基于木素磺化改性的纤维素酶解障碍消除机制研究

Presently,enzymatic hydrolysis is facing the problems of low efficiency and high cost. An important reason is the obstacles resulted from non-cellulosic components of lignocellulose, including the non-productive binding of enzyme to lignin and the enzyme inhibitors in pretreatment hydrolysate. In the present research, pretreatment that is characterized by lignin sulfonation will be developed to eliminate these obstacles in the perspective of surface chemistry. Firstly, study on the electrostatic interaction between lignin and enzyme will be performed. The effects of lignin sulfonation and chemical environment on the surface charge of lignin will be investigated.The mechanisms used to describe the elimination of non-productive binding through lignin modification will be revealed. Secondly,the lignosulfonates released during pretreatment will be analyzed as polyelectrolyte. The Polyelectrolyte-Enzyme Complexes will be studied, including the formation, structure, and chemical stability.The inhibitors isolation and enzyme protection by the Polyelectrolyte-Enzyme Complexes will also be explored to interpret the inhibition elimination of hydrolysate through lignin sulfonation. The successful implementation of the present research will promote the enzymatic hydrolysis of cocktail containing both solid substrate and liquid substrate. Meanwhile, the efficiency of enzymatic hydrolysis at high solid content will be greatly enhanced due to the elimination of obstacles from non-cellulosic components. In this context, sustainability of biorefinery will be significantly promoted.

当前，木质纤维素的酶解依然面临着低效率和高成本问题，一个重要的原因是非纤维素组分造成的酶解障碍，这包括木质素组分对酶分子的非生产性吸附和预处理废液中降解产物对酶活性的抑制。本项目从表面化学的角度提出在预处理段对木质素进行磺化改性消除酶解障碍的思路。首先，通过对木质素与酶分子间静电作用的剖析，探讨表面改性和化学环境对木质素表面电位的调控作用，揭示木质素改性消除固态底物非生产性吸附的作用原理；其次，以磺化产物木素磺酸盐为切入点，通过对其聚电解质特征的分析，探讨聚电解质-酶分子复合体的形成过程、空间结构和环境稳定性。并进一步研究该复合结构隔离毒性抑制物和保护酶活的行为，阐明磺化产物消除预处理废液酶解抑制性的作用机制。本研究可解决预处理废液不能直接用于酶解的难题，为固液混合酶解奠定理论基础。同时，非纤维素组分酶解障碍的消除将显著提升高浓酶解的效力，促进生物质精炼的可持续发展。

木质纤维素是大量的可再生资源，其主要成分纤维素可经过酸解或酶解转化糖，然后通过生物技术发酵为人类所需的能源、化学品、食品。本项目为克服木质纤维素酶解的天然抗性，通过对原料进行磺化处理，使抑制酶解和发酵的固态底物和液态环境发生变化，促进生物转化。本项目揭示酶解体系中非纤维组分与酶分子间的表面化学行为，在微观水平上阐明磺化改性消除酶解障碍的作用机制，建立木质纤维素酶解多元体系的界面化学理论，为高浓酶解和固液混合酶解提供理论支撑。在本项目的资助下，发表SCI论文8篇，国家发明专利授权两项，培养硕士研究生4名，邀请国外专家交流并讲座一次，出国参加国际及会议并汇报1次，国内举办的国际会议1次。