Immobilization of glucose isomerase

AbstractThe immobilization of glucose isomerase (D‐xylose ketol isomerase, EC 5.3.1.5) by covalently bonding to various carriers and by adsorption to ion exchange resins was attempted in order to obtain a stable immobilized enzyme which can be used for continuous isomerization of glucose in a column.Of the covalent bonding methods, the colloidal silica‐glutaraldehyde method showed the highest binding capacity and gave the stablest immobilized glucose isomerase. The LUDOX HS‐30 bound glucose isomerase column showed a half‐life of 24 days and an enzyme usage of 0.07 units per gram of isomerized sugar (d.s., fructose 45%).Of the resins used, the macromolecular type or porous type strongly basic anion exchange resins showed the highest binding capacity and gave the stablest immobilized glucose isomerase. The Amberlite IRA‐904 resine‐bound glucose isomerase showed a half‐life of 23 days and an enzyme usage of 0.06 units per gram of isomerized sugar (d. s., fructose 45%).Based on the ease of the immobilization process, the possibility of carrier ruse the extensive use already achieve by ion exchange resins in the sugar industry, IRA‐904 resin was selected as the candidate for commercialization.