Studies have been devoted to deep eutectic solvent (DES) pretreatment of biomass to improve its enzymatic efficiency, while subsequent processing of regenerated lignin was absent. Nanosizing is one of the common approaches to the value-addition of lignin, based on this, we reported a facile strategy to prepare lignin nanoparticles (LNPs) from walnut shells (WS), combining DES pretreatment and antisolvent precipitation. Three DESs (choline chloride (ChCl): oxalic acid (OA): ethylene glycol (EG) = 1:1:1, ChCl: p-toluenesulfonic acid (TsOH): EG (1:1:1), and ChCl: TsOH: EG (1:1:2)) were assessed for enzymatic hydrolysis efficiency of cellulose solids (CSs) and evaluated the yield and functional properties of LNPs. After pretreatment of ChCl: TsOH: EG (1:1: 2) at 90 ℃ for 2 h, 42.72% of lignin in WS was converted into LNPs with a particle size of 157.71 nm and ζ-potential of − 24.85 mV under dropping speed of 0.15 mL/min and reaction pH of 6, meanwhile, the pretreatment resulted in 2.6 times enzymatic efficiency relative to untreated WS. LNPs prepared from ChCl: OA: EG (1:1:1) exhibited excellent stability (ζ-potential of −31.97 mV) and antioxidant properties (radical scavenging rate of 61.43%), and the lignin molecules possessed high content of functional groups. Our study is expected to provide implications for the chemical deep processing of biomass and the preparation of LNPs.

研究一直致力于生物质的低共熔溶剂 (DES) 预处理以提高其酶促效率，而再生木质素的后续处理却不存在。纳米化是木质素增值的常用方法之一，基于此，我们报道了一种从核桃壳 (WS) 中结合 DES 预处理和反溶剂沉淀制备木质素纳米粒子 (LNP) 的简便策略。三种DESs（氯化胆碱（ChCl）：草酸（OA）：乙二醇（EG）=1:1:1，ChCl: p-甲苯磺酸 (TsOH): EG (1:1:1) 和 ChCl: TsOH: EG (1:1:2)) 评估了纤维素固体 (CSs) 的酶水解效率，并评估了纤维素固体 (CSs) 的产率和功能特性LNP。ChCl: TsOH: EG (1:1: 2) 90 ℃ 2 h预处理后，WS中42.72%的木质素在滴速下转化为粒径为157.71 nm、ζ电位为−24.85 mV的LNPs 0.15 mL/min 和反应 pH 为 6，同时，相对于未处理的 WS，预处理导致酶促效率提高 2.6 倍。由 ChCl: OA: EG (1:1:1) 制备的 LNPs 表现出优异的稳定性（ζ-电位为 -31.97 mV）和抗氧化性能（自由基清除率为 61.43%），木质素分子具有高含量的官能团。