Scientists are trying to bioengineer cow microbes so they produce less methane, a potent greenhouse gas. Changing how the animals process their diet — through gene editing — could buy valuable time to delay global warming. A scientist working on this is Ermias Kebreab, UC Davis professor of animal science.
He explains that cows release 97% of their methane from their mouths and nostrils. Millions of microbes in their stomachs help them break down the grass and fiber they consume.
“The byproduct of that is hydrogen gas and carbon dioxide. And there are other microbes, particularly methanogens, that then use this hydrogen as a source of energy. But then, unfortunately, the byproduct of this process is methane,” he says.
Despite the effort to steer people toward a plant-based diet to curb climate change, Kebreab has observed increased global demand for meat and milk products. He says,“Since it's the microbes that are doing this, why not work with them, and just turn off the gene that directs them to produce this methane?”
Kebreab says his team is trying to understand the entire microbiome (aka stomach), how different microbes work, and what happens when methane levels are low or nonexistent. It’ll help them identify which gene to target with CRISPR.
“[CRISPR] goes exactly to the area where the gene resides, and basically cuts that particular gene. … It's switched off. So this is the proven technology that's been now actually used for [the] prevention of genetically-based diseases in humans. And so we are extending the use … for microbes.”
Kebreab expects researchers will understand the cow’s microbiome within the next year or two, and coming up with the CRISPR solution would take another year or two.
He points out that methane remains in the atmosphere for about 10 years, so if it’s reduced it now, “it gives us some time to … get our acts together to reduce carbon dioxide.”
“While [methane is] in the atmosphere, it could be up to 80-85 times more damage than carbon dioxide. So reducing methane now really, really is impactful — we can see the effect in the next 10 years. While if you reduce carbon dioxide now, we're not going to see that, in fact, for another 1,000 years. So that's why we're focusing on methane, not just from cows, but also from every source, particularly from oil and gas, from coal mines, from landfills.”