Biological Methanation of H2 and CO2 with Mixed Cultures: Current Advances, Hurdles and Challenges

Rafrafi, Yan; Laguillaumie, Léa; Dumas, Claire

doi:10.1007/s12649-020-01283-z

Cited by 49 publications

(33 citation statements)

References 91 publications

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“…The reactors were continuously fed with varying glucose loads. Methanotrix species apparently cannot carry out hydrogenotrophic methanogenesis, therefore their predominance under these conditions can be rationalized by the combined effects of glucose and CO-rich syngas addition via carboxydotrophic methanogenesis [ 55 ]. In addition, the recently recognized capability of Methanotrix species to carry out direct electron transfer (DIET) to drive CO 2 reduction could facilitate the Methanotrix predominance [ 56 , 57 ].…”

Section: Discussionmentioning

confidence: 99%

Early response of methanogenic archaea to H2 as evaluated by metagenomics and metatranscriptomics

et al. 2021

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Background The molecular machinery of the complex microbiological cell factory of biomethane production is not fully understood. One of the process control elements is the regulatory role of hydrogen (H2). Reduction of carbon dioxide (CO2) by H2 is rate limiting factor in methanogenesis, but the community intends to keep H2 concentration low in order to maintain the redox balance of the overall system. H2 metabolism in methanogens becomes increasingly important in the Power-to-Gas renewable energy conversion and storage technologies. Results The early response of the mixed mesophilic microbial community to H2 gas injection was investigated with the goal of uncovering the first responses of the microbial community in the CH4 formation and CO2 mitigation Power-to-Gas process. The overall microbial composition changes, following a 10 min excessive bubbling of H2 through the reactor, was investigated via metagenome and metatranscriptome sequencing. The overall composition and taxonomic abundance of the biogas producing anaerobic community did not change appreciably 2 hours after the H2 treatment, indicating that this time period was too short to display differences in the proliferation of the members of the microbial community. There was, however, a substantial increase in the expression of genes related to hydrogenotrophic methanogenesis of certain groups of Archaea. As an early response to H2 exposure the activity of the hydrogenotrophic methanogenesis in the genus Methanoculleus was upregulated but the hydrogenotrophic pathway in genus Methanosarcina was downregulated. The RT-qPCR data corroborated the metatranscriptomic Results H2 injection also altered the metabolism of a number of microbes belonging in the kingdom Bacteria. Many Bacteria possess the enzyme sets for the Wood-Ljungdahl pathway. These and the homoacetogens are partners for syntrophic community interactions between the distinct kingdoms of Archaea and Bacteria. Conclusions External H2 regulates the functional activity of certain Bacteria and Archaea. The syntrophic cross-kingdom interactions in H2 metabolism are important for the efficient operation of the Power-to-Gas process. Therefore, mixed communities are recommended for the large scale Power-to-Gas process rather than single hydrogenotrophic methanogen strains. Fast and reproducible response from the microbial community can be exploited in turn-off and turn-on of the Power-to-Gas microbial cell factories.

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Section: Discussionmentioning

confidence: 99%

Early response of methanogenic archaea to H2 as evaluated by metagenomics and metatranscriptomics

et al. 2021

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“…The results corroborated the existence of a delicate balance between homoacetogenesis and methanogenesis, which is closely regulated by the H 2 level within the system [20,62,63]. The time resolution of sampling, analytical measurements, and the complexity of the biochemical reactions in the system did not allow calculation of a precise mass balance in this system.…”

Section: Discussionmentioning

confidence: 78%

“…Hydrogenotrophic methanogens reduce carbon dioxide (CO 2 ) to CH 4 when the appropriate reducing power, i.e., H 2 or low redox potential electrons, is available. H 2 can be obtained from water electrolysis powered by renewable electricity, closing the circular character of this energy conversion process, called Power-to-Methane (P2M) [7,15,19,20]. P2M is accomplished either within the biogas producing AD reactor, i.e., in situ P2M, or in a separate reactor vessel, i.e., ex situ P2M, or in a combination thereof [15,19].…”

