• 한국미생물·생명공학회지
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• 제26권5호
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• pp.442-449
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• 1998

CGTase를 이용한 당전이 xylitol의 합성과 당전이 xylitol의 비피더스균 생육증식 효과에 대한 연구를 수행하였다. 수종의 세균류가 분비하는 CGTase의 xylitol에 대한 당전이능을 비교하였으며, Thermoanaerobacter sp. 유래의 CGTase가 가장 우수한 당전이능을 보였다. 각종 당공여체를 검토한 결과 압출전분이 가장 우수한 결과를 보였으며, 당전이 효소반응의 최적 조건을 검토하였다. 생성된 당전이 xylitol을 활성탄-셀라이트 칼럼 크로마토그래피를 이용하여 분리하여 두 개의 fraction인 F-I, F-II를 얻었다. 이들의 당쇄결합 양상을 FAB mass spectrometer와 $^{13}$C-NMR spectrometer, 그리고 glucoamylase을 이용한 효소소화법을 이용하여 분석한 결과 xylitol에 glucose와 maltose 분자가 $\alpha$-1,4 결합되어 있는 것으로 유추되었다. 얻어진 당전이 xylitol은 xylitol과는 달리 Bifidobacterium breve에 대한 생육촉진효과를 보였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권3호
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• pp.174-180
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• 2000

Cyclodextrin glucanotransferase (CGTasa) from Thermoanaerobacter sp. was adsorbed on the ion exchange resin Amberlite IRA-900. The optimum conditions for the immobilization of the CGTase were pH6.0 and 600 U CGTase/g resin, and the maximum yield of immobilization was around 63% on the basis of amount ratio of the adsorbed enzyme to intial amount in the solution. Immobilixation of CGTase shifted the optimum temperature for the enzyme to peoduce transglycosylated xylitol from 7$0^{\circ}C$ to 9$0^{\circ}C$ and improved the thermal stability of immobilized CGTase, especially after the addition of soluble starch and calcium ions. Transglycosylated xylitol was continuoncly produced using immobilized CGTase in the column type packed bed reactor, and the operating conditions for maximum yield were 10%(w/v) dextrin (13 of the dextrose equivalent) as the glycosyl donor, 10%(w/v) dextrin (13 of the dextrose equivalent) as the glycosyl donor, 10%(w/v) xylitor as the glycosyl acceptor, 20mL/h of medium fiow rate, and 6$0^{\circ}C$. The maximum yield of transglycosylated xylitol and productivity were 25% and 7.82 g.L-1.h-1, respectively. The half-life of the immobilized CGTase in a column type packed bed reactor was longer than 30 days.

• Journal of Microbiology and Biotechnology
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• 제16권11호
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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.