Studies On The Production Of Isomaltooligosaccharide With Immobilized Enzyme And Its Purification

Systematic studies on the production of isomaltooligosaccharide with immobilized α-glucosidase and its purification through fermentation by Saccharomyces cerevisiae were carried out in this dissertation. The main results are as following:1. When 240 000 U α-glucosidase was adsorbed with 1g dry chitosan at pH6.0 and normal atmosphere temperature for 6 hours, and then treated with 3.5% glutaraldehyde at 45℃ for 6 hours, the activity of immobilized α-glucosidase was 143 000 U and its recovery ratio was 59.6%. The optimum pH of the immobilized enzyme was 4.5, which was 0.5 lower than the nature one's; its optimum action temperature was 70℃, which was 5℃ higher than the nature one's. And the stability of immobilized enzyme for enduring pH changing, heat, and long-time storing was much better than the nature one's, which was useful to industrialized production.2. The key factors for preparation of spherical microporous chitosan carrier were the scope of chitosan's molecular mass, the concentration of chitosan solution, and the composition of coagulation liquid. For spherical microporous chitosan carrier which was made of deacetyl chitosan (the degree of deacetyl was 88%), when 300 000 U α -glucosidase was adsorbed with lg dry chitosan beads at pH6.0 and normal atmosphere temperature for 8 hours, and then treated with 2.0% glutaraldehyde at 45 °C for 9 hours, the activity of immobilized α-glucosidase was 234 200 U and its recovery ratio was 78.1%, while the strength of the immobilized enzyme remained good enough.Some physical and chemical properties of the α-glucosidase (TGL) and the immobilized α-glucosidase (ITGL) were tested, and the results showed that the optimum pH and the optimum action temperature of the microspherical ITGL was the same as the powder ITGL. The stability of ITGL for enduring pH changing and heat was much better than the TGL's. TGL and ITGL were both unstable to high ion...