• KSBB Journal
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• v.15 no.6
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• pp.556-559
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• 2000

Cyclodextrin Glucanotransferase(EC 2.4.1.19 : 1,4-${\alpha}$-glucano) transferase, cyclizing; CGTase) can be separated and recovered in an aqueous two-phase system composed of poly(ethylene glycol)(PEG)/dextran and PEG/salt. In an aqueous two-phase system consisting of PEG 35000 (5%) and dextran T2000 (7%), all cell and debris were collected at the interphase. CGTase partitioned to the denser dextran phase at an yield of 83.4%. On the other hand, in an aqueous two-phase system consisting of PEG 35000 (10%) and sodium phosphate (15%), CGTase partitioned to the denser salt phase at an yield of 95.5%. In order to recover CGTase using an aqueous two-phase system, the PEG/salt system proved to be more efficient than the PEG/dextran system in terms of yield and cost.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.344-347
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• 1992

Simultaneous liquefaction and cyclodextrin (CD) production were conducted on potato starch using cyclomaltodextrin glucanotransferase (CGTase) from a mutant strain MNNG 8 of Bacillus stearothermophilus No. 239. A high concentration (30%) of potato starch was converted to cyc1o-dextrins (CDs) with 29% yield in the conditions of pH 6.0, temperature $80^{\circ}C$, 4.3 mM $CaCl_2$, CGTase addition of 3.0 dextrinizing activity unit (DAU) at $40^{\circ}C$/g starch.

• 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.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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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.

• The Korean Journal of Food And Nutrition
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• v.8 no.3
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• pp.253-261
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• 1995

A strain of alkalophilic Bacillus sp. C-21 has been Isolated from sold. The strain was capable of producing large amount of cyclodextrin glycosyltransferase (CGTase) in the high alkaline pH medium. The preferable medium composition was determined to be as follows : 1.0% soluble starch, 1.0% peptone, 0.5% yeast extract, 0.1% K2HP04, 0.02% MgSO4.7H2O and 1.0% Na2CO3(pH 10.0) The highest enzyme production was observed after 30hours of cultivation at 33$^{\circ}C$. The optimum temperature and pH for the activity of crude enzyme were 6$0^{\circ}C$ and 6.0, respectively. The enzyme was stable between pH 6.0 and 9.6, and up to 55$^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.1
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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.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.370-378
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• 1989

An Alkalophilic Bacillus circulans that can produce significant amount of cyclodextrin glucanotransferase (CGTase) was newly isolated from soil. The culture filtrate was successively purified by ($NH_4$)$_2$$SO_4$precipitation, DEAE-Sephadex column chromatography, and Sephadex G-100 column chromatography. The enzymatic properties, including molecular weight, optimal pH and temperature, stability, and kinetic parameters, were determined. The cyclodextrin synthesis reaction catalized by the purified CGTase was also studied. The sweet potato and corn starch were found to be the most suitable substrates with 60% conversion to cyclodextrin. The highest conversion was achieved at the CGTase concentration of 900-1,100 units/g of soluble starch. The purified CGTase could also catalize the transglycosylation on stevioside.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.969-973
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• 1997

In order to produce transglucosylated steviosides continuously, some types of bioreactors were investigated with cyclodextrin glucanotransferase immobilized on a high porous anion exchange resin, Diaion HPA75. Among the bioreactors, the packed-bed reactor (PBR) showed the highest specific productivity. The effect of linear velocity in a PBR on the stevioside conversion was not significant in the range of $10{\sim}60\;cm/hr$ at the same space velocity of $1.2\;hr^(-1)$. When the space velocity of bioreactor was varied from 0.2 to $1.1\;hr^{-1}$, the optimal velocity of substrate solution was determined as $0.7\;hr^(-1)$. The stevioside conversion of more than 70% was maintained during 20 days in the continuous operation, if about 20% of immobilized enzyme was replaced in the top of reactor after two weeks operation as the one of the control methods in bioreactor. The specific production, which refers to as the amount of commercially valuable transglucosylated steviosides produced by a unit amount of immobilized cyclodextrin glucanotransferase, was found to be ca. 150g product/g immobilized enzyme.

• Journal of Microbiology and Biotechnology
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• v.1 no.1
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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.