Turning Chimney Smoke into Sustainable Fuel: How CO₂-Eating Bacteria Are Revolutionizing Carbon Capture

“In a net-zero future, we need to use technology that recycles the CO2 we capture instead of continuing to extract more from the ground,” says Amalie Kirstine Hessellund Nielsen, a PhD student at the Department of Biological and Chemical Engineering (left). Right is Postdoc Mads Ujarak Sieborg. Credit: Aarhus University / Peer Klercke

In the fight against climate change, reducing carbon dioxide (CO₂) emissions from industrial processes is one of the biggest challenges. Traditionally, carbon capture methods focus on trapping CO₂ and storing it underground, but what if we could take those emissions and turn them into something useful?

A revolutionary new technology developed by researchers at Aarhus University (AU) offers a game-changing alternative—using specially adapted microorganisms to convert CO₂ from industrial emissions into valuable fuels and chemicals. This bio-integrated approach could significantly reduce our reliance on fossil fuels while making carbon capture more efficient and cost-effective.

How CO₂-Eating Bacteria Transform Industrial Emissions

Flue gases released from factories, power plants, and other industrial processes are a major source of CO₂ pollution. Typically, these emissions are difficult and expensive to capture because CO₂ is mixed with other gases, requiring energy-intensive processes to separate and store it.

However, AU researchers have developed a novel method that integrates carbon capture with biological conversion—a process known as Bio-Integrated Carbon Capture and Utilization (BICCU). Instead of storing the captured CO₂ underground, this approach directly transforms it into useful products such as methane (a green natural gas alternative) and acetic acid (a valuable industrial chemical).

This process eliminates the need for high-temperature separation, significantly reducing energy costs and making carbon capture more viable for widespread industrial adoption.

From CO₂ to Sustainable Products: The Science Behind the Process

Traditional Carbon Capture vs. Bio-Integrated Carbon Capture

Most existing carbon capture and storage (CCS) systems operate in two stages:

1. Absorption – CO₂ is removed from flue gases using chemical solvents like amines, a process known as amine scrubbing.

2. Release & Storage – The captured CO₂ is separated from the chemicals using high heat (120-140°C), then compressed and stored underground.

While effective, this method is energy-intensive and costly, consuming up to 30% of a power plant’s energy output.

How Bio-Integrated Carbon Capture Works

The new BICCU approach keeps the first step of amine scrubbing but introduces a biological conversion step instead of high-temperature separation.

• Microorganisms (CO₂-eating bacteria) are introduced into the system.

• These microbes metabolize the CO₂ and convert it into useful byproducts such as methane and acetic acid.

• The result is a low-energy, cost-effective solution that turns industrial waste into valuable resources.

  
  

“Microorganisms are incredibly specialized at absorbing and transforming CO₂—they’ve been refining this process for billions of years. By leveraging their abilities, we can remove CO₂ from industrial emissions while producing valuable fuels and chemicals,”

explains Mads Ujarak Sieborg, a postdoctoral researcher at Aarhus University and one of the lead authors of the study published in Nature Communications.

The Potential Impact: A Game-Changer for Industry and Sustainability

The adoption of biological CO₂ conversion could transform several key industries by offering:

• Lower Carbon Capture Costs – Eliminating high-heat separation reduces energy demand, making CO₂ recycling more affordable.

• Sustainable Fuel Production – The methane produced by the bacteria can be used as a green alternative to natural gas, reducing dependence on fossil fuels.

• Circular Carbon Economy – Industries that require carbon-based raw materials (such as chemicals and plastics) could use recycled carbon instead of extracting it from petroleum and natural gas.

  
  

Real-World Applications and Challenges

Although the technology shows promise, scaling up remains a challenge. Microorganisms require hydrogen to convert CO₂ efficiently, which is currently a limiting factor due to production costs.

“Hydrogen is a key component in this process, and while we obtain it through electrolysis, we need to optimize the system to make it more cost-effective. However, we already have multiple reactor designs ready for testing,”

says Amalie Kirstine Hessellund Nielsen, a PhD researcher at Aarhus University.

Despite these hurdles, this technology could play a critical role in decarbonizing industries that are difficult to electrify, such as:

• Cement and steel production

• Chemical and fertilizer industries

• Biogas plants that capture and recycle CO₂

  
  

The Future of CO₂ Utilization: A Step Toward Net-Zero Emissions

The global push toward net-zero emissions requires a multi-faceted approach, combining renewable energy expansion, carbon capture, and sustainable fuel production. While CO₂ utilization alone cannot replace renewable energy, it is a crucial tool in mitigating industrial emissions.

This innovative technology highlights the potential of nature-inspired solutions in addressing climate challenges. Instead of viewing CO₂ as waste, we can harness microbial power to create a circular, sustainable carbon economy.

As industries and governments look for scalable carbon reduction solutions, bio-integrated carbon capture could help bridge the gap between today’s emissions and tomorrow’s net-zero future.

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📌 Further Reading:

🔹 How Microorganisms Are Shaping the Future of Sustainable Energy

🔹 Carbon Capture vs. Carbon Utilization: Which Strategy Works Best?

🔹 The Role of Hydrogen in Next-Generation Industrial Decarbonization