CO2capture

Capture of CO2 from exhaust gases using photosynthetic microorganisms

Human activities release vast amounts of CO2 that harm the climate and society, yet this carbon also represents a largely untapped resource for sustainable biotechnology. This project investigated how photosynthetic microorganisms can be used to capture CO2 from industrial exhaust gases, where CO2 concentrations are far higher than those found in natural environments.

Although all photosynthetic organisms are highly efficient at sequestering atmospheric CO2, they are not naturally adapted to the extreme CO2 levels present in exhaust gases. The aim of the project was to understand why elevated CO2 concentrations inhibit photosynthesis and growth in cyanobacteria—even when pH is maintained at optimal levels—and to identify strategies to overcome this limitation. We found that high CO2 induces a distinct stress response that disrupts photosynthesis, cellular regulation, and growth, and we identified key physiological and regulatory bottlenecks underlying this response. Importantly, we also demonstrated that targeted genetic modifications can significantly improve tolerance to high CO2, enabling sustained growth and CO2 uptake under these conditions.

Overall, the project opens new opportunities for sustainable biotechnology by enabling efficient CO2 capture and its conversion into biomass and other valuable products.

 

Section for Marine Biology (MBS), Department of Biology (BIO), University of Copenhagen


Center for non-coding RNA in Technology and Health (RTH), Department of Veterinary and Animal Sciences (IVH), University of Copenhagen


External collaborators

  • Professor, Dr. Wolfgang Hess, University of Freiburg, Germany
  • Professor Paul Hudson, KTH Royal Institute of Technology, Stockholm, Sweden
  • Professor Brian F. Pfleger, University of Wisconsin – Madison, USA
  • Dr. Carsten Hjort, Senior Science Director, Novozymes A/S, Denmark

 

 

  • E. Carrasquer-Alvarez, U. A. Hoffmann, A. S. Geissler, A. Knave, J Gorodkin, S. E. Seemann, E. P. Hudson, N.-U. Frigaard (2025) Photosynthesis in Synechocystis sp. PCC 6803 is not optimally regulated under very high CO2. Applied Microbiology and Biotechnology 109(1):33. https://doi.org/10.1007/s00253-025-13416-2 
  • E. Carrasquer-Alvarez, A. S. Geissler, J. P. Abraham, J. Gorodkin, B. F. Pfleger, S. E. Seemann, N.-U. Frigaard (2026) Light and excessive CO2 uptake inhibit growth of Synechococcus sp. PCC 7002 under very high CO2 levels. Algal Research, https://doi.org/10.1016/j.algal.2026.104705 
  • A. S. Geissler, E. Carrasquer-Alvarez, C. Anthon, N.-U. Frigaard, J. Gorodkin, S. E. Seemann (2026) Exploring the regulatory potential of RNA structures in 202 cyanobacterial genomes. Nucleic Acids Research 54:gkag081. https://doi.org/10.1093/nar/gkag081 
  • A. S. Geissler, E. Carrasquer-Alvarez, J. Gorodkin, N.-U. Frigaard, S. E. Seemann (2026) Very high CO2 concentrations inhibit photosynthesis and trigger transcriptomic stress responses in cyanobacteria. NAR Genomics and Bioinformatics 8:lqaf207. https://doi.org/10.1093/nargab/lqaf207

 

 

Student projects are offered related to the biology and applications of CO2 metabolism in photosynthetic microorganisms (cyanobacteria and microalgae).

 

 

Funding



Grant: 6.2 million DKK

Period: August 2021 – January 2026

Project Coordinator: Niels-Ulrik Frigaard

Contact

Assoc. Prof. Niels-Ulrik Frigaard
Photosynthetic Microbes Laboratory
Marine Biological Section
Department of Biology
Faculty of Science
Strandpromenaden 5
DK-3000 Helsingør

E-mail: nuf@bio.ku.dk
Phone: +45 35 32 19 57

Assoc. Prof. Stefan E Seemann
Center for non-coding RNA in Technology and Health
Department of Veterinary and Animal Sciences
Faculty of Health and Medical Sciences
Thorvaldsensvej 57
DK-1871 Frederiksberg

E-mail: sse@sund.ku.dk