CHARACTERIZATION OF AN EXTRACELLULAR FLOCCULATING SUBSTANCE PRODUCED BY A PLANKTONIC CYANOBACTERIUM, ANABAENA SP

Two planktonic cyanobacteria, Anabaena sp. N1444 and Anabaena sp. PC-I , and a green eukaryotic alga, Scenedesmus sp,, produced extracellular flocculants. The flocculant of Anabaena PC-I, when purified, was foun d to be a macromolecular polysaccharide consisting of neutral sugars, uronic acids, and proteins, but not keto acids, hexosamines nor fatty acids. The flocculant bound a cationic dye, Alcian Blue, indicating it to be polyanionic. The flocculating activity was high under acidic co nditions, slightly enhanced by the addition of salts and metals, and i ncreased to about 40% upon heating at 100 degrees C for 7 min. The flo cculant could flocculated various inorganic and organic compounds in s olution.