Dilute solution viscosity of red microalga exopolysaccharide

摘要: The red microalga Porphyridium sp (P. sp) is encapsulated in a sulphated polysaccharide. external part of this capsule dissolves the growth medium. This extracellular polysaccharide heteropolyelectrolyte with molecular weight ∼ 6 × 106 Da. effect solvent, counterion and pH on chain flexibility structural features dilute solution exopolysaccharide was investigated by intrinsic viscometry. From dependence viscosity [η] ionic strength, it estimated that stiffness P. chains same range as xanthan DNA. found to be specific dependent type valence counterion. polyelectrolyte behaviour polymer confirmed decrease addition salt without any observable order-disorder conformational transition aqueous solutions commonly used strength (0.01–1.0). At considerably lower (<0.01) there an indication polyion conformation, most likely reflecting contraction from highly stretched stiff, wormlike chain. It hypothesized overall biopolymer molecules adopt stiff ordered conformation solution.