Norway uses microbes to make 96% pure

August 10, 2025

Scientists at the Norwegian Institute of BIOeconomy Research (NIBIO) have turned to biofilms to turn carbon-based gases such as carbon dioxide (CO2) and carbon monoxide (CO) into biomethane, a green and sustainable alternative to natural gas. 

These biofilm-based processes can produce biomethane with 96 percent purity, an organizational press release said. 

Biofilm is the term used to describe a community of different microorganisms that stick to each other and surfaces, forming a slimy extracellular matrix.

Inside the matrix are biological components such as lipids, proteins, and sugars that work to process gases and convert them into methane. 

Biofilms are often described as cities for microbes and can form on living or non-living surfaces. 

Unlike a traditional biogas production plant, where matter decomposition leads to methane formation, carbondixode and other gases, a biofilm-based process can process different gas streams to primarily produce methane, giving greater purity yields. 

“Our aim has been to engineer the biofilm to work for us for targeted conversion, either by using fixed or moving bed reactors,” explained Lu Feng, research scientist at NIBIO, who was involved in the work.

“This opens new opportunities to convert climate-impacting gases into valuable energy.”

Aiming for high methane quality

Industrial gas streams are usually directed to bioreactors to convert them into usable fuel such as methane. However, higher levels of other gases such as hydrogen sulphide (H2S) and ammonia can affect methane outputs. 

Higher ammonia levels are common when animal or food waste is used for biogas production. Feng and his team turned to a different type of reactor called Anaerobic Moving Bed Biofilm Reactor (AnMBBR) in their work to overcome challenges of ammonia and H2S gases. 

Using biofilms, the researchers were able to develop a more stable and efficient process, which improved the gas-liquid contact, thereby increasing the surface area available for the reaction. 

“The results showed that systems without biofilm lost up to 30 percent of the methane, while the biofilm reactors maintained high methane quality even at extremely high H2S content,” added Feng in a press release. 

Using unconventional substrates

The research team has also looked beyond the conventional biogas applications to see if the use of biofilms could improve the production of other gases. One such application was for the production of syngas – a combination of hydrogen and carbon monoxide. 

Feng and his colleagues found that using biofims also allowed them to utilize woody biomass and plastic waste in syngas production, something that has resisted degradation in bioprocesses before. 

Adding hydrogen has to the process showed an increase in methane production. However, adding too much hydrogen imbalanced the process. 

“This shows that biofilm reactors have great potential, but also that they require careful control to function optimally at an industrial scale,” said Feng. 

“Biofilm-based processes offer a robust and flexible platform for future biogas production. This could become an important contribution to reducing harmful gas emissions while producing renewable energy,” concluded Feng.