Sunday, April 29, 2007

Production of cyclodextrin from two cyclomaltodextrin glucanotransferase (CGTase) in the hydrolysis of different substrates

Heloiza F. Alves-Prado1, Andreia A. J. Carneiro2, Eleni Gomes2, and Roberto DaSilva2. (1) Food Tecnology Department - DFTASE, UNESP, Avenida Brasil, 56 - Centro, Caixa Postal 31, Ilha Solteira, 15385-000, Brazil, (2) Biochemistry and Applied Microbiology Laboratory, UNESP, Rua Cristovão Colombo nº 2265, Sao José do Rio Preto, 15055-000, Brazil

Cyclodextrins (CDs) are cyclic oligasaccharides composed by the D-glucose monomers jointed by alpha-1,4-D glicosidic linkages. The main types of cyclodextrins are alpha-, beta- e gamma-CDs consisting of six, seven and eight glucose monomers in cycle, respectively. Their ability of forming inclusion complexes with various compounds is named "molecular encapsulation" and this is the more important characteristic, allowing their wide industrial application. The CD-complexed compound can be changed improving stability, volatility, solubility or bio-availability. The increasing importance of cyclodextrins in the food and pharmaceutic industries makes the knowledge of enzimatic prduction of these compounds essential. The cyclomaltodextrin glucanotransferase (CGTase, EC is a unique enzyme capable to converting starch into CD molecule. In the present study, the CGTase produced by two microorganisms Paenibacillus campinasensis strain H69-3 and Bacillus clausii strain E16 was purified previously through different chromatographic process. These enzymes show interesting properties to industrial application such as thermostability. So, these enzymes were submitted to cyclodextrin production using maltodextrin and soluble starch as substrate, on concentrations of 1.0% and 2.5% for each substrate source. The ratio of alpha-, beta- and gamma-CD were determined by HPLC. It was observed that the substrate sources can influence the cyclodextrin type. Considering the CD types with more conversions were mainly beta-CD and gamma-CD. The alpha-CD was produced in minor quantities on studied conditions. Depending of substrate source, the alpha-CD was not produced. These results demonstrating that these CGTases can be characterized as beta-CGTases because of the better beta-CD production. Supported by FAPESP