Characterization of microbial consortia from marine sediments of the Venice lagoon capable of PCB dechlorination.

In this study we investigated how widespread is the capability of bacterial communities from contaminated and not contaminated sediments to degrade different PCBs mixtures. To reach our aim we used a “multilevel approach” that includes the investigation on the functionality and the structure of the microbial community and the detection of strains eventually involved in the degradation process. Samples from different sites of Venice lagoon were used to set up microcosms spiked with mixtures consisting in five coplanar PCBs or Aroclor 1242. Cultivation-independent methods such as LH-PCR (Length Heterogeneity PCR) and DGGE (Denaturing Gradient Gel Electrophoresis) were applied to characterize the bacterial community structure and diversity of the two sets of microcosms. Specific PCR tests were used to search for Dehalococcoides-like bacteria correlated to PCBs dechlorination. In order to give an ecological interpretation to the differences occurring between the bacterial community structure of the two sediments, the Pareto-Lorenz curve interpretation was applied.