Section: Introductionmentioning

confidence: 99%

Development of Stable Mixed Microbiota for High Yield Power to Methane Conversion

et al. 2021

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The performance of a mixed microbial community was tested in lab-scale power-to-methane reactors at 55 °C. The main aim was to uncover the responses of the community to starvation and stoichiometric H2/CO2 supply as the sole substrate. Fed-batch reactors were inoculated with the fermentation effluent of a thermophilic biogas plant. Various volumes of pure H2/CO2 gas mixtures were injected into the headspace daily and the process parameters were followed. Gas volumes and composition were measured by gas-chromatography, the headspace was replaced with N2 prior to the daily H2/CO2 injection. Total DNA samples, collected at the beginning and end (day 71), were analyzed by metagenome sequencing. Low levels of H2 triggered immediate CH4 evolution utilizing CO2/HCO3− dissolved in the fermentation effluent. Biomethanation continued when H2/CO2 was supplied. On the contrary, biomethane formation was inhibited at higher initial H2 doses and concomitant acetate formation indicated homoacetogenesis. Biomethane production started upon daily delivery of stoichiometric H2/CO2. The fed-batch operational mode allowed high H2 injection and consumption rates albeit intermittent operation conditions. Methane was enriched up to 95% CH4 content and the H2 consumption rate attained a remarkable 1000 mL·L−1·d−1. The microbial community spontaneously selected the genus Methanothermobacter in the enriched cultures.

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“…The reactors were continuously fed with varying glucose loads. Methanotrix species apparently cannot carry out hydrogenotrophic methanogenesis, therefore their predominance under these conditions can be rationalized by the combined effects of glucose and CO-rich syngas addition via carboxydotrophic methanogenesis [51]. In addition, the recently recognized capability of Methanotrix species to carry out direct electron transfer (DIET) to drive CO 2 reduction could facilitate the Methanotrix predominance [52,53].…”

Section: Discussionmentioning

confidence: 99%

Early response of methanogenic archaea to H2 as evaluated by metagenomics and metatranscriptomics

Kakuk

Wirth

Maróti³

et al. 2021

Preprint

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Background. The detailed molecular machinery of the complex microbiological cell factory of biogas/biomethane production is not fully understood. One of the main puzzling process control elements is the formation, consumption and regulatory role of hydrogen (H2). Reduction of carbon dioxide (CO2) by H2 is rate limiting factor in methanogenesis, but the community intends to keep H2 concentration low in order to maintain the redox balance of the overall system. H2 metabolism in methanogens becomes increasingly important in the Power-to-Gas renewable energy conversion and storage technologies. Results. The early response of the mixed mesophilic microbial community to H2 gas injection was investigated with the goal of uncovering the first responses of the microbial community in the CH4 formation and CO2 mitigation Power-to-Gas process. The overall microbial composition changes, following a 10 min H2 injection by excessive bubbling of H2 through the reactor, was investigated via metagenome and metatranscriptome sequencing. The overall composition and taxonomic abundance of the biogas producing anaerobic community did not change appreciably two hours after the H2 treatment, indicating that this time period was too short to display differences in the proliferation of the members of the microbial community. There was, however, a substantial increase in the expression of genes related to hydrogenotrophic methanogenesis of certain groups of Archaea. H2 injection also altered the metabolism of a number of microbes belonging in the kingdom Bacteria. The importance of syntrophic cross-kingdom interactions in H2 metabolism and the effects on the related Power-to-Gas process are discussed. Conclusion s. External H2 regulates the functional activity of certain Bacteria and Archaea. Mixed communities are recommended for the large scale Power-to-Gas process rather than single hydrogenotrophic methanogen strains. Fast and reproducible response from the microbial community can be exploited in turn-off and turn-on of the Power-to-Gas microbial cell factories.

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Biological Methanation of H2 and CO2 with Mixed Cultures: Current Advances, Hurdles and Challenges

Cited by 49 publications

References 91 publications

Early response of methanogenic archaea to H2 as evaluated by metagenomics and metatranscriptomics

Early response of methanogenic archaea to H2 as evaluated by metagenomics and metatranscriptomics

Development of Stable Mixed Microbiota for High Yield Power to Methane Conversion

Early response of methanogenic archaea to H2 as evaluated by metagenomics and metatranscriptomics

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