棉杆强化亚硫酸盐预处理组分溶出机理及酶水解效率研究

项目名称： 棉杆强化亚硫酸盐预处理组分溶出机理及酶水解效率研究

项目编号： No.31200454

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 林学

项目作者： 朱文远

作者单位： 南京林业大学

项目金额： 23万元

中文摘要： 酸性亚硫酸盐法预处理针叶木、阔叶木进行生物质转化，不仅可有效降低预处理的磨浆能耗，而且预处理底物的纤维酶水解效率高。棉杆作为农业废弃物，可用于生产生物质燃料，但其结构和化学成分与木材原料差别较大，采用现有的酸性亚硫酸盐预处理技术，所得棉杆底物的酶水解糖化效率较低。项目拟采用新型强化酸性亚硫酸盐技术，如更高预处理温度和硫酸浓度等，将棉杆皮、杆和芯分别进行预处理，通过复合水解因子表征预处理强度，优化最佳预处理条件；通过HPLC等分析预处理废液中半纤维素的单糖组成及含量，阐明半纤维素溶出机理；用超滤膜分离废液中的磺化木素，揭示木素磺化过程和溶出机理；研究残留木素结构和磺化度对底物纤维酶水解的影响；SEM、AFM显微技术辅助分析原料和预处理底物的微观结构的变化规律。通过研究，揭示强化亚硫酸盐预处理棉杆组分溶出和提高底物酶水解糖化效率的机理，成果可为农林废弃物的高效转化与高附加值利用提供科学依据。

中文关键词： 酸性亚硫酸盐；预处理；生物质转化；磺化木素；半纤维素

英文摘要： In this study, a modified SPORL, process with stronger pretreatment conditions, will be applied to the pretreatment of the bark, stalk, and core of cotton stalk for bioconversion. A combined hydrolysis factor (CHF) will be adopted to investigate the dissolution of xylan and lignin from cotton stalk for optimizing the modified SPORL pretreatment conditions. The removal of hemicelluloses from cotton stalk will be identified by determining the concentrations of monosaccharides in pretreated liquor. Sulfonated lignin will be separated from spent liquor using ultrafiltration membrane, opening the door to understanding of the fundamentals of lignin sulfonation and dissolution. On the other hand, the effect of structure and sulfonation degree of the lignin remained in substrate on enzymatic digestibility of the substrate will be investigated. Another task of this study is to analyse the variation of microstructures of raw materials and pretreated substrate by SEM and AFM. As a result, the mechanisms regarding the dissolution of lignocellulosic materials from cotton stalk, saccharification of enzyme-hydrolyzed stalk, and substrate cellulose digestibility will be elucidated. In summary, the research findings of this project would provide a strong scientific basis for the commercial bioconversion and value-added utilizati

英文关键词： bisulfite；pretreatment；bioconversion；lignosulfonate；hemicellulose