Some bacteria and archaea use atmospheric carbon monoxide (CO) as an energy source. Bacteria use an enzyme called Mo-CODH to convert CO into carbon dioxide (CO₂) and transfer electrons to the respiratory chain. However, it’s unclear how these enzymes work at low CO concentrations and interact with the respiratory chain.
A new study by Monash University uncovered new information about how microbes consume vast amounts of carbon monoxide (CO) and help reduce levels of this deadly gas.
Researchers have uncovered how microbes consume atmospheric carbon monoxide (CO) at an atomic level. They use a special CO dehydrogenase enzyme to extract energy from this toxic gas.
Ashleigh Kropp, from Monash Biomedicine Discovery Institute’s Greening lab and the University of Melbourne’s Grinter lab, said the study showed for the first time how this enzyme extracts atmospheric CO and powers cells.
Credit: Credit Ashleigh Kropp and Dr David Gillett
Ms Kropp said, “This enzyme is used by trillions of microbes in our soils and waters. These microbes consume CO for their own survival but inadvertently help us in the process.”
Dr. David Gillett, who completed his PhD research in the Greening Lab, highlighted the microbial ingenuity in transforming toxic CO into something useful.
“These microbes help clean our atmosphere,” Dr. Gillett said. “This counteracts air pollution, which kills millions annually, and reduces global warming since CO is indirectly a greenhouse gas.”
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Although this discovery may not directly combat or monitor CO emissions, it enhances our understanding of atmospheric regulation and potential responses to future changes.
Professor Chris Greening, co-senior author and head of BDI’s Global Change Program, said the discovery highlighted the broader importance of microbes.
“Microbes play countless roles essential for both human and planetary health. Yet, because they’re invisible and often misunderstood, their contributions frequently go unnoticed,” he said.
Ms Kropp said microbes were a big reason why our air was breathable. “They make half the oxygen we breathe and detoxify various pollutants like CO. It’s crucial we better understand and appreciate how they support our own survival.”
Journal Reference:
- Kropp, A., Gillett, D.L., Venugopal, H. et al. Quinone extraction drives atmospheric carbon monoxide oxidation in bacteria. Nat Chem Biol (2025). DOI: 10.1038/s41589-025-01836-0
Source: Tech Explorist
