• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.82-85
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• 1998

1. 서론 : Cyclodextrin(CD) 동족체(homologues)는 $\alpha$-, $\beta$-, $\gamma$-CD로 구분되며, 이들 각각은 $\alpha$-D-glucopyranose 단위체 6,7, 및 8개가 비환원성 환상구조로 연결된 cyclic maltooligosaccaride의 일종으로 외부는 친수성이고, 내부는 소수성인 공동 구조를 갖고 있다. 따라서 각 CD는 동공의 크기가 달라 다른 크기의 소수성 물질들과 선택적인 포접화합물 (inclusion compound)을 형성하는 특징이 있다. CD 동족체는 전분 분해 효소인 cyclodextrin glycosyltransferase(CGTase)에 의해 전분으로부터 생산되는데, 반응용액 내에서의 CD 동족체 농도가 어느 한계값 이상으로 높아지면 생산물 저해와 다른 환원당으로의 분해 때문에 생산성이 감소하여 이의 효과적 생산에 어려움이 있다. 본 연구는 dead-end 및 cross-flow형 막 생물반응기를 사용하여 CGTase에 의한 전분의 CD 동족체로의 분해반응시 생산물 저해를 억제시켜 생산성을 향상시키고, 동시에 조작조건 변화에 따른 생산물인 CD 동족체의 효과적인 연속분리 가능성을 검토하였다.

• Journal of Life Science
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• v.10 no.1
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• pp.86-93
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• 2000

Specific molecular recognition of cyclodextrin and aspirin was determined. A stable 1:1 inclusion complex was established in solution. The distinct structure of inclusion complex was elucidated by FT-IR, FAB-MS, UV, 1H NMR, and 13C NMR spectroscopy. Based on the 1H NMR data, a time-averaged conformation of $\alpha$-cyclodextrin exhibited significant catalytic activity toward the hydrolysis of aspirin in alkaline solution.

• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.75-84
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• 1997

Chromatographic retention behavior and separation of various phenol derivatives on a Partisil 10 ODS 3 column-with mobile phase containing $\alpha$-cyclodextrin-were systematically studied. The decrease in k' values caused by the addition of cyclodextrins in the mobile phase was based on the formation of an inclusion complex, resulting in weakening of the hydrophobic interaction between solutes and the stationary phase. The content of the organic solvent in the mobile phase also influenced k' values of the solutes, and k' values increased with a decrease of the content of organic solvent in the mobile phase. A simple equation has been derived that reveals the hyperbolic dependence of the capacity factor on the total concentration of cyclodextrin. A plot of the reciprocal of the capacity factor against (CD)$_T$ gives a straight line and the dissociation constant, K$_D$, of the inclusion complex can be calculated from the slope. The capacity factor decreased with increasing temperature. The enthalpy was calculated from the slope of van't Hoff plots. Under optimum conditions, some mixtures of phenol derivatives were able to separated successfully.

• Analytical Science and Technology
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• v.15 no.2
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• pp.115-119
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• 2002

The formation of inclusion complexes between cyclodextrin(CD) and Congo red was studied by spectrophotometric methods at various temperatures. The cavity sizes are 0.49 nm, 0.62 nm for $\alpha$-and $\beta$-CD, respectively. Therefore, $\alpha$-CD was not found to form an inclusion complex with Congo red due to steric hinderance. In the $\beta$-CD use two $\beta$-CD molecules formed an inclusion complex with one molecule of Congo red, from the slope of the S-shaped curve increased. Two prominent isosbestic points appear at 346 nm and 478 nm. The formation constants were decreased with the increasing temperatures, due to low binding energy between $\beta$-CD and Congo red. The thermodynamic parameters were calculated from the plot of $lnK_f$ vs 1/T. The $\Delta$H, $\Delta$S and $\Delta$G were -50.73 kJ/mol, $-108.96J/K{\cdot}mol$ and -18.26 kJ/mol, respectively.

• Journal of the Korean Society of Tobacco Science
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• v.24 no.2
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• pp.94-100
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• 2002

Cyclodextrin glucanotransferase from Bacillus stearothemophilus and Bacillus macerans synthesized maltol and ethyl maltol monoglucoside, with a series of its maltooligo-glucosides by transglycosylation with dextrin as a donor, and maltol or ethyl maltol as an acceptor. The monoglucoside formed from reaction mixture of maltol or ethyl maltol by the successive actions of Bacillus stearothemophilus cyclodextrin glucanotransferase and Rhizopus glucoamylase was isolated by Diaion HP-20 column and silica gel column chromatography. The structure of the isolated monoglucoside was identified as maltol-$\alpha$-D-glucoside and ethyl maltol-$\alpha$-D-glucoside, respectively, by FAB-MS, UV, $^1$H-NMR, $^{13}$ C-NMR spectra and products by hydrolysis with acid, $\alpha$ - and $\beta$ -glucosidases.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.29-36
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• 2004

