Dechlorination of trichlorofluoromethane (CFC-11) by sulfate-reducing bacteria from an aquifer contaminated with halogenated aliphatic compounds.

AUTOR(ES)

Sonier, D N

RESUMO

Groundwater samples were obtained from a deep aquifer contaminated with halogenated aliphatic compounds. One-milliliter samples contained 9.2 x 10(5) total bacteria (by acridine orange microscopic counts) and 2.5 x 10(3) sulfate-reducing bacteria (by most probable number analysis). Samples were incubated anaerobically in a basal salts medium with acetate as the electron donor and nitrate and sulfate as the electron acceptors. Residual levels of trichlorofluoromethane (CFC-11) in samples were biotically degraded, while trichloroethylene was not. When successively higher levels of CFC-11 were added, increasingly rapid degradation rates were observed. Concomitant with CFC-11 degradation was the near stoichiometric production of fluorodichloromethane (HCFC-21); the production of HCFC-21 was verified by mass spectrometry. CFC-11 degradation was dependent on the presence of acetate (or butyrate) and sulfate but was independent of nitrate. Other carbon sources such as lactate and isopropanol did not support the degradation. The addition of 1 mM sodium sulfide completely inhibited CFC-11 degradation; however, degradation occurred in the presence of 2 mM 2-bromoethanesulfonic acid. These results indicate that the anaerobic dechlorination of CFC-11 is carried out by sulfate-reducing bacteria and not by denitrifying or methanogenic bacteria.

Documentos Relacionados

• Activity and Diversity of Sulfate-Reducing Bacteria in a Petroleum Hydrocarbon-Contaminated Aquifer
• Biodegradation of an Alicyclic Hydrocarbon by a Sulfate-Reducing Enrichment from a Gas Condensate-Contaminated Aquifer
• Anaerobic degradation of halogenated phenols by sulfate-reducing consortia.
• Isolation of Sulfate-Reducing Bacteria from Human Thoracoabdominal Pus
• Stable Carbon Isotope Fractionation by Sulfate-Reducing Bacteria