In vitro degradation of polycyclic aromatic hydrocarbons by Sphingobium xenophagum, Bacillus pumilus and Pseudomonas plecoglossicida

Polycyclic aromatic hydrocarbons are a class of organic compounds with carcinogenic and genotoxic properties. Biodegradation of such pollutants using microorganisms, especially bacteria, would be a cheap and environmentally safe clean up method. In the present study, a total of 30 anthracene, phenanthrene and pyrene degrading bacteria were isolated from two petroleum contaminated soils in Isfahan-Iran using enrichment technique. Three isolates, showing the highest growth and the lowest pH in their media, were considered as the best hydrocarbon degraders. These isolates were identified to be Sphingobium xenophagum ATAI16, Bacillus pumilus ATAI17 and Pseudomonas plecoglossicida ATAI18 using 16S rDNA gene sequences analyses, and were submitted to GenBank under accession number of KF040087, KF040088 and KF113842, respectively. They were able to degrade 43.31% of phenanthrene, 56.94% of anthracene and 45.32% of pyrene after 9 days, respectively. Strain ATAI18 produced dioxygenase enzyme as an important metabolite for hydrocarbon degradation. The production of biosurfactant was reported positive for both strains of ATAI17 and ATAI18. It was concluded that these three new strains could be used to improve the bioremediation process in a polluted area.

Polycyclic aromatic hydrocarbons; Biodegradation; Sphingobium xenophagum; Bacillus pumilus; Pseudomonas