Amylosucrase as a Versatile Biocatalyst for Next-Generation Functional Ingredients: Starch Modification and Glycoside Synthesis.

Amylosucrase (ASase, E.C. 2.4.1.4) is a transglucosidase that catalyzes α-glucan synthesis and transglycosylation reactions using sucrose as the sole substrate. Unlike Leloir glycosyltransferases requiring expensive nucleotide sugars, ASases utilize readily available sucrose as a cost-effective glucose donor, offering economic advantages for industrial applications. This review comprehensively examines the current state of ASase research, covering structural characteristics, catalytic mechanisms, substrate specificities, and industrial applications. Major applications include the synthesis of functional carbohydrates, such as short-chain glucan microparticles for encapsulation and rare sugars (turanose and trehalulose), as well as starch modification for enhanced nutritional profiles. Furthermore, the enzyme plays a crucial role in generating α-glycosides of bioactive compounds, significantly improving their physicochemical stability and bioavailability. Recent advances in protein engineering have improved enzyme thermostability and expanded substrate scope, though challenges remain in industrial-scale implementation. Current limitations in enzyme stability and product yields are critically analyzed, alongside future research directions for improving catalytic performance and process economics. The diverse applications of ASases in food, nutraceutical, and cosmetic industries demonstrate their potential as versatile biocatalysts for producing functional ingredients with improved properties.