Climate change research reveals tiny microbes that eat two powerful greenhouse gases

A researcher who’s coming to the University of Calgary has helped to discover tiny microbes that eat two powerful greenhouse gases — methane and nitrous oxide — often at the same time.

The research, published in Nature Communications in May, showed that the bacteria found in methane-producing environments such as acidic wetlands and rice paddies could be used to help to clean up the atmosphere.

“It has been pretty surprising,” said Dr. Samuel Imisi Awala, who’s the lead author on the paper and assistant professor in research at Chungbuk National University in South Korea, where he worked on the project with principal investigator and professor Sung-Keun Rhee.

Awala will join the University of Calgary’s Faculty of Science later this summer as a postdoctoral scholar to work with Dr. Peter Dunfield, PhD.

Dunfield, a professor of biological sciences who’s a co-author on the paper, said it’s important work.

“Climate change … is by far the most important problem that we are facing at the moment,” Dunfield said in an interview. “There are three main gases that contribute to climate change: carbon dioxide, methane and nitrous oxide.”

These greenhouse gases go up into the atmosphere and heat the planet, which has led to more extreme weather. Reducing emissions of these gases could help to slow down climate change.

Awala said the research has shown that methane-eating microbes — or aerobic methanotrophic bacteria — have an enzyme that can also break down nitrous oxide.

Nitrous oxide is seen as the third most important greenhouse gas, he said, but its warming effects are almost 300 times higher than carbon dioxide. Similarly, he noted that methane’s warming potential is about 25 times higher than carbon dioxide.

“It’s very important to attend to these greenhouse gases,” said Awala. “Previously the focus has been on carbon dioxide but now there’s a lot of attention on methane and nitrous oxide. People are trying to find biology-based strategies to effectively remove these two greenhouse gases from the atmosphere.”

The study, he said, provided some new insight into the microbes.

“For the first time, we are able to show … they can actually respire nitrous oxide,” Awala said. “Nitrous oxide is particularly significant in acidic environments, where the microbial consumption of this gas is strongly inhibited.

“The group of microbes that we found were acid lovers capable of consuming nitrous oxide.”

Awala said they were also able to show that the microbes could break down methane and nitrous oxide — often at the same time.

“That was the very interesting part for us,” he said, suggesting it could have implications in similar environments, such as the oilsands tailings ponds in northern Alberta.

Dunfield said the research could also help in the fight against global warming. “If we want to get climate change under control, the first thing we should do — the thing that’s going to bring the biggest returns — is to figure out how to get rid of methane and nitrous oxide,” he said.

“So, this bacterium is really cool because it’s really the first bacterium that switches back and forth between using methane and using nitrous oxide.

“It’s a super greenhouse gas-consuming bacterium.”