Biodegradation of anthracene by Bacillus sp. in wastewater contaminated with polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are one of the most important pollutants that majorly originate from industrial production, transportation, refuse burning, gasification and plastic waste incineration and therefore must be degraded or removed. One of the safest and cheapest methods is the utilization of biologic processes such as bioremediation. In this method, microorganisms are employed to remove or reduce the pollutants toxicity. Bioremediation of anthracene as one of the tricyclic PAHs by a local bacterium that was isolated from wastewater of oil tankers station was investigated in this study.
Inorganic basal medium containing anthracene as the sole source of carbon and energy, biochemical tests and 16s rDNA gene analyses were applied respectively for bacterium isolation and identification. In wastewater analysis, the parameters such as total petroleum hydrocarbons (TPHs), aromatic hydrocarbons and biological oxygen demand (BOD) were measured. For anthracene degradation, different concentrations of anthracene (100, 150, 200, 250, 300 and 350 mg/l) were used. Gas chromatography (GC) and Gas chromatography-mass spectrometry (GC-Mass) were applied to determine anthracene residue and metabolites from anthracene degradation, respectively.
The current study showed the ability of Bacillus sp. Caspian1394to grow in wastewater and tolerate PAH pollutants with high concentration and also degrade anthracene. This bacterium degraded 100 and 350 mg/l concentrations of anthracene with 99.5% and 3.4% efficiency, respectively. Some of the metabolites derived from anthracene degradation were 1,4-methanoazulene, 2,5-cyclohexadiene, hexadecane, heptadecane, ocadecane and eicosane
Discussion and The studied bacterial strain can grow in wastewater with high contamination to hydrocarbons and tolerate high concentrations of different PAHs. It is a spore forming bacterium leading to its resistance to unfavorable conditions and also dispersion in different environments. Then, it can be proposed as a candidate in bioremediation of environments contaminated with anthracene.