Wang Hanmin, Wang Bing, Sun Dan, Shi Quentin, Zheng Lu, Wang Shuangfei, Liu Shijie, Xia Ruirui, Sun Runcang
Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, P.R. China.
Shanghai Dssun New Material Co., Ltd., Shanghai, P.R. China.
ChemSusChem. 2019 Mar 7;12(5):1059-1068. doi: 10.1002/cssc.201802592. Epub 2019 Feb 5.
Efficient deconstruction of lignocellulose is vitally important for the biorefinery industry because lignin structures play a crucial role in the high value-added conversion of lignin. In this study, an integrated process based on hydrothermal pretreatment (HTP) and Kraft delignification was proposed to deconstruct lignocellulosic biomass. It was found that the HTP not only facilitated the production of xylo-oligosaccharides but also reduced the chemicals dosage of the following delignification. The structural characteristics of lignin obtained from the integrated process were investigated by NMR spectroscopy and gel-permeation chromatography. Additionally, double enzymatic lignins (DELs) isolated from different feedstocks were used as "model lignin" to delineate the structural transformations of lignin during H O , ClO , and O bleaching. Significant changes of the lignin structure were observed during the ClO bleaching process, including degradation of aromatic rings, enrichment in p-hydroxyphenyl units, and increase of carboxylic groups. A comparison of the structural characteristics of the bleached lignins indicated that HTP benefited the subsequent bleaching process. Enhanced knowledge of lignin chemistry during deconstruction and delignification could provide valuable insight into the current lignocellulose biorefinery.
木质纤维素的高效解构对生物炼制行业至关重要，因为木质素结构在木质素的高附加值转化中起着关键作用。在本研究中，提出了一种基于水热预处理（HTP）和硫酸盐法脱木素的集成工艺来解构木质纤维素生物质。结果发现，水热预处理不仅促进了低聚木糖的产生，还降低了后续脱木素过程中的化学药剂用量。通过核磁共振光谱和凝胶渗透色谱法研究了从集成工艺中获得的木质素的结构特征。此外，从不同原料中分离出的双酶解木质素（DELs）被用作“模型木质素”，以描绘木质素在H₂O₂、ClO₂和O₂漂白过程中的结构转变。在ClO₂漂白过程中观察到木质素结构发生了显著变化，包括芳环降解、对羟基苯基单元富集以及羧基增加。对漂白木质素结构特征的比较表明，水热预处理有利于后续的漂白过程。深入了解解构和脱木素过程中的木质素化学性质可为当前的木质纤维素生物炼制提供有价值的见解。
