Oscillation of Filamentous Bacterium Sphaerotilus sp. in Continuous Culture

概要

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In pure continuous cultures of the filamentous bacterium Sphaerotilus sp. strain F6,which had been isolated from filamentous bulking activated sludge, periodic increases and decreases of biomass concentration were observed under a dissolved oxygen concentration close to the air saturation. At the same time, the pH and the dissolved oxygen concentration fluctuated periodically. The oscillation was not observed when the dissolved oxygen concentration was less than 1 mg/l or when the pH was controlled at 6.5. A time lag of the growth response was observed when the controlled pH value was changed from 6.5 to 5.5. In batch cultures with a glucose-containing medium, pyruvic acid was produced, and the pH was reduced from 7 to nearly 5. The pyruvic acid concentration also fluctuated with the oscillation of the cell concentration.From these results, a mathematical model was developed to describe this phenomenon. This model was made up of descriptions of the pyruvic acid production, the pH lowering by it, and the time lag of the growth response behind the pH change : that is the product inhibition model. The oscillatory phenomenon could be well simulated by this model.
公益社団法人日本生物工学会の論文
1984-10-25