| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 18451 | Enzyme and Microbial Technology | 2006 | 4 Pages |
The extracellular enzyme cyclodextrin gluconotransferase (CGTase, EC 2.4.1.19) was produced by Bacillus macerans ATCC 8244 at optimized conditions. The CGTase activity was found to be 495 μg β-CD/(ml min). The enzyme was partially purified by 40–60% ammonium sulfate precipitation. The enzyme was immobilized by sodium alginate beads and kinetic studies were performed. The enzymatic activity of both free and immobilized CGTase was highest at temperature 60 °C and pH 7.5. The analysis of kinetic parameters Km and Vmax was obtained by the action of CGTase on the starch with respect to β-CD. The enzyme exhibits substrate inhibition and the values are 10 and 5.5 μg starch/ml for free and immobilized enzyme, respectively. The effect of salt concentration on enzyme activity was studied and it was found that Cu2+, Fe2+, Zn2+, Co2+, Mg2+ and Hg2+ were inhibitory, however Ca2+ showed a relative increase in enzyme activity. The immobilization of the enzyme showed a high operational stability by retaining almost 75% of the initial activity after seventh use.
