Abstract: A polychlorinated biphenyls-degrading DN2，which can use biphenyl as the sole carbon source and energy, was isolated from the long-term PCBs-contaminated soil by enrichment in the soil first. According to 16S rDNA sequence analysis results，the strain was identified as Pseudomonas sp preliminarily. This pure strain was tested for biodegradation of several different PCBs by grew cells with transformer oil as food. The results showed the isolated strain degraded up to 67% of 10 mg/L Aroclor 1242. The bphA1 gene core, encoding the catalytic site of the large subunit of biphenyl dioxygenase, was also detected by PCR amplification and confirmed by DNA sequencing. It’s also showed Glu-X3-4-Asp-X2-His-X4-5-His domain existed in its constitution by bphA1 gene core.

Key words: PCBs, biodegradation, bphA1, Pseudomonas