Degradation of polycyclic aromatic hydrocarbons (pyrene and fluoranthene) by bacterial consortium isolated from contaminated road side soil and soil termite fungal comb

Polycyclic aromatic hydrocarbons (PAHs) are often present in the environment at concentrations detrimental to both human health and eco-quality. Hence, PAH degradability has been of significant interest, and biological methods seem to be preferred to other options such as chemical oxidation, photolysis and adsorption. Present study was designed to isolate potential PAH-degrading bacteria from termite fungal comb and road side soil with the aim of evaluating the degradation of fluoranthene and pyrene using the isolated microbes. Therefore, 97-99 % pure PAHs (fluoranthene and pyrene) were subjected to biodegradation using bacteria consortiums from soil and the termite fungal comb in separate tests. At varying concentrations (50, 100 and 150 mg l(-1)) of both PAHs, amendments characterized of Ralstonia pickettii, Burkholderia cepacia and Pseudomonas resinovorans from road side soil reduced fluoranthene more than Ochrobactrum sp. and Pseudomonas sp. isolated from termite fungal comb. The overall comparison of the PAH degradation showed that the microbial consortium degraded pyrene more than fluoranthene. However, the efficiency of the biodegradation tests on fluoranthene and pyrene was < 50 %. The study inferred that isolated bacterial species from termite fungal comb and road side soil when used as consortium can remedy contaminations attributed to more than one PAH. But the degree of degradation by bacteria species may depend on the source of isolation.