RICHLAND, Wash. — Methane gas coming from cow burps and farts may sound like the setup for a joke, but some researchers say it’s actually a serious environmental problem. Methane is the second largest greenhouse gas contributor and it’s roughly 30 times more potent at heating up the atmosphere than carbon dioxide. Now, scientists from Washington State University are proposing an equally smelly solution to this noxious environmental issue — baby kangaroo poop!
How is adding kangaroo feces into this equation going to help? The team at WSU explain that a microbial culture developed from kangaroo droppings successfully inhibits methane production within a simulation of a cow’s stomach.
After adding both the baby kangaroo culture and a known methane inhibitor to this model, the stomach produced acetic acid instead of methane. While methane comes out of cattle through flatulence, acetic acid actually benefits cows by promoting muscle growth.
“Methane emissions from cows are a major contributor to greenhouse gases, and at the same time, people like to eat red meat,” says corresponding author Birgitte Ahring, a professor in the Bioproducts, Sciences and Engineering Laboratory at the WSU Tri-Cities campus, in a university release. “We have to find a way to mitigate this problem.”
Cow farts play a major role in climate change?
Cattle methane emissions are a very real environmental problem, study authors emphasize. Scientists believe over half of the methane released into the atmosphere originates from the agricultural sector, with ruminant animals like cattle and goats being the biggest methane contributors. Moreover, even the process of creating methane takes as much as 10 percent of the animal’s energy.
Various solutions have been in development in recent years, including changing cows’ diets and giving them chemical inhibitors to stop methane production. Unfortunately, it usually doesn’t take long for the methane-producing bacteria to become resistant to such chemicals. Scientists have also attempted the creation of vaccines, but the microbiome of a cow depends heavily on its diet, and there are just too many varieties of the methane-producing bacteria on a worldwide scale. These interventions may also negatively influence the animals’ biological processes.
The team at WSU studies fermentation and anaerobic processes, and previously designed an artificial rumen (the largest stomach compartment found in ruminant animals) in order to simulate cow digestion. Thanks to a number of enzymes capable of breaking down natural materials, rumens have “amazing abilities,” Prof. Ahring adds.
Baby kangaroos produce acetic acid instead of methane
While investigating how to outcompete the methane-producing bacteria in their reactor, Prof. Ahring discovered that kangaroos have acetic acid-producing (instead of methane-producing) bacteria in their foreguts. So, her students tracked down a few kangaroos and collected fecal samples. This led to the revelation that this specialized acetic acid-producing process only occurs in baby kangaroos. Researchers couldn’t pick out specific bacteria that might be producing the acetic acid, so they used a stable mixed culture developed using the feces of a baby kangaroo.
After lowering the methane-producing bacteria in the reactor with a specialized chemical to start, the acetic acid bacteria then replaced the methane-producing microbes for several months with a similar growth rate as the methane-producing microbes. Now that the research team has tested their system in the simulated rumen, they hope to try it on real cows sometime in the near future.
“It is a very good culture. I have no doubt it is promising,” Prof. Ahring concludes. “It could be really interesting to see if that culture could run for an extended period of time, so we would only have to inhibit the methane production from time to time. Then, it could actually be a practice.”
The study is published in Biocatalysis and Agricultural Biotechnology.