常压甘油相有机溶剂预处理解构木质纤维素类生物质及促进其高效酶解的机理分析

找到有效的预处理方法来疏解木质纤维素类生物质顽抗性以促使其高效酶解，是当前酶基生物质炼制工业化瓶颈的破解之道。常压甘油相有机溶剂预处理已初步显示出独特优势，但缺乏系统性分析和机理性认识。因此，本课题围绕“阐明甘油有机溶剂处理提高基质可酶解性的机制”提出如下研究思路：首先，课题拟分析比较各种甘油有机溶剂预处理过程，研究纤维素分离点、木质素-碳水化合物的断裂位点/方式和木质素溶出规律；接着，本课题拟利用现代分析技术手段多尺度表征基质在预处理和酶解时组成结构变化，定量分析甘油半纤维素多糖的主/侧链糖单元和甘油木质素组成结构单元的特征，以便解析该预处理选择性脱除组分和有效促进基质水解的原因；最后，课题拟研究甘油在预处理后基质和溶液里化学分布和存在方式，结合模拟实验阐明常压甘油相有机溶剂预处理不产生糠醛类抑制物的真正原因。本课题的实施将为该技术的工艺应用型研究，提供理论依据和技术支撑。

The key to current enzyme-based biorefinery industrialization is to find an efficient pretreatment strategy that is supposed to deconstruct the recalcitrant cell wall of lignocellulosic biomass, and thus to enhance the enzymatic hydrolysis of it efficiently. Numerous studies made by us and other researchers on the pretreatment have demonstrated glycerol organosolv pretreatment (GOP) is extremely effective and competitive in improving the hydrolyzability of lignocellulosic biomass, but the mechanism behind that is yet to elucidate with the overall analysis. To shed light on the process mechanism of the GOP improving the substrate susceptibility effectively, accordingly, some plans have been made in this research proposal as follows: First, such aspects as disintegration point of the fiber and split-off place / way of the lignin-carbohydrates, involving the lignin dissolution, will be taken into consideration during the various GOP condition. Then, the chemical compositional and physical structural changes, including supermolecular structure, of substrates during the GOP and enzymatic hydrolysis will be characterized and compared at multi-dimensional scales with various modern analytic equipment. Meantime, the main / side chain sugar units of hemi-cellulosic polysaccharides and constitutional units of lignin polymers will be characterized with quantitative analysis, to gain insights into why the pretreatment has presented such a good selectivity at component removal, thereafter resulting in the superior hydrolyzability of substrates. Finally, our efforts will be made to understand the reason that the atmospheric GOP process initiated by us has resulted hardly in producing furan inhibitors to the downstream saccharification / fermentation from lignocellulosic feedstock. To make it clear, the chemical distribution and state of the glycerol bound in dissolved polysaccharides and pretreated substrates will be studied, together with some model experiments. The research proposal is purposed to supply a solid support to further development and scale-up of the GOP process.