The methane microbiome: How cattle’s gut bacteria affect greenhouse gas emissions

Renowned microbiologist and Professor Emeritus at the University of Aberdeen John Wallace speaks about his studies in the gut microorganisms of cattle. Wallace visited the K-State campus on Tuesday, speaking to K-State students studying different biological fields about how his research has affected the conversation of climate change. (Olivia Bergmeier | Collegian Media Group)

Professor Emeritus John Wallace from the University of Aberdeen in Scotland, who specializes in animal and human digestive tract microbiology, presented a lecture at Kansas State on Tuesday about his latest research. Recently, Wallace has been focused on how specific microbiomes and meta-genomes affect the amounts of methane emitted by beef and dairy cattle.

His studies in the microbiomes of the guts of cattle have shed light and information into the realm of sustainability and climate change. At the lecture on Tuesday, he spoke of his work on a project named “RuminOmics.”

Wallace said he believes cattle contribute about 10 percent of the total methane in the atmosphere. Methane is a greenhouse emission.

Some methane emission, Wallace said, comes from methanogenic archaea, which exist in the rumen, the first stomach of animals like cattle where food is partially digested before moving on through the over stomachs. These particular archaea make up smaller portions of the microbiome than typical bacteria do.

In his years of research, Wallace said he found a major contributing factor affecting the microbiome of cattle rumen: what they are fed. He said by adjusting the substances cattle are fed by ranchers and lot owners, greenhouse emissions through methane can be reduced.

Another way Wallace said these microbiomes can be adjusted is through the breeding. Breeding of different species for a desired microbiome or meta-genome in the rumen of cattle can almost half methane emissions, he said.

Part of the reason in the decrease of methane emissions by the cattle has to do with the existence of the bacteria succinic vibrionaceae in the gut because such bacteria do not produce methane.

Cory Oltjen, senior in animal sciences and industry, said he felt he learned a lot from the lecture.

“I didn’t realize that there was so many specific and such variation of bacteria in the rumen that you have to look at,” Oltjen said. “That there are certain [archaea] that produced more methane than others.”