Methanogens are microorganisms belonging to the Archaea domain and represent the primary source of biotic methane. Methanogens encode a series of enzymes which can convert secondary substrates into methane following three major methanogenesis pathways. Initially recognized as environmental microorganisms, methanogens have more recently been acknowledged as host-associated microorganisms after their detection and initial isolation in ruminants in the 1950s. Methanogens have also been co-detected with bacteria in various pathological situations, bringing their role as pathogens into question. Here, we review reported associations between methanogens and bacteria in physiological and pathological situations in order to understand the metabolic interactions explaining these associations. To do so, we describe the origin of the metabolites used for methanogenesis and highlight the central role of methanogens in the syntrophic process during carbon cycling. We then focus on the metabolic abilities of co-detected bacterial species described in the literature and infer from their genomes the probable mechanisms of their association with methanogens. The syntrophic interactions between bacteria and methanogens are paramount to gut homeostasis. Therefore, any dysbiosis affecting methanogens might impact human health. Thus, the monitoring of methanogens may be used as a bio-indicator of dysbiosis. Moreover, new therapeutic approaches can be developed based on their administration as probiotics. We thus insist on the importance of investigating methanogens in clinical microbiology.
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http://dx.doi.org/10.1007/s00248-021-01796-7 | DOI Listing |
Sci Total Environ
January 2025
Program of Sustainability in Biosystems, Institute of Agrifood Research and Technology (IRTA), Caldes de Montbui, Barcelona, Spain. Electronic address:
Paddy fields are a major anthropogenic source of global methane (CH) emissions, a powerful greenhouse gas (GHG). This study aimed at gaining insights of different organic and inorganic conductive materials (CMs) - biochar, fungal melanin, and magnetite - to mitigate CH emissions, and on their influence on key microbial populations, mimicking the postharvest season throughout the degradation of rice straw in microcosms under anaerobic conditions encompassing postharvest paddy rice soils from the Ebro Delta, Spain. Results showed that fungal melanin was the most effective CM, significantly reducing CH emissions by 29 %, while biochar amendment also reduced emissions by 10 %.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada.
Benzene degradation under anoxic conditions was first reported more than 25 years ago; however, the activation mechanism in the absence of oxygen remains elusive. Progress has been hindered by the difficulty in cultivating anaerobic benzene-degrading enrichment cultures. Our laboratory has sustained a methanogenic enrichment culture harboring ORM2, a benzene fermenter distinct from any known genus but related to other known or predicted benzene degraders.
View Article and Find Full Text PDFEnviron Res
December 2024
Newe Ya'ar Research Center, Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel. Electronic address:
In soil polluted with benzene, toluene, ethylbenzene, and xylenes (BTEX), oxygen is rapidly depleted by aerobic respiration, creating a redox gradient across the plume. Under anaerobic conditions, BTEX biodegradation is then coupled with fermentation and methanogenesis. This study aimed to characterize this multi-step process, focusing on the interactions and functional roles of key microbial groups involved.
View Article and Find Full Text PDFFront Microbiol
December 2024
Frazer Institute, Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia.
Methanogenic archaea are a group of microorganisms found in the gastrointestinal tract of various herbivores and humans; however, the quantity (intensity) of methane emissions during feed digestion varies. Macropodids, such as the Eastern Gray Kangaroo (), are considered to be low methane-emitting animals, but their gut methanogenic archaea remain poorly characterized. Characterizing methanogens from animals with low methane emissions offers the potential to develop strategies and interventions that reduce methane emissions from livestock.
View Article and Find Full Text PDFJ Environ Manage
December 2024
ENGIE Lab Crigen, 93240, Stains, Paris, France. Electronic address:
Bioelectrochemically improved anaerobic digestion (AD-BES) represents an upgrading strategy for existing biogas plants, consisting of the integration of bioelectrodes within the AD reactor. For this study, a series of laboratory-scale AD-BES reactors were operated, valorising agricultural digestates through the production of biogas. The reactors were inoculated and started-up with three different digestates, leading to significant differences in the microbial community developed on the bioelectrodes.
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