Energy-dependent accumulation of particulate biosurfactant by Pseudomonas marginalis

The amount of particulate lipopolysaccharide-containing polymeric biosurfactant PM-factor formed by Pseudomonas marginalis was proportional to the amount of biomass produced. Specific production of PM-factor by growing cells was independent of the substrate used as carbon source and of hydrocarbons added to the growth medium. Rifamycin and chloramphenicol did not influence extracellular surfactant accumulation. Respiratory inhibitors (cyanide and azide), uncouplers of oxidative phosphorylation (carbonylcyanide m-chlorophenylhydrazone), and an ion conductor (gramicidin D) strongly suppressed PM-factor accumulation in the culture broth. Inhibitors of H+-ATPase (dicyclohexylcarbodiimide) and glycolysis (fluoride) did not affect PM-factor accumulation. These observations suggest that PM-factor is released into the surrounding medium by an energy-dependent mechanism.