β-半乳糖苷酶的微生物细胞表面展示及其应用

Overview of microbial cell surface display of β-galactosidase and its application

β-半乳糖苷酶是一种在乳制品生产、医药、生化分析等领域得到广泛应用的酶制剂。商品化β-半乳糖苷酶多以游离形式存在,但游离的β-半乳糖苷酶制造过程复杂、稳定性低、易失活、有机溶剂耐受性差、重复利用率低,这些制约因素限制了β-半乳糖苷酶的进一步应用。将β-半乳糖苷酶通过基因工程技术固定在微生物细胞表面,该系统的优点有:1)在工业生产过程中,无需经复杂的分离纯化和固定化操作,成本低;2)稳定性高、有机溶剂耐受性强,既可用于反应条件温和又能满足复杂体系、反应条件剧烈的催化需求;3)拓展β-半乳糖苷酶在蛋白质工程研究、生物传感器制造等领域的应用。β-半乳糖苷酶表面展示所用宿主包括乳酸菌、酵母和芽孢,该文分别综述这3种宿主中β-半乳糖苷酶表面展示系统的研究进展及其在酶的生产、作为报告蛋白和全细胞生物催化方面的应用。

β-galactosidase is an important industrial enzyme with broad applications in dairy production, medicine and biochemical analysis. The most commercially available β-galactosidase is generally made in free form. However, the free β-galactosidase requires complex production steps and often shows low stability, easy inactivation, poor tolerance to organic solvents, and poor reusability, which restrict its use in industrial application. The microbial cell surface display technology that enables the expression of β-galactosidase on the cell surface through genetic engineering confers several advantages: 1) there is no need for complicated purification and immobilization steps during industrial production process, thus lowering the cost;2) owing to its good stability and excellent resistance to organic solvents, cell-surface displayed β-galactosidase can be used as an catalyst under both mild and harsh conditions;3) widens its application feilds in protein engineering and biosensor. The hosts used for surface display of β-galactosidase include lactic acid bacteria, yeast and spore. In this paper, recent progress on microbial cell surface display for β-galactosidase and its application in enzyme production, acting as an report protein as well as whole cell biocatalysis were summarized.