Bacterial adherence at the hydrocarbon-water interface

Large differences were observed in the ability of eight Acinetobacter calcoaceticus strains to adhere to liquid hydrocarbon. Four strains exhibited extremely high affinity for hexadecane, two strains were moderately adherent and two other strains exhibited low affinity for the test hydrocarbon. Adherence of A. calcoaceticus RAG-1 to hexadecane was a function of culture age and growth conditions. In general, late exponential and stationary phase cells were more adherent than exponential phase cells. A. calcoaceticus RAG-1 cells cultured on hexadecane in flasks were adherent throughout growth. In contrast, a hydrocarbon-degrading strain of Pseudomonas aeruginosa adhered poorly to hydrocarbons, even following growth on hexadecane. Adherence of bacteria to hydrocarbons is discussed in terms of the bacterial cell surface, microbial growth on oil, and microbial contamination of surfaces.