Determination of cyclodextrin production by cyclodextrin glycosyltransferase from alkalophilic Bacillus circulans strain B-65

New alkalophilic Bacillus sp. producers of cyclodextrin glycosyltransferase (CGTase) were isolated from 54 different soil samples (Serbian springs and soils). Amylolytic activity of isolates was found to be in the range of 0.4 to 12.2 U/mL and cyclodextrinogenic activity in the range of 0.02 to 0.53 U/mL. The isolate designated as B-65 showed the highest amylolytic and cyclodextrinogenic activity. On the basis of morphological, physiological and biochemical characteristics, isolate B-65 was identified as an alkalophilic Bacillus circulans strain. Cyclodextrinogenic and amylolytic activity
gradually increased over 96 h of incubation in a laboratory bioreactor. After 30 h of incubation,
CGTase converted 40% of starch to cyclodextrins (CDs), whose final concentration reached 20 g/L.
Analysis by HPLC revealed b-, a- and g- cyclodextrins with relative abundances of 95, 3 and 2%, respectively.