酵母表面展示体系的构建及在纤维素降解中的应用*

纤维素是来源广泛且储量较大的低成本可再生资源,但其结构致密难以利用。目前降解纤维素需要多种纤维素酶协作,而游离纤维素酶成本高、难以重复利用等问题限制了其广泛应用。利用酵母表面展示技术,可以将多个纤维素酶分别与锚定蛋白融合后共展示在细胞表面,从而构建酵母表面展示纤维素酶体系。这一体系可高效降解纤维素,一方面可以充分发挥表面展示的优点,如易回收、稳定性好、操作简单、成本低;另一方面可以将纤维素有效地降解为葡萄糖,并具有代谢产生物乙醇的潜力。阐述了酵母表面展示体系的构建原则,总结了影响展示体系效率的因素,介绍了这一技术在降解纤维素中的应用,为构建高效酵母表面展示纤维素酶体系及其他多酶体系提供参考。

Construction of Yeast Surface Display System and Application in Cellulose Degrading

Cellulose is a low-cost and renewable resource with abundant reserves, but it is difficult to be used because of its compact structure. Currently, the degradation of cellulose requires the cooperation of a variety of cellulases, but the high cost and the difficulty of re-use of free cellulase have limited its wide application. Yeast surface display technology can display multiple cellulase enzymes on the cell surface after being fused with the anchoring protein, so that a yeast surface display cellulase system could be constructed. This system can degrade cellulose efficiently. On the one hand, it has the advantages of surface display, such as easy recycling, good stability, simple operation, and low cost; on the other hand, it can also degrade cellulose into glucose effectively, and has the potential to produce bioethanol by metabolism. The paper summarizes the construction principles of a yeast surface display system, and divides yeast surface display systems into direct display systems and indirect display systems according to the different anchoring methods of exogenous proteins. The direct display system is that the exogenous protein is directly connected to the cell through the anchor protein. Indirect display systems are linked to cells through exogenous proteins by means of scaffolds. Factors affecting the efficiency of the display system mainly include cell type, anchor protein, scaffold, environmental factors and promoter type. The surface display system consists of GPI system, Pir system and FlO1 system according to different anchor proteins. The yeast surface display cellulase system can ferment cellulose to produce ethanol, and a lot of progress has been made so far, which provides a reference for the construction of an efficient yeast surface display cellulase system and other multi-enzyme systems. The review describes the construction principles of a yeast surface display system, summarizes the influence of major factors on the display system, and introduces the application of this technology in the degradation of cellulose. It provides guidance for the construction of high-efficiency yeast surface display of cellulase and other multi-enzyme systems.