Abstract

Roda F. Al-Thani1, Desouky A. M. Abd-El-Haleem2* and Mona Al-Shammri1

Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were isolated from contaminated soil samples collected from the industrial zone at Umm-Saied city, state of Qatar. Isolation was occurred by enrichment using naphthalene, phenanthrene or anthracene as the sole source of carbon and energy. The isolates were characterized using a variety of phenotypic, morphologic and molecular properties. Three isolates showed the highest growths during screening as demonstrated by the increase in their optical densities (OD600) were selected for further studies. The isolates showed a concentrationdependent growth in all examined PAH-compounds they grew in. There were visible changes in the color of the growth medium of the isolates during their incubation, suggesting the production of different metabolites. Each isolate of them was able to grow on the three tested PAH compounds. Molecular identification of the isolates based on partial 16S rDNA gene sequences assigned them to Pseudomonas geniculata and Achromobacter xylosoxidans, respectively. This study indicates that the contaminated soil samples contain a diverse population of PAH -degrading bacteria and the use of soilassociated microorganisms has the potential for bioremediation of PAH contaminated sites.