Abstract: The effects of dilute acid pretreatment conditions of Pennisetum grass on the composition,celluloses enzymatic hydrolysis yield, and the yield of total sugars in liquids were investigated at medium-low temperature. And the fiber structures of pretreated residues were studied with scanning electron microscope (SEM).With the increase of sulfuric concentration,temperature,and retention time,the hemicelluloses content declined considerably,and the yield of enzymatic hydrolysis increased gradually.The recovery of cellulose was 87.48%,the hemicelluloses hydrolysis rate was 93.68%,the yield of enzymatic hydrolysis was 86.3%,and the total sugars yield was 54.53 g/100 g after the pretreatment when the pretreatment conditions were sulfuric acid concentration 4.0%,temperature 110 ℃,residence time 8 h,and cellulase dosage 40 FPIU/g cellulose.The results indicated that the fiber surface and cell wall of Pennisetum grass were broken after acid pretreatment,thus the specific surface area and pore volume increased,and it was beneficial to the enzymatic hydrolysis.

Key words: Pennisetum grass(Pennisetum hydridum), dilute sulfuric acid pretreatment, hemicellulose hydrolysis, enzymatic hydrolysis, scanning electron microscope (SEM)