Isolation and identification of PCB-degrading microorganisms from contaminated sediments

PCBs represent a serious ecological problem due to their low degradability, high toxicity, and strong bioaccumulation. The goal of this study was to analyze the PCB-contaminated sediments from Strazsky canal and Zemplinska sirava water reservoir from several points of view. The study of ecotoxicity confirmed that both sediments were toxic for various tested organisms. The genotoxicity test has not proved the mutagenic effect. The subsequent step included microbiological analysis of the contaminated sediments and isolation of pure bacterial cultures capable of degrading PCBs. In order to determine the genetic potential for their biodegradability, the gene bphA1 encoding the enzyme biphenyldioxygenase, responsible for the first step of PCB aerobic degradation, was identified using a PCR technique. The ultimate goal of the work was to perform aerobic biodegradation of PCBs in the sediments. The bacteria present in both sediments are able to degrade certain low chlorinated congeners. The issue of biodiversity is still open and has to be studied in more detail to reveal the factual interactions between bacteria. (C) 2008 Elsevier Ltd. All rights reserved.