木质素-碳水化合物复合物结构变化对纤维素酶吸附影响的机理研究

首先利用稀酸和稀碱分别对稻草原料进行预处理，再从预处理前后原料中分离出木质素-碳水化合物复合物样品；然后利用化学方法和波谱手段分析表征木质素-碳水化合物复合物在预处理过程中的变化：1、化学组成：木质素含量、碳水化合物含量及糖基组成，2、结构和属性：分子量、组分间共价键、官能团等；最后制备木质素-碳水化合物复合物基传感器，利用QCM原位、实时地监测木质素-碳水化合物复合物与纤维素酶相互作用过程。最终，1、阐明木质素-碳水化合物复合物在预处理过程中结构及属性变化对纤维素酶吸附影响的机理；2、揭示木质素-碳水化合物复合物与纤维素酶相互作用的“构效关系”；3、为阐述木质素-碳水化合物复合物如何影响木质纤维原料酶水解提供相应的理论基础。

Lignocellulose (rice straw) will be pretreated by the dilute sulfuric acid and the green liquor (alkali pretreatment), respectively. Then, lignin-carbohydrate complexes is being isolated from native and pretreated samples. The wet chemistry will be applied to determine the changes of the chemical components of the samples such as lignin content, carbohydrate content and polysaccharide components. The structural changes of lignin-carbohydrate complexes (LCCs) such as molecular weight, function groups, linkages between lignin and carbohydrate, etc. are being comprehensively characterized by chromatographic instruments such as 31P, 13C, 1H-13C HSQC NMR, UV, FTIR and GPC etc. Therefore, the changes of LCCs induced by the pretreatments will be elucidated comprehensively. Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) will be used to characterize the interaction between cellulase and LCCs in this study. First of all, the sensor of QCM-D covered with nano-film of LCCs will be prepared with 1, 4-dioxane (96% V/V) (proposed) through electrostatic spinning coating. Then, the interaction between cellulase and lignin-carbohydrate complexes will be monitored by QCM-D in real time. Based on the result of QCM-D and the structure LCCs, the adsorption kinetics of cellulase on LCCs will be revealed. And the effects of the structural changes of LCCs induced by the pretreatments on the adsorption of cellulase will be demonstrated, as well. As a result, this study will provide essential and fundamental knowledge to improve pretreatment and/or to modify the cocktails of enzymes for better enzymatic saccharification on lignocellulosic materials.