Reductive dechlorination of 1,2-dichloroethane and chloroethane by cell suspensions of methanogenic bacteria

Abstract

Concentrated cell suspensions of methanogenic bacteria reductively dechlorinated 1,2-dichloroethane via two reaction-mechanisms: a dihalo-elimination yielding ethylene and two hydrogenolysis reactions yielding chloroethane and ethane, consecutively. The transformation of chloroethane to ethane was inhibited by 1,2-dichloroethane. Stimulation of methanogenesis caused an increase in the amount of dechlorination products formed, whereas the opposite was found when methane formation was inhibited. Cells of Methanosarcina barkeri grown on H2/CO2 converted 1,2-dichloroethane and chloroethane at higher rates than acetate or methanol grown cells.

Carbon and Chlorine Isotope Analysis to Identify Abiotic Degradation Pathways of 1,1,1-Trichloroethane

“…While biotic sequential reductive dechlorination (i.e., 1,1,1-TCA → 1,1-DCA → CA → ethane) would produce ethane initially depleted in 13 C relative to 1,1-DCA, the opposite was observed for reaction with Fe(0). However, although biodegradation of CA to ethane has been reported, 67 there is currently a lack of comprehensive experimental evidence for complete anaerobic dechlorination of 1,1,1-TCA via hydrogenolysis. 3 One of the main applications of CSIA to field studies is the estimation of contaminant degradation extent using the Rayleigh equation.…”

Development of an integrated in-situ remediation technology. Topical report for task No. 7 entitled: Development of degradation processes, September 26, 1994--May 25, 1996

“…Several pure cultures of microorganisms are now available that can also reduce PCE fuaher to cDCE (Holliger, et al, 1993;Neumam, et 81., 1994;Scholz-Muramatsu, et al ., 1995;Holliger and Schumacher, 1995;Sharma and McCarty, 1995). Holliger et al (1993Holliger et al ( ,1995 reported on a strictly anaerobic 'microorganism called Dehatubacter resITictus that grows only on hydrogen or formate as electron donors and PCE or TCE as electron acceptors, The newly isolated microorganism reported by Neuman et al (1994) and Scholz-Muramatsu (1995) is c g e d DehQlospiriZlum muttivorans and is also a strict anaerobe that can use PCE as an electron acceptor for growth, but it can use a variety of organic subskates as electron donors as well as hydrogen.…”

“…Holliger et al (1993Holliger et al ( ,1995 reported on a strictly anaerobic 'microorganism called Dehatubacter resITictus that grows only on hydrogen or formate as electron donors and PCE or TCE as electron acceptors, The newly isolated microorganism reported by Neuman et al (1994) and Scholz-Muramatsu (1995) is c g e d DehQlospiriZlum muttivorans and is also a strict anaerobe that can use PCE as an electron acceptor for growth, but it can use a variety of organic subskates as electron donors as well as hydrogen. Acetate is used as a carbon source.…”

Methyl-coenzyme M reductase of Methanobacterium thermoautotrophicum delta H catalyzes the reductive dechlorination of 1,2-dichloroethane to ethylene and chloroethane

“…Purified methyl-CoM reductase, together with flavin adenine dinucleotide and a crude component A fraction which reduced the nickel of factor F430 in methyl-CoM reductase, converted 1,2-DCA to ethylene and CA with H2 as the electron donor. In this system, methyl-CoM reductase was also able to transform its own inhibitor 2-bromoethanesulfonate to ethylene.Hydrogenotrophic and acetoclastic methanogenic bacteria reductively dechlorinate 1,2-dichloroethane (1,2-DCA) to ethylene and chloroethane (CA) (5,12,26). Corrinoids or factor F430, two cofactors present in high amounts in methanogens (10,11,20,35), catalyzed the same transformations in buffer with Ti(III) citrate as the electron donor (27).…”

“…Hydrogenotrophic and acetoclastic methanogenic bacteria reductively dechlorinate 1,2-dichloroethane (1,2-DCA) to ethylene and chloroethane (CA) (5,12,26). Corrinoids or factor F430, two cofactors present in high amounts in methanogens (10,11,20,35), catalyzed the same transformations in buffer with Ti(III) citrate as the electron donor (27).…”