Production and extraction optimization of xylanase and β-mannanase by Penicillium chrysogenum QML-2 and primary application in saccharification of corn cob

Abstract

Significant variables for production of xylanase and β-mannanase including moisture content, initial pH and inoculum size and significant variables for enzymes extraction including volume of solvent, extraction time and agitation speed were screened and optimized, respectively. With the use of mixture of corn stover powder and wheat bran as substrates and double distilled water as solvent for enzymes extraction, maximum xylanase activity (19613.25U/g) and β-mannanase activity (8479.82U/g) could be obtained under the optimized conditions [moisture content 74.0%, initial pH 4.5, inoculum size 11.6% (v/w), volume of solvent 16.0ml/g dry substrate, extraction time 108min and agitation speed 172rpm]. Cellulases activities including endoglucanase activity (195.13U/g), filter paper activity (41.87U/g) and β-glucosidase activity (132.63U/g) were obtained concomitantly. Compared with xylanase activity (1734.78U/g) and β-mannanase activity (928.41U/g) under initial conditions, optimization resulted in 10.31-fold increase for xylanase activity and 8.13-fold increase for β-mannanase activity, respectively. The crude enzymes solution was suitable for saccharification of aqueous ammonia solution pretreated corn cob powder and maximum yields of xylose (236.63mg/g) and reducing sugar (553.94mg/g) were obtained.