MethaSyn

Effective and stable methane production

In the X-Energy sub-project MethaSyn, fundamental relationships and efficiency influences of syntrophic, i.e. mutually beneficial, mixed microorganism cultures for biological methane production were explored. This new and innovative approach can contribute to increasing gas production and the stability of biological methanisation. It was also investigated in how far the syntrophic mixed cultures are also suitable applications for electromethanogenesis (X-Energy sub-projects DUEME  and EmSpe).

Biological methanisation (BM), i.e. the biological conversion of hydrogen (H2) and carbon dioxide (CO2) to methane, is a way of making green electricity storable. A major advantage of methane gas over the direct use of hydrogen produced by electrolysis is the wide range of technical applications and storage options designed for natural gas. As the availability of electricity from renewable energy sources to generate the hydrogen required for the BM varies greatly due to fluctuating wind and solar conditions, a BM should ideally be able to withstand these fluctuations without a reduction in performance.

Results

MethaSyn's novel approach aims to use a further group of organisms in addition to the methanogenic archaea traditionally used to ensure almost uninterrupted methane production despite pauses in hydrogen production, thus achieving greater overall efficiency. When H2 and CO2 are fed in, acetogenic bacteria and methanogenic archaea convert these reactant gases equally: to acetic acid by the bacteria and to methane by the archaea. During pauses in the feed, the residual dissolved hydrogen is still converted, then the archaea switch to utilising the acetic acid produced and form methane from this. If H2 and CO2 are fed in again, hydrogen is again favoured due to the better energy production through hydrogenotrophic methanogenesis. The advantage of acetogenic bacteria is that the pH value is stabilised by capturing the acetic acid formed. The methanogenic archaea benefit from the intermediate substrate acetic acid as an energy source and thus the maintenance of their metabolism.

By using pure green, electrolytically produced hydrogen and CO2 from industrial processes or CO2 extraction from the air, the MethaSyn project has contributed to a new solution for the effective and stable production of biomethane.

 

Project Team:

Dr. Sandra Off
Duration
-
Budget
145.200
Funding
Federal Ministry of Education and Research
Unit
CC4E - Competence Center for Renewable Energies and Energy Efficiency
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