Isolation and Characterization of Polyromatic Hydrocarbon Bacteria from Contaminated Site

Abstract: Polyaromatic Hydrocarbons (PAH) are considered as Priority Pollutants in ecosystem. Bioremediation is the strategy for PAH removal because microorganism can metabolize PAHs to inert substances, CO2 and Water. Three PAH degrading bacteria were isolated from soil sample contaminated with PAH containing waste by enrichment culture method using naphthalene as the sole source of carbon and energy. The isolates were characterized by a various phenotypical, morphological and biochemical properties and were found to belong to genera Pseudomonas. Of the three isolates, two of them were identified as Pseudomonas aerugenosa. Effect of two different soluble forms and concentrations of iron significantly affected growth of bacteria in presence of aromatic compounds because it is a co-factor for the enzymes involved in biodegradation pathway. Chemotaxis, the ability of bacteria to sense and locate particular carbon source, was tested with a swarm plate assay method and all the isolates were found to be chemotactically attracted to naphthalene. Carbon source utilization was studied by growing the isolates on various PAHs and measuring the growth of the culture by reading an absorbance at 600 nm. Also, plasmids profiles of the three isolates revealed the possibility of presence of multiple plasmids in two of the isolates that were identified as Pseudomonas aerugenosa and a single high molecular weight plasmid in other isolate belonging to genera Pseudomonas.