Cyclodextrin glycosyltransferases for food innovation: from molecular mechanism to industrial application

Cyclodextrin glycosyltransferase (CGTase) is a key starch-processing enzyme capable of converting starch into cyclodextrins (CDs). Due to the multifunctional catalytic abilities, CGTases are widely used in the food industry to modify functional ingredients for better solubility and sensory qualities. However, challenges such as low natural CGTase yield, complex catalytic behavior, and limitations in expression efficiency restrict its broader application. This review provides a comprehensive overview of CGTases, covering microbial sources, structural characteristics, catalytic mechanisms, and heterologous expression. With the emphasis on conserved domain structure and strategies for enhancing heterologous expression, this review offers a theoretical basis and guarantee for the customized application of CGTase. It further highlights recent advances in heterologous expression systems and enhancement strategies, including the optimization of vectors and regulatory elements, fermentation strategies, and metabolic regulation. Finally, the practical applications of CGTases in the food industry, particularly their roles in CD production, enzymatic inclusion, glycosylation, baking, and modification of starch digestibility are discussed. This review offers a theoretical basis for further research and technological innovation, promoting efficient and targeted use of CGTases in food processing and functional product development.