The mode of interaction between the substrate and cell surface of the hydrocarbon-utilizing yeast Candida tropicalis

A method for the measurement of the affinity of the cell surface to hydrocarbons is described. The affinity was basically unaffected by different pH values and temperature as well as by the chain length of the substrate. The contact time required for saturation of the cell surface with substrate was 30 sec. Cells grown on glucose showed a 25% lower adsorption capacity compared to those grown on n-alkane. The glucose grown cells showed also a more distinguished dependence of the amount of adsorbed hydrocarbon on the quality of the emulsion. The interaction between the substrate and cell surface turned out to be an adsorption that did not involve an enzymatic reaction. These results led to the conclusion that a lipopolysaccharide moiety present at the cell surface is responsible for the affinity.