$\alpha$-Cyclodextrin glucanotransferase excreted from a newly isolated Geobacillus thermosacchalytycus was purified through the ultrafiltraion, hydrophobic Sepharose CD-4B affinity chromatography, and gel filtration on Sephadex G-75, respectively. The molecular weight of the purified CGTase was 69 kDa and its N-terminal amino acid sequence was determined to be Asn-Leu-Asn-Lys-Val-Asn-Phe-Val-Ser-Asp-Val-Val-Val-Gln-Ile. The optimum pH and temperature were pH 6.0 and$ 60^{\circ}C$, respectively, and stably at the pH range of 6.0-8.0 and $60^{\circ}C$ in the presence of $Ca^{++}$. The excreted CGTase from the thermophilic G. thermosacchalytycus was $\alpha$-type showing a high coupling activity for the transglycosylation on various glucosides. The coupling reaction was carried out according to the random ternary complex mechanism.m.

• KSBB Journal
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• v.19 no.2
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• pp.164-167
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• 2004

Cyclodextrin glucanotransferase (EC 2.4.1.19, abbreviated as CGTase) is one of the most applied industrial enzymes that produces cyclodextrins from starch and related ${\alpha}$-1,4-glucans by intramolecular transglycosylation reaction upon Ca$\^$2＋/ dependent manner. The reaction of CLEC, ${\alpha}$-CGTases from Bacillus macerans with the soluble starch as a substrate reveals that the surfactants (SDS, N-octyl-${\beta}$-D-glucoside) significantly affect not only the overall products of CDs but also their selectivity. The surfactants (SDS, Lubrol PX) trigger the increase of ${\alpha}$-CD production, but Triton x-100 and Tween 80 suppress ${\alpha}$-CD specificity. Organic solvents (dimethyl sulfoxide, formamide, 2-methyl-2,4-pentandiol, and ethylene glycol) also cause changes of total product and product selectivity.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.293-297
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• 2002

The cyclodextrin glucanotransferase (CGTase) gene from Bacillus stearothermophilus NO2 was expressed in Saccharomyces cerevisiae 2805 under the adhl promoter. The CGTase was purified from S. cerevisiae 2805/pVT-CGTS. The purified enzyme exhibited a optima of activity around pH 7.0 and $65^{\circ}C$. Thermal stability of the enzyme was increased fairly as compared with the CGTase of B. stearothermophilus NO2. The conversion yield of cyclodextrin (CD) and the production ratio of $\alpha$-, $\beta$,-, ${\gamma}$-CD from starch were showed similarly aspect to the CGTase of B. stearothermophilus NO2.

• Journal of Life Science
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• v.8 no.3
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• pp.326-332
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• 1998

Cyclodextrin glucanotransferase from B. stearothermophilus KJ16 that can produce both cyclodextrin glucanotransferase and cyclodextrinase was purified by ammonium sulfate precipitation, DEAE-cellulose chromatography, Sephadex G-100 chromatography, and FPLC. The molecular weight of the purifice enzyme was about 65,000 dalton by SDS-PAGE. The optimal pH and temperature were 6.0 and $60^{\circ}C$, respectively. The enzyme was stable at $50^{\circ}C$ for 1 hr and in the pH range of 5.5 and 8.5. Mercaptoethanol and dithiothreitol inhibited the enzyme activity strongly. The enzyme produced 60% cyclodextrin(CD) from 5% soluble starch with the $^{\alpha}$, $^{\beta}$, $^{\gamma}$-CD ratio of 42:46:12. Amylopectin was the most suitable substrate with 67% conversion to CD.

• Microbiology and Biotechnology Letters
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• v.21 no.2
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• pp.119-124
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• 1993

An alkalophilic microorganism for overproduction of cyclodextrin glucanotransferase (CGTase) was newly isolated from hot-water spring soil, and identified as Bacillus firmus var. alkalophilus H609. The strain maintained stability during preservation and cultivation for the enzyme production, and produced significant amount of CGTase corresponding to the volumetric activity of 75 units/mL at 37C, initial pH of 11.2, and after 40 hours. The strain excreted several different proteins showing CGTase activity that catalyzed the formation of mainly beta-and Gamma-type cyclodextrin (ratio of 7:1) from soluble starch without accumulation of alpha-type. Other enzymatic properties were also investigated.