Koji Kawashima

A new method of immobilizing enzymes by radiopolymerization under low temperature

A new method of immobilizing enzymes by ionizing radiation is described. The mixed aqueous solution of enzyme and polymerizing reagents were quickly frozen at about -70°C then were irradiated with 200 to 500 Krad by60Co γ ray. Irradiation was conducted aerobically under the low temperature. The enzyme was entraped in the resulting polymer. As the polymerizing reagent some water soluble polymers having vinyl bonds were also applicable. By this method an immobilized enzyme was prepared in bead, membrane, bag, or tube form having high enzymic activity. When the bead form was to be prepared, the mixture of enzyme and reagents were injected into precooled solvent such as n-hexane, toluene, or petroleum ether. the size of the bead was controlled freely from 10 μm to 1 cm in diameter. The surface of the bead had numerous small holes and the cross section of the bead showed a spongy structure. some acrylates were suitable for the immobilization of enzymes which required the corresponding metal ion as the essential substance. Microorganisms and multienzymes will be immobilized by this technique. This method is inexpensive, quick, simple, and reliable. Immobilized microbial cells can be sterilized by γ irradiation. Invertase was immobilized and the application test was conducted in an enzyme column.