Rotaru Lab

University of Southern Denmark

Status: completed (2015-2019)

InnovationsFonden awarded 20 mil. DKK for the project “Electrogas” a joint project between danish, US, and Australian Universities and danish companies. At SDU we are getting a share of ca. 2.6 mil DKK to study the mechanisms of electron transfer to methanogenic Archaea capable of electromethanogenesis.
  • Amelia-Elena Rotaru (PI, SDU)
  • Yee Mon Oo (PhD student) studies how methanogens interact with cathodes
  • Oona Snoeyenbos-West (postdoc guest) – studies DIET-interactions in biogas upgrading

Project summary

ElectroGas is about storing electricity. The approach is biogenic production of CH4 from CO2 in anaerobic digesters (AD), by either ex-situ or in-situ supply of reducing equivalents which may be added indirectly via the addition of H2 gas produced by electrolysis, or directly via a cathodic supply of electrons to the microbes. ElectroGas use recent advances in fundamental microbial ecology, bioelectric synthesis, ion-permeable membranes, gas-liquid mixing and AD engineering to overcome the microbial limitations and engineering constraints for biogenic energy conversion (CO2 methanisation) in operating ADs. Two approaches on different Technology Readiness Levels (TRL’s EU H2020 definition) will be used: I) Electrolysis of H2O to H2, subsequently added to the AD (TRL3 to TRL6). Engineering research will be on solutions to efficiently mass transfer very large volumes (>4 times reactor volume per day) of H2 gas directly to the homoacetogenic bacteria or hydrogenothrophic methanogens to 1000-5000 m3 scale AD reactors. Main scientific work will be on microbial community dynamics upon pulse H2 additions and microbial kinetics when CO2 is limited. II) Microbial electrosynthesis (ME) using direct electron transfer (DIET) to a biofilm on a biocathode, ideally inside the AD (TRL 2 to TRL4). Scientific work includes the investigation of biofilms and their mechanisms capable of DIET and the potential surface-specific current densities. Engineering research includes the development of scalable anode and cathode designs with new membranes, materials, and structures for efficient charge (e- and H+) transfer. ME on large cathodes has the clear advantage of omitting stand-alone H2 production and gas mass transfer of H2 to the liquid, and possible lower conversion loss.

Publications fully or partially funded by Electrogas

Contributions to WP4 by the SDU team
  1. Yee et al., 2020. Nanotechnology (accepted)
  2. Yee & Rotaru, 2020. Sci. Rep. 10:327
  3. Yee et al., 2019. Front. Energy Res. 7: 1-10
  4. Holmes et al., 2018. Front. Microbiol. 9: 3109
  5. Ueki et al. 2018. mBio 9(4)
  6. Holmes et al. 2018. Microbial Ecology: 1-8
  7. Rotaru and Shrestha. 2016. Frontiers in Microbiology 7:662
Ph.D. thesis fully funded by Electrogas 

Yee, M. O. (2019). Extracellular Electron Transfer in Methanogenic Archaea. PhD thesis. The University of Southern Denmark.