Inulin and its enzymatic production by inulosucrase: Characteristics, structural features, molecular modifications and applications.

Inulin, a natural fructan, cannot be hydrolyzed by digestive enzymes in the human body and plays a role as a dietary fiber and prebiotic. Due to its versatile physicochemical properties and physiological functions, inulin has been widely applied in food, pharmaceuticals, and many other fields. The microorganism-derived inulin-forming enzyme inulosucrase (ISase) (EC: 2.1.4.9) can biosynthesize higher-molecular-weight inulin than plants using sucrose as the sole substrate, and the enzyme also shows transfructosylation activity toward other saccharide acceptors. In this article, the properties, functions, and applications of inulin are overviewed. The biosynthesis of inulin by ISase is addressed, including ISase characteristics, structural features, molecular modifications and applications.