Isolation and characterization of exopolysaccharides from seaweed associated bacteria Bacillus licheniformis

In the present study, EPS secreted by the endophytic bacterium Bacillus licheniformis was isolated and characterized. The molecular masses of the EPS were 1540 and 44,565 kDa and 1H NMR, FT-IR and UV–Vis spectral analyses revealed prevalence of characteristic primary amine-group, aromatic-compound, halide and aliphatic alkyl-group in addition to Na, P, Ca, C, O, Cl and S as inferred from EDX analysis. XRD and DSC analysis confirmed the amorphous nature of EPS, showing an average particle size of 24.977 μm (d 0.5) with 191 nm average roughness. The positive ion reflector mode of MALDI TOF-TOF MS exhibited a series of low and high mass peaks corresponding to various oligosaccharides and polysaccharides respectively. Further, GC–MS analysis revealed its four monosaccharide constituents glucose, galactose, mannose and arabinose. The potential heterogeneous properties of EPS as revealed in the present study may be explored in various biotechnological and industrial applications.