Methanogen

About: Methanogen is a research topic. Over the lifetime, 1146 publications have been published within this topic receiving 48254 citations.

Methanogen Communities in a Drained Bog: Effect of Ash Fertilization

Abstract: Forestry practises such has drainage have been shown to decrease emissions of the greenhouse gas methane (CH4) from peatlands. The aim of the study was to examine the methanogen populations in a drained bog in northern Finland, and to assess the possible effect of ash fertilization on potential methane production and methanogen communities. Peat samples were collected from control and ash fertilized (15,000 kg/ha) plots 5 years after ash application, and potential CH4 production was measured. The methanogen community structure was studied by DNA isolation, PCR amplification of the methyl coenzyme-M reductase (mcr) gene, denaturing gradient gel electrophoresis (DGGE), and restriction fragment length polymorphism (RFLP) analysis. The drained peatland showed low potential methane production and methanogen diversity in both control and ash-fertilized plots. Samples from both upper and deeper layers of peat were dominated by three groups of sequences related to Rice cluster-I hydrogenotroph methanogens. Even though pH was marginally greater in the ash-treated site, the occurrence of those sequences was not affected by ash fertilization. Interestingly, a less common group of sequences, related to the Fen cluster, were found only in the fertilized plots. The study confirmed the depth related change of methanogen populations in peatland.

Methylotrophic methanogenesis governs the biogenic coal bed methane formation in Eastern Ordos Basin, China.

Abstract: To identify the methanogenic pathways present in a deep coal bed methane (CBM) reservoir associated with Eastern Ordos Basin in China, a series of geochemical and microbiological studies was performed using gas and water samples produced from the Liulin CBM reservoir. The composition and stable isotopic ratios of CBM implied a mixed biogenic and thermogenic origin of the methane. Archaeal 16S rRNA gene analysis revealed the dominance of the methylotrophic methanogen Methanolobus in the water produced. The high potential of methane production by methylotrophic methanogens was found in the enrichments using the water samples amended with methanol and incubated at 25 and 35 °C. Methylotrophic methanogens were the dominant archaea in both enrichments as shown by polymerase chain reaction (PCR)–denaturing gradient gel electrophoresis (DGGE). Bacterial 16S rRNA gene analysis revealed that fermentative, sulfate-reducing, and nitrate-reducing bacteria inhabiting the water produced were a factor in coal biodegradation to fuel methanogens. These results suggested that past and ongoing biodegradation of coal by methylotrophic methanogens and syntrophic bacteria, as well as thermogenic CBM production, contributed to the Liulin CBM reserves associated with the Eastern Ordos Basin.

Hydrophobicities and Electrophoretic Mobilities of Anaerobic Bacterial Isolates from Methanogenic Granular Sludge

Abstract: The hydrophobicities and electrophoretic mobilities of isolates from methanogenic anaerobic granular sludge were measured and compared with those of strains from culture collections. All new isolates were highly hydrophobic, indicating that the upflow anaerobic sludge blanket reactor concept selects for hydrophobic bacteria. Methanothrix soehngenii, a methanogen often observed in methanogenic granular sludge, was highly hydrophobic and showed low electrophoretic mobility at pH 7. The role of this strain in the formation of methanogenic granular sludge is discussed.

Disproportionate increase in freshwater methane emissions induced by experimental warming

Abstract: Net emissions of the potent GHG methane from ecosystems represent the balance between microbial methane production (methanogenesis) and oxidation (methanotrophy), each with different sensitivities to temperature How this balance will be altered by long-term global warming, especially in freshwaters that are major methane sources, remains unknown Here we show that the experimental warming of artificial ponds over 11 years drives a disproportionate increase in methanogenesis over methanotrophy that increases the warming potential of the gases they emit The increased methane emissions far exceed temperature-based predictions, driven by shifts in the methanogen community under warming, while the methanotroph community was conserved Our experimentally induced increase in methane emissions from artificial ponds is, in part, reflected globally as a disproportionate increase in the capacity of naturally warmer ecosystems to emit more methane Our findings indicate that as Earth warms, natural ecosystems will emit disproportionately more methane in a positive feedback warming loop

Methyl Sulfide Production by a Novel Carbon Monoxide Metabolism in Methanosarcina acetivorans

Abstract: We observed dimethyl sulfide and methanthiol production in pure incubations of the methanogen Methanosarcina acetivorans when carbon monoxide (CO) served as the only electron donor. Energy conservation likely uses sodium ion gradients for ATP synthesis. This novel metabolism permits utilization of CO by the methanogen, resulting in quantitative sulfide methylation.