A Chloroflexi bacterium dechlorinates polychlorinated biphenyls in marine sediments under in situ-like biogeochemical conditions

► VL-CHL1 is the first PCB dechlorinating Chloroflexi identified in a marine sediment. ► VL-CHL1 dechlorination activity is the broadest among those of known dechlorinators. ► VL-CHL1 dechlorinates PCBs under actual site marine biogeochemical conditions.