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Methanogenesis

About: Methanogenesis is a research topic. Over the lifetime, 5064 publications have been published within this topic receiving 244478 citations. The topic is also known as: methane biosynthetic process & methane biosynthesis.


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Journal ArticleDOI
27 Mar 2014-Nature
TL;DR: Seasonal variations in CH4 emissions from a wide range of ecosystems exhibit an average temperature dependence similar to that of CH4 production derived from pure cultures of methanogens and anaerobic microbial communities, suggesting that global warming may have a large impact on the relative contributions of CO2 and CH4 to total greenhouse gas emissions from aquatic ecosystems, terrestrial wetlands and rice paddies.
Abstract: Methane (CH4) is an important greenhouse gas because it has 25 times the global warming potential of carbon dioxide (CO2) by mass over a century. Recent calculations suggest that atmospheric CH4 emissions have been responsible for approximately 20% of Earth's warming since pre-industrial times. Understanding how CH4 emissions from ecosystems will respond to expected increases in global temperature is therefore fundamental to predicting whether the carbon cycle will mitigate or accelerate climate change. Methanogenesis is the terminal step in the remineralization of organic matter and is carried out by strictly anaerobic Archaea. Like most other forms of metabolism, methanogenesis is temperature-dependent. However, it is not yet known how this physiological response combines with other biotic processes (for example, methanotrophy, substrate supply, microbial community composition) and abiotic processes (for example, water-table depth) to determine the temperature dependence of ecosystem-level CH4 emissions. It is also not known whether CH4 emissions at the ecosystem level have a fundamentally different temperature dependence than other key fluxes in the carbon cycle, such as photosynthesis and respiration. Here we use meta-analyses to show that seasonal variations in CH4 emissions from a wide range of ecosystems exhibit an average temperature dependence similar to that of CH4 production derived from pure cultures of methanogens and anaerobic microbial communities. This average temperature dependence (0.96 electron volts (eV)), which corresponds to a 57-fold increase between 0 and 30°C, is considerably higher than previously observed for respiration (approximately 0.65 eV) and photosynthesis (approximately 0.3 eV). As a result, we show that both the emission of CH4 and the ratio of CH4 to CO2 emissions increase markedly with seasonal increases in temperature. Our findings suggest that global warming may have a large impact on the relative contributions of CO2 and CH4 to total greenhouse gas emissions from aquatic ecosystems, terrestrial wetlands and rice paddies.

688 citations

Journal ArticleDOI
TL;DR: Under conventional growth conditions, the isotope fractionation of methanogenesis by M. kandleri strain 116 was similar to values previously reported for other hydrogenotrophic methanogens, but under high hydrostatic pressures, the atom fractionation effect became much smaller, and the kinetic isotope effect was one of the smallest effects ever reported.
Abstract: We have developed a technique for cultivation of chemolithoautotrophs under high hydrostatic pressures that is successfully applicable to various types of deep-sea chemolithoautotrophs, including methanogens. It is based on a glass-syringe-sealing liquid medium and gas mixture used in conjunction with a butyl rubber piston and a metallic needle stuck into butyl rubber. By using this technique, growth, survival, and methane production of a newly isolated, hyperthermophilic methanogen Methanopyrus kandleri strain 116 are characterized under high temperatures and hydrostatic pressures. Elevated hydrostatic pressures extend the temperature maximum for possible cell proliferation from 116°C at 0.4 MPa to 122°C at 20 MPa, providing the potential for growth even at 122°C under an in situ high pressure. In addition, piezophilic growth significantly affected stable carbon isotope fractionation of methanogenesis from CO2. Under conventional growth conditions, the isotope fractionation of methanogenesis by M. kandleri strain 116 was similar to values (−34‰ to−27‰) previously reported for other hydrogenotrophic methanogens. However, under high hydrostatic pressures, the isotope fractionation effect became much smaller (<−12‰), and the kinetic isotope effect at 122°C and 40 MPa was −9.4‰, which is one of the smallest effects ever reported. This observation will shed light on the sources and production mechanisms of deep-sea methane.

684 citations

Journal ArticleDOI
TL;DR: In this article, a review examines the interactions among physical, chemical, and biological factors responsible for methane (CH4) emission from natural wetlands, showing that about 20 to 40% of the CH4 produced in anaerobic wetland soils is oxidized in the rhizosphere and in surficial oxic layers during diffusive transport to the soil surface.
Abstract: This review examines the interactions among physical, chemical, and biological factors responsible for methane (CH4) emission from natural wetlands. Methane is a chemically and radiatively important atmospheric trace gas. Emission from wetlands is a significant component of the atmospheric CH4 budget, releasing 145 Tg CH4 annually to the atmosphere, or about 25% of total emissions from all anthropogenic and natural sources. Wetlands are characterized by a subsurface, anaerobic zone of CH4 production by methanogenic bacteria and an surficial, aerobic zone of CH4 oxidation by methanotrophic bacteria. Wetlands transfer CH4 to the atmosphere by diffusion, ebullition, and by transport through arenchymous vascular plants. However, about 20 to 40% of the CH4 produced in anaerobic wetland soils is oxidized in the rhizosphere and in surficial oxic layers during diffusive transport to the soil surface. Rates of CH4 emission in wetlands are commonly 100 mg m-2 day-1, and represent the net effect of production and co...

