微生物来源淀粉分支酶异源高效表达策略的研究进展

Starch-branching enzyme (SBE, EC 2.4. 1. 18) is a glycosyltransferase involved in starch biosynthesis. It can cut the a-1, 4-glycosidic bond in starch molecules and form non-reducing oligosaccharide connecting to the receptor chain through a-1, 6-glycosidic bond to form a-1, 6 branching sites. Through these "cutting-transfer-linking" processes, a new type of biologically modified starch named highly branched starch can be obtained. Microbial-derived starch branching enzymes have the advantages of high yield and better stability as well. It can be easily expressed in heterologous hosts. As a consequence, mass production of SBE has become a research hotspot in recent years. Among many hosts for enzyme expression, Escherichia coli and Bacillus subtilis are the most common host strains for heterologous expression of SBE. This paper focused on recent advances in strategies for high-efficiency heterologous expression of microbial-derived SBEs in these two hosts, providing important references for further investigation of the mechanism of SBE function and the industrialized application of modified starch.