DENTON (UNT), Texas — In 2019, Calvin Henard’s transitioned from a researcher at the National Renewable Energy Lab in Colorado back to his home state of Texas, where he joined the University of North Texas Department of Biological Sciences as an assistant professor and a researcher at the BioDiscovery Institute.
His research and teaching center around microbiology, and the focus of his lab is to use methanotrophic bacteria to convert methane gas into bioplastics, biofuels and other valuable products, rather than allow it to be released into the atmosphere.
“Methanotrophic bacteria play a really important role in the carbon cycle on earth, since they are the only organisms that are able to use atmospheric methane. They actually eat about 10% to 15% of methane in the atmosphere,” Henard said. “The real focus of the lab is to leverage these organisms to mitigate atmospheric greenhouse gases.”
While working at the National Renewable Energy Laboratory, he began research evaluating the role of the enzyme RubisCO in methanotrophic bacteria, an enzyme also found in plants that is responsible for the majority of carbon dioxide utilization on Earth. Henard has continued his research at UNT, which was recently published in the journal Applied and Environmental Microbiology and chosen by its editors as a spotlight article.
“RubisCO has been known to be expressed by a subset of methanotrophic bacteria for decades, but the role of that enzyme in these bacteria has been unknown and elusive,” Henard said. “What we did is essentially re-evaluate the role of that enzyme and show that it’s not only functional, but essential for growth of the bacteria.”
Through this research, Henard learned that some methanotrophs consume carbon dioxide in addition to methane.
“Some methanotrophs, including this organism, use both methane and carbon dioxide, and there could be a lot more of these types of dual methane/carbon dioxide-utilizing organisms in the environment, but they haven’t been looked for yet,” Henard said.
Henard speculates that it’s highly likely these bacteria are consuming methane and carbon dioxide in the soil. He just needs to provide experimental evidence that the co-consumption of these gases is already occurring in the environment. His research serves as a benchmark establishing this metabolism exists, and now researchers can find new ways to convert the two most abundant greenhouse gases into products using methanotrophic bacteria.
“Our goal is to simultaneously utilize and mitigate greenhouse gases in a single, sustainable process that converts the gases into valuable chemicals,” Henard said. “We could make products from methane and carbon dioxide that would normally be derived from petroleum. It’s a dual route to help the planet and have a sustainable bioeconomy.”