Purification and characterization of cycloinulooligosaccharide fructanotransferase (CFTase) from Bacillus circulans MCI-2554.

Cycloinulooligosaccharide fructanotransferase (CFTase) that produces cyclofructan from inulin was purified about 69-fold from a culture broth of Bacillus circulans MCI-2554 by column chromatographies on DEAE-Toyopearl, QAE-Toyopearl, hydroxyapatite, and phenyl-Sepharose. The molecular mass of the enzyme was estimated to be 115 kDa by SDS-polyacrylamide gel electrophoresis and gel filtration, indicating a monomer structure. Maximal activity was observed at pH 7.5 and 45 degrees C. The enzyme was active from pH 5.5 to pH 9.5, and at temperatures up to 45 degrees C. The enzyme activity was inhibited by Fe2+ and Cu2+. A part of the amino acid sequence was identical with that of beta-fructofuranosidases of Zymomonas mobilis, carrot, Salmonella typhimurium, and mung bean.