Fructosyltransferase that catalyzes the polymerization of the fructose moiety of sucrose to produce levan polymer and the fructo-oligosaccharide (FOS) 1-kestose. Is also able to convert raffinose into a fructan polymer and a single oligosaccharide (most likely Gal-Glc-Frc-Frc) in vitro; however, L.gasseri strain DSM 20077 is unable to ferment raffinose. Also displays sucrose hydrolase activity. [6)-beta-D-fructofuranosyl-(2->](n) alpha-D-glucopyranoside + sucrose = [6)-beta-D-fructofuranosyl-(2->](n+1) alpha-D-glucopyranoside + D-glucose Calcium ions are required for optimal activity, but do not seem to be essential since addition of EDTA causes only a 48% drop in activity. Optimum pH is 3.5-4.5. Optimum temperature is 55 degrees Celsius. Activity drastically decreases at 60 degrees Celsius. Belongs to the glycosyl hydrolase 68 family.