Rheological properties of extracellular polysaccharide, pestan, produced by Pestalotiopsis SP

The fluid behaviour of Pestan produced from Pestalotiopsis sp. KCTC 8637P was as a non-Newtonian fluid. The rheological behaviour of Pestan solution was examined by Power-law model, Herschel-Bulkley model and Arrhenius equation. As the result, Pestan solution was pseudoplastic behaviour with yield stress. According to increase of Pestan concentration, its flow index was decreased. Thus, low concentrations of Pestan solution were well exposed pseudoplastic property. Apparent viscosity of 0.2% Pestan solution was 268.2 cP at 14.3 sec super(-1) and was higher about 2.8 times than that of Xanthan gum solution. Apparent viscosity of Pestan solution was stable over a wide pH and was maximum at pH 8. Also, consistency index of Pestan solution was very stable over wide temperature than that of Xanthan gum solution (DBO).