isolation and identification of phenanthrene-degrading endemic bacteria from crud oil contaminated soils around abadan refinery and evaluation of their growth

polycyclic aromatic hydrocarbons (pahs) are one of the most common contaminants found in soil. pahs exhibit a significant concern because of their toxicity, carcinogenic, teratogenic and mutagenic properties. using microorganisms for cleaning the pollution of soil can be cheap, effective and can provide environmental immunity. the goal of this study is to isolate and identify phenanthrene degrading bacteria from contaminated crud oil soils around refinery and evaluation of their growth. the soil samples were collected from three areas around refinery. the numbers of bacteria were counted at the nutrient agar culture with and without  phenanthrene. isolation of bacteria was done by culturing the samples on phenanthrene broth with basic mineral medium, and on phenanthrene agar medium. then, the bacteria were determined by the biochemical diagnosis tests. finally, with the cultivation of bacteria in concentrations of 0.5 to 0.8 g/l phenanthrene, the ability of phenanthrene biodegradation was measured. in this study, the maximum number of degrading bacteria was 8.083±0.10 at c station, and the minimum number of degrading bacteria was 5.442±0.10 at b station. in this study, the bacillus sp, pseudomonas aeruginosa, corinebacterium sp, micrococcus luteus, staphylococcus epidermidis bacteria was isolated and identified, respectively. pseudomonas and bacillus had the most growth and degradation in different concentrations of phenanthrene. the results of this study showed that soil around refinery has lots of phenanthrene degrading bacteria, especially bacillus and pseudomonas.