[Levan synthesis by a Bacillus sp. culture].

A strain of Bacillus sp. was isolated which is an active producer of levan. The dynamics of the polysaccharide biosynthesis was studied depending on concentrations of sucrose in the medium. The amount of the synthesized levan was proportional to the concentration of sucrose ranging from 0.2 to 6%, being a maximum of 28.2 mg/ml in the medium containing 12% of sucrose. The presence of urea or ammonium sulfate in the medium stimulates the levan biosynthesis. A medium with pH 6.0--6.8 is optimal for the polysaccharide formation. Levan, synthesized by Bacillus sp., is a polysaccharide with the molecular weight more than 2 mln. Levansucrase is an induced enzyme, whose inductors are sucrose and raffinose.