Stabilization of oil/water emulsions by hydrophobic bacteria

Bacterial degradation of hydrocarbons is a major route for removal of petroleum pollutants from the environment. This process requires interaction between the hydrated microbial surface and hydrophobic hydrocarbons. Even though mechanisms to facilitate contact between hydrocarbons and bacterial surfaces are known, including direct bacterial attachment to the oil/water interface and release of extracellular compounds, the actual mechanism involved in hydrocarbon transport is a debatable issue.; The aim of this study was to determine the relationship between bacterial surface properties, bacterial adhesion to oil/water interfaces and stabilization of emulsions.; It was found that intact bacterial cells were able to stabilize emulsions without changing the interfacial tension, by inhibition of droplet coalescence similar to emulsion stabilization by silica particles. Contact angle measurements revealed values in the range of 40° to 123° and were in qualitative agreement with the stabilized emulsion volumes, which ranged up to 80% of the mixture total volume.