Isolation and identification of benzene-degrading bacteria from oil polluted soils of Maroon II oil field (Omidieh) and their growth kinetics assay

Benzene is a one of toxic hydrocarbon in the environment that is absorbed effectively through breathing and also causes heart diseases and cancer. The purpose of this study is isolation and identification of benzene-degrading bacteria from Maroon II oil field and assays their growth kinetics Soil samples were collected from 3 polluted stations of Maroon II oil field. The numbers of bacteria were counted in the nutrient agar medium with and without benzene. Isolation of bacteria was done by culturing the samples on the benzene broth with basal mineral medium and culturing on benzene agar medium. Then, bacteria were identified by usual biochemical tests. Finally, the kinetic growth of the isolated bacteria was evaluated during one week. Logarithmic average number of benzene degrading bacteria, in different stations showed the maximum and the minimum number of bacteria was in station B and A respectively. Bacillus sp, Corynebacterium sp, Staphylococcus sp, Pseudomonas sp, Micrococcus sp bacteria were isolated and identified as benzene degrading bacteria. Bacillus and Corynebacterium bacteria showed the best growth with 0.8 g/l benzene during third and fourth days of incubation. Results indicated Maroon II oil field has lots of benzene degrading bacteria, especially Bacillus and Corynebacterium. With providing optimum growth condition for these bacteria, they can be used for bioremediation of dangerous pollutant such as benzene.