Biodegradation of petroleum hydrocarbons by two Pseudomonas aeruginosa strains with different uptake modes.

The uptake modes of alkanes by two strains (Pseudomonas aeruginosa S and Pseudomonas aeruginosa Y) were compared in this article. It was found that the strain of P. aeruginosa S showed low cell surface hydrophobicity and the surface tension of the broth decreased when the strain was cultivated on alkanes. On the contrary, P. aeruginosa Y showed higher cell surface hydrophobicity and the change in surface tension was not significant. This suggests that P. aeruginosa Y accessed hydrocarbon droplets by direct contact mode, while P. aeruginosa S engaged hydrocarbon droplets by biosurfactant-medium mode. The biodegradation of petroleum hydrocarbons by the two strains was also investigated. The results showed that irrespective of the substrate utilized: liquid hydrocarbons, solid hydrocarbons or crude oil in contaminated soil, the degradation by P. aeruginosa S was faster than that by P. aeruginosa Y. It was also deduced that the produced biosurfactant is advantageous in improving the biodegradation process.