Development of Stable Mixed Microbiota for High Yield Power to Methane Conversion
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 H<sub>2</sub>/CO<sub>2</sub> supply as the sole substrate. Fed-batch reactors...
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| Autores principales: | , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/1afbdd60633c44399af9ecd401e0544b |
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| Sumario: | 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 H<sub>2</sub>/CO<sub>2</sub> supply as the sole substrate. Fed-batch reactors were inoculated with the fermentation effluent of a thermophilic biogas plant. Various volumes of pure H<sub>2</sub>/CO<sub>2</sub> 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 N<sub>2</sub> prior to the daily H<sub>2</sub>/CO<sub>2</sub> injection. Total DNA samples, collected at the beginning and end (day 71), were analyzed by metagenome sequencing. Low levels of H<sub>2</sub> triggered immediate CH<sub>4</sub> evolution utilizing CO<sub>2</sub>/HCO<sub>3</sub><sup>−</sup> dissolved in the fermentation effluent. Biomethanation continued when H<sub>2</sub>/CO<sub>2</sub> was supplied. On the contrary, biomethane formation was inhibited at higher initial H<sub>2</sub> doses and concomitant acetate formation indicated homoacetogenesis. Biomethane production started upon daily delivery of stoichiometric H<sub>2</sub>/CO<sub>2</sub>. The fed-batch operational mode allowed high H<sub>2</sub> injection and consumption rates albeit intermittent operation conditions. Methane was enriched up to 95% CH<sub>4</sub> content and the H<sub>2</sub> consumption rate attained a remarkable 1000 mL·L<sup>−1</sup>·d<sup>−1</sup>. The microbial community spontaneously selected the genus <i>Methanothermobacter</i> in the enriched cultures. |
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