Preparation of Cyclodextrin Glucanotransferase from Bacillus circulans DF 9R

NATALIA SZERMAN, ADRIANA ROSSO, ANA LÍA ROSSI, SUSANA FERRAROTTI Y NORBERTO KRYMKIEWICZ.

Villa Carlos Paz, Cordoba, Argentina

Congreso; SAIB XXXVIII; 2002

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Cyc1omaltodextrin Glucanotransferase (CGTase) converts starch       in cyclodextrins. These cyclic oligosaccharides have a widespread application in pharmaceutical, agricultural, food, cosmetic and chemical industries. Bacillus circulans DF 9R was grown in saline medium with starch. After centrifugation the supernatant was used as crude enzyme. Two methods were used to prepare CGTase: ammonium sulphate precipitation and starch adsorption. When ammonium sulphate precipitation was made most CGTase precipitated at 20-40% and 40-60% saturation. In those fraction, was found a 50% of the crude enzyme activity. On the other hand, crude CGTase was adsorbed on soluble starch. The adsorbed enzyme was eluted with distilled water by incubation at 40°C. The enzyme recovery was 43% and it increased to 64% in presence of 10 mM alfa cyclodextrin. Trials were carried out to determinate if the CGTase adsorbed on starch remained active after being lyophilized or vacuum dried. The percentage of enzymatic activity in the lyophilized was 82% of the crude enzyme, whereas in dried sample was 65%. The results show a higher CGTase yield with starch adsorption than ammonium sulphate precipitation. The enzyme can be used adsorbed on starch or after its elution for cyclodextrin production.