基于纤维小体展示技术的酿酒酵母纤维素乙醇研究进展

Recent advances in cellulosic ethanol production using cellulosome-displayed Saccharomyces cerevisiae

利用联合生物加工工艺生产第二代燃料乙醇(纤维素乙醇)是国内外的研究热点.前期的研究结果表明,酿酒酵母分泌或展示非复合型纤维素酶体系的应用效果并不理想,而复合型纤维素酶体系(即纤维小体)因对纤维素的降解能力比非复合型纤维素酶体系更强,所以其在酿酒酵母细胞表面的组装研究受到越来越多的关注.目前,单支架和双支架纤维小体在酵母细胞表面的完全自组装以及多细胞协同参与的非完全自组装均已实现.纤维小体展示型酿酒酵母已能直接利用结晶型纤维素发酵生产乙醇,但由于降解模块的结构缺陷,纤维素乙醇的产量仍然偏低.本文对纤维小体的酵母展示技术及其在纤维素乙醇发酵中的应用研究进行了论述,并对该领域的发展方向进行了展望.

It has become a research focus in the world that using consolidated bioprocessing to produce the second generation bioethanol （cellulosic ethanol）. However, previous studies indicated that the non-complexed cellulase systems engineered in Saccharomyces cerevisiae did not work efficiently. During recent years, cell-surface assembly of complexed cellulase systems （cellulosomes） on S. cerevisiae has attracted continued interests, because of their greater abilities in cellulose hydrolysis than non-complexed cellulase systems. Up to now, the self-assembly and semi-self-assembly of celllulosomes using single scaffoldin or two scaffoldins have been achieved. The cellulosome-displayed yeast has been able to directly convert avicel to ethanol, but the productivity was still quite low because of some design flaws of cellulosome. In this paper, the methods for cellulosome assembly on yeast cell surface and their applications in cellulosic ethanol production are reviewed. Also, the prospects of this research field are given based on our analysis of the problems that still have not solved by the previous studies.