Exo-fructosidase that can hydrolyze both levan and inulin, leading to the production of free fructose. Is also able to hydrolyze sucrose and to a small extent raffinose, but not melezitose, stachylose, cellobiose, maltose, and lactose. Hydrolysis of terminal, non-reducing (2->1)- and (2->6)-linked beta-D-fructofuranose residues in fructans. Is completely inhibited by Ag(+) and Hg(2+) ions. Optimum pH is 5.5 for inulin hydrolysis. Optimum temperature is 55 degrees Celsius for inulin hydrolysis. Is rapidly inactivated at 60 degrees Celsius. High stable at 50 and 55 degrees Celsius. Induced by low concentrations of fructose, but not by sucrose. Repressed by glucose or high concentrations of fructose. Levanase cannot be detected in the wild-type B.subtilis but is mostly secreted into the culture medium by SacL mutants, especially at the end of the exponential growth phase. Belongs to the glycosyl hydrolase 32 family.