Biotechnology methods for succession of bacterial communities in polychlorinated biphenyls (PCBs) contaminated soils and isolation novel PCBs-degrading bacteria

Polychlorinated Biphenyls (PCBs) are persistence in the contaminated sites as a result of lacking PCBs-degrading microorganisms. Cultivation-independent technique called single-strand-conformation polymorphism (SSCP) based on 16SrRNA genes was chosen to characterize the diversity of bacterial communities in PCBs polluted soil samples. The bacterial communities showed an increasing diversity from the genetic profiles using SSCP technique. 51 single products were identified from the profiles using PCR reamplification and cloning. DNA sequencing of the 51 products, it showed similarities to Acidobacteria, Actinobacteria, Betaproteobateria, Gammaproteobacteria and Alphaproteobacteria, the range of similarities were 92.3 to 100%. Pure 23 isolates were identified from PCBs contaminated sites. The identified isolates belonged to genus Bacillus, Brevibacillus, Burkholderia, Pandoraea, Pseudomonas, and Rhodococcus. The new strains have the capability to use PCBs as a source of sole carbon and harbor 2,3-dihydroxybiphenyl dioxygenase (DHBDO) which could be used as molecular marker for detection PCBs-degrading bacteria in the PCBs contaminated sites. This finding may enhance the PCBs bioremediation by monitoring and characterization of the PCBs degraders using DHBDO in PCBs contaminated sites.