稀酸预处理对玉米秸秆纤维组分及结构的影响

Effects of Dilute Acid Pretreatment on Fibre Components and Structure of Corn Stover

研究了稀硫酸预处理对玉米秸秆化学组成变化及纤维素酶水解得率的影响,并采用扫描电镜(SEM)、X射线衍射仪(XRD)、红外光谱(IR)和热重分析(TG)对玉米秸秆纤维结构特性进行了分析。结果表明随着硫酸浓度的增大、温度的升高和时间的延长,纤维素和木质素含量有所增加,而半纤维素含量大幅度降低,且预处理后纤维素酶水解得率也逐渐增大。当处理条件为硫酸质量分数0.75%、温度150℃、时间80 min时,半纤维素降解率为98.02%,所得固体渣纤维素酶水解得率为66.95%(纤维素酶用量20 FPUI/g纤维素)。稀酸预处理后玉米秸秆纤维表面和细胞壁受到不同程度的破坏,表面积增大,孔洞增加,纤维素的结晶度降低,有利于纤维素酶水解作用的进行。

The effects of dilute sulfuric acid pretreatment on the composition and enzymatic hydrolysis rate of solid residues for corn stover were investigated,and the fiber structure property of the pretreated residues were studied with scanning electron microscope,infrared,X-rays diffraction and thermal gravity.Results： With the increase of sulfuric concentration,temperature and retention time,the contents of cellulose and lignin increase slightly,the hemicellulose content largely declines,and the yield of enzymatic hydrolysis increases gradually.The degradation rate of hemicellulose is 98.02% and the yield of enzymatic hydrolysis is 66.95% when the pretreatment conditions are sulfuric acid concentration 0.75%,cellulase dosage 20 FPUI/g cellulose,temperature 150 ℃ and time 80 min.The fiber surface and cellular wall of corn stover are broken after the dilute acid pretreatment,thus increasing specific surface area and pore volume,decreasing the crystallization degree of cellulose,so favorable for the enzymatic hydrolysis.