• 한국미생물·생명공학회지
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• 제17권4호
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• pp.370-378
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• 1989

토양으로부터 역가높은 CGTase를 분비하는 호알칼리성 미생물을 분리하였으며, 동정 결과 Bacillus circulans로 판정되었다. 배양액 중의 CGTase를 ammonium sulfate 침전, DEAE-Sephadex 그리고 Sephadex G-100 column chromatography로 분리, 정제하여 단일 단백질 band를 얻었다. 정제된 CGTase의 분자량은 약 93,000, 최적 pH와 온도는 6.0, $50^{\circ}C$였으며, pH와 온도안정성은 5.5-11, $65^{\circ}C$까지였다. Soluble starch를 기질로 할 때의 $V_{max}$ 와 $K_{m}$ 값은 각각 0.16$\mu$mole $\beta$-CD/min, 14.3mg soluble starch/mi이였고 24시간 반응액의 $\alpha$-：$\beta$-:${\gamma}$-CD 의 생성비율은 1：8.1：1.9로서 $\beta$-CD를 우선적으로 합성하였다. 기질로 glucose와 maltose를 사용하였을 때 CD합성작용이 없었으며, sweet potato 그리고 cornstarch를 사용하였을 때 가장 높은 CD합성작용을 보였다. 어느 수준 이상의 과다한 CGTase 첨가경우에는 $\alpha$-CD생성이 급격히 증가하였다. 또한 정제된 CGTase는 stevioside에로의 당전이성을 갖고 있었다.

• Journal of Microbiology and Biotechnology
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• 제1권1호
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• pp.63-69
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• 1991

Performance of column type bioreactor packed with immobilized cyclodextrin glucanotransferase (CGTase) on chitosan and Amberite IRA 900 was evaluated for cyclodextrin(CD) production. For CGTase immobilized on chitosan, the maximum CD conversion yield of 42% was achieved at the range of 88-168 units of immobilizied CGTase per gram of chitosan, retention time of 0.3 hr, and from 5.0% (w/v) of partially cyclized soluble starch. On the other hand, for CGTase immobilized on Amberite IRA 900, the maximum conversion yield of 40% was obtained at the range of 3.6-11.0 units of immobilized CGTase per gram of carrier and retention time of 1.2 hr from 5.0% of substrate. Above CD conversion yields are almost identical level with that can be obtained with soluble CGTase of 47%. The productivities of bioreactor packed with immobilized CGTase were 17.0g of CD/lㆍhr for amberite IRA 900 and 15.5g of CD/lㆍhr for chitosan. The partially cyclized starch with soluble CGTase were more suitable as substrate to achieve better CD conversion yield, and 5% (w/v) of partially cyclized soluble starch containing 10% (w/w) of CD was found to be most suitable to obtain maximum CD conversion yield.

• 한국미생물·생명공학회지
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• 제20권3호
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• pp.344-347
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• 1992

Bacillus stearothermophilus No.239의 돌연변이주 MNNG 8이 생산하는 CGTase를 사용하여 감자전분을 동시 액화, cyclodextrin(CD) 생산을 하였다. 고농도(30)의 감자전분이 29의 수율로 CD로 전환 되었으며 그 때의 조건은 pH 6.0, $80^{\circ}C$, 4.3mM, $CaCl_2$, $40^{\circ}C$에서 1g의 전분당 3.0 DAU의 CGTase를 첨가하는 것이다.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.156-163
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• 1992

Cyclodextrin glucanotransferase 생산균주 선발배지를 이용하여 국내 토양으로부터 CGTase 활성이 우수한 Bacillus sp. E1균주를 분리하였다. FPLC를 이용하여 gel filtration과 anion exchange column chromatography를 한 결과 순수 정제된 단일 단백질을 얻을 수 있었으며, 정제된 효소의 최적 작용 pH 범위는 6에서 8까지 였고, 온도는 $60^{\circ}C$에서 최적을 나타냈다. 정제된 단백질의 분자량은 114,000, 등전점은 4.3이었다. 생성된 cyclodextrin은 $\beta$와 $\gamma$-cyclodextrin이 주였으며, 특이하게도 $\alpha$-cyclodextrin은 거의 생성되지 않았다. 작용 후 25시간 후 최대의 $\beta$-cyclodextrin이 생성되었으며, 이때 $\beta$-cyclodextrin과 $\gamma$-cyclodextrin의 생성비율은 7:1이었다.

• 한국미생물·생명공학회지
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• 제19권2호
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• pp.163-170
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• 1991

Production of cyclodextrin (CD) directly from raw corn starch without liquefaction using cyclodextrin glucanotransferase (CGTase) was carried out in an agitated bead reaction system. Similar CD yield and production rate comparable with those of conventional method using liquefied starch were obtained. Especially high purity-CD in the reaction mixture without accumulation of malto-oligosaccharides was obtained. The maximum 54g/l of CD was obtained at raw starch concentration of 200g/l. CD yield was inversely proportional to raw starch concentration, and conversion yield was 0.48 at substrate concentration of 100g/l. The optimal amount of enzyme (CGTase unit/g raw starch) was found to be around 6.0. Granular structure of raw starch degraded by CGTase was observed by SEM in order to investigate the enhancing mechanism, along with those of acid or alkali pretreated raw starch, amylose, and amylopectin. Kinetic constants of CGTase on raw starch in an agitated bead reaction system were evaluated, and CGTase was competitively inhibited by CD.

