稀酸法预处理对橡子壳纤维组成和结构的影响

Effect of Dilute Acid Pretreatment on Fibre Components and Structure of Oak Shell

以橡子壳为木质纤维素原料,考察了酸法预处理对其化学组成变化以及酶水解得率的影响,并采用电子扫描电镜(SEM)、红外光谱(IR)和X射线衍射分析(XRD)对橡子壳纤维结构特征进行了表征。结果表明:橡子壳用2%硫酸溶液按固液比1∶8(g∶mL)室温处理48 h,半纤维素和木质素去除率分别为21.6%和6.6%;酶水解得率从42.8%增加至71.4%,总体葡萄糖产率达到71.2%,提高了66.4%。经过121℃(0.15 MPa)处理1 h,半纤维素和木质素的去除率分别为84.6%和24.5%。酶水解得率为72.1%,较处理前提高了68.5%,但由于纤维素损失率较高,导致总体葡萄糖产率增幅不大。经过酸处理后,橡子壳纤维比表面积增大、表面孔洞增加,纤维结构的结晶度下降,有利于纤维素酶水解作用的进行。

The effect of dilute acid pretreatment on the composition and enzymatic hydrolysis rate of Sawtooth Oak （ Quercus acutissima） shells was investigated. And the fiber structures of pretreated residues were studied with scanning electron microscopy （ SEM） , infrared spectra （ IR ） and X-ray diffraction spectrum （ XRD ） . Results showed that after pretreatment at room temperature with 2% H2 SO4 , the contents of hemicellulose and lignin were reduced by 21. 6% and 6. 6%, respectively. The enzymatic hydrolysis yield reached 71. 4% from 42. 8%, and total glucose yield was 71. 2% which was 66. 4% more than that of untreated oak shell. After pretreatment at 121℃ （0. 15 MPa） for 1 h, the contents of hemicellulose and lignin were reduced by 84. 6% and 24. 5%, respectively. The enzymatic hydrolysis yield reached 72. 1% which was 68. 5% more than that of untreated oak shell. Because of the high cellulose loss, the glucose yield improvement was not so obvious. The fiber surface and pore volume increased and the crystallinity of cellulose decreased, which are favorable to increase the enzymatic hydrolysis rate.