Investigation on Cyclodextrin Production with Cyclodextrin Glucanotransferase from Bacillus megaterium
Boriana Yordanova Zhekova1*, Ivan Genov Pishtiyski1 and Veselin Stanchev Stanchev2
1Department of Biochemistry and Molecular Biology, University of Food Technologies, 26 Maritza Blvd., BG-4000 Plovdiv, Bulgaria
2Department of Automatics, Information and Control System, University of Food Technologies, 26 Maritza Blvd., BG-4000 Plovdiv, Bulgaria
Article history:
Received June 25, 2006
Accepted November 2, 2006
Key words:
coupling activity, cyclodextrins, cyclodextrin glucanotransferase, optimal composite design, β-cyclodextrin production, product inhibition, starch
Summary:
The process of producing cyclodextrins from starch with cyclodextrin glucanotransferase from Bacillus megaterium has been studied. The effect of starch and enzyme concentrations was evaluated using optimal composite designs and the response surface methodology. Mathematical models describing the process in two overlapping areas of variation of the independent variables were developed. The models were used to determine the optimal values of the variables. The increase in starch concentration resulted in an increase in the amount of β-cyclodextrin formed, but lowered the yield. The optimal starch concentration was considered to be 50.0 mg/mL. The critical cyclodextrin glucanotransferase concentration necessary for maximum β-cyclodextrin production was 2.0 U/g. Factors that limit the complete conversion of starch to cyclodextrins were established. The enzyme activity was strongly inhibited by the reaction products. The coupling activity of cyclodextrin glucanotransferase was proved. The enzyme was able to degrade high concentrations of β-cyclodextrin and to transform different types of cyclodextrins one into another. Cyclodextrin glucanotransferase formed α-, β- and γ-cyclodextrins in different ratios, depending on the duration of the process.
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