Abstract
Amylase (Dabiase K-27) was immobilized covalently on enteric coating polymers that were reversibly soluble-insoluble (S-IS) depending on pH. Among several immobilized amylase preparations, the amylase immobilized on Eudragit L (Dabiase-Eudragit: D-E) showed good response of solubility to pH change without decrease in activity. The specific activity per amount of enzyme protein of D-E for raw starch was more than 85% that of the native enzyme. In the hydrolysis reaction of raw starch, changing the pH of the reaction medium at an appropriate interval allows the insoluble D-E and the reaction product, glucose, to be repeatedly separated. By the hydrolysis method with repeated removal of the reaction inhibitor, glucose, the time required for converting a high-concentration raw starch to glucose was significantly reduced. The reaction method using the reversibly S-IS enzyme is a promising procedure for repeatedly utilizing the enzyme in a heterogeneous reaction system containing raw starch as a substrate.
