A novel transfructosylating enzyme, which produces fructo-oligosaccharides from sucrose from Bacillus macerans EG-6 were purified 63.5-fold by ammonium sulphate precipitation (20-60%), CM-Sepharose CL 6B and fast protein liquid chromatographies on Resource Q, Phenyl-Superose HR 5/5 and Mono S (Pharmacia, Uppsala, Sweden). The minimum molecular mass of the purified enzyme was 66 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable at the pH range of 5.0-7.0 and had an optimum pH at 5.0. The optimum temperature for enzyme activity was at 50 degreesC. The oligosaccharide compositions in reaction products were significantly different on using the enzyme obtained from each purification step. For example, crude enzyme unusually produced selectively GF(5)- and GF(6)-fructo-oligosaccharide whereas purified enzyme produced mainly 1-kestose (GF(2)) and nystose (GF(3)) as in the case of other transfructosylating enzymes.