全生物基三元DES预处理促进芦竹酶解机理研究

Study on Mechanism of Improving Enzymatic Hydrolysis of Arundo donax L. Pretreated with Bio-based Ternary DES

中文关键词:  芦竹  三元DES  预处理  酶水解  复合动力学模型

Key Words:Arundo donax L.  ternary DES  pretreatment  enzymatic hydrolysis  compound kinetic model

中文摘要:

      针对二元中性低共熔溶剂（DES）体系效率低的问题，构建新型全生物基三元DES（氯化胆碱/乙酰丙酸/1，4-丁二醇）体系，并用于芦竹（Arundo donax L.）预处理；采用成分分析、扫描电子显微镜（SEM）、X射线衍射仪（XRD）、傅里叶变换红外光谱仪（FT-IR）对预处理前后芦竹化学成分、结构及表面形貌变化等进行分析，结合复合动力学模型探究预处理促进芦竹酶解机理。结果表明，三元DES是高效的预处理体系，在140 ℃下处理3 h后，木质素和半纤维素的脱除率分别达46.4%和75.6%，残渣纤维素和聚木糖酶解率高达~100%和96.6%；建立的复合动力学模型可准确地描述三元DES预处理耦合酶解过程中葡萄糖和木糖变化行为（R² > 0.99）。由预处理温度升高引起的半纤维素和木质素高效脱除、纤维表面粗糙度增大及纤维素结晶结构破坏是促进芦竹酶解的主要原因。

Abstract:

      To address the problem of inefficiency of binary neutral deep eutectic solvent （DES）， a bio-based ternary DES （choline chloride/levulinic acid/1，4-butanediol） system was constructed and used to pretreat Arundo donax L. The chemical composition， structure， and surface morphology of Arundo donax L. before and after pretreatment were analyzed by component analysis， scanning electron microscopy （SEM）， X-ray diffraction （XRD）， and Fourier-transform infrared spectrometer （FT-IR）， and the mechanism of promoting enzymatic hydrolysis was explored using the compound kinetic model.The results showed that the ternary DES pretreatment was highly effective； the removal rates of lignin and hemicellulose were 46.4% and 75.6%， respectively， and the enzymatic hydrolysis efficiencies of residual cellulose and xylan were ~100% and 96.6%， respectively， after pretreatment at 140 ℃ for 3 h. Meanwhile， the as-constructed compound kinetic model accurately described the variation behavior of glucose and xylose during ternary DES pretreatment coupled with enzymatic hydrolysis （R²>0.99）. The high-efficient removal of hemicellulose and lignin， the increment of fiber surface roughness， and the destruction of cellulose crystal structure caused by increased pretreatment temperature were the main factors improving the enzymatic hydrolysis of Arundo donax L.