A novel flocculant biopolymer produced by Pestalotiopsis sp. KCTC 8637P

Abstract

A white rot fungus was isolated from rotted 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 tile addition of cationic solutions, especially 8 mM CaCl2·2H2O or 8 mM FeCl3. The thermal stability of Pestan was sustained up to 70°C.