• 한국식품영양과학회지
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• 제27권4호
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• pp.609-617
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• 1998

A microorganism capable of producing high level of extracellular cyclodextrin glucanotransferase(EC 2.4.1.19 ; CGTase) was isolated from Kimchi. 2-O-$\alpha$-D-glucopyranosyl L-ascorbic acid(AA-2G) was synthesized by transglycosylation reaction of CGTase using starch as a donor and L-ascorbic acid as an acceptor. The isolated strain S-6 was identified as Bacillus sp. S-6. The maximal CGTase production was observed in a medium containing 0.5% soluble starch, 1% yeast extract, 1% NaCO3, 0.1% K2HPO4, and 0.02% MgSO4 with initial pH 8.0. The strain was cultured at 37$^{\circ}C$ for 40 hr with reciprocal shaking. Using the culture supernatant as crude enzyme, the optimal pH and temperature of the CGTase activity of this strain were 7.0 and 4$0^{\circ}C$. In the effects of pH and temperature on the stability of the enzyme, the enzyme was stable in the range of pH 6.0~10.0 and up to 45$^{\circ}C$, respectively.

• 한국식품영양과학회지
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• 제29권1호
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• pp.49-56
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• 2000

The 2-O-$\alpha$-D-glucopyranosyl L-ascorbic acid (AA-2G) which was enzymatically glucosylated with the cyclodextrin glucanotransferase (CGTase) [EC 2.4.1.19] from Bacillus sp. JK-43 has been reported previously. The presnet experiments examined the optimal conditons for the productio of AA-2G from AA and soluble starch, and characterized the properties of the CGTase from Bacillus sp. JK-43. The reaction mixture for the maximal production of AA-2G was followings; 12% total substrate concentration, 1,400 usits/mL of CGTase and a mixing ratio of 2 : 3(g or AA : g of soluble starch). Under this condition, 1.76mM of AA-2G, which corresponded to 2.53% yield based on AA, was produced after incubation for 24hrs at 45$^{\circ}C$ (pH 5.5). The optimum pH and temperature for the CGTase activity were 6.0 and 45$^{\circ}C$, respectively. The enzyme was stable at pH 5.5 to 9.5, and at temperature up to 5$0^{\circ}C$. The thermostability of the enzyme could be enhanced up to 6$0^{\circ}C$ by the addition of 30mM CaCl2.

• 한국식품과학회지
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• 제26권1호
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• pp.6-11
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• 1994

토양에서 분리한 Bacillus sp. I-5의 cyclodextrin glucanotransferase(CGTase)는 ${\beta}-$ 및 ${\gamma}-cyclodextrin(CD)$를 주로 생성하는 효소로서 최적 반응조건은 pH 8.0, $50^{\circ}C$에서 최적 반응이었다. 생성되는 CD의 조성비는 buffer 용액에 따라 영향을 받았으며 sodium acetate의 농도를 200mM로 하였을 때 ${\gamma}-CD$의 생성은 35% 가량 증가하였다. 기질인 가용성 전분의 DE value에 따라 CD의 생성이 달라져 $3.5{\sim}6.0$범위의 DE value의 전분을 기질로 사용하였을 때 CD이 가장 많이 생성되었다. CD을 연속적으로 생산하기 위하여 CGTase를 가역적으로 용해-침전되는 담체인 hydroxypropyl methylcellulose acetate succinate에 고정화하였고 고정화된 CGTase는 pH 7.5에서 물에 용해되고 pH 6.0에서 쉽게 침전되는 특성을 나타내었다. CD의 연속적 생산은 고정화된 CGTase에 의한 CD의 생산, 반응하지 않은 기질을 glucose로 분해, glucose를 알코올로 발효시키는 단계로 하는 효소반응기를 개발하여 최종적으로 CD 혼합액과 에탄올이 생성되도록 하였다. 10%의 가용성 전분으로부터 생산된 전체 CD의 양은 3.65g이었다.

• 생명과학회지
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• 제14권5호
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• pp.794-799
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• 2004

Bacillus subtilis NAl/pKBl으로부터 생산된 cyclodextrin glucanotransferase (CGTase)는 cyclodextrin (CD)의 생산에 이용되었으며, 이에 사용된 CGTase는 ion-exchange chromatography와 gel filtration chromatography에 의해 정제되었다. 정제된 CGTase는 pH 6.0-7.0 범위, 60-$70^{\circ}C$에서 최대 활성을 나타내었으며, 다양한 이온결합성 고정화 담체를 이용하여 정제 효소의 고정화를 실시한 결과, 강염기성 음이온교환수지인 Amberlite IRA-900이 가장 우수한 고정화 효율을 나타내었다. 고정화된 효소는 pH 6.0, $60^{\circ}C$에서 최대 활성을 나타내었고, 그 활성이 약 1개월간 유지되어 cyclodextrin을 생산하기 위한 연속반응기내에서 장기간 사용이 가능함을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.1002-1005
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• 2002

The effects of GroEL/ES chaperone on the production of soluble form of B. macerans cyclodextrin glucanotransferase (CGTase) in recombinant E. coli were investigated. The cgt gene and groEL/ES genes are under the control of T7 promoter and Pzt-1 promoter, respectively. The optimal concentrations of inducers, IPTG and tetracycline, were found to be 1.0 mM and 10 ng/ml, respectively. When tetracycline and IPTG were added at the early exponential phase (2h) and exponential phase (3h) of growth, respectively, about 1.5-fold increase of soluble CGTase activity and 1.6-fold increase of soluble CGTase protein were obtained. An SDS-PAGE analysis revealed that about $37.2\%$ of total CGTase protein was in the soluble fraction when GroEL/ES chaperone was overexpressed.