Methanogen

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

Determination of number of methanogen cells or methane production activity of methanogen

Abstract: PURPOSE:To determine the number of methanogen cells or the methane-production activity of methanogen, in high sensitivity, by heating a specimen containing methanogen, irradiating the specimen with excitation light of a specific wavelength range, and measuring the intensity of fluorescent light emitted from the specimen and having a specific wavelength range. CONSTITUTION:A specimen containing methanogen is heated at 60-120 deg.C, irradiated with excitation light of a specific wavelength range. e.g. 380-440nm, and the intensity of fluorescent light emitted from the specimen and having a specific wavelength range is measured. In the above process, the fluorescent light having the above wavelength range is emitted from the F420 substance inherent to the methanogen and existing in the electron transfer system in the energy metabolic system of the methanogen. The number of the methanogen cells or the methane-production activity of methanogen can be determined by this process. The measurement can be carried out even in a mixture of microorganisms containing foreign materials such as the digested sludge in a methane fermentation tank, etc.

Effects of Spartina alterniflora invasion on methane emission in coastal salt marsh.

Abstract: To investigate the effects of Spartina alterniflora invasion on methane emission from coastal salt marsh, three S. alterniflora invasive levels were established nearby Taizhou City of Zhejiang Province, including native community, mixed community with S. alterniflora and native weeds, and mono-community of S. alterniflora. The results showed that the CH4 flux in the three communities ranged from 0.68 to 5.88 mg·m-2·h-1, and CH4 flux increased significantly with S. alterniflora invasion. CH4 flux in the mono-community of S. alterniflora being 8.7 and 2.3 times as that in the native and mixed communities, respectively. S. alterniflora invasion increased significantly methanogens number, methane production potential, methanotrophs number, methane oxidation potential, plant biomass, soil organic carbon content and soil pH, but decreased significantly soil total nitrogen content. The correlation analysis showed that the CH4 flux was positively related to methanogens number, methane production potential, methanotrophs number, methane oxidation potential, plant biomass and soil pH, but negatively related to soil total nitrogen content. Overall, our results suggested that S. alterniflora invasion improved plant biomass production and soil pH, resulting in the increases in methanogens number and methane production potential to further drive soil CH4 emission.

Potential metabolic and genetic interaction among viruses, methanogen and methanotrophic archaea, and their syntrophic partners

Abstract: Abstract The metabolism of methane in anoxic ecosystems is mainly mediated by m ethanogens and m ethane-oxidizing a rchaea (MMA), key players in global carbon cycling. Viruses are vital in regulating their host fate and ecological function. However, our knowledge about the distribution and diversity of MMA viruses and their interactions with hosts is rather limited. Here, by searching metagenomes containing mcrA (the gene coding for the α-subunit of methyl-coenzyme M reductase) from a wide variety of environments, 140 viral operational taxonomic units (vOTUs) that potentially infect methanogens or methane-oxidizing archaea were retrieved. Four MMA vOTUs (three infecting the order Methanobacteriales and one infecting the order Methanococcales ) were predicted to cross-domain infect sulfate-reducing bacteria. By facilitating assimilatory sulfur reduction, MMA viruses may increase the fitness of their hosts in sulfate-depleted anoxic ecosystems and benefit from synthesis of the sulfur-containing amino acid cysteine. Moreover, cell-cell aggregation promoted by MMA viruses may be beneficial for both the viruses and their hosts by improving infectivity and environmental stress resistance, respectively. Our results suggest a potential role of viruses in the ecological and environmental adaptation of methanogens and methane-oxidizing archaea.

Characterization of Microbial Community Structure and Diversity, Present in Thermophilic Anaerobic Digestion of Waste-Activated Sludge

Abstract: The microbial community structures present in the thermophilic anaerobic digestion (TAD) of waste-activated sludge (WAS) and WAS were analyzed with molecular biological techniques including polymerase chain reaction-denature gradient gel electrophoresis (PCR-DGGE), real-time PCR, and cloning analysis. No significant differences in the microbial community structures present in TAD were observed among three reactors operated with hydraulic retention times of 10, 20 and 30 days. The microbial community present in TAD had less diversity than that present in WAS, and the sequences obtained in WAS were not present in TAD by the cloning analysis. In the TAD bacterial clone library, 97.5% of the total clones belonged to Firmicutes and 73.1% belonged to Coprothermobacter. Real-time PCR and cloning analyses revealed that the number of Methanosarcina thermophila, which is an acetoclastic methanogen, was larger than that of Methanoculleus thermophilus, which is a hydrogenotrophic methanogen, in terms of the numbers of copies of 16S rDNA.

Phylogenetic Diversity of Methanogen Endosymbionts of Anaerobic Ciliates

Abstract: Anaerobic environments occur widely wherever the accumulation of organic material exceeds the rate at which oxygen becomes available for its aerobic decomposition. Examples include marine and freshwater sediments, anaerobic sewage deposits, landfill sites and the guts of many animals (Fenchel and Finlay, 1991a). In these situations protozoa and ciliates in particular, survive by feeding on rich and varied prokaryote communities. Ciliates which live exclusively in anaerobic environments lack mitochondria and their metabolism is based upon fermentation and substrate level phosphorylation (Muller, 1988; Fenchel and Finlay, 1991a). Most of the anaerobic ciliates contain microbodies some of which have been shown to be capable of oxidizing pyruvate to acetate with the production of ATP, CO2 and H2. In such cases they are called hydrogenosomes (Muller, 1988). The origins of hydrogenosomes are unresolved, but in some ciliates they contain cristae and a double membrane and thus they resemble mitochondria (Finlay and Fenchel, 1989).