Biosynthesis of levan and a new method for the assay of levansucrase activity

Abstract

The polysaccharide levan was synthesized in a solidified agar medium containing sucrose as a source of fructose. The biosynthesis was achieved by the enzyme levansucrase (2,6-fructan–d-glucose 6-fructosyltransferase, EC 2.4.1.10), a small quantity of which was placed in circular wells cut in the agar gel. The enzyme slowly diffused through the agar–sucrose medium and the synthesis of levan was observed as circular white areas, the size of which was dependent on the time of incubation and the concentration of enzyme used.