Microbial reductive dehalogenation of aromatic and aliphatic organohalides in marine sediments from Adriatic Sea

Many chlorinated recalcitrant pollutants accumulate in the anoxic layers of sediments due to their hydrophobicity. Organohalide respiring bacteria are able to remove chlorine atoms from such compounds, a process called microbial reductive dehalogenation, transforming these contaminants into less toxic and more easily biodegradable products. The process however has been rarely detected in anaerobic marine sediments under in situ biogeochemical conditions (Zanaroli et al., 2015). In this work, the ability of native microbial populations from Ravenna harbour and Venice lagoon contaminated sediments to perform dechlorination of several organochloride substrates was assessed. Specifically, chlorobenzenes (hexachlorobenzene, HCBe), polychlorobyphenyls (PCBs) and trichloroethene (TCE) were tested. To further determine specificity of substrates, the PCB halorespiring communities enriched from Venice lagoon were tested for their dechlorinating capability against the other compounds mentioned above.