• Microbiology and Biotechnology Letters
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• v.21 no.5
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• pp.461-467
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• 1993

Transglycosylation reaction of cyclodextrin glucanotransferase (CGTase) was analyzed in the attrition coupled heterogeneous reaction system using raw starch as a donor` and mono-, di-saccharide, and glycoside as acceptors. For transglycosylation reaction of stevioside, the transglycosylation rate was similar and the transglycosylation yield was increased compare with conventional process using liquefied starch as the donor. Also the accumulation of maltooligosaccharides in reaction mixture was minimized.

• Microbiology and Biotechnology Letters
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• v.22 no.3
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• pp.252-258
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• 1994

Transglycosylation of stevioside in the attrition coupled heterogeneous reaction system using raw starch as a glycosyl donor has significant advantages over conventional reaction systems using liquefied starch as a donor. The transglycosylation of stevioside under the presence of organic solvent showed that transglycosylation reaction occurs via two steps ; initially from raw starch to cyclodextrin(CD), and then followed by transglycosylation of produced CD. Comparison of the transglycosylation efficiency of c$\alpha $-, $\beta $, $\gamma $-CDs indicated that $\alpha $-, $\beta $-CD are mainly utilized as a glycosyl donor for following reaction. The reaction mechanism of transglycosylation between stevioside and CD proceeded according to random sequential bireactant mechanism. The equilibrium constant of transglycosylation reaction of cyclodextrin glucanotransferase wase also evaluated. The structure of transglycosylated stevioside was confirmed by TLC, and it was found that glycosyl group(G$_{1}, $ ~ G$_{4}$-glycosidic bond.

• KSBB Journal
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• v.9 no.2
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• pp.108-114
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• 1994

Kinetic equations for transglycosylation of stevioside in the attrition coupled reaction system using raw starch as a glycosyl donor were derived considering that the reaction was carried out through two steps; production of cyclodextrin(CD) from raw starch in the attrition coupled reaction system and then transglycosylation of glycosyl residues to stevioside from produced CD. Kinetic constants of derived equation were evaluated. The simulation result showed that the derived kinetic equations could predict the experimental data reasonably well and that can be utilized for optimization and scale-up of transglycosylation reactor and process developments.