Bioremediation of Polycyclic Aromatic Hydrocarbons by Bacillus Licheniformis ATHE9 and Bacillus Mojavensis ATHE13 as Newly Strains Isolated from Oil-Contaminated Soil

Abstract

Removal of Polycyclic Aromatic Hydrocarbons (PAHs) from the environment is important because of their potentially deleterious affect human health. Biological methods that was applied in the present study is typically contain microbial processes. It is the most innocuous and effective solution that transform pollutant to nontoxic or less toxic substances. The objectives of the present study are enrichment, isolation and identification of PAHs degrading bacteria from oil-contaminated soil by molecular detection methods. Eight indigenous bacteria were isolated from oil-contaminated soils by using the enrichment methods. Two isolates with the highest optical density potentials were selected in media with 12.8 mg. L-1 of 16 PAHs as the sole source of carbon. They were identified as Bacillus licheniformis ATHE9 and Bacillus mojavensis ATHE13 by subjected to polymerase chain reaction with 16SrDNA primer and biochemically characterized. The bacterium strain including Bacillus licheniformis ATHE9 was isolated and removed by Acenaphtylene, Acenaphtene and Indeno pyrene in 72, 96 and 96 hours, respectively. The Bacillus mojavensis ATHE13 could remove Naphthalene in 72 hours and Acenaphtene, Acenaphtylene, Benzo(ghi)prylene, Dibenzo(ah)anthracene and Indeno pyrene in 96 hours. The results of this study strongly indicate that some of the indigenous bacteria have the potential role to remediate polycyclic aromatic hydrocarbons from oil-contaminated sites. These bacterial strains were able to grow in media with 12.8 mg. L-1 of 16 PAHs and reach the stationary phase. The results showed that using native bacteria with PAH-utilizing capabilities in contaminated sites could be useful for removal of these compounds from the environment.