Structural analysis of macromolecular levan produced by Bacillus megaterium GJT321 based on enzymatic method.

Extracellular polysaccharide (EPS) produced by Bacillus megaterium GJT321 was isolated from fermentation broth and further purified by gel filtration chromatography. The molecular weight of EPS was estimated as 1946kDa by gel permeation chromatography (GPC), so this EPS was determined as macromolecular polysaccharide. Fourier transform infrared spectrometry (FT-IR) showed that the kind of heterocyclic compound composing EPS was furanose. The structural characteristics of EPS were investigated by means of enzymatic method, electrospray ionization mass spectrometry (ESI-MS) and NMR spectra analysis. The structure elucidation of the EPS was accomplished, and it was β - (2, 6) -D- fructofuranose, namely levan.