Purification and characterization of beta-fructofuranosidase from Aspergillus japonicus TIT-KJ1.

A beta-fructofuranosidase (EC 3.2.1.26) was purified to homogeneity from Aspergillus japonicus TIT-KJ1. The enzyme had an optimum pH for activity of 5.4 and pH stability at 7.0-8.4. The optimum temperature at pH 5.4 was 60 degrees C. The enzyme had a molecular weight of 236,000 with two subunits and an isoelectric point of pH 4.0. The enzyme was inactivated by 5 mM Hg2+ and Ag+. The enzyme had a high transfructosylating activity. Treatment of 50% (w/v) sucrose with the enzyme under optimum conditions afforded more than 55% fructooligosaccharides.