Detection of polychlorinated biphenyl-degrading bacteria in soil

摘要

This work is based on research which focuses on the study of the possible mutual relationship of microorganisms and plants in PCB metabolism. Three different plant species - Nicotiana tabacum (tobacco), Solanum nigrum (black nightshade) and Medicago sativa (alfalfa) - were cultivated in real soil from an industrial site. After six months the decrease of PCB content in soil and the PCB accumulation in plant tissue was analysed. The highest decrease of PCB concentration was measured from the soil vegetated with tobacco. From this polluted soil, bacteria which potentially participate in the biodegradation of PCBs were isolated and were screened for the presence of bphA1 and bphC genes. These genes are a part of the bph operon, which is very important for PCB degradation. The PCR primers were designed for conserved regions of bphA1 and bphC genes from an alignment of previously published sequences. The degradative capabilities of the isolates were confirmed by growing in the presence of biphenyl as a cosubstrate. For the extraction of DNA directly from soil a commercial DNA purification kit and a laboratory-devised method based on mechanical lysis were used.