Naphthalene Biodegradation by Novel Soil Isolate of Vehicle Service Station Sites

Abstract:-New bacterial strains were isolated, identified and screened for their naphthalene degradation ability from the soil contaminated with oil (lubricating oil, petrol and diesel etc.) of 3 different vehicle service station sites of Chandigarh, India. Enriched media (0.5% peptone and 0.1% w/v naphthalene in basal salt mineral medium) was used to isolate the naphthalene degrading bacteria and the concentration of peptone was decreased to 0.25g, 0.1g and to 0.0g during successive enrichments. After one month of enrichment, out of the total 59 strains screened, only 3 strains were found to be potent naphthalene degrader. These 3 strains were further sub-cultured for 10 days and on the basis of naphthalene degradation (in percent), strain IR1 was found to degrade 74.8% naphthalene supplemented in BSM medium at 0.1% concentration (w/v) as sole source of carbon and energy and was identified as Pseudomonas sp. Antibiotic sensitivity test revealed that the strain IR1 – Pseudomonas sp. was resistant to cefadroxil and ampicillin among the seven antibiotics tested. Plasmid curing of the isolate lead to complete loss of plasmid and the naphthalene degradation activity suggesting that the plasmid could have a role in naphthalene degradation activity.

Key words: naphthalene, Pseudomomas sp., degradation, antibiotic, plasmid curing.

I. INTRODUCTION

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds containing carbon and hydrogen, composed of two or more fused aromatic rings in linear, angular and cluster arrangements. Polycyclic aromatic hydrocarbons (PAH) comprise a substantial fraction of petroleum mixtures, including crude oils, coal tar creosote, and refined fuel mixtures such as diesel. Soil is a valuable resource as it regulates biogeochemical cycles, filters and remediates pollutants and enables food production. As such, their presence in soil makes biodegradation of these compounds a prime concern (Miya and Firestone, 2000). PAHs are ubiquitous in the environment and cause great environmental concern because they are persistent, mutagenic and can be toxic and/or carcinogenic and as such PAH contamination is of ecological and human health concern (Juhasz and Naidu, 2000; Sverdrup et al., 2002).
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