An anaerobic consortium taken from brackish sediments, enriched byPCE/CH3OH sequential feeding, was capable of completely dechlorinating tetrachloroethene(PCE) to ethene (ETH). In batch experiments, PCE (0.5 mM) was dechlorinated to ethene (ETH) in approximately 75 h with either CH3OH or H2 as the electron donor. When VC (0.5 mM) was added instead of PCE it was dechlorinated without any initial lag by the PCE/CH3OHenriched consortium, although at a lower dechlorination rate. In batch tests H2 could readilyreplace CH3OH for supporting PCE dechlorination, with a similar PCE dechlorination rate andproduct distribution with respect to those observed with methanol. This indicates that H2 productionduring CH3OH fermentation was not the rate-limiting step of PCE or VC dechlorination.Acetogenesis was the predominant activity when methanol was present. A remarkable homoacetogenicactivity was also observed when hydrogen was supplied instead of methanol.