抄録
Bacterial population in mixed culture is evaluated from the property of removal activity of selected substrates in considering of the substrate interaction. When the substrate interaction does not occur in removal of the mixture of two substrates, i. e., the TOC removal rate of the mixture is shown by the summation of the TOC removal rate of each substrate, it is recognized that there are two kinds of bacteria which uptake different substrates, respectively. When this interaction occurs, i. e., the TOC removal rate of the mixture is shown by the TOC removal rate of one of substrates, it is recognized that identical bacteria uptake one of two different substrates each other. The concept of the substrate interaction is also valid from the respiration rate of mixed culture. The activated sludge acclimated with acetate is composed of three kinds of bacteria which uptake acetate, glucose and medium-chain saturated fatty acids, respectively, however medium-chain fatty acids such as butyrate, valerate and caproate, are uptaken by identical bacteria.
