Microbial community of H2/CO2 gas fermentation reactor
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PROVIDER: PRJNA698443 | ENA |
REPOSITORIES: ENA
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Project description:Clostridium ljungdahlii not only utilizes CO, but also H2 as energy source during autotrophic growth. In theory, CO is a more energetically and thermodynamically favourable energy source than H2 in the gas fermentation of C. ljungdahlii. However, how C. ljungdahlii conserves energy for growth and ethanol/acetate formation grown on CO or CO2/H2 is not in great detail. In this study, C. ljungdahlii was fermented on CO and CO2/ H2 at pH 6.0 with 0.1 MPa gas pressure. C. ljungdahlii produced 27 g/L acetate, 9 g/L ethanol, 8 g/L 2,3-butanediol and traces of lactate in the presence of CO as energy source, while it produced 25.8 0.1 g/L acetate, 1.8 0.1 g/L ethanol, 0.7 0.01g/L 2,3-butanediol and trances of lactate in the same fermentation condition using H2 as energy source. Therefore, comparative transcriptomes between cells grown on CO and cells grown on H2/CO2 were performed to investigate gene expression profiles based on three biological replicates.
2020-04-01 | E-MTAB-8260 | biostudies-arrayexpress
Project description:RECIRCULATION OF H2, CO2, AND ETHYLENE IMPROVES YIELDS AND CARBON FIXATION OF ANAEROBIC FERMENTATION
| PRJEB41050 | ENA
Project description:Background: The global demand for affordable carbon has never been stronger, and there is an imperative in many industrial processes to use waste streams to make products. Gas-fermenting acetogens offer a potential solution and several commercial gas fermentation plants are currently under construction. As energy limits acetogen metabolism, supply of H2 should diminish substrate loss to CO2 and facilitate production of reduced and energy-intensive products. However, the effects of H2 supply on CO-grown acetogens have yet to be experimentally quantified under controlled growth conditions. Results: Here, we quantify the effects of H2 supplementation by comparing growth on CO, syngas, and a high-H2 CO gas mix using chemostat cultures of Clostridium autoethanogenum. Cultures were characterised at the molecular level using metabolomics, proteomics, gas analysis, and a genome-scale metabolic model (GEM). CO-limited chemostats operated at two steady-state biomass concentrations facilitated co-utilisation of CO and H2. We show that H2 supply strongly impacts carbon distribution with a four-fold reduction in substrate loss as CO2 (61% vs. 17%) and a proportional increase of flux to ethanol (15% vs. 61%). Notably, H2 supplementation lowers the molar acetate/ethanol ratio by five-fold. At the molecular level, quantitative proteome analysis showed no obvious changes leading to these metabolic rearrangements suggesting the involvement of post-translational regulation. Metabolic modelling showed that H2 availability provided reducing power via H2 oxidation and saved redox as cells reduced all the CO2 to formate directly using H2 in the Wood-Ljungdahl pathway. Modelling further indicated that the methylene-THF reductase reaction was ferredoxin-reducing under all conditions. In combination with proteomics, modelling also showed that ethanol was synthesised through the acetaldehyde:ferredoxin oxidoreductase (AOR) activity. Conclusions: Our quantitative molecular analysis revealed that H2 drives rearrangements at several layers of metabolism and provides novel links between carbon, energy, and redox metabolism advancing our understanding of energy conservation in acetogens. We conclude that H2 supply can substantially increase the efficiency of gas fermentation and thus the feed gas composition can be considered an important factor in developing gas fermentation-based bioprocesses.
