Degradation of naphthalene by bacterial isolates from the Gol Gohar Mine, Iran

Abstract

Naphthalene is an ubiquitous pollutant of the environment and the biodegradation of this pollutant has been receiving constant scientific consideration. The aim of this study was to isolate and identify bacteria that could degrade naphthalene from three regions of the Gol Gohar Mine at Sirjan, Iran. In this study, the total naphthalene degrading bacteria were quantified with the most probable number (MPN) and the colony forming unit (CFU) methods. The results showed that most of the bacteria communities capable of degrading naphthalene aggregated in the (WG) site. Among 22 isolated bacteria, seven strains were selected for their ability to grow at higher concentrations of naphthalene (300 and 400 mg/l) and biochemical characteristics. Finally, two strains named isolates 72N and 79N were selected for analysis of the 16S rRNA sequences. Strain 72N was identified as Pseudomonas fluorescens AHB72N and strain 79N was shown to be related to Pseudomonas gessardii AHB79N. The results of biodegradation tests showed that these two strains could degrade 600 mg/l naphthalene in 7 days. The results indicated that strain 79N showed higher potential for removing naphthalene than strain 72N. Practical application of bacterial strains for the degradation of naphthalene from the industrial zones opens interesting prospects. The results of this study provide useful information in evaluating naphthalene degraders isolated from wastewater and industrial sites.