It was studied whether and in what manner various solid-liquid interface affect the metabolic activities of Escherichia coli. Solid materials tested were 5 kinds of organic polymers, 4 kinds of clay minerals and 3 kinds of mineral oxides. Rates of glucose uptake and oxygen consumption by the organism were determined with and without addition of each material. Three of the materials, styrene-divinylbenzene copolymer (SDB), polytetrafluoroethylene (TFE) and pyrophyllite significantly increased the respiratory activity and simultaneously decreased the rate of glucose uptake. Other materials showed weak or no effects. When SDB and TFE were removed from the cell suspension, their effects on the respiration and glucose uptake disappeared immediately. Thus it was apparent that these effects were reversible.
The ratio of glucose metabolized by respiration was inversely proportional to the rate of glucose uptake. This relation is discussed in connection with the interface effect on the organism as a living system.