To reduce the dependence on chemical inputs during biomass pretreatment, an integrated process on the basis of hydrothermal pretreatment followed by twin-screw extrusion for poplar was proposed. A comparative study was conducted on the pore structure, crystallinity, relative surface lignin concentration, cellulose accessibility, and enzymatic hydrolysis efficiency of the pretreated materials. Results suggested that the relative surface lignin concentration of fibers pretreated by hydrothermal treatment (conducted at 170 ℃ for 90 min) coupled with extrusion (HE) treatment was decreased compared to the sole hydrothermal (H) process, which had a positive impact on the subsequent enzymatic hydrolysis. Additionally, the HE process resulted in an increase in pore size by 34.4%, pore volume by 447.5%, and specific surface area by 93.5%, which enhanced the penetration and interaction of water into the fibers and thus increased cellulose accessibility by 143.2%. SEM and TEM observations revealed that fibers were separated and finely fibrillated, large amounts of fragmentary structure and cracks appeared on the fiber. In addition, the cell wall structure was deformed and damaged, when pretreated by HE process. Overall, this work showed that hydrothermal treatment followed by twin-screw extrusion was an achievable strategy for high fermentable sugar production of hardwood.

中文翻译：

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提高杨木酶解效率的综合预处理策略：水热处理后双螺杆挤出

为了减少生物质预处理过程中对化学品投入的依赖，提出了一种基于水热预处理和双螺杆挤出的杨木集成工艺。对预处理材料的孔结构、结晶度、相对表面木质素浓度、纤维素可达性和酶水解效率进行了比较研究。结果表明，水热处理（170 ℃，90 min）联合挤出（HE）处理的纤维相对表面木质素浓度较单独水热（H）工艺有所降低，这对后续处理产生积极影响。酶促水解。此外，HE工艺使孔径增加了34.4%，孔体积增加了447.5%，比表面积增加了93.5%，增强了水对纤维的渗透和相互作用，从而使纤维素的可及性增加了143.2%。SEM和TEM观察表明纤维分离且细原纤化，纤维上出现大量碎片结构和裂纹。此外，HE工艺预处理时，细胞壁结构发生变形和破坏。总体而言，这项工作表明，水热处理后进行双螺杆挤出是硬木高发酵糖生产的可实现策略。