• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1550-1553
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• 2007

The functional characteristics of a ${\beta}$-cyclodextrin glucanotransferase (CGTase) excreted from alkalophilic Bacillus sp. BL-31 that is highly specific for the intermolecular transglycosylation of bioflavonoids were investigated. The new ${\beta}$-CGTase showed high specificities for glycosyl acceptor bioflavonoids, including naringin, rutin, and hesperidin, and especially naringin. The transglycosylation of naringin into glycosyl naringin was then carried out under the conditions of 80 units of CGTase per gram of maltodextrin, 5 g/l of naringin, 25 g/l of maltodextrin, and 1 mM $Mn^{2+}$ ion at $40^{\circ}C$ for 6 h, resulting in a high conversion yield of 92.1%.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1678-1683
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• 2006

A novel suspension-phase enzyme reaction system for the intermolecular transglycosylation of L-ascorbic acid into 2-O-${\alpha}$-D-glucopyranosyl L-ascorbic acid supplementing extrusion starch as the glycosyl donor was developed using cyclodextrin glucanotransferase from Thermoanaerobacter sp. A high conversion yield compared to the conventional soluble-phase enzyme reaction system using cyclodextrins and soluble starch was achieved. The optimal reaction conditions were 2,000 units of cycIodextrin glucanotransferase, 20 g/l of L-ascorbic acid, and 50 g/l of extrusion starch at $50^{\circ}C$ for 24 h. The new suspension-phase enzyme reaction system also exhibited several distinct advantages other than a high conversion yield, including a lower accumulation of oligosaccharides and easily separable residual extrusion starch by centrifugation or filtration in the reaction mixture, which will facilitate the purification of 2-O-${\alpha}$-D-glucopyranosyl L-ascorbic acid. The new suspension-phase enzyme reaction system seems to be potentially applicable as the industrial process for the production of thermally and oxidatively stable 2-O-${\alpha}$-D-glucopyranosyl L-ascorbic acid.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.454-460
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• 2007

Enzymatic properties and substrate specificity of recombinant $\beta-glycosidases$ from a hyperthermophilic archaeon, Sulfolobus shibatae (rSSG), were analyzed. rSSG showed its optimum temperature and pH at $95^{\circ}C$ and pH 5.0, respectively. Thermal inactivation of rSSG showed that its half-life of enzymatic activity at $75^{\circ}C$ was 15 h whereas it drastically decreased to 3.9 min at $95^{\circ}C$. The addition of 10 mM of $MnCl_2$ enhanced the hydrolysis activity of rSSG up to 23% whereas most metal ions did not show any considerable effect. Dithiothreitol (DTT) and 2-mercaptoethanol exhibited significant influence on the increase of the hydrolysis activity of rSSG rSSG apparently preferred laminaribiose $(\beta1\rightarrow3Glc)$, followed by sophorose $(\beta1\rightarrow2Glc)$, gentiobiose $(\beta1\rightarrow6Glc)$, and cellobiose $(\beta1\rightarrow4Glc)$. Various. intermolecular transfer products were formed by rSSG in the lactose reaction, indicating that rSSG prefers lactose as a good acceptor as well as a donor. The strong intermolecular transglycosylation activity of rSSG can be applied in making functional oligosaccharides.

• KSBB Journal
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• v.15 no.1
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• pp.35-41
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• 2000

We tried to prepare encapsulated whole cell cyclodextrin glucanotransferase(CGTase) in order to produce glycosyl-xylitol using xylitol as glucosyl acceptor. The organic nitrogen source was more effective for the production of CGTase from Bacillus macerans IFO 3490 than the inorganic one. Most of the CGTase which had been produced during cultivation was excreted to the growth medium. B. macerans cells inocculated in the capsule failed to grow to the high cell density. Adsorbents such as activated charcoal, Sephadex and Amberite resins could not adsorb efficiently the CGTase from the broth solution. We obtained successfully the encapsulated whole cell CGTase by immobilizing the concentrated broth solution in the calcium alginate capsules. The encapsulated whole cell CGTase carried out the transglycosylation reaction which converts xylitol into glucosyl-xylitol using dextrin as glucosyl donor.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.442-449
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• 1998

Several transglucosylated xylitols were synthesized using intermolecular transglucosylation reaction of cyclodextrin glucanotransferase (CGTase) and their bifidogenic effects were investigated. The CGTase from Thermoanaerobacter sp. showed the highest transglycosylation activity on xylitol compared to those obtained from other strains. Extruded starch was identified to be the most suitable glucosyl donor for transglucosylation reaction on xylitol molecule by CGTase. The optimum reaction conditions for transglucosylation were also studied using extruded starch as a glucosyl donor. The transglucosylated xylitols were purified by activated carbon column chromatography with ethanol gradient elution from 0 to 18%, and their chemical structures were analyzed by fast atom bombardment mass spectrometer, $\^$13/C-nuclear magnetic resonance spectrometer, and enzyme digestion method. Two transglucosylated xylitol, F-I and F-II, which had one or two glucose molecules attached to maternal xylitol by ${\alpha}$-1,4-linkage, were mainly obtained. F-II showed increased stimulation effect on the growth of Bifidobacterium breve compared to xylitol, indicating the possibility utilized as a new functional alternative sweetners having bifidogenic effects.