PURIFICATION AND PROPERTIES OF BACILLUS-COAGULANS CYCLOMALTODEXTRIN GLUCANOTRANSFERASE

Cyclomaltodextrin glucanotransferase (CGTase), produced in a culture filtrate by Bacillus coagulans, was purified to a single, homogeneous protein. It has a monomeric structure with a molecular weight of 65,000, isoelectric point of 4.6, and contains 2 mol of Ca2+ per mol of the enzyme. The enzyme was most active at pH 6.0 and at 70-degrees-C. It did not lose its activity by heat treatment at 70-degrees-C for 10 min in the presence of CaCl2 in the pH range of 5.5 approximately 9.5, and by incubation in the pH range of 5.0 approximately 10.5 at 4-degrees-C for one month. The enzyme converted about 60% of potato starch to cyclodextrins for 20 h at 50-degrees-C, and the ratio of alpha-: beta-: gamma-cyclodextrin produced was 8.1:8.9:1.0. B. coagulans CGTase was compared with B. macerans CGTase which was purified by the same method.