimum temperature and pH were 25 degrees C and 5 respectively. Under optimum condition, 5.35-fold increase in CMCase and 6.62-fold increase in FPase activity was obtained as compared to un-optimized condition. Crude cellulase enzyme was subjected to different purification techniques and comparative evaluation of their efficiency was performed. The aqueous two-phase system using polyethylene glycol 8000/MnSO4 system showed maximum purification with 10.4-fold increase in activity, 79.5% yield and 0.5 partition coefficient. The cellulase enzyme obtained from S. commune NAIMCC-F-03379 has shown high stability i.e. more than 55% relative activity after 12h of incubation over wide range of temperature (25-65 degrees C) and pH (3-10). The molecular weight of the cellulase enzyme was estimated as similar to 60kDa by using sodium dodecyl sulphate-polyacrylamide electrophoresis (SDS-PAGE) and zymography. K-m and V-max value of cellulase on carboxy-methyl cellulose were obtained as 0.0909mg/mL and 45.45mol/minmg respectively. Rice straw and wheat bran were subjected to hydrolysis using cellulase and cellulase-xylanase cocktail and analysed by thin layer chromatography and high performance liquid chromatography (HPLC). The HPLC analysis showed glucose concentration of 1.162mg/mL after enzymatic hydrolysis of rice straw.