Operation by Fluid Viscosity and Temperature

Satoh (1961) has studied the rheological properties of kanamycin fermentation broth which displayed typical Bingham behaviour in the course of fermentation, so that it became difficult to disperse the nutrients uniformly and to supply oxygen to the microbial population. 

When a kanamycin broth was diluted with 5% by volume of sterile water to reduce the viscosity, the yield increased by 20%. Therefore, it may be possible to improve the performance of a fermentation by controlling its viscosity on the basis of an understanding of the rheological properties of the fermentation fluid. 

An investigation was made of the influence of temperature on the rheological properties of kanamycin fermentation by Satoh (1963), and the method of reducing viscoelasticity was applied to a non-Newtonian fluid. Andrade (1930) obtained already the following relation between the viscosity and temperature using the energy barrier theory. 

On the othw hand, Owen and Johnson (1955) have reported on the effect of temperature changes on the production of penicillin, and it was found that 50% more penicillin was produced by fermentations started 

Here we have apparent discrepancies between the results of two studies. The organisms employed differ markedly in oxygen and nutrient requirements as well as in antibiotic production. Furthermore, the morphological changes arising from agitation result in broths markedly different in their physical characteristics, and it is also extremely difQcult to compare the aeration efficiencies at each stage of two fermentations. 

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