Effect of steam-explosion pretreatment on chemical components and cellulosic structure of corn stalk.

The effects of steam-explosion pretreatment on composition and enzymatic hydrolysis rate of solid residues for corn stalk were investigated and the fiber structure of pretreated residues were studied with scanning electron microscopy(SEM),infrared(IR) and X-rays diffraction spectrum methods.There was no significant difference in cellulose content.Hemicellulose was largely degraded,and a portion of lignin was also solubilized.The digestibility of solid residues after steam explosion increased with the increase of steaming pressure and residence time.When an enzyme loading of cellulase 20 FPIU/g of cellulose was applied and hydrolyzed for 72 h,the highest enzymatic hydrolysis yield 75.76 % was obtained when corn stalk was pretreated at 1.6 MPa for 9 min.The results indicated that fiber surface and cellular wall of corn stalk are broken in various extents,such as the increasing of specific surface area and pore volume,the decreasing of crystallinity of cellulose,which are favorable to increase the enzymatic hydrolysis rate.Steam explosion is one of the effective pretreatment methods for pretreating lignocellulosic biomass.