Rheological studies on Streptomyces fradiae ScF-5 in submerged fermentation.

Studies on the rheology of Streptomyces fradiae ScF-5 in a lo-dm3 submerged
fermenter for the production of intracellular glucose isomerase
revealed that the apparent viscosity of the broth increased with increase in
cell density up to 24 h and then declined while the density of the broth
remained constant. The plot of shear stress versus shear rate at various
fermentation periods showed the applicability of the Casson model. The
yield stress and consistency index were found to increase gradually then
decrease subsequently. In contrast, the flow behaviour index was less than
unity and remained constant throughout the fermentation. The results
contrast with the findings of other workers on the Newtonian and non-
Newtonian character of fermentation broths and the applicability of the
power law model to such systems.