Abstract: Lignocellulose is the most abundant renewable biomass on the earth. Enzymatic hydrolysis of cellulosic polysaccharide is key step of lignocellulose biorefineries. To enhance efficiency of cellulose hydrolysis, pretreatment is necessary for effectively breaking its recalcitrant structure.  So, great attentions have been paid for design of pretreatment technologies to crack recalcitrant characteristics of lignocellulose. In this paper,the latest research progresses on lignocellulose pretreatment and recalcitrant characteristics were reviewed, focusing on the new pretreatment technologies and their main advantages,including combined pretreatment, cold pretreatment, green solvents pretreatment and electrochemical approach. Otherwise, the influence of recalcitrant characteristics, such as lignin, crystallinity, accessibility, on cellulose hydrolysis was discussed. The new methods used for analysis of recalcitrant characteristics and the new insight obtained are highlighted in this review. These are useful for evaluation of pretreatment technologies, and identification of key factors that limit cellulose hydrolysis, and can also be a basis for design and screen of appropriate pretreatment technologies, as well as for understand of lignocellulose hydrolysis mechanism.

Key words: biomass, lignocellulose, pretreatment, enzymatic hydrolysis, recalcitrant characteristics

摘要： 木质纤维素是地球上最丰富的可再生生物质资源，其中纤维类多糖的酶催化降解是木质纤维素生物精炼的关键环节之一。对木质纤维素进行预处理，破坏底物的顽抗特性，是实现木质纤维素高效酶解糖化的必要途径。为此，各国学者围绕预处理技术开发以及底物顽抗特性开展了大量研究，本文对近几年来在这两方面取得的最新成果进行了综述和分析。在预处理方面，重点介绍了组合预处理、低温预处理、绿色溶剂与电化学预处理4类新型预处理技术，并对预处理效果与技术优势进行了评价；在底物顽抗特性方面，综述了木质素、结晶度、酶可及度等不同顽抗特性对纤维素酶解的影响规律，重点总结了近年来顽抗特性研究方面的新方法、新认识与新理解。上述研究成果有助于了解当前木质纤维素预处理研究的导向以及明确制约纤维素酶解的关键因素，为设计和筛选适宜的预处理方式、深刻理解纤维素酶解机制提供基础和指导。

关键词: 生物质, 木质纤维素, 预处理, 酶解, 顽抗特性