The search for renewable deep eutectic solvents (DESs) for efficient biomass pretreatment based on a closed-loop biorefinery is of great interest and importance. Herein, we reported three novel lignin-based DESs prepared by choline chloride (ChCl) and 3-(4-hydroxyphenyl)propionic acid (HPA), 3-(4-hydroxy-3-methoxyphenyl)propanoic acid (HMPA) and their combination for corn stover pretreatment. The effects of three lignin-based DESs pretreatments on the chemical compositions of raw material, structural features of lignin, and enzymatic digestibility of cellulose were comprehensively analyzed, among which ChCl/HPA DES exhibited superior pretreatment efficiency, affording 58% of delignification, 62% of hemicellulose removal, and 85% of glucose yield. A high abundance of -coumaric acid in the regenerated and remaining lignin samples makes them a sustainable feedstock to produce hydrogen bond donors of ChCl/HPA DES, as demonstrated by the results from 2D HSQC NMR analysis and catalytic depolymerization of lignins. These results could be conducive to creating an integrated biorefinery strategy for biomass valorization. Mass balance analysis indicated 81% of cellulose, 90% of hemicellulose, and 91% of lignin components in corn stover could be collected after DES pretreatment. This contribution offers a novel and efficient pretreatment method for corn stover fractionation based on a closed-loop biorefinery.

中文翻译：

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使用源自木质素的 3-苯基丙酸的低共熔溶剂对玉米秸秆进行高效分馏：迈向闭环生物精炼厂


寻找可再生的低共熔溶剂（DES）用于基于闭环生物精炼厂的高效生物质预处理具有极大的兴趣和重要性。在此，我们报道了由氯化胆碱（ChCl）和3-（4-羟基苯基）丙酸（HPA）、3-（4-羟基-3-甲氧基苯基）丙酸（HMPA）及其组合制备的三种新型木质素基DES用于玉米秸秆预处理。综合分析了三种木质素基DES预处理对原料化学成分、木质素结构特征和纤维素酶消化率的影响，其中ChCl/HPA DES表现出优异的预处理效率，脱木质素率为58%，脱木质素率为62%。半纤维素去除率和葡萄糖产量的 85%。再生的和剩余的木质素样品中含有大量的 β-香豆酸，使其成为生产 ChCl/HPA DES 氢键供体的可持续原料，正如 2D HSQC NMR 分析和木质素催化解聚的结果所证明的那样。这些结果可能有助于制定生物质增值的综合生物炼制策略。质量平衡分析表明，经过DES预处理后，玉米秸秆中可以收集到81%的纤维素、90%的半纤维素和91%的木质素成分。这一贡献为基于闭环生物精炼厂的玉米秸秆分馏提供了一种新颖有效的预处理方法。