• 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.

• 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.

• 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.20 no.2
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• pp.156-163
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• 1992

Bacillus sp. was isolated from soil for its strong activity of cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19). The enzyme was purified by gel filtration and anion exchange column chromatography using FPLC. The purified enzyme exhibited its maximum CGTase activity in the pH range of 6~8 and the temperature range of 50~$70^{\circ}C$. The molecular weight was estimated as 114,000 by SDS-PAGE. The isoelectric point of the enzyme was 4.3. The CGTase of Bacillus sp. E l produced $\beta$-cyclodextrin mainly and did not produce a-cyclodextrin. The product ratio of $\beta$-cyclodextrin to $\gamma$-cyclodextrin was 7:l.

• 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.

• 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.

• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.6-11
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• 1994

A cyclodextrin glucanotransferase(CGTase)-producing Bacillus sp. I-5 was isolated from soil and the enzyme exhibited the maximum reaction rate at pH 8.0 and $50^{\circ}C$. It was found that CGTase of I-5 produced ${\beta}-$ and ${\gamma}-CD$ mainly but the production ratio of cyclodextrins (CDs) was influenced by the buffer solution. Sodium acetate significantly stimulated the formation of ${\gamma}-CD$, increasing the content by 35%. The production of CDs was influenced by DE value of starch. The results indicated that DE value in the range of $3.5{\sim}6.0$ were most effective for the CD formation. CGTase was immobilized on the reversibly soluble-insoluble carrier, hydroxypropyl mothylcellulose acetate succinate. The immobilized CGTase was soluble at pH 7.5, and precipitated easily at pH 6.0. Enzyme reactor was designed to produce CD continuously. It was composed of three major stages-CD produttion by immobilized CGTase, conversion of the residual dextrin to glucose by amylase and glucoamylase and alcohol fermentation by yeasts to remove the glucose into alcohol. The yield of total CDs was 3.65g from 10g soluble starch.

• Journal of Life Science
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• v.14 no.5
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• pp.794-799
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• 2004

Cyclodextrin glucanotransferase (CGTase) produced by Bacillus subtilis NAl/pKBl was used for the production of cyclodextrin (CD). The enzyme was purified by ion exchange and gel filtration chromatography. The purified enzyme exhibited its maximum activity in the pH range of 6.0 to 7.0 and temperature range of 60 to $70^{\circ}C$. Immobilization of purified CGTase was carried out with various immobilization matrices. Amberlite IRA-900, a strong basic anion exchange resin, showed the highest immobilization ability (38 units per gram resin). Optimal pH and temperature for enzymatic reaction of the immobilized CGTase were pH 6.0 and 60t. The activity of immobilized CGTase maintained more than a month and could be reused for a month in a continuous enzyme reactor for the production of CD.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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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.