Production of Cycloisomaltooligosaccharides from Dextran Using Enzyme Immobilized in Multilayers onto Porous Membranes

Allion-exchange porous hollow-fiber membranes with a thickness of about 1.2 mm and a pore size of about 0.30 ~m were used as a supporting matrix to immobilize cycloisomaltooligosaccharide glucanotransferase (CITase). CITase was immobilized to the membrane via anion-exchange adsorption and by subsequent enzymatic crosslinking with transgiutaminase, the amount of which ranged from 3 to 110 mg per gram of the membrane. The degree of enzyme multilayer binding was equivalent to 0.3—9.8. Dextran, as the substrate, was converted into seven- to nine-glucosemembered cycloisomaltooligosaccharides (CI-7, -8, and -9) at a maximum yield of 28% in weight at a space velocity of 10 per hour during the permeation of 2.0% (w/w) dextran solution across the CITase-immobilized porous hollow-fiber membrane. The yield of CIs increased with increasing degree of CITase multilayering.