title: Complete biological reductive transformation of tetrachloroethene to ethane.
abstract: Reductive dechlorination of tetrachloroethene (perchloroethylene; PCE) was observed at 20 degrees C in a fixed-bed column, filled with a mixture (3:1) of anaerobic sediment from the Rhine river and anaerobic granular sludge. In the presence of lactate (1 mM) as an electron donor, 9 microM PCE was dechlorinated to ethene. Ethene was further reduced to ethane. Mass balances demonstrated an almost complete conversion (95 to 98%), with no chlorinated compounds remaining (less than 0.5 micrograms/liter). When the temperature was lowered to 10 degrees C, an adaptation of 2 weeks was necessary to obtain the same performance as at 20 degrees C. Dechlorination by column material to ethene, followed by a slow ethane production, could also be achieved in batch cultures. Ethane was not formed in the presence of bromoethanesulfonic acid, an inhibitor of methanogenesis. The high dechlorination rate (3.7 mumol.l-1.h-1), even at low temperatures and considerable PCE concentrations, together with the absence of chlorinated end products, makes reductive dechlorination an attractive method for removal of PCE in bioremediation processes.
authors.affiliation: Department of Microbiology, Wageningen Agricultural University, The Netherlands.
authors.forename: W P
authors.initials: WP
authors.lastname: de Bruin
authors.forename: M J
authors.initials: MJ
authors.lastname: Kotterman
authors.forename: M A
authors.initials: MA
authors.lastname: Posthumus
authors.forename: G
authors.initials: G
authors.lastname: Schraa
authors.forename: A J
authors.initials: AJ
authors.lastname: Zehnder
mesh_terms: D004980:Ethane / Q000493:pharmacokinetics; D008658:Inactivation, Metabolic; D010084:Oxidation-Reduction; D013750:Tetrachloroethylene / Q000493:pharmacokinetics*; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics
chemical_list: D014874:Water Pollutants, Chemical; D004980:Ethane; D013750:Tetrachloroethylene