Isolation and identification α-Naphthol-degrading bacteria from oil-contaminated soils of Masjed-e-Soleyman

Abstract

Introduction: α-Naphthol is a two-ring aromatic hydrocarbon that is a toxic compound for all organisms in different ecosystems. Bioremediation technology for remediating PAH-contaminated sites has been proposed to be an efficient, economical and versatile alternative compared with physicochemical methods. Materials and Methods: In this study, the basal salt medium was prepared and then α-Naphthol was added with the concentration of 100ppm. α-Naphthol was a sole source of carbon for the growth of bacteria. Eventually, the medium was inoculated with the soil samples collected from polluted region and incubated for six weeks. Bacteria were isolated using double-layer BSM-agar containing the α-naphthol concentration of 200ppm. The degradation rate of α-naphthol and the other PAHs were determined using HPLC and the effective isolate was finally identified using biochemical and ‏molecular methods. Results: In this study, two isolates (N1 and N2) were isolated that were able to utilize α-Naphthol as a sole source of carbon. The isolate N1 could degrade α-naph‏thol by 80.5%. Moreover, it was effectively able to degrade the other PAHs than the isolate N2, therefore, it was selected as an efficient isolate. The isolate N1 was identified as Psuedomonas putida UW4 with respect to its 16S rDNA sequence and using biochemical tests. Discussion and conclusion: The isolate N1 could degrade α-naph‏thol by 80.5% from BSM medium at 30° C, pH 7.0 and the α-naph‏thol concentration of 100ppm in fifteen days of incub‏a‏tion. According to the results, the isolate N1 can remove a large amount of the α-naph‏thol from BSM medium under the mentioned conditions and it is possible that under a similar situation the isolate N1 can remove a large amount of α-naph‏thol.

Keywords

• α-Naph‏thol
• Psuedomonas putida
• PAHs
• Masjed-e-Soleyman