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.
ACKNOWLEDGMENT
This research was financially supported by the National Natural Science Foundation of China (30370049).