Novel Polyaromatic Hydrocarbon (PAH) degraders from oil contaminated soil samples

Manuscript History: Background: Polycyclic aromatic hydrocarbons (PAHs) are generally a hazardous class of organic compounds. They may be produced as a result of combustion or pyrolysis of fossil fuels or other organic matter. Microbial degradation is majorly responsible for ecological recovery of PAHs from sites contaminated with it. The present study was conducted to isolate microbial strains capable of degrading naphthalene with the aid of biosurfactant production. Methods: Oil contaminated soil samples collected from Oil and Natural Gas Corporation (ONGC), Karaikal, Tamil Nadu, India were enriched, serially diluted and spread plated in Bushnell Haas (BH) medium with naphthalene as a carbon source. The isolates grown from the enriched samples were further screened for naphthalene degraders and for biosurfactant production by appropriate protocols. Results: A total of 13 naphthalene degrading strains extended among 9 genera namely Morganella, Actionomyces, Pseudomonas, Stenotrophomonas, Bacillus, Corynebacterium, Actinomadura, Serratia and Staphylococcus were isolated from the samples. This is the first report which describes new strains capable of degrading naphthalene. These include species of Actinomadura, Morganella, Stenotrophomonas and Serratia. Morganella morganii subspecies morganii was found to be the best PAH degrader. Strains from the genera Serratia and Stenotrophomonas were identified as the best biosurfactant producers. Conclusion: The isolates obtained were screened for their ability to utilize naphthalene as a sole source of carbon and energy with the aid of biosurfactant production. This confirms high degradative ability and ubiquity associated with these isolates as it concerns biodegradation of both soil and water environments polluted with petroleum and its many products. Further studies in this direction can reveal interesting options in bioremediation of PAH.