木质纤维素高固酶解过程扩散-吸附-反应的分析与调控

木质纤维素高固酶解工艺具有耗水少、能耗低、产能大、糖浓度高等优点，但存在水解效率随固含量增加而线性下降的共性技术问题。本项目旨在揭示高固酶解效率下降的关键因素和调控途径，以酶解体系的扩散、吸附与反应为主线，开展酶解过程的多尺度表征、机理分析与过程调控。①多尺度表征：组合色谱、波谱和电镜分析与CFD模拟，定量描述宏观底物颗粒、介观纤维素酶、微观产物糖的分布（扩散）、转移（吸/脱附）与变化（反应）；②机理分析：通过研究纤维素酶分布、活力变化、产物抑制与吸附行为，探讨酶解反应受扩散、吸附/脱附的影响规律，构建扩散-吸附-反应动力学模型，明确水解效率下降的存在环节和关键因素；③过程调控：基于动力学模型和机理分析，确定提高水解效率的调控途径，优化反应器设计、酶与底物预混、补料设计、酶制剂复配等工艺。研究成果将为高固酶解体系工艺优化提供理论依据，促进纤维素乙醇和生物基化学品的基础研究并推进其开发应用。

For enzymatic conversion of lignocellulosic biomass, conducting at high solids (substrate) concentrations is advantageous, since it increases product concentrations and plant productivity while lowering energy and water input. However, it has been shown that at increasing substrate concentration, the corresponding conversion efficiency of cellulose linearly decreases for a number of lignocellulosic substrates. The purpose of this proposal is to discover the key factors and the effective regulating ways for the decreasing efficiency of enzymatic conversion at high solids loading. Therefore, the main works are focused on multi-scale characterization, theoretical analysis and process optimization by setting the study of the whole process of cellulase diffusion, adsorption and reaction as the central research line. (1) Multi-scale charaterization: quantitatively analyzing the distribution (diffusion), transfer (adsorption/ desorption) and variation (reaction) of macroscopic substrate particles, mesoscopic cellulase and microscopic sugars; (2) Theoretical analysis: investigating the changes in the reactivity of various components of cellulases, the distribution and adsorption of cellulases together with product inhibition; discussing the influence of diffusion and adsorption/desorption on enzymatic conversion of cellulose; constructing the diffusion-adsorption-reaction kinetics for high solids cellulose hydrolysis; and discovering the process steps, the key factors and the control approaches for the decrease in cellulose conversion; (3) Process optimization: Determining the effective way to improve the hydrolysis efficiency based on the kinetic model and theoretical analysis, and optimizing the bioreactor design, the premixing of substrate and cellulase, fed-batch strategy and enzyme mixture design to enhance the hydrolysis efficiency. This research will provide the theoretical basis for the operation of high solids enzymatic hydrolysis of lignocellulose, and further promote the fundamental and application study of cellulosic ethanol and biomass-based chemicals.