• Applied Biological Chemistry
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• v.39 no.3
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• pp.165-171
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• 1996

The rheological properties of biopolymers produced by Bacillus sp. K-1 and its mutant strains(KM-21, KM-83) were studied. Apparent viscosity of biopolymers decreased as rising the temperature. The biopolymer produced by KM-21 strain showed 1.7 times low viscosity, 2.7 times low viscosity by K-1 and 1.9 times low viscosity by KM-83 at $80^{\circ}C$ compared with at $20^{\circ}C$ respectively. The viscosity of biopolymer solution also increased with increasing the polymer concentration and showed pseudoplastic characteristics which is high temperature dependency in all concentration. The change of the biopolymer viscosity on the pH showed the highest value at the pH 7.0 and it showed lower at acidic condition than at alkaline condition comparatively.