Immobilization of glucose isomerase to ion‐exchange materials

Abstract

Abstract Glucose isomerase ( D ‐xylose ketol‐isomerase EC 5.3.1.5) from Bacillus Coagulans was partially purified and immobilized by adsorption to anion exchangers. The highest activities were obtained when the enzyme was adsorbed to DEAE‐cellulose. On immobilization to DEAE‐cellulose the measured optimum pH value for enzyme activity shifted from 7.2 to 6.8. There was no appreciable difference between the heat stabilities of soluble and immobilized enzyme. The K m app values for the immobilized enzyme were found to be 0.25 M in the presence of 0.01 M Mg 2+ and 0.19 M with 0.005 M Mg 2+ , while those enzyme were 0.11 and 0.17 M , re spectively. Under conditions of contimuous of D ‐glucose, a decrease of activity with time was observed, but this decrease was less at a low Mg 2+ concentration and was affected by column geometry. There were no appreciable diffusional limitation effects in packed‐bed columns.