Degradation of methyl bromide by methanotrophic bacteria in cell suspensions and soils

• Published in: Applied and Environmental Microbiology 1994-10, Vol.60 (10), p.3640-3646
• Main Authors: Oremland, R.S, Miller, L.G, Culbertson, C.W, Connell, T.L, Jahnke, L
• Format: Article
• Language: English
• Subjects: ANAEROBIOSE; ANAEROBIOSIS; BACTERIA; BACTERIA GRAM NEGATIVA; BACTERIE GRAM NEGATIF; BIODEGRADACION; BIODEGRADATION; Biodegradation of pollutants; Biodegradation, Environmental; Biological and medical sciences; Biotechnology; BROMURE DE METHYLE; BROMURO DE METILO; Cellular biology; CULTIVO DE CELULAS; CULTURE DE CELLULE; Environment and pollution; Environmental Pollutants - metabolism; FLORA DEL SUELO; FLORE DU SOL; Fundamental and applied biological sciences. Psychology; Hydrocarbons, Brominated - metabolism; Industrial applications and implications. Economical aspects; METABOLISME; METABOLISMO; METANO; METHANE; Methylococcaceae - metabolism; Methylococcus capsulatus; MICROORGANISME; MICROORGANISMOS; MINERALISATION; MINERALIZACION; OXIDACION; Oxidation-Reduction; OXYDATION; Soil Microbiology; Soils; SOL AGRICOLE; SUELOS AGRICOLAS
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/aem.60.10.3640-3646.1994

Cell suspensions of Methylococcus capsulatus mineralized methyl bromide (MeBr), as evidenced by its removal from the gas phase, the quantitative recovery of Br(-) in the spent medium, and the production of (14)CO2 from [(14)C]MeBr. Methyl fluoride (MeF) inhibited oxidation of methane as well as that of [(14)C]MeBr. The rate of MeBr consumption by cells varied inversely with the supply of methane, which suggested a competitive relationship between these two substrates. However, MeBr did not support growth of the methanotroph. In soils exposed to high levels (10,000 ppm) of MeBr, methane oxidation was completely inhibited. At this concentration, MeBr removal rates were equivalent in killed and live controls, which indicated a chemical rather than biological removal reaction. At lower concentrations (1,000 ppm) of MeBr, methanotrophs were active and MeBr consumption rates were 10-fold higher in live controls than in killed controls. Soils exposed to trace levels (10 ppm) of MeBr demonstrated complete consumption within 5 h of incubation, while controls inhibited with MeF or incubated without O2 had 50% lower removal rates. Aerobic soils oxidized [(14)C]MeBr to (14)CO2, and MeF inhibited oxidation by 72%. Field experiments demonstrated slightly lower MeBr removal rates in chambers containing MeF than in chambers lacking MeF. Collectively, these results show that soil methanotrophic bacteria, as well as other microbes, can degrade MeBr present in the environment