Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China.
Liaoning Key Laboratory of Lignocellulose Chemistry and Biomaterials, Dalian Polytechnic University, Dalian 116034, China.
Int J Biol Macromol. 2023 Dec 31;253(Pt 4):127057. doi: 10.1016/j.ijbiomac.2023.127057. Epub 2023 Sep 25.
Deep eutectic solvents (DESs) have emerged as promising and eco-friendly solvents for the efficient extraction of lignin from biomass due to their low cost and environmental benefits. Nevertheless, the prevalent use of acidic DESs in lignin extraction often results in excessive depolymerization and recondensation of lignin, thereby impeding its downstream applications. In this study, we developed a range of alkaline DESs (ADESs), both pure and peroxide-containing, for the extraction of high-quality lignin from bamboo. Moreover, carbon dioxide (CO) was employed for the precipitation and regeneration of the extracted lignin. The obtained lignin fractions were comprehensively characterized in terms of yield, purity, morphology, solubility, structural features, and anti-UV/oxidant activity. The results showed that the monoethanolamine-based ADES demonstrated superior performance among the pure ADESs. Structural analysis confirmed the well-preserved substructures of lignin fractions obtained using ADESs, with β-O-4 bond retention ranging from 49.8 % to 68.4 %. The incorporation of a suitable amount of peroxide improved lignin yield, morphology, solubility, and anti-UV/oxidant activity. Additionally, the anti-UV/oxidant activity of lignin exhibited a positive correlation with its phenolic hydroxyl content. This study provides a valuable reference for the green and sustainable production and valorization of lignin within the existing biorefinery framework.
深共熔溶剂（DESs）由于其低成本和环境效益，已成为从生物质中高效提取木质素的有前途和环保的溶剂。然而，由于酸性 DESs 在木质素提取中普遍使用，往往会导致木质素过度解聚和再缩合，从而阻碍其下游应用。在本研究中，我们开发了一系列碱性 DESs（ADESs），包括纯 DESs 和含过氧化物的 DESs，用于从竹子中提取高质量的木质素。此外，还使用二氧化碳（CO）进行提取木质素的沉淀和再生。从产率、纯度、形态、溶解度、结构特征和抗 UV/抗氧化活性等方面对获得的木质素级分进行了全面表征。结果表明，在纯 ADESs 中，单乙醇胺基 ADES 表现出优异的性能。结构分析证实，ADESs 获得的木质素级分保留了较好的亚结构，β-O-4 键的保留率在 49.8%至 68.4%之间。适量添加过氧化物可以提高木质素的产率、形态、溶解度和抗 UV/抗氧化活性。此外，木质素的抗 UV/抗氧化活性与其酚羟基含量呈正相关。本研究为现有生物炼制框架内木质素的绿色可持续生产和增值提供了有价值的参考。
