H2 and CH4
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ABSTRACT:
PROVIDER: PRJEB20160 | ENA |
REPOSITORIES: ENA
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Project description:Metabolic flexibility in aerobic methane oxidising bacteria (methanotrophs) enhances cell growth and survival in instances where resources are variable or limiting. Examples include the production of intracellular compounds (such as glycogen or polyhydroxyalkanoates) in response to unbalanced growth conditions and the use of some energy substrates, besides methane, when available. Indeed, recent studies show that verrucomicrobial methanotrophs can grow mixotrophically through oxidation of hydrogen and methane gases via respiratory membrane-bound group 1d [NiFe] hydrogenases and methane monooxygenases respectively. Hydrogen metabolism is particularly important for adaptation to methane and oxygen limitation, suggesting this metabolic flexibility may confer growth and survival advantages. In this work, we provide evidence that, in adopting a mixotrophic growth strategy, the thermoacidophilic methanotroph, Methylacidiphilum sp. RTK17.1 changes its growth rate, biomass yields and the production of intracellular glycogen reservoirs. Under nitrogen-fixing conditions, removal of hydrogen from the feed-gas resulted in a 14 % reduction in observed growth rates and a 144% increase in cellular glycogen content. Concomitant with increases in glycogen content, the total protein content of biomass decreased following the removal of hydrogen. Transcriptome analysis of Methylacidiphilum sp. RTK17.1 revealed a 3.5-fold upregulation of the Group 1d [NiFe] hydrogenase in response to oxygen limitation and a 4-fold upregulation of nitrogenase encoding genes (nifHDKENX) in response to nitrogen limitation. Genes associated with glycogen synthesis and degradation were expressed constitutively and did not display evidence of transcriptional regulation. Collectively these data further challenge the belief that hydrogen metabolism in methanotrophic bacteria is primarily associated with energy conservation during nitrogen fixation and suggests its utilisation provides a competitive growth advantage within hypoxic habitats.
2019-10-01 | GSE132517 | GEO
Project description:Manufactured nanomaterials (MNMs) are increasingly incorporated into consumer products that are disposed into sewage. In wastewater treatment, MNMs adsorb to activated sludge biomass where they may impact biological wastewater treatment performance, including nutrient removal. Here, we studied MNM effects on bacterial polyhydroxyalkanoate (PHA), specifically polyhydroxybutyrate (PHB), biosynthesis because of its importance to enhanced biological phosphorus (P) removal (EBPR). Activated sludge was sampled from an anoxic selector of a municipal wastewater treatment plant (WWTP), and PHB-containing bacteria were concentrated by density gradient centrifugation. After starvation to decrease intracellular PHB stores, bacteria were nutritionally augmented to promote PHB biosynthesis while being exposed to either MNMs (TiO2 or Ag) or to Ag salts (each at a concentration of 5 mg L-1). Cellular PHB concentration and PhyloChip community composition were analyzed. The final bacterial community composition differed from activated sludge, demonstrating that laboratory enrichment was selective. Still, PHB was synthesized to near-activated sludge levels. Ag salts altered final bacterial communities, although MNMs did not. PHB biosynthesis was diminished with Ag (salt or MNMs), indicating the potential for Ag-MNMs to physiologically impact EBPR through the effects of dissolved Ag ions on PHB producers. 18 samples; Triplicate PHB-enriched bacterial communities recovered from activated sludge were exposed to nanoparticle (TiO2 or Ag) or AgNO3 (as a silver control) or were not exposed to an nanoparticles (control) to determine if the naoparticles affected PHB production.
2014-12-03 | E-GEOD-63781 | biostudies-arrayexpress
Project description:.RAW files and Compound Discoverer peak lists used for a manuscript regarding changes the chemical fingerprint of sewage sludge during the COVID-19 pandemic
2021-01-08 | MSV000086676 | MassIVE
Project description:Manufactured nanomaterials (MNMs) are increasingly incorporated into consumer products that are disposed into sewage. In wastewater treatment, MNMs adsorb to activated sludge biomass where they may impact biological wastewater treatment performance, including nutrient removal. Here, we studied MNM effects on bacterial polyhydroxyalkanoate (PHA), specifically polyhydroxybutyrate (PHB), biosynthesis because of its importance to enhanced biological phosphorus (P) removal (EBPR). Activated sludge was sampled from an anoxic selector of a municipal wastewater treatment plant (WWTP), and PHB-containing bacteria were concentrated by density gradient centrifugation. After starvation to decrease intracellular PHB stores, bacteria were nutritionally augmented to promote PHB biosynthesis while being exposed to either MNMs (TiO2 or Ag) or to Ag salts (each at a concentration of 5 mg L-1). Cellular PHB concentration and PhyloChip community composition were analyzed. The final bacterial community composition differed from activated sludge, demonstrating that laboratory enrichment was selective. Still, PHB was synthesized to near-activated sludge levels. Ag salts altered final bacterial communities, although MNMs did not. PHB biosynthesis was diminished with Ag (salt or MNMs), indicating the potential for Ag-MNMs to physiologically impact EBPR through the effects of dissolved Ag ions on PHB producers.
