Kangaroo fecal microbes could reduce methane from cows

Baby kangaroo feces might help provide an unlikely solution to the environmental problem of cow-produced methane. A microbial culture developed from the kangaroo feces inhibited methane production in a cow stomach simulator in a Washington State University study.

After researchers added the baby kangaroo culture and a known methane inhibitor to the simulated stomach, it produced acetic acid instead of methane. Unlike methane, which cattle discard as flatulence, acetic acid has benefits for cows as it aids muscle growth.

"Methane emissions from cows are a major contributor to greenhouse gases, and at the same time, people like to eat red meat," said Birgitte Ahring, corresponding author on the paper and a professor in with the Bioproducts, Sciences and Engineering Laboratory at the WSU Tri-Cities campus. "We have to find a way to mitigate this problem."

The WSU researchers study fermentation and anaerobic processes and had previously designed an artificial rumen, the largest stomach compartment found in ruminant animals, to simulate cow digestion. With many enzymes that are able to break down natural materials, rumens have "amazing abilities," said Ahring.

Looking to investigate how to outcompete the methane-producing bacteria in their reactor, Ahring learned that kangaroos have acetic acid-producing, instead of methane-producing, bacteria in their foregut. Her students tracked down some kangaroos, took samples and learned that the specialized acetic acid-producing process only occurred in baby kangaroos – not in adults. Unable to separate out specific bacteria that might be producing the acetic acid, the researchers used a stable mixed culture developed from the feces of the baby kangaroo.

After initially reducing the methane-producing bacteria in their reactor with a specialized chemical, the acetic acid bacteria were able to replace the methane-producing microbes for several months with a similar growth rate as the methane-producing microbes.

Image source: Pixabay/CC0 Public Domain.