Turning Cow Emissions into Energy

Researchers study how cattle create methane — and how to stop it

by Julie Shlisky

If you’re worried about global warming and methane emissions, the elephant in the room is the cow burping in the pasture. Researchers in the Department of Biochemistry are unraveling the mechanisms behind how cows produce methane and how those emissions might be reduced.

Ruminant animals such as cows depend on special microbes in their stomachs to digest plants like grass and hay. This process creates methane, a potent greenhouse gas that has a warming potential greater than 25 times that of carbon dioxide. The U.S. Environmental Protection Agency reports that 37 percent of human-related methane emissions come from livestock and agricultural practices.

Associate Professor Kylie Allen in the Department of Biochemistry studies digestive enzymes found in methane-producing microbes that live in the guts of ruminants. Her work focuses on metalloenzymes — enzymes that require metal atoms to form methane. These enzymes are dependent on nickel and iron.

Allen’s Hatch project explores how these unique enzymes work and whether they could be key to reducing methane production in cattle. Using genetic and biochemical tools, she works to pinpoint which enzymes are essential to methane formation and when they act in the process.

“Understanding the enzymes involved in methane production could inform new strategies that limit methane emissions and improve feed efficiency — a major cost for farmers,” Allen said.

Feed efficiency measures much useful output come from the feed you give an animal. When cattle produce methane, about 10 percent of the energy from that feed is lost. Reducing methane production would improve cattle feed efficiency, lowering costs for producers while cutting greenhouse gas emissions. Because beef cattle and dairy products rank among Virginia’s top agricultural commodities, this research could have big impacts for the state’s producers.

Allen’s lab has identified modified forms of the nickel-containing coenzyme that catalyzes the final step of methane production. The team has also discovered proteins that help gather and deliver nickel to enzymes that need it. By understanding the detailed steps in methane production, researchers hope to learn how to adjust enzyme activity and speed up or slow down methane formation.

Biochemistry faculty, including Allen, also collaborate with a biotechnology company BiomEdit, Inc., which develops innovative products including feed additives to mitigate methane production from livestock animals.

“Very few researchers have expertise working with metalloenzymes” said Dwi Susanti, head of methane emissions reduction research at BiomEdit.

Partnering to gain a better understanding of the biochemistry microbes use to generate methane could support development of new products that increase feed efficiency and reduce emissions.

Methane can also serve as a renewable energy source. That means insights into how these specific methane-creating enzymes work could have bioenergy applications.

“If methane were converted into a more stable form, the energy could be maintained and reused rather than put out into the environment,” Allen said.

Such advances would not only support Virginia’s producers, but any creature interested in a stable climate.

To learn more about this story, contact Julie Shlisky at juliesb@vt.edu.