Tailored Enzymes for Difructose Anhydrides: From Biosynthesis to Degradation

Difructose anhydrides (DFAs), distinctive cyclic disaccharides mainly naturally produced by heating (caramelization), serve as potential candidates of functional sugars that modern humans consume on a daily basis due to their remarkable physiological effects. This review explores the complex domain of specialized enzymes implicated in the metabolism of DFAs, covering the entire process from biosynthesis to degradation. We provide a detailed examination of the enzymes responsible for DFA formation and degradation, specifically those classified within the GH91, GH32, and GH172 glycoside hydrolase families. Furthermore, the evolutionary relationships among the related enzymes were systematically analyzed. Subsequently, the underlying enzymatic mechanisms that drive DFAs' metabolism were elucidated, and key insights into the intricate interplay between enzyme structure and function were unveiled. Additionally, innovative strategies for enzyme engineering were discussed, aimed at improving thermostability, enhancing catalytic activity, and altering catalytic function. Finally, the applications of the related enzymes were comprehensively summarized with a focus on their product yields, conversion rates, and methods for product purification. Here, the review presents a comprehensive investigation into enzymatic degradation and biosynthesis pathways of DFAs.