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

Anion‐exchange porous hollow‐fiber membranes with a thickness of about 1.2 mm and a pore size of about 0.30 μm 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 cross‐linking with transglutaminase, 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‐glucose‐membered 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.