Cyclodextrin Glucanotransferase의 고정화와 당전이 스테비오사이드 제조에 관련된 반응 특성

For the continuous production of transglucosylated steviosides, cyclodextrin glucanotransferase from Bacillus macerans was immobilized onto Diaion HPA 75 (styrene-divinylbenzene resin) that was screened from ion exchange resins, synthetic adsorbents and chitosan derivatives. The parameters influencing enzyme immobilization were examined in order to maximize the activity of immobilized enzyme. The optimum conditions for immobilization turned out to be: contact time 2 hr at 30$circ$C, pH 6$sim$9, and enzyme loading 20mg protein/g resin at 4.4 Os/Kg as osmolarity. Competing with other molecules having low molecular weight, enzyme was immobilized reversibly. The activity of immobilized enzyme was as high as 180U/g resin when the diafiltrated solution of stock enzyme was used. The optimum conditions for transglucosylation were as follows: pH 6.0, temperature 50$circ$C, 30% substrate solution composed of 15% stevioside mixture and 15% dextrin of which value of dextrose equivalent was about 9.0.