On a dairy farm, cow burps aren’t the only big source of emissions. Manure “lagoons” also pump out large amounts of methane, a potent greenhouse gas. But some dairy farms are now beginning to test a new solution: methane-eating microbes that can naturally convert the pollution into fertilizer.

Windfall Bio, the startup that designed the new process, announced today that it raised a $28 million Series A funding round. The money will help it begin to scale up manufacturing of its microbes.

The solution isn’t limited to farms. The microbes can also capture pollution at oil wells, landfills, or even natural methane sources like wetlands or melting permafrost. The company’s aim was to find an economically viable way to tackle the problem of methane.

Why methane is crucial in the climate fight

Methane has 86 times the warming power of CO2 over a 20-year period. And because it doesn’t last in the atmosphere for centuries, like CO2, capturing methane emissions can quickly have an outsized impact on the overall amount in the atmosphere. That can help slow down climate change. Right now, methane emissions are responsible for around 30% of the rise in global temperatures.

“It’s a huge issue for climate that we think is very much under-appreciated, under-reported, and underfunded, relative to carbon dioxide-based climate solutions,” says Josh Silverman, cofounder and CEO of Windfall Bio.

Methane-eating microbes

Silverman, a biochemist, realized that microbes found in soil could help. The organisms naturally produce nitrogen fertilizer as they consume methane. The company doesn’t genetically modify the organisms, but mixes various types to make them more effective together. Then it exposes them to much more methane than they would normally see in nature.

“All of those things together mean that they can convert and eat orders of magnitude more methane than they normally would if they were out just sitting in the dirt in a forest,” he says. At a dairy, farmers can connect a tank filled with the microbes to an exhaust pipe from a dairy barn, or to a pipe from a covered manure lagoon. (If farmers add microbes directly to a field, the microbes can also pull methane from the air, but they’re more efficient when there’s more pollution. The number of microbes that naturally live in soil—especially heavily-farmed soil—has dropped in recent years, so adding microbes there still helps.)

After the microbes produce fertilizer, a farmer can spread that on their fields. An organic farmer, who doesn’t buy cheap fossil-fuel based fertilizer, could theoretically rely entirely on the product. Conventional farmers might use a mix of synthetic fertilizer and Windfall’s product. The microbe-produced fertilizer helps improve soil health and is less likely to runoff the soil and pollute water. The cost is around 50% of buying an equivalent non-organic fertilizer, Silverman says. It’s even cheaper when compared to organic alternatives.

For other industries that emit methane, the technology can help give the gas value when it didn’t have any before. “If it comes out of a landfill, or an oil well, or a coal mine, we pipe it in and the cells eat it exactly the same way,” Silverman says. At an oil field in Texas, for example, oil wells are typically surrounded by farmland. An oil company could use the tech to make fertilizer to sell to local farmers.

Scaling up

Windfall has proved that the process works in its lab, the company says. Now it’s running pilots with multiple customers, including dairies in Whole Foods’s supply chain. It’s also planning how to build out its manufacturing capacity to meet the demand that it already has.

There’s plenty of room to expand: If all the methane in the world was captured, Silverman says, it would produce the equivalent of 10% of the world’s synthetic fertilizer. (A staggering 118 million metric tons of nitrogen fertilizer was produced in 2021.) Because making fertilizer usually relies on fossil fuels and huge amounts of energy, the process has the double benefit of helping clean up the fertilizer industry.