为了探索基于乙醇胺的深度共熔溶剂预处理生物质的作用机制，本研究以氯化胆碱为氢键受体（HBA），以乙醇胺的化合物为氢键供体（HBD），合成了7种DES对其理化特性进行了测定，对比研究不同DES对小麦秸秆组分和酶解效率的影响。结果表明：30 ℃下，DES的粘度介于0.04~1.37 Pa·s，导电率0.29~3.57 ms/cm，5 mM DES的pH值介于7.41~11.02；90 ℃下对木质素和木聚糖的溶解度高达425 mg/g和523 mg/g，而对纤维素几乎不溶；经这些DES预处理后，小麦秸秆中的多糖酶解效率得到了显著提高，并且DES的预处理效果依赖于pH值，其中[氯化胆碱]:[乙二胺]为最适小麦秸秆预处理溶剂，90 ℃下预处理4 h后木质素去除率83.14%，还原糖收率为93.88%。该类DES可选择性地从小麦秸秆中除去大量木质素和部分木聚糖，而未改变纤维素的晶体结构，从而提高后续酶解效率显著，并发现该类DES对禾本科类生物质和桉木有良好的预处理效果，预处理后糖收率明显提高（57.10%~98.13%），但对松木效果不佳。本研究可为用于生物质预处理的新型DES的合理设计提供一定的理论参考。

In order to explore the mechanism of deep eutectic solvents (DESs) pretreatment of lignocellulosic biomass, seven DESs with choline chloride (ChCl) as hydrogen bond acceptor (HBA) and seven DESs with ethanolamine compounds as hydrogen bond donor (HBD) were employed to pretreat wheat straw. Their physical and chemical properties were measured, and the effects of different DES on the components and enzymatic hydrolysis efficiency of biomass were studied. The results indicated that the viscosity of DES was between 0.04~1.37 Pa·s, the conductivity was 0.29~3.57 ms/cm, and the pH of 5 mM DES was between 7.41~11.02 at 30 ℃; it was effective for lignin and xylan. The solubility of DES was as high as 425 mg/g and 523 mg/g at 90 ℃, and it was almost insoluble to cellulose. After these DES pretreatments, the enzymatic hydrolysis efficiency of polysaccharides in wheat straw was significantly improved, and the pretreatment effect depended on the pH value. Among them, [Choline chloride]: [ethylenediamine] was the most suitable solvent for pretreatment of wheat straw. After 4 h of pretreatment at 90 ℃, the removal rate of lignin was 83.14% and the yield of reducing sugar was 93.88%. A large amount of lignin and part of xylan were selectively removed from wheat straw without changing the crystal structure of cellulose, and the efficiency of subsequent enzymatic hydrolysis was significantly improved. It found that this type of DES is good for grass biomass and eucalyptus. After the pretreatment, the sugar yield was obviously improved (57.10~98.13%), but it was not effective for pine. This work would provide a theoretical basis for rational design novel DESs for biomass pretreatment.

国家自然科学基金项目（21706052）；河南农业大学创新基金项目（KJCX2017C05）