INTERMOLECULAR TRANSGLYCOSYLATING REACTION OF CYCLODEXTRIN GLUCANOTRANSFERASE IMMOBILIZED ON CAPILLARY MEMBRANE

The intermolecular transglycosylating reaction of cyclodextrin glucano transferase ([EC 2.4.1.19]; CGTase) immobilized on a capillary membran e was investigated using low molecular weight substrates such as cyclo dextrin (CD), maltooligosaccharide (MOS), and a CD-MOS mixture. The im mobilized CGTase catalyzed the conversion reaction of alpha-CD to beta -CD and MOS or beta-CD to alpha-CD and MOS within a short residence ti me. The conversion ratio increased as the amount of immobilized CGTase increased. The addition of glucose, maltose, and sucrose as accepters in the substrate solution containing CD resulted in the acceleration of CD degradation compared with only CD substrate. Furthermore, the MO S substrate (degree of polymerization=2-6) was disproportionated with a conversion ratio exceeding 70% by the immobilized CGTase. These data demonstrate that immobilized CGTase can catalyze intermolecular trans glycosylation between low molecular substrates in a few minutes by reg ulating the amount of immobilized enzyme and the residence time. This might contribute to our comprehension of CGTase-immobilized bioreactor s for CD production as well as to the development of new glycosides th rough its excellent transglycosylation ability.