School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
Bioresour Technol. 2019 Apr;278:360-371. doi: 10.1016/j.biortech.2019.01.098. Epub 2019 Jan 23.
Pullulanases (EC 3.2.1.41) are well-known starch-debranching enzymes widely used to hydrolyze α-1,6-glucosidic linkages in starch, pullulan, amylopectin, and other oligosaccharides, with application potentials in food, brewing, and pharmaceutical industries. Although extensive studies are done to discover and express pullulanases, only few are available with desirable characteristics for industrial applications. This raises the challenge to mine new enzyme sources, engineer proteins based on sequence/structure, and regulate expressions. We review here the identification of extremophilic and mesophilic microbes as sources of industrial pullulanases with desirable characteristics, including acid-resistance, thermostability, and psychrotrophism. We present current advances in site-directed mutagenesis and sequence/structure-guided protein engineering of pullulanases. In addition, we discuss heterologous expression of pullulanases in prokaryotic and eukaryotic microbial systems, and address the effectiveness of the expression elements and their regulation of enzyme production. Finally, we indicate future research needs to develop desired industrial pullulanases.
普鲁兰酶（EC 3.2.1.41）是一种众所周知的淀粉分支酶，广泛用于水解淀粉、普鲁兰、支链淀粉和其他寡糖中的α-1,6-葡萄糖苷键，在食品、酿造和制药行业具有应用潜力。尽管已经进行了广泛的研究来发现和表达普鲁兰酶，但只有少数具有工业应用所需特性的普鲁兰酶可用。这就提出了挖掘新酶源、基于序列/结构工程蛋白质以及调节表达的挑战。我们在这里回顾了从极端微生物和嗜温微生物中鉴定工业普鲁兰酶的来源，这些普鲁兰酶具有理想的特性，包括耐酸性、热稳定性和嗜冷性。我们介绍了普鲁兰酶的定点突变和基于序列/结构的蛋白质工程的最新进展。此外，我们还讨论了普鲁兰酶在原核和真核微生物系统中的异源表达，并讨论了表达元件及其对酶生产的调节的有效性。最后，我们指出了未来开发所需工业普鲁兰酶的研究需求。
