Abstract

In the present paper attempt was made to produce an excipient, β-cyclodextrin from starch by the action of an enzyme cyclodextrin glucosyl transferase. The microbial strain utilized was Bacillus circulans because of its specificity for production of β-cyclodextrin. First the culture was grown under controlled conditions to obtain an enzyme cyclodextrin glucosyl transferase which was isolated and purified. The crude enzyme was employed for bioconversion of starch to β-cyclodextrin. Some parameters like incubation pH, incubation and fermentation time and effect of certain additives like polyethylene glycol and calcium chloride added during incubation were studied to optimize its yield. The maximum yield of cyclodextrin glucosyl transferase was after 36 h of fermentation. β-cyclodextrin yield was found to increase with the increase in incubation period, by the addition of polyethylene glycol 200, polyethylene glycol 400 and at pH 6. The activity and stability of enzyme was found to increase by addition of calcium chloride.