Characterization of extracellular polymeric substances produced by micro-algae Dunaliella salina

Extracellular polymeric substances comprised of average molecule size 1264.354 μm, exhibited characteristic diffraction peaks at 6.025°, 9.675°, 22.775° and 28.475° with d-spacing 14.74755, 9.36297, 3.88747 and 3.11512 Å, respectively. EDX confirms the presence of sulphate (2.7%) and 1H NMR reveals uronic acid, primary amine, aromatic-compounds, halides, aliphatic alkyl and sulfides. EPSs were thermostable upto 270 °C with CIxrd 0.12 and CIDSC 0.18. The dynamic viscosity is significantly high at pH 3.0 and decreases concomitantly with shear rate, confirming pseudoplastic rheological property. MALDI TOF–TOF represents a series of masses in linear mode corresponding to mass of pentose and hexose with ions. The positive ion reflector mode exhibited low mass peaks (m/z) corresponding to oligosaccharide and higher peaks for polysaccharide consist of different ratio of pentose and hexose associated with ions. EPSs allow further exploration of D. salina as potential EPSs producer and make it a promising candidate for biotechnological and industrial exploitation.