Abstract: The crude polysaccharide was extracted from Gracilaria Lemaneiformis with hot water and was then purified by DE-22 and Sephadex G-200 column chromatograph. The purified polysaccharide contained little sulfate. Its homogeneity was identified with Q-Sepharose column chromatography. The ultraviolet spectrum showed that there are no protein and nucleic acids in the purified polysaccharide. The infrared spectrum indicated that there are special absorption of 3,6-anhydro-galactose and very little sulfate absorbance peaks. There are two weight loss courses during the increasing temperature from 0 to 700 ℃, while there is a transition course from double helix structure to random coil with increasing temperature in the polysaccharide solution.

Key words: Gracilaria Lemaneiformis, polysaccharide, isolation and purification, characterization