Cyclomaltodextrin glucanotransferases

An export-affinity fusion vector containing the gene cgt encoding cyclomaltodextrin glucanotransferase (CGTase) from Bacillus circulans var. alkalophilus has been described... 

Villette, J.R., Helbecque, N., Albani, J.R., Sicard, P.J. and Bouquelet, S.J. (1993). Cyclomaltodextrin glucanotransferase from Bacillus circulans E 192 nitration with tetranitromethane. Biotechnology and Applied Biochemistry, 17, 205-216. 

The cyciomaitodextrins (a-CD, -CD, and y-CD) can be selectively obtained from a fermentation culture or an enzyme digest of cyclomaltodextrin glucanotransferase reaction with solubilized starch. The majority of the cyclomaltohexaose (a-CD) can be separated from cycloma-Itoheptaose (/3-CD) and y-CD by their selective precipitation with p-cymene from the culture supernatant or from an enzyme digest [168]. The a-CD can then be precipitated from the supernatant with cyclohexene, which is extracted with acetone to remove the cyclohexene and the a-CD can be crystallized from water or a propanol-1/water solution [169]. The p-cymene precipitates of /3-CD and y-CD are put into a water solution and /3-CD selectively precipitated from y-CD with fluorobenzene. The y-CD is then precipitated with anthracene saturated in diethyl ether. After the removal of the fluorobenzene from /3-CD with acetone or ethanol extraction, /3-CD can be crystallized from water, and after the removal of anthracene with acetone or ethanol extraction from y-CD, it can also be crystallized from water [170,171]. The selective precipitations of the cyciomaitodextrins with various organic molecules is based on the selective formation of complexes of the organic molecules with the specific sizes of the cyciomaitodextrins and the relatively hydrophobic interior cavities of the cyciomaitodextrins [166,167,168]. 

Since CD production without the application of solvents may lead to microbial contamination, the process should be conducted at increased reaction temperature. A heat-resistant cyclomaltodextrin glucanotransferase, stable at temperatures above 100 °C, was isolated from Thermococcus species. The enzyme possesses also a-amylase activity and the production of CD is possible without the addition of a-amylase for the preliminary starch liquefaction [48]. 

Methods and Supports for Immobilization and Stabilization of Cyclomaltodextrin Glucanotransferase from Thermoanaerobacter... 

Terada, Y, H Sanbe and T Takaha (2001). Comparative study of the cyclization reactions of three bacterial cyclomaltodextrin glucanotransferase. Applied and Environmental Microbiology, 67, 1453-1460. 

The discovery and chemistry of the non-reducing, chemically stable 2-0-a-D-glucopyranosyl-L-ascorbic acid has been reviewed, and a new synthesis of it has been described in which L-ascorbate and a-cyclodextrin interact in the presence of a cyclomaltodextrin glucanotransferase from Bacillus stearothermophilus. Other products with higher maltooligosaccharides linked to 0-2 of the ascorbate were also formed, but glucoamylase could be used to convert these to more 2-0-a-glucopyranosyl-L-ascorbic acid.7 ... 

Goel, A., Nene, S. A novel cyclomaltodextrin glucanotransferase fmm Bacillus firmus that degrades raw starch. Biotechnology Letters 1995,17(4), 411 16. 

Kaneko, T, Hamamoto, T, Horikoshi, K. Molecular cloning and nucleotide sequence of the cyclomaltodextrin glucanotransferase gene from the alkalophilic Bacillus sp. strain no. 3%-2.JGenMicmbiol 1988,134, 97-105. 

Wong, T. E., Rahman, R. A., Ismail, A. F., Salleh, M. M., Hassan, O., Kamaruddin, K. Initial screening of fermentation variables for the production of cyclomaltodextrin glucanotransferase (CGTase) from local isolated Ba 7/ s stearothermophillus HRl. Developments in Chemical Engineering and Mineral Processing 2008, 13(5-6), 541-547. 

It is prepared from 5% solutions of - potato starch, which is incubated at 40 °C with the - enzyme cyclomaltodextrin glucanotransferase (CG-tease) (EC 2.4.1.19 nomenclature a-l,4-D-glu-can-4-a-D-( 1,4-a-glucano)-transferase). 

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