Abstract: Objective: Comparison of physical and chemical characteristics between intracellular and extracellular polysaccha- rides extracted from Microcystic aeruginosa was studied in order to be availably used as profitable resource. Methods: IAPS and EAPS were obtained by different methods of extraction, isolation and purification. HPLC, UV, IR, and 13CNMR etc. were used for the analyses of molecular weight, monosaccharide constituents and spectroscopic characteristics of IAPS and EAPS. Results: The mean molecular weight of IAPS (2.0025×105D) was heavier than that of EAPS (2.0025×105D). IAPS consisted of 12.75% uronic acid while EAPS I consisted of 10.74% uronic acid. The monosaccharide constituents of IAPS are D(+) xylose (31.8341%), D-rhamnose (33.0053%), D-galactose (4.1284%), L-arabinose (21.8689%) and those of EAPS are D(+) xylose (9.6549%), D-fructose (19.2522%), glucose (71.0930%). Analysis results of IR and 13C-NMR of these two IAPS and EAPS also demonstrate that their structures and monosaccharide constituents are obviously different. Conclusion: The physical character- istics of IAPS and EAPS are different.

Key words: Microcystic aeruginosa, intracellular acidic polysaccharide(IAPS), extracellular acidic polysaccharide(EAPS), physical and chemical characteristics