Isolation and identification of aerobic polychlorinated biphenyls degrading bacteria

Nabavi, Bibi Fatemeh; Nikaeen, Mahnaz; Amin, Mohammad Mehdi; Hatamzadeh, Maryam

doi:10.4103/2277-9183.122443

Isolation and identification of aerobic polychlorinated biphenyls degrading bacteria

Document Type : Original Article

Authors

Bibi Fatemeh Nabavi

Mahnaz Nikaeen

Mohammad Mehdi Amin

Maryam Hatamzadeh

Environment Research Center, Isfahan University of Medical Sciences (IUMS), Isfahan and Department of Environmental Health Engineering, School of Health, IUMS, Isfahan, Iran

10.4103/2277-9183.122443

Abstract

Aims: The purpose of this study was to isolate and identify aerobic polychlorinated biphenyls (PCBs) degrading bacteria. Materials and Methods: This study was performed in lab scale aerobic sequencing batch biofilm reactor. Polyurethane foams were used as bio-carrier and synthetic wastewater was prepared with PCBs in transformer oil as the main substrate (20-700 μg/l) and acetone as a solvent for PCBs as well as microelements. After achieving to adequate microbial population and acclimation of microorganisms to PCB compounds with high efficiency of PCB removal, identification of degrading microbial species was performed by 16s rRNA gene sequencing of isolated bacteria. Results: Gene sequencing results of the isolated bacteria showed that Rhodococcus spp., Pseudomonas spp., Pseudoxanthomonas spp., Agromyces spp., and Brevibacillus spp. were dominant PCB-degrading bacteria. Conclusion: PCB compounds can be degraded by some microorganisms under aerobic or anaerobic conditions or at least be reduced to low chlorinated congeners, despite their chemical stability and toxicity. Based on the results of the study, five bacterial species capable of degrading PCBs in transformer oil have been identified.

Keywords

Aerobic bacteria

biodegradation

polychlorinated biphenyls