2018-03-05 | PXD008367 | Pride
Project description:Gas fermentation offers both fossil carbon-free sustainable production of fuels and chemicals and recycling of gaseous and solid waste using gas-fermenting microbes. Bioprocess development, systems-level analysis of biocatalyst metabolism, and engineering of cell factories are advancing the widespread deployment of the commercialised technology. Acetogens are particularly attractive biocatalysts but effects of the key physiological parameter – specific growth rate (μ) – on acetogen metabolism and the gas fermentation bioprocess have not been established yet. Here, we investigate the μ-dependent bioprocess performance of the model-acetogen Clostridium autoethanogenum in CO and syngas (CO+CO2+H2) grown chemostat cultures and assess systems-level metabolic responses using gas analysis, metabolomics, transcriptomics, and metabolic modelling. We were able to obtain steady-states up to μ ~2.8 day-1 (~0.12 h-1) and show that faster growth supports both higher yields and productivities for reduced by-products ethanol and 2,3-butanediol. Transcriptomics data revealed differential expression of 1,337 genes with increasing μ and suggest that C. autoethanogenum uses transcriptional regulation to a large extent for facilitating faster growth. Metabolic modelling showed significantly increased fluxes for faster growing cells that were, however, not accompanied by gene expression changes in key catabolic pathways for CO and H2 metabolism. Cells thus seem to maintain sufficient “baseline” gene expression to rapidly respond to CO and H2 availability without delays to kick-start metabolism. Our work advances understanding of transcriptional regulation in acetogens and shows that faster growth of the biocatalyst improves the gas fermentation bioprocess.
2022-04-12 | GSE196640 | GEO
Project description:H2 and CO2 enriched mixed culture fermentation Raw sequence reads
| PRJNA433311 | ENA
Project description:The expression profile of C. autoethanogenum DSM 10061 grown autotrophically with H2:CO:CO2 under visible light at an intensity of 4200 lux versus the expression profile of C. autoethanogenum DSM 10061 grown autotrophically in the dark
2023-07-01 | GSE207468 | GEO
Project description:thermophilic HfMBR for H2 and CO2 utilization Raw sequence reads
| PRJNA449240 | ENA
Project description:Molecular hydrogen (H2) has been used in several clinical cases. However, few studies have been reported on the use of hydrogen therapy for treatment of sepsis, and the anti-inflammatory mechanism of H2 remains majorly unknown. The aim of this study is to confirm the effects of H2 therapy for sepsis and reveal its therapeutic mechanism by performing RNA-seq in multiple organs in the septic mice. Nine-week-old C57BL/6 male mice underwent cecal ligation and puncture procedure (CLP) or sham procedure. Subsequently, the CLP model received an immediate +/- continuous inhalation of 7% H2. The H2 gas-treated groups were housed in the same cage, and they were put in a designated box that was able to maintain the concentration of H2 through constant H2 supply by a gas generator. Mice were observed for a week to assess their survival rates. Serum inflammatory cytokines were evaluated with ELISA at 24 h after the CLP procedure.
2021-02-28 | GSE152527 | GEO
Project description:Molecular hydrogen (H2) is a biologically active gas that is used medically to ameliorate various systemic pathological conditions. H2 also regulates gene expression involved in intracellular signaling and metabolic pathways. Therefore, we attempted to identify genes that exhibit similar changes in expression in response to H2 by employing DNA microarrays and gene set enrichment analysis. We found that H2 activated the expression of sets of genes regulated by histone H3K27 methylation status. H2 also modified the expression of many genes regulated by a wide variety of signaling pathways.
2017-09-08 | GSE102869 | GEO
Project description:Cyanobacteria are oxygenic photoautotrophs notable for their ability to utilize atmospheric CO2 as the major source of carbon. The prospect of using cyanobacteria in converting solar energy and high concentrations of CO2 (e.g. flue gas from coal power plants) efficiently into biomass and renewable energy sources is of interest to many research fields. In order to guide further advances in this area, a better understanding about the metabolic changes that occur under conditions of high CO2 is important. The objective of this study is to utilize genome-wide microarray expression profiling in the unicellular diazotrophic cyanobacterium Cyanothece 51142 grown in 8% CO2-enriched air and to determined the impact of high CO2 on cyanobacterial cell physiology and growth.
2012-10-30 | GSE37621 | GEO