novel flocculant biopolymer produced by Pestalotiopsis sp. KCTC 8637P

A white rot fungus was isolated from rolled leaves and identified as Pestalotiopsis sp. KCTC 8637P. It produced a flocculant biopolymer. A flocculant was partially purified from the culture broth by series of precipitations with 95% ethanol and named as Pestan. The components of Pestan were consisted of glucose: glucosamine: glucuronic acid: rhamnose with a approximately molar ratio of 100:3.5:1.6:1.3. In kaolin suspension(final concentration was 4,800 mg/l), the highest flocculating activity was attained at the biopolymer flocculant concentration of 1 mg/l. The flocculating activity was observed most highest by the addition of cationic solutions, especially 8mM CaCl2.2H2O or 8mM FeCl3. The thermal stability of Pestan was sustained up to 70 degrees C.