Increasing the activities of exo-β-glucanases

one of the important components of cellulase

is a key to strengthening the synergistic degradation of cellulase and reducing the cost of cellulolytic hydrolysis. The methods of MCC-agar plate screening and liquid culture medium of filter paper were used in this work respectively to screen Trichodermareesei transformants

obtaining 6 superior transformants with higher filter paper collapsing rate and growing rate on MCC-agar plates. Further screening experiment was conducted under shaking flask condition

obtaining the highly exo-b-glucanase (C1)-producing transformant T.reesei ZU-101 whose C1 activity was18.24 U·ml-1 after 48 h liquid culture

2.16-fold higher than the original strain. Analysis results demonstrated that filter paper activity (FPA) of the cellulase system of the transformant

representing total activity

increased by 61.9% as exo-β-glucanase activity ascended significantly

although endo-b-glucanase and cellobiase activities varied insignificantly from the original strain. The enzymatic hydrolysis yield of T.reesei ZU-101's cellulase in the hydrolysis of alkali pretreated corn stover was 94.4% when the enzyme dosage and hydrolysis time were 20 FPIU·(g substrate)-1 and 48 h

respectively. The results of the present work have promising application prospects in the bioconversion and utilization of renewable cellulosic materials.