Meet the 'methane man' with a mission: Using microbes to eat up the greenhouse gas

Josh Silverman is obsessed with methane.

The serial entrepreneurial and biochemist has been focused on methane for 15 years. Most recently, he's zeroed in on the idea of using methane-eating microbes to combat climate change.

That obsession, and a lot of persistence getting investors to pay attention, led Silverman to launch his latest company, Windfall Bio. The startup was founded in 2022 and sells methane-eating microbes, or methanotrophs, to its pilot customers, farmers.

Farmers have a lot of methane on hand from cow burps and cow manure. These enzymes eat the methane, which contributes to climate change, and captures nitrogen from the air to make fertilizer, a critical and expensive commodity that the farmer can then turn around and use right there on the farm.

On Wednesday, Windfall Bio is revealing its mission to the public for the first time and announcing a $9 million round of funding from venture firm Mayfield, with participation from other investors, including Bill Gates' Breakthrough Energy Ventures.

It's taken a long time for Silverman, who's co-founder and CEO of Windfall Bio, to get this far. For years, he struggled to get investors to pay attention to the idea because carbon dioxide has taken center stage in the climate change conversation.

Carbon dioxide is the single largest contributor to global warming, but methane is in second place, responsible for about 30% of the global increase in temperature since the Industrial Revolution, according to the International Energy Agency. Methane gets scrubbed out of the atmosphere faster than carbon dioxide, but during its first two decades in the air, it's more than 80 times as potent as CO2 at trapping heat, according to NASA.

"If you only look at the long term, and you don't spend anything on short term, you end up tripping over your feet," Silverman told CNBC.

"Just in the last couple of years, I think that perception is really changing."

Silverman got his Ph.D. in biochemistry from Stanford in 2002, and his spent the first years of his career developing therapeutic drugs. But he grew tired of the slow pace of getting those drugs to the market, so turned his expertise toward industrial processes instead.

In 2007, he co-founded a company called Siluria, which specialized in turning natural gas, which is mostly methