Abstract: Reducing the cost of enzymatic hydrolysis is the key step in bio-ethanol production from cellulose. In order to enhance the conversion of cellulose into ethanol, the enzymatic hydrolysis condition of corn stalk pretreated by steam explosion was optimized by enzyme complex formulation. The affecting rules of cellulase, xylanase and β-glycosidase on enzymatic hydrolysis efficiency were studied by single-factor experiment and orthogonal test. The results showed that the cellulose content of steam-exploded corn stalk reached 42.21%, and the hemicellulose content was only 3.65%. Cellulase was crucial to the enzymatic hydrolysis process, the enzymatic hydrolyzation yield was 75.45% when added by 40 FPU/g. Xylanase promoted more cellulose exposed, enzymatic hydrolyzation yield reached 78.03% when added by 1 500 IU/g. β-glucosidase was conducive to eliminate the feedback inhibition caused by cellobiose, when dosage was in 40 IU/g, the concentration of cellobiose was 0.330 4 g/100 mL, enzymatic hydrolyzation yield reached 76.45%. The optimal conditions for the process by orthogonal experiment were as follows：cellulase 30 FPU/g, xylanase 800 IU/g, and β-glucosidase 40 IU/g, under this and when the substrate concentration was 25%, glucose was up to 9.3 g/100 mL, i.e., increased by 57.63% compared to using a single cellulase while the glucose was only 5.9 g/100 mL. The affecting significance of three enzymes was ordered as follows：cellulase > xylanase > β-glucosidase.

Key words: corn stalk, cellulase, xylanase, β-glucosidase, complex formulation