Anthracene degradation by an oligotrophic bacterium isolated from refinery soil

Anthracene is a widespread environmental pollutant with carcinogenic and genotoxic properties. Biodegradation is a simple, cost-effective and safe technique to clean-up contaminated environments. The aims of this study are isolation and characterization of an oligotrophic bacterium with the ability to degrade anthracene and assessment of in vitro biodegradation process. For this purpose petroleum contaminated soil was collected from Isfahan refinery. Soil sample was found to be neutral and slightly saline with high concentration of anthracene. The population of total heterotrophic bacteria and anthracene degrading bacteria were 2.50 × 103 and 1.96 × 103 CFU/g, respectively. Seven anthracene degrading bacteria were isolated using enrichment culture technique in Basal Salt Medium (BSM) supplemented with 50 mg/L anthracene. An oligotrophic bacterium was selected based on growth on carbon free medium. This isolate was identified as Methylobacterium rhodesianum ATAI15, submitted to GenBank under accession number of KC469989.1. The biodegradation rate of 50 mg/L anthracene by this isolate during 9 days was 41.2%, determined by gas chromatography. This bacterium was adapted to survive in nutrient deficient medium and high concentration of anthracene (up to 12000 mg/l). Use of this isolate with other PAH degrading bacteria can be effective in bioremediation of polluted environments.