Methanogenesis

Abstract

Methanogenesis is an anaerobic respiration that generates methane as the final product of metabolism. In aerobic respiration, organic matter such as glucose is oxidized to CO, and O is reduced to HO. In contrast, during hydrogenotrophic methanogenesis, H is oxidized to H, and CO is reduced to CH. Although similar in principle to other types of respiration, methanogenesis has some distinctive features: the energy yield is very low, ≤1 ATP per methane generated, and only methanogens - organisms capable of this specialized metabolism - carry out biological methane production. Methanogens, like the process they catalyze, are similarly distinctive. Methanogens are comprised exclusively of archaea. They are obligate methane producers, that is, they do not grow using fermentation or alternative electron acceptors for respiration. Finally, methanogens are strict anaerobes and do not grow in the presence of O. Historically, methanogenesis has been viewed as a highly specialized metabolism restricted to a narrow group of prokaryotes. However, recent developments have revealed enormous diversity within the methanogens and suggest that this metabolism is one of the most ancient on earth.

Seasonal dynamics of methane cycling microbial communities in Amazonian floodplain sediments

“…Despite the lack of knowledge in the mechanisms underpinning this process, the resistance of methanogens to drainage was also reported by Ma and Lu (2011). It is likely that those microbes may present protection against oxidative stress, as already reported for methanogens (Angle et al, 2017; Lyu, Shao Akinyemi, & Whitman, 2018). According to Hernández et al (2019), the abundance of methanogens could be an indication of the flooding history of the Amazon floodplain.…”

Rewetting of Three Drained Peatlands Drives Congruent Compositional Changes in Pro- and Eukaryotic Soil Microbiomes through Environmental Filtering

“…Methanomassiliicoccales were detected in every site with Methanomassiliicoccales specific qPCR primers AS1/AS2 [60] (data not shown). Their high abundance in Percowet indicates that besides the well reported hydrogenotrophic and acetotrophic pathways [15], methylotrophic methanogenesis may contribute more to peatland CH4 emissions than currently assumed [19,61].…”

“…Boxplots shows relative abundance in depth and triplicate samples. X-axes represent fen type: alder carr (A), coastal fen (C), percolation fen (P), hydrological state drained (D) and rewetted (W), depth in cm (05, 15,25). Functional groups were assigned from 16S rRNA gene amplicon data by FAPROTAX analysis.…”

“…Rewetting is a proven strategy to protect the large SOC stocks; however, it can also lead to increased emissions of the potent GHG CH4 and to the release of dissolved organic matter (DOM). While effects of peatland rewetting on GHG and DOM fluxes are comparably well studied [11][12][13][14][15], the impact on the peat microbiota, the primary driver of GHG production and emissions, is poorly understood, since it has been not well studied in temperate fens (see an exception in [16]). The major players in soil organic matter (SOM) decomposition in peat soils are microorganisms of the bacterial, archaeal and eukaryotic (e.g.…”

Long-Term Rewetting of Three Formerly Drained Peatlands Drives Congruent Compositional Changes in Pro- and Eukaryotic Soil Microbiomes through Environmental Filtering

“…Long-term rewetting is a proven strategy to protect large SOC stocks; however, it can also lead to increased emissions of the potent GHG CH 4 , and to the release of dissolved organic matter (DOM). While effects of peatland rewetting on GHG and DOM fluxes have been relatively well studied [11][12][13][14][15], the impact on the peat microbiota, the primary driver of GHG production and emissions, is poorly understood, since it has been not well studied in temperate fens (see an exception in Reference [16]). The major players in soil organic matter (SOM) decomposition in peat soils are microorganisms of the bacterial, archaeal, and eukaryotic (e.g., fungi) domains of life, participating in a cascade of SOM degradation steps [9,17] and eventually resulting in emissions of CH 4 and CO 2 .…”