Xie Xiaofang, Li Caiming, Ban Xiaofeng, Yang Hongshun, Li Zhaofeng
Department of Food Science and Technology, National University of Singapore, Singapore, Singapore.
National University of Singapore (Suzhou) Research Institute, Suzhou, Jiangsu, P. R. China.
Crit Rev Biotechnol. 2025 Mar;45(2):353-372. doi: 10.1080/07388551.2024.2368517. Epub 2024 Jul 7.
D-allulose, an epimer of D-fructose at C-3 position, is a low-calorie rare sugar with favorable physiochemical properties and special physiological functions, which displays promising perspectives in the food and pharmaceutical industries. Currently, D-allulose is extremely sparse in nature and is predominantly biosynthesized through the isomerization of D-fructose by D-allulose 3-epimerase (DAEase). In recent years, D-allulose 3-epimerase as the key biocatalyst for D-allulose production has received increasing interest. The current review begins by providing a summary of D-allulose regarding its characteristics and applications, as well as different synthesis pathways dominated by biotransformation. Then, the research advances of D-allulose 3-epimerase are systematically reviewed, focusing on heterologous expression and biochemical characterization, crystal structure and molecular modification, and application in D-allulose production. Concerning the constraint of low yield of DAEase for industrial application, this review addresses the various attempts made to promote the production of DAEase in different expression systems. Also, various strategies have been adopted to improve its thermotolerance and catalytic activity, which is mainly based on the structure-function relationship of DAEase. The application of DAEase in D-allulose biosynthesis from D-fructose or low-cost feedstocks through single- or multi-enzymatic cascade reaction has been discussed. Finally, the prospects for related research of D-allulose 3-epimerase are also proposed, facilitating the industrialization of DAEase and more efficient and economical bioproduction of D-allulose.
D-阿洛酮糖是D-果糖在C-3位的差向异构体，是一种低热量的稀有糖，具有良好的理化性质和特殊的生理功能，在食品和制药行业展现出广阔的前景。目前，D-阿洛酮糖在自然界中极为稀少，主要通过D-阿洛酮糖3-差向异构酶（DAEase）将D-果糖异构化来生物合成。近年来，作为生产D-阿洛酮糖的关键生物催化剂，D-阿洛酮糖3-差向异构酶受到了越来越多的关注。本综述首先概述了D-阿洛酮糖的特性、应用以及以生物转化为主的不同合成途径。然后，系统综述了D-阿洛酮糖3-差向异构酶的研究进展，重点关注其异源表达和生化特性、晶体结构和分子修饰以及在D-阿洛酮糖生产中的应用。针对工业应用中DAEase产量低的限制，本综述阐述了在不同表达系统中为提高DAEase产量所做的各种尝试。此外，还采用了各种策略来提高其耐热性和催化活性，这主要基于DAEase的结构-功能关系。讨论了DAEase通过单酶或多酶级联反应从D-果糖或低成本原料生物合成D-阿洛酮糖的应用。最后，还提出了D-阿洛酮糖3-差向异构酶相关研究的前景，以推动DAEase的工业化以及更高效、经济地生物生产D-阿洛酮糖。
