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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: In this paper, the authors analyzed the sediment microbiota of three eutrophic tropical urban freshwater reservoirs, in different seasons and evaluated the correlations between microorganisms and the atmospheric CH4 and CO2 flows, also correlating them to limnological variables.
Abstract: Freshwater reservoirs emit greenhouse gases (GHGs) such as methane (CH4) and carbon dioxide (CO2), contributing to global warming, mainly when impacted by untreated sewage and other anthropogenic sources. These gases can be produced by microbial organic carbon decomposition, but little is known about the microbiota and its participation in GHG production and consumption in these environments. In this paper we analyzed the sediment microbiota of three eutrophic tropical urban freshwater reservoirs, in different seasons and evaluated the correlations between microorganisms and the atmospheric CH4 and CO2 flows, also correlating them to limnological variables. Our results showed that deeper water columns promote high methanogen abundance, with predominance of acetoclastic Methanosaeta spp. and hydrogenotrophs Methanoregula spp. and Methanolinea spp. The aerobic methanotrophic community was affected by dissolved total carbon (DTC) and was dominated by Crenothrix spp. However, both relative abundance of the total methanogenic and aerobic methanotrophic communities in sediments were uncoupled to CH4 and CO2 flows. Network based approach showed that fermentative microbiota, including Leptolinea spp. and Longilinea spp., which produces substrates for methanogenesis, influence CH4 flows and was favored by anthropogenic pollution, such as untreated sewage loads. Additionally, less polluted conditions favored probable anaerobic methanotrophs such as Candidatus Bathyarchaeota, Sva0485, NC10, and MBG-D/DHVEG-1, which promoted lower gaseous flows, confirming the importance of sanitation improvement to reduce these flows in tropical urban freshwater reservoirs and their local and global warming impact.
10 citations
TL;DR: In this paper , the authors investigated if ammonia tolerant methanogenic consortia can be stored in gel (biogel) and used in a later time on-demand as bioaugmentation inocula, to efficiently relieve ammonia inhibition in continuous biomethanation systems.
10 citations
TL;DR: In this article, the anaerobic degradation of 2-propanol, an important industrial solvent, was scaled-up from batch assays to a pilot expanded granular sludge bed (EGSB) reactor at 25°C.
10 citations
TL;DR: In this paper, the authors investigated if ammonia tolerant methanogenic consortia can be stored in gel (biogel) and used in a later time on-demand as bioaugmentation inocula, to efficiently relieve ammonia inhibition in continuous biomethanation systems.
10 citations
TL;DR: Van der Heijden et al. as mentioned in this paper studied the effect of five priority pollutants in the Rhine Action Programme on Dutch river sediments, which are produced in high quantities and are relatively toxic and persistent.
Abstract: High numbers of bacteria are found in Dutch river sediments, which have a large capacity for the biodegradation of organic compounds and play an important role in the cycling of nutrients and elements. The bacteria are of vital importance in the functioning of river ecosystems. The methanogenic bacteria are responsible for the production of methane. Methanogenesis is the last stage of the anaerobic decomposition of organic matter. Without methanogen activity the degradation of organic matter cannot be carried out completely and acetic acid (and other organic acids) would accumulate. In anaerobic freshwater sediments acetate is the substrate used in about 70% of the methane production. An inhibitory effect on any of the processes carried out by the microbial consortium degrading organic matter, can lead to a decrease of methane production. The 5 toxicants used in this study are priority pollutants in the Rhine Action Programme, which are produced in high quantities and are relatively toxic and persistent. Benzene is an organic toxicant without a specific mode of action and thus exhibiting minimum toxicity. Chloroform is not very toxic under aerobic conditions. Van der Heijden quotes a value for initial reduction of cell multiplication of a Pseudomonas putida strain under aerobicmore » aqueous conditions at 125 mg/L chloroform. Under anaerobic conditions however, toxic free radicals can be formed during the reductive dechlorination of chloroform. Therefore anaerobic bacteria might be more sensitive to chloroform. The mode of action of 1,2-dichloroethane might be similar to chloroform. Pentachlorophenol is an uncoupler of the proton motive force. Zinc is known to be relatively toxic to microbial processes. Monitoring the effect of these very different pollutants on the methane production give information about the effect of these compounds on the microflora decomposing organic matter in a particular methanogenic ecosystem. 17 refs., 1 fig., 1 tab.« less
10 citations