木质纤维素水解副产物对乙醇发酵的影响及应对措施

The Effects of By-products of Hydrolyzing Lignocellulose on Ethanol Fermentation and Relevant Countermeasures

利用木质纤维素原料生产燃料乙醇,预处理是必需的环节,在预处理过程中会产生一些对微生物生长和发酵有抑制作用的化合物,这些抑制剂可分为3类:呋喃醛类化合物、酚类化合物和弱酸。近些年来,关于抑制剂的研究取得了一些重要的研究进展。介绍了各种抑制剂的产生、作用机理及近几年的相关研究成果;阐述了应对抑制剂影响的多种措施,包括采用新型的预处理方式在源头上控制抑制剂的产生、发酵前利用有效的脱毒方法减少抑制剂的浓度、耐受抑制剂的菌株的选育、通过发酵过程的控制有效减少抑制物的毒害作用等。目前,大量研究集中在抑制剂耐受性菌株的开发上,总结了通过诱变、驯化、代谢工程改造等方法以及这些方法的联用选育耐受性菌株的研究成果及进展,指出对微生物进行代谢工程改造是克服抑制剂对乙醇发酵影响的最有前途的方法,并对将来的研究方向进行了展望,以期为该领域研究人员提供方法的参考。

The pretreatment of raw materials is necessary in ethanol production from lignocellulose,in which some compounds ofinhibiting microbial growth and subsequent fermentation are generated. The inhibitors are usually classified into three major groups ：furanaldehydes,phenolics and weak acids. In recent years,significant progress has been earned in the research of inhibitory compounds. Firstly,we introduced the generation and the inhibition mechanisms of the inhibitors,focusing on the researches in recent years. Then,we discussedthe countermeasures to inhibitors,including using new pretreatment methods to eliminate the generation of inhibitors,using effectivedetoxification of the pretreated substrates to reduce the concentration of inhibitors before fermentation,breeding of the inhibitor-tolerant strainsand also fermentation control to reduce the toxic effects of the inhibitor. At present,a large number of studies focus on the development ofinhibitor-tolerant strains,we summarized these methods of mutagenic breeding,adaption and metabolic engineering,as well as the researchprogresses and achievements of jointly using these methods. We pointed out that the metabolic engineering of microorganisms is the mostpromising approach for overcoming the effects of inhibitors on ethanol fermentation,and prospected the future research direction,aiming atproviding references for the researchers in this field.