Introduction of carbonyl group to sugars using pyranose 2-oxidase-immobilized membrane

To introduce the carbonyl group to sugars in a continuous process, pyranose 2-oxidase was immobilized on a poly(vinylidene fluoride) membrane by hydrophobic interaction, and sugar solutions were passed through the membrane. The amount of immobilized pyranose 2-oxidase reached 14 mg g−1 in 1 h in permeation mode. With increase in the space velocity of the solution of one of the sugars used (sucrose), the reactivity of the membrane decreased, indicating that the space velocity of the system should be less than 10 h−1. Glucose, sucrose, and dextran solutions were circulated through the enzyme-immobilized membrane. Glucose and sucrose were completely converted to keto-glucose and keto-sucrose in 75 and 225 h, respectively, whereas dextran was not converted. The operational and storage stabilities were investigated using glucose as substrate, resulting that relative activity of pyranose 2-oxidase immobilized onto Durapore was kept for 7 days. The membrane system immobilizing pyranose 2-oxidase is thus effective for conversion of monosaccharides or disaccharides by introduction of carbonyl groups.