2014-12-03 | GSE63781 | GEO
Project description:Background: Methane yield and biogas productivity of biogas plants depend on microbial community structure and functionality, substrate supply, and general process parameters. Little is known, however, about the correlations between microbial community function and the process parameters. To close this knowledge gap the microbial community of 40 industrial biogas plants was evaluated by a metaproteomics approach in this study. Results: Liquid chromatography coupled to tandem mass spectrometry (Elite Hybrid Ion Trap Orbitrap) enabled the identification of 3138 metaproteins belonging to 162 biological processes and 75 different taxonomic orders. Therefore, database searches were performed against UniProtKB/Swiss-Prot and several metagenome databases. Subsequent clustering and principal component analysis of these data allowed to identify four main clusters associated to mesophilic and thermophilic process conditions, upflow anaerobic sludge blanket reactors and sewage sludge as substrate. Observations confirm a previous phylogenetic study of the same biogas plant samples that was based on 16S-rRNA gene by De Vrieze et al. (2015) (De Vrieze, Saunders et al. 2015). Both studies described similar microbial key players of the biogas process, namely Bacillales, Enterobacteriales, Bacteriodales, Clostridiales, Rhizobiales and Thermoanaerobacteriales as well as Methanobacteriales, Methanosarcinales and Methanococcales. In addition, a correlation study and a Gephi graph network based on the correlations between the taxonomic orders and process parameters suggested the presence of various trophic interactions, e.g. syntrophic hydrogen transfer between Thermoanaerobacteriales and Methanomicrobiales. For the elucidation of the main biomass degradation pathways the most abundant 1% of metaproteins were assigned to the KEGG map 1200 representing the central carbon metabolism. Additionally, the effect of the process parameters (i) temperature, (ii) organic loading rate (OLR), (iii) total ammonia nitrogen (TAN) and (iv) sludge retention time (SRT) on these pathways was investigated. For example high TAN correlated with hydrogenotrophic methanogens and bacterial one-carbon metabolism, indicating syntrophic acetate oxidation. Conclusion: This study shows the benefit of large-scale proteotyping of biogas plants, enabling the identification of general correlations between the process parameters and the microbial community structure and function. Changes in the level of microbial key functions or even in the microbial community type represent a valuable hint for process problems and disturbances.
2016-04-19 | PXD003526 | Pride
Project description:Caldicellulosiruptor saccharolyticus is an extremely thermophilic, gram-positive anaerobe which ferments a broad range of substrates to mainly acetate, CO2, and hydrogen gas (H2). Its high hydrogen-producing capacity make this bacterium an attractive candidate for microbial biohydrogen production. However, increased H2 levels tend to inhibit hydrogen formation and leads to the formation of other reduced end products like lactate and ethanol. To investigate the organism’s strategy for dealing with elevated H2 levels and to identify alternative pathways involved in the disposal of the reducing equivalents, the effect of the hydrogen partial pressure (PH2) on fermentation performance was studied. For this purpose cultures were grown under high and low PH2 in a glucose limited chemostat setup. Transcriptome analysis revealed the up-regulation of genes involved in the disposal of reducing equivalents under high PH2, like lactate dehydrogenase and alcohol dehydrogenase as well as the NADH-dependent and ferredoxin-dependent hydrogenases. These findings were in line with the observed shift in fermentation profiles from acetate production under low PH2 to a mixed production of acetate, lactate and ethanol under high PH2. In addition, differential transcription was observed for genes involved in carbon metabolism, fatty acid biosynthesis and several transport systems. The presented transcription data provides experimental evidence for the involvement of the redox sensing Rex protein in gene regulation under high PH2 cultivation conditions. Overall, these findings indicate that the PH2 dependent changes in the fermentation pattern of C. saccharolyticus are, in addition to the known regulation at the enzyme/metabolite level, also regulated at the transcription level.
2013-08-28 | GSE40430 | GEO
Project description:Rhodobacter sphaeroides produces hydrogen gas (H2) via its nitrogenase enzyme during photoheterotrophic growth under nitrogen-limited conditions. We find that cells produce different amounts of H2 and show different growth rates, depending on the organic substrate provided (lactate, succinate, glucose, xylose, or glycerol). We used global transcript analyses to determine what genes are involved in the onset of H2 production, and those that lead to different H2 production capacities in cells fed different organic substrates.
2011-08-22 | GSE29811 | GEO
Project description:Microalgae are natural biocatalysts of Hydrogen. Their ability to convert solar energy to valuable compounds with minimal ecological footprint potentially puts them as significant contributors to clean energy transition. Currently, this process, although promising, is not scalable because it is limited to oxygen-free conditions and is short-lived due to electron loss to other processes, mainly carbon fixation. Here we show that a strain, defected in thylakoid proton gradient regulation, ∆pgr5, bypasses both challenges simultaneously, leading to a prolonged 12-day hydrogen production under ambient mixotrophic conditions in a one-liter set-up. We report that ∆pgr5 possess a repressed ability to fixate carbon and this limitation is counterbalanced by an enhanced chloroplast-mitochondrion energetic exchange. This unique physiology supported the simplistic, yet robust and scalable hydrogen production capability of ∆pgr5.
2022-11-09 | PXD028843 | Pride
Project description:Methanococcus maripaludis is a methanogenic Archaea that conserves energy from molecular hydrogen to reduce carbon dioxide to methane. Chemostat grown cultures limited for phosphate or leucine were compared to determine the regulatory response to leucine limitation. Keywords: archaea, hydrogen, leucine, phosphate, nutrient limitation, growth rate, methanogen
2007-08-30 | GSE8728 | GEO