From problem to resource: Microbiological conversion of CO2 from flue gas to acetate
PhD defense, Thursday, 20 august 2026, Amalie Kirstine Hessellund Nielsen
During her PhD studies, Amalie Kirstine Hessellund Nielsen developed a concept, where microorganisms convert CO2 captured from flue gas to acetate, which further can be converted to fossil-free chemicals, materials and protein.
CO2 is captured from industrial sources by a liquid chemical, which both inhibits microorganisms and contaminates the produced acetate. Amalie discovered that both inhibition and contamination can be avoided by separating the CO2-rich liquid and the microorganism by a CO2-permable membrane. The new membrane system achieved production rates at level with conventional reactor designs, and the research further found that the production rates were influenced by the CO2 concentration in the capture solvent, and the choice of both microorganism and membrane.
The developed concept supports the application of microorganisms to valorize dilute CO2-gases as a carbon source in a future fossil free society.
The PhD study was completed at the Department of Biological and Chemical Engineering, Faculty of Technical Sciences, Aarhus University.
This summary was prepared by the PhD student.
Time: Thursday, 20th august 2026 at 13:00
Place: Building 1593, room 012, Aarhus University, Gustav Wieds Vej 22, 8000, Aarhus C
Title of PhD thesis: Converting dilute CO2 sources into methane and acetate in a membrane bioreactor
Contact information: Amalie Kirstine Hessellund Nielsen, e-mail: amalie-hessellund@hotmail.com, tel.: +45 20852568
Members of the assessment committee:
Associate Professor Massimiliano Errico, Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Italy
Professor Annemiek ter Heijne, Environmental Technology, Wageningen University & Research, The Netherlands
Associate Professor Bekir Engin Eser, Department of Biological and Chemical Engineering, Aarhus University (Chair), Denmark
Main supervisor: Associate Professor Michael Vedel Wegener Kofoed, Department of Biological and Chemical Engineering, Aarhus University, Denmark
Co-supervisor: Professor Lars Ditlev Mørck Ottosen, Department of Biological and Chemical Engineering, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English
The defence is public.
The PhD thesis is available for reading at the Graduate School of Technical Sciences/GSTS, Ny Munkegade 120, building 1521, 8000 Aarhus C.