EFFECT OF A LIQUID-LIQUID INTERFACE ON THE METABOLIC ACTIVITY OF ESCHERICHIA COLI

Abstract

This is a report on whether and in what manner the metabolic activity of Escherichia coli is affected when liquid normal alkanes such as hexane, octane, decane to hexadecane and octadecane are dispersed in the cell suspension. Among these alkanes, dodecane, tridecane and tetradecane markedly enhanced the respiratory activity and depressed the rate of glucose uptake. The other alkanes did not show such marked effects. The ratio of glucose metabolized by respiration (respiratory ratio), calculated from the amount of oxygen and glucose taken up by E. coli, was inversely proportional to the rate of glucose uptake. The number and the activity of the cells adsorbed to these alkanes were too small to be detected. These effects of the alkanes on the activities of the organism were reversible as indicated by their disappearance after the removal of the alkanes from the cell suspension. Consequently the organism received these effects reversibly from the interface between the alkanes and the cell suspension. These results coincide with those obtained with solid hydrophobic materials (1).
A notable relation was found between the interface effect and the surface tension of the alkanes, in which the interface effect has a maximum at the tension of 24-26dyn/cm.