Purification and properties of beta-cyclomaltodextrin glucanotransferase from Bacillus flexus SV 1

Cyclomaltodextrin glucanotransferase is a unique enzyme that degrades starch into cyclic oligosaccharides called cyclodextrins, which have numerous applications in various industries such as pharmaceutical, textile, agricultural, cosmetics etc. Due to its wide applications, microorganism producing one type of cyclodextrin is of interest as it simplifies the down streaming process of separating mixture of cyclodextrins. In the present study, β-CGTase was isolated from Bacillus flexus SV 1 and biochemically characterized. Enzyme was purified by starch adsorption followed by DEAE cellulose column chromatography which resulted in a fold purification of 6.1, with a yield of 44.07%. Molecular weight of the purified enzyme was found to be 96.68 kDa, enzyme was monomeric in nature with a K_m and V_max of 0.08976 μmol mL^-1 and 585.1 μmol/ml/min, respectively. Optimum pH and temperature of the purified enzyme was found to be 8.0 and 60 °C. Ca²⁺ showed significant increase in enzyme activity. The inhibition of enzyme by EDTA indicates that CGTase is a metalloenzyme. CGTase produced majorly β-CD and was alkalotolarent and active at high temperatures which is a promising candidate for various industries such as textile, food, agriculture, and pharmaceuticals.