水热耦合稀乙酸拆解杨木纤维的条件优化及表征

Optimization and Characterization of Deconstructing Poplar Fiber by Hydrothermal Coupling with Dilute Acetic Acid

关键词:  水热预处理  乙酸  杨木  木糖  纤维素拆解

Key Words:hydrothermal pretreatment  acetic acid  poplar  xylose  cellulose deconstruction

摘要:采用水热耦合稀乙酸预处理技术对速生杨木进行拆解，研究了乙酸质量分数、固液比、温度及反应时间对杨木木糖去除率和纤维素拆解分离得率的影响规律。结果表明，在乙酸质量分数0.5%、固液比1∶20、温度170℃、反应时间30 min条件下，木糖去除率为92.9%，纤维素拆解分离得率为94.0%。通过对水热残渣和预处理液的结构与成分分析，表明水热耦合稀乙酸预处理是一种温和的拆解分离方法，其主要去除杨木纤维中半纤维素的木糖成分，将大部分木糖转化为低聚木糖，同时对纤维素和木质素的破坏较小，从而保护纤维素、提高纤维素酶的可及度。

Abstract:The fast-growing poplar was deconstructed by hydrothermal coupling dilute acetic acid pretreatment technology， and the effects of acetic acid concentration， solid-to-liquid ratio， temperature and reaction time on the removal rate of xylose and the cellulose retention yield in poplar were studied. The results showed that under the conditions of acetic concentration of 0.5%， solid-liquid ratio of 1∶20， temperature of 170℃ and reaction time of 30 min， the removal rate of xylose was 92.9%， and the cellulose retention yield was 94.0%. Through the analysis of the structure and composition of the hydrothermal residue and pretreatment liquid， it was shown that the hydrothermal coupling dilute acetic acid pretreatment was a mild method， which mainly removed the xylose of hemicellulose in poplar fiber， most of which was transformed into xylo-oligosaccharide， and simultaneously had less damage to cellulose and lignin， thereby protecting cellulose and improving cellulase accessibility.