Complete dechlorination of tetrachloroethene to ethene in presence of methanogenesis and acetogenesis by an anaerobic sediment microcosm.
An anaerobic consortium taken from brackish sediments, enriched by PCE/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/CH3OH enriched consortium, although at a lower dechlorination rate. In batch tests H2 could readily replace CH3OH for supporting PCE dechlorination, with a similar PCE dechlorination rate and product distribution with respect to those observed with methanol. This indicates that H2 production during CH3OH fermentation was not the rate-limiting step of PCE or VC dechlorination. Acetogenesis was the predominant activity when methanol was present. A remarkable homoacetogenic activity was also observed when hydrogen was supplied instead of methanol.
Aulenta
Federico
F
Department of Chemistry, University of Rome La Sapienza, P.le Aldo Moro 5, 00185 Rome, Italy. federico.aulenta@uniroma1.it
Majone
Mauro
M
Verbo
Paolo
P
Tandoi
Valter
V
D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004785:Environmental Pollutants / Q000378:metabolism*; D005030:Ethylenes; D006859:Hydrogen; D007220:Industrial Waste / Q000517:prevention & control*; D007700:Kinetics; D000432:Methanol; D013750:Tetrachloroethylene / Q000378:metabolism*
D004785:Environmental Pollutants; D005030:Ethylenes; D007220:Industrial Waste; D006859:Hydrogen; C036216:ethylene; D013750:Tetrachloroethylene; D000432:Methanol