Over two billion tons of carbon monoxide are released into the atmosphere globally each year. Diverse bacteria and archaea consume about 250 million tons of this, reducing carbon monoxide to safer levels. According to new research, these microbes use a special enzyme, called the CO dehydrogenase, to extract energy from this universally present but highly toxic gas.
Kropp et al. demonstrate that the CO dehydrogenase is capable of oxidizing carbon monoxide to subatmospheric levels. Image credit: NASA / NOAA / GSFC / Suomi NPP / VIIRS / Norman Kuring.
“Carbon monoxide is both a potent poison of multicellular life and a high-energy fuel and carbon source for microorganisms,” said Ashleigh Kropp from Monash University and colleagues.
“Carbon monoxide is released into the atmosphere in vast quantities, with natural and anthropogenic sources contributing an estimated 2,600 million tons of carbon monoxide emissions annually.”
“Despite this, average carbon monoxide concentrations in the atmosphere remain extremely low, at around 100 ppb, because of consumption by abiotic processes and microbial oxidation.”
“Microbial consumption accounts for an estimated 10-15% of carbon monoxide removed from the atmosphere (approximately 250 million tons annually).”
In their study, the authors showed for the first time how the CO dehydrogenase extracted atmospheric carbon monoxide and powered cells.
“This enzyme is used by trillions of microbes in our soils and waters. These microbes consume carbon monoxide for their own survival, but in the process inadvertently help us,” Kropp said.
“This was a fantastic example of microbial ingenuity: how life has evolved ways to turn something toxic into something useful,” said Dr. David Gillett, also of Monash University.
“These microbes help clean our atmosphere. This counteracts air pollution, which kills many millions of people each year, and also reduces global warming given carbon monoxide is indirectly a greenhouse gas.”
“While this discovery is unlikely to be directly used to combat or monitor carbon monoxide emissions, it deepens our understanding of how the atmosphere is regulated and how it might respond to future changes.”
“The discovery highlighted the broader importance of microbes,” said Monash University’s Professor Chris Greening.
“Microbes play countless roles essential for both human and planetary health. Yet, because they’re invisible and often misunderstood, their contributions frequently go unnoticed.”
“Microbes were a big reason why our air was breathable,” Kropp said.
“They make half the oxygen we breathe and detoxify various pollutants like carbon monoxide.”
“It’s crucial we better understand and appreciate how they support our own survival.”
The findings appear in the journal Nature Chemical Biology.
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A. Kropp et al. Quinone extraction drives atmospheric carbon monoxide oxidation in bacteria. Nat Chem Biol, published online January 29, 2025; doi: 10.1038/s41589-025-01836-0
Source : Breaking Science News