Factors Affecting the Activity and Stability of Glucose Isomerase Immobilized on Porous Glass.

摘要

The purpose of this investigation has been to determine accurately the catalytic activity and the thermal stability of glucose isomerase from Streptomyces sp. as a function of reactor temperature and chemical composition. The reason is for the conversion of cornstarch to glucose. Glucose isomerase was immobilized on zirconium oxide-coated porous glass beads via glutaraldehyde coupling and was tested for relative activity and stability in a continuous,single-pass,differential,packed bed reactor system. The immobilized enzyme displayed activity responses quite similar to those previously reported for free and immobilized glucose isomerases,with an energy of activation of 17kcal. Mg ions produced optimal activity at pH 7.0and 55C. Addition of Co ions produced little further enzyme activation. Co ions alone were one-third as effective as Mg. Addition of Co ions to Mg ions enhanced stability ten-fold at pH 7.0,while addition of Mg to Co did not increase stability.