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Characterisation of cyclodextrin glucanotransferase fromBacillus circulans ATCC 21783 in terms of cyclodextrin production |
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| Authors: | Anna Vassileva Nikolina Atanasova Viara Ivanova Pascal Dhulster Alexandra Tonkova |
| Institution: | 1. Department of Extremophilic Bacteria, Institute of Microbiology, Bulgarian Academy of Sciences, 26, Acad. G. Bonchev str., 1113, Sofia, Bulgaria 2. Department of Organic Chemistry and Microbiology, University of Food Technologies, 26, Maritsa str., 4002, Plovdiv, Bulgaria 3. Laboratoire PROBIOGEM, UPRES-EA 1026, Polytech’Lille, aile C, boulevard Paul Langevin, cite scientifique, 59655, Villeneuve d’Ascq, France |
| Abstract: | Cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19) fromBacillus circulans ATCC 21783 was purified by ultrafiltration and a consecutive starch adsorption. Total enzyme yield of 75.5% and purification factor of 13.7 were achieved. CGTase was most active at 65°C, possessed two clearly revealed pH-optima at 6.0 and 8.6 and retained from 75 to 100% of its initial activity in a wide range of pH, between 5.0 and 11.0. The cyclising activity was enhanced by 1 mM CaCl2 or 4 mM CoCl2. The enzyme was thermostable up to 70°C, and 64% of the original activity remained at 70°C after 30 min heat treatment. Up to 41% conversion into cyclodextrins was obtained from 40 g l?1 starch without using any additives. This CGTase produced two types of cyclodextrins, beta and gamma, in a ratio 73:27 after 4 h reaction time at 65°C. This feature of the enzyme could be of interest for industrial cyclodextrin production. |
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