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Methanogen

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


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Journal ArticleDOI
TL;DR: A SYBR green I quantitative PCR (qPCR) assay to quantify total numbers of methyl coenzyme M reductase α-subunit (mcrA) genes and TaqMan probes were designed to target nine different phylogenetic groups of methanogens in qPCR assays.
Abstract: Methanogens are of great importance in carbon cycling and alternative energy production, but quantitation with culture-based methods is time-consuming and biased against methanogen groups that are difficult to cultivate in a laboratory. For these reasons, methanogens are typically studied through culture-independent molecular techniques. We developed a SYBR green I quantitative PCR (qPCR) assay to quantify total numbers of methyl coenzyme M reductase α-subunit (mcrA) genes. TaqMan probes were also designed to target nine different phylogenetic groups of methanogens in qPCR assays. Total mcrA and mcrA levels of different methanogen phylogenetic groups were determined from six samples: four samples from anaerobic digesters used to treat either primarily cow or pig manure and two aliquots from an acidic peat sample stored at 4°C or 20°C. Only members of the Methanosaetaceae, Methanosarcina, Methanobacteriaceae, and Methanocorpusculaceae and Fen cluster were detected in the environmental samples. The three samples obtained from cow manure digesters were dominated by members of the genus Methanosarcina, whereas the sample from the pig manure digester contained detectable levels of only members of the Methanobacteriaceae. The acidic peat samples were dominated by both Methanosarcina spp. and members of the Fen cluster. In two of the manure digester samples only one methanogen group was detected, but in both of the acidic peat samples and two of the manure digester samples, multiple methanogen groups were detected. The TaqMan qPCR assays were successfully able to determine the environmental abundance of different phylogenetic groups of methanogens, including several groups with few or no cultivated members.

241 citations

Journal ArticleDOI
TL;DR: In this paper, a semi-continuous reactor for the production of hydrogen was maintained at 4.5±0.2 by fixing the influent alkalinity to 1000 mg / l as CaCO3.

236 citations

Journal ArticleDOI
TL;DR: The results indicate the methanogens and sulfate reducers compete for DMS when it is present at low concentrations; however, at high concentrations, DMS is a "noncompetitive" substrate for methanogenesis.
Abstract: Addition of dimethylsulfide (DMS), dimethyldisulfide (DMDS), or methane thiol (MSH) to a diversity of anoxic aquatic sediments (eg, fresh water, estuarine, alkaline/hypersaline) stimulated methane production The yield of methane recovered from DMS was often 52 to 63%, although high concentrations of DMS (as well as MSH and DMDS) inhibited methanogenesis in some types of sediments Production of methane from these reduced methylated sulfur compounds was blocked by 2-bromoethanesulfonic acid Sulfate did not influence the metabolism of millimolar levels of DMS, DMDS, or MSH added to sediments However, when DMS was added at ∼2-μM levels as [14C]DMS, metabolism by sediments resulted in a 14CH4/14CO2 ratio of only 006 Addition of molybdate increased the ratio to 18, while 2-bromoethanesulfonic acid decreased it to 0, but did not block 14CO2 production These results indicate the methanogens and sulfate reducers compete for DMS when it is present at low concentrations; however, at high concentrations, DMS is a “noncompetitive” substrate for methanogens Metabolism of DMS by sediments resulted in the appearance of MSH as a transient intermediate A pure culture of an obligately methylotrophic estuarine methanogen was isolated which was capable of growth on DMS Metabolism of DMS by the culture also resulted in the transient appearance of MSH, but the organism could grow on neither MSH nor DMDS The culture metabolized [14C]-DMS to yield a 14CH4/14CO2 ratio of ∼28 Reduced methylated sulfur compounds represent a new class of substrates for methanogens and may be potential precursors of methane in a variety of aquatic habitats

235 citations

Journal ArticleDOI
TL;DR: High-throughput 16S rRNA sequencing revealed that the microbial community was resided by novel phylotypes belonging to the uncultured order MBA08 and to Bacteroidales, and only hydrogenotrophic methanogens were identified belonging to Methanothermobacter and Methanoculleus genera.

230 citations

Journal ArticleDOI
TL;DR: In this article, the greenhouse gases nitrous oxide and methane, which are produced by nitrifying and denitrifying prokaryotes and methanogenic archaea, are discussed.
Abstract: Changes in chemical properties in soil around plant roots influence many microbial processes, including those having an impact on greenhouse gas emissions. To potentially mitigate these emissions according to the Kyoto protocol, knowledge about how and where these gases are produced and consumed in soils is required. In this review, we focus on the greenhouse gases nitrous oxide and methane, which are produced by nitrifying and denitrifying prokaryotes and methanogenic archaea, respectively. After describing the microbial processes involved in production and consumption of nitrous oxide and methane and how they can be affected in the rhizosphere, we give an overview of nitrous oxide and methane emissions from the rhizosphere and soils and sediments with plants. We also discuss strategies to mitigate emissions from the rhizosphere and consider possibilities for carbon sequestration.

223 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202379
2022139
202189
202067
201974
201863