655 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated factors controlling the concentration of dissolved hydrogen gas in anaerobic sedimentary environments and found that only microorganisms catalyze the oxidation of H 2 coupled to the reduction of nitrate, Mn(IV), Fe(III), sulfate, or carbon dioxide.

642 citations

Journal ArticleDOI
TL;DR: The complete genome sequence of an acetate-utilizing methanogen, Methanosarcina acetivorans C2A, is reported, which indicates the likelihood of undiscovered natural energy sources for methanogenesis, whereas the presence of single-subunit carbon monoxide dehydrogenases raises the possibility of nonmethanogenic growth.
Abstract: The Archaea remain the most poorly understood domain of life despite their importance to the biosphere. Methanogenesis, which plays a pivotal role in the global carbon cycle, is unique to the Archaea. Each year, an estimated 900 million metric tons of methane are biologically produced, representing the major global source for this greenhouse gas and contributing significantly to global warming (Schlesinger 1997). Methanogenesis is critical to the waste-treatment industry and biologically produced methane also represents an important alternative fuel source. At least two-thirds of the methane in nature is derived from acetate, although only two genera of methanogens are known to be capable of utilizing this substrate. We report here the first complete genome sequence of an acetate-utilizing (acetoclastic) methanogen, Methanosarcina acetivorans C2A. The Methanosarcineae are metabolically and physiologically the most versatile methanogens. Only Methanosarcina species possess all three known pathways for methanogenesis (Fig. ​(Fig.1)1) and are capable of utilizing no less than nine methanogenic substrates, including acetate. In contrast, all other orders of methanogens possess a single pathway for methanogenesis, and many utilize no more than two substrates. Among methanogens, the Methanosarcineae also display extensive environmental diversity. Individual species of Methanosarcina have been found in freshwater and marine sediments, decaying leaves and garden soils, oil wells, sewage and animal waste digesters and lagoons, thermophilic digesters, feces of herbivorous animals, and the rumens of ungulates (Zinder 1993). Figure 1 Three pathways for methanogenesis. Methanogenesis is a form of anaerobic respiration using a variety of one-carbon (C-1) compounds or acetic acid as a terminal electron acceptor. All three pathways converge on the reduction of methyl-CoM to methane (CH ... The Methanosarcineae are unique among the Archaea in forming complex multicellular structures during different phases of growth and in response to environmental change (Fig. ​(Fig.2).2). Within the Methanosarcineae, a number of distinct morphological forms have been characterized, including single cells with and without a cell envelope, as well as multicellular packets and lamina (Macario and Conway de Macario 2001). Packets and lamina display internal morphological heterogeneity, suggesting the possibility of cellular differentiation. Moreover, it has been suggested that cells within lamina may display differential production of extracellular material, a potential form of cellular specialization (Macario and Conway de Macario 2001). The formation of multicellular structures has been proposed to act as an adaptation to stress and likely plays a role in the ability of Methanosarcina species to colonize diverse environments. Figure 2 Different morphological forms of Methanosarcina acetivorans. Thin-section electron micrographs showing M. acetivorans growing as both single cells (center of micrograph) and within multicellular aggregates (top left, bottom right). Cells were harvested ... Significantly, powerful methods for genetic analysis exist for Methanosarcina species. These tools include plasmid shuttle vectors (Metcalf et al. 1997), very high efficiency transformation (Metcalf et al. 1997), random in vivo transposon mutagenesis (Zhang et al. 2000), directed mutagenesis of specific genes (Zhang et al. 2000), multiple selectable markers (Boccazzi et al. 2000), reporter gene fusions (M. Pritchett and W. Metcalf, unpubl.), integration vectors (Conway de Macario et al. 1996), and anaerobic incubators for large-scale growth of methanogens on solid media (Metcalf et al. 1998). Furthermore, and in contrast to other known methanogens, genetic analysis can be used to study the process of methanogenesis: Because Methanosarcina species are able to utilize each of the three known methanogenic pathways, mutants in a single pathway are viable (M. Pritchett and W. Metcalf, unpubl.). The availability of genetic methods allowing immediate exploitation of genomic sequence, coupled with the genetic, physiological, and environmental diversity of M. acetivorans make this species an outstanding model organism for the study of archaeal biology. For these reasons, we set out to study the genome of M. acetivorans.

626 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023331
2022768
2021367
2020312
2019336
2018267