University Of Tehran Press Pollution 2383-451X 3 1 2017 01 01 Biodegradation of polycyclic aromatic hydrocarbons by Pseudomonas species 9 19 59566 10.22059/poll.2017.59566 EN Imaneh Amini Department of Microbiology, Islamic Azad University, Falavarjan Branch, Falavarjan, Isfahan, Iran Arezoo Tahmourespour Department of Basic Medical Sciences,Islamic Azad University, Khorasgan Branch, Isfahan, Iran Atousa Abdollahi Department of Basic Sciences, Islamic Azad University, Khorasgan Branch, Isfahan, Iran Journal Article 2016 01 27 Biodegradation of polycyclic aromatic hydrocarbons, toxic compounds widely distributed in the environment by bacteria, is a cheap and safe cleaning up method. The present study attempts to isolate and characterize dioxygenase-producing bacteria which are able to degrade phenanthrene and pyrene from refinery soils. It also aims to assess in vitro biodegradation. To do so, two contaminated soil samples were collected from Isfahan-Iran refinery. The population of phenanthrene and pyrene degrading bacteria were 2.17 × 10³ and 1.19 × 10³ CFU/g in sample 1 and  21.50 × 10³ and 19.40 × 10³ CFU/g in sample 2. A sum of 18 phenanthrene and pyrene degrading bacteria were isolated using enrichment culture technique, three of them getting selected which had dioxygenase activity and produced biosurfactant. Identified as <em>Pseudomonas plecoglossicida</em> ATAI18, <em>Pseudomonas aeruginosa</em> ATAI19, and <em>Pseudomonas stutzeri</em> ATAI21, they were submitted to GenBank under the accession number of KF113842, KF113843, and KF113845 respectively. The degradation rate of pyrene (50 mg/L) by strains ATAI18 and ATAI19 was 45.32% and 31.23%, respectively. The strain ATAI21 degraded 39.38% of phenanthrene (50 mg/L) after 9 days. These isolated bacteria can be used to improve microbial population of other hydrocarbon-polluted soils for faster bioremediation of such areas. https://jpoll.ut.ac.ir/article_59566_45a4872a507c6460ebe446fef39c31fe.pdf