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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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TL;DR: The co-culture of the anaerobic fungus and the methanogen is a good model for studying the microbial interaction between H1-producing and H2-utilizing microorganisms, however, metabolism in hydrogenosome needs to be further studied to gain better insight in the hydrogen transfer among microorganisms.
Abstract: OBJECTIVE The purpose of this study was to reveal the metabolic shift in the fungus cocultured with the methanogen (Methanobrevibacter thaueri). METHODS Gas chromatography-mass spectrometry was used to investigate the metabolites in anaerobic fungal (Pecoramyces sp. F1) cells and the supernatant. RESULTS A total of 104 and 102 metabolites were detected in the fungal cells and the supernatant, respectively. The partial least squares-discriminant analysis showed that the metabolite profiles in both the fungal cell and the supernatant were distinctly shifted when co-cultured with methanogen. Statistically, 16 and 30 metabolites were significantly (p<0.05) affected in the fungal cell and the supernatant, respectively by the co-cultured methanogen. Metabolic pathway analysis showed that co-culturing with methanogen reduced the production of lactate from pyruvate in the cytosol and increased metabolism in the hydrogenosomes of the anaerobic fungus. Citrate was accumulated in the cytosol of the fungus co-cultured with the methanogen. CONCLUSION The co-culture of the anaerobic fungus and the methanogen is a good model for studying the microbial interaction between H2-producing and H2-utilizing microorganisms. However, metabolism in hydrogenosome needs to be further studied to gain better insight in the hydrogen transfer among microorganisms.
6 citations
Patent•
28 Sep 1994
TL;DR: In this paper, the pH at the vicinity of an inflow part 5 of a liq. to be treated in the anaerobic reactor 1 is measured with a pH measuring device 6, a quantity of the pH adjusting agent to be injected to the liqs.to be treated from a chemical injecting pump 13 is controlled with a controlling device 14 so that this measured value may be kept at a prescribed value.
Abstract: PURPOSE: To adjust a pH to a level suitable to an activity of methanogen with a low amount of pH adjusting agent and to efficiently execute an anaerobic treatment. CONSTITUTION: In an anaerobic treating method in which org. waste water is passed through an anaerobic reactor 1 keeping an anaerobic sludge 2 containing anaerobic microorganisms in one direction stream substantially, the pH at the vicinity of an inflow part 5 of a liq. to be treated in the anaerobic reactor 1 is measured with a pH measuring device 6, a quantity of the pH adjusting agent to be injected to the liq. to be treated from a chemical injecting pump 13 is controlled with a controlling device 14 so that this measured value may be kept at a prescribed value.
6 citations
TL;DR: In this article , the authors determined the TM content and its impact on AD in an anaerobic membrane bioreactor operated to treat dairy processing wastewater (DPW) and showed that a deficiency in TMs resulted in the slow deterioration of the process, reducing biogas production, disrupting the buffer system, and the massive accumulation of organic acid.
6 citations
TL;DR: In this paper, the author demonstrates a case of organic matter application, enumeration and isolation of methanogenic archaea and methanotrophic bacteria in a subtropical paddy field, and co-culture of a strictly anaerobic methnogenic archaeon and an obligately aerobic methanOTrophic bacterium using sterilized paddy soil was carried out.
Abstract: In flooded rice fields, methanogenic archaea produce CH4, while methanotrophic bacteria oxidize a part of the produced CH4. Thus, the latter bacteria are considered as suitable organisms for controlling CH4 emission from paddy fields. In this paper, the author demonstrates a case of organic matter application, enumeration and isolation of methanogenic archaea and methanotrophic bacteria in a subtropical paddy field. The rice rhizosphere is one of the typical areas where anaerobic and aerobic environments interface, methanogens produce CH4 and methanotrophs utilize it for energy. Although how they interact in the anaerobic and aerobic interfaces is an attractive research area, it has not yet been fully elucidated, because a two-member co-culture of methanogen and methanotroph is not well developed. Co-culture of a strictly anaerobic methanogenic archaeon and an obligately aerobic methanotrophic bacterium using sterilized paddy soil was carried out. The rice root system affects CH4 production and oxidation in the rice rhizosphere, and its influence varies with different rice cultivars. Rice cultivars with few unproductive tillers, a small root system, high root oxidative activity, and high harvest index are ideal for mitigating CH4 emission in paddy fields.
6 citations
TL;DR: In this article, the authors focused on the tropical millipede species Archispirostreptus gigas and Epibolus pulchripes, which release considerable amounts of methane.
Abstract: Methanogens represent the final decomposition step in anaerobic degradation of organic matter, occurring in the digestive tracts of various invertebrates. However, factors determining their community structure and activity in distinct gut sections are still debated. In this study, we focused on the tropical millipede species Archispirostreptus gigas (Diplopoda, Spirostreptidae) and Epibolus pulchripes (Diplopoda, Pachybolidae), which release considerable amounts of methane. We aimed to characterize relationships between physicochemical parameters, methane production rates, and methanogen community structure in the two major gut sections, midgut and hindgut. Microsensor measurements revealed that both sections were strictly anoxic, with reducing conditions prevailing in both millipedes. Hydrogen concentration peaked in the anterior hindgut of E. pulchripes. In both species, the intestinal pH was significantly higher in the hindgut than in the midgut. An accumulation of acetate and formate in the gut indicated bacterial fermentation activities in the digestive tracts of both species. Phylogenetic analysis of 16S rRNA genes showed a prevalence of Methanobrevibacter spp. (Methanobacteriales), accompanied by a small fraction of so-far-unclassified "Methanomethylophilaceae" (Methanomassiliicoccales), in both species, which suggests that methanogenesis is mostly hydrogenotrophic. We conclude that anoxic conditions, negative redox potential, and bacterial production of hydrogen and formate promote gut colonization by methanogens. The higher activities of methanogens in the hindgut are explained by the higher pH of this compartment and their association with ciliates, which are restricted to this compartment and present an additional source of methanogenic substrates. IMPORTANCE Methane (CH4) is the second most important atmospheric greenhouse gas after CO2 and is believed to account for 17% of global warming. Methanogens are a diverse group of archaea and can be found in various anoxic habitats, including digestive tracts of plant-feeding animals. Termites, cockroaches, the larvae of scarab beetles, and millipedes are the only arthropods known to host methanogens and emit large amounts of methane. Millipedes are ranked as the third most important detritivores after termites and earthworms, and they are considered keystone species in many terrestrial ecosystems. Both methane-producing and non-methane-emitting species of millipedes have been observed, but what limits their methanogenic potential is not known. In the present study, we show that physicochemical gut conditions and the distribution of symbiotic ciliates are important factors determining CH4 emission in millipedes. We also found close similarities to other methane-emitting arthropods, which might be associated with their similar plant-feeding habits.
6 citations