Physicochemical properties of a high molecular weight levan from Brenneria sp. EniD312

A high molecular weight levan was produced by a novel levansucrase and some properties of this polymer were investigated. The levan exhibited a poroid microstructure as well as series of individual ellipsoidal or spheroidal particles. The weight-average molecular weight (M¯w) of the levan was determined to be 1.41 × 108 Da. In a 0.1% solution, the levan showed a mean diameter of 176 nm, while in a 1% solution the diameter was 182 nm. The decomposition temperature was determined to be 216.67 °C, with an endothermic peak at 147.41 °C and a melting enthalpy of 76.9 J/g. The small angle X-ray diffraction pattern showed a distinctive peak pattern between 15° and 40° (2q). The levan solution showed a shear-thinning behaviour. These results suggest this levan could be a good additive in the food processing industry, as well as an important bio-based material in the medicinal or chemical industry.