Institute of Biomass Engineering, Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture and Rural Affairs, South China Agricultural University, Guangzhou, Guangdong 510642, PR China; College of Environmental Sciences, Sichuan Provincial Engineering Research Center of Agricultural Non-point Source Pollution Control, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China.
College of Environmental Sciences, Sichuan Provincial Engineering Research Center of Agricultural Non-point Source Pollution Control, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China.
Int J Biol Macromol. 2024 Jan;254(Pt 2):127853. doi: 10.1016/j.ijbiomac.2023.127853. Epub 2023 Nov 5.
In this work, Lewis acids (FeCl, AlCl) and bases (NaCO, NaSO) were incorporated into a neutral deep eutectic solvent (DES, choline chloride/glycerin) to intensify the lignocellulose fractionation. The efficiency of fractionation in terms of the maximum delignification rate (89.7 %) and well-pleasing cellulose saccharification (100 %) could be achieved by the Lewis acid-mediated DES. An in-depth insight of the evolution of lignin structure revealed that Lewis acid-mediated DES could cleave the β-O-4 linkages efficiently to achieve a high yield lignin fragments. Meanwhile, the lignin fragments with the enhanced amphiphilic properties facilitate the preparation of lignin nanospheres (LNSs) via the self-assembly process. The resultant LNSs extracted by Lewis acid-mediated DES exhibited an excellent thermal stability, and enhanced antibacterial capacity, which were associated with the phenolic OH content. However, the extracted lignin by Lewis base-mediated DES was mainly attributed to the cleavage of lignin-carbohydrate complexes bond, especially the lignin-carbohydrate ester bond, which retained more ether bonds and a relatively complete structure. This study illuminated the different mechanisms of lignin extraction and the structural evolution of lignin from Lewis acid/base-mediated DES, and provided guidance to select suitable fractionation techniques for upgrading the downstream products.
在这项工作中，路易斯酸（FeCl、AlCl）和路易斯碱（Na2CO3、Na2SO4）被掺入中性深共熔溶剂（DES，氯化胆碱/甘油）中，以强化木质纤维素的分级分离。路易斯酸介导的 DES 可以实现最高脱木质素率（89.7%）和令人满意的纤维素糖化率（100%）的分离效率。对木质素结构演变的深入了解表明，路易斯酸介导的 DES 可以有效地切割β-O-4 键，以获得高产率的木质素片段。同时，具有增强的两亲性质的木质素片段有利于通过自组装过程制备木质素纳米球（LNS）。通过路易斯酸介导的 DES 提取的所得 LNS 表现出优异的热稳定性和增强的抗菌能力，这与酚羟基含量有关。然而，路易斯碱介导的 DES 提取的木质素主要归因于木质素-碳水化合物复合物键的断裂，特别是木质素-碳水化合物酯键，其保留了更多的醚键和相对完整的结构。本研究阐明了路易斯酸/碱介导 DES 中木质素提取和木质素结构演变的不同机制，为选择合适的分级分离技术以提高下游产品的质量提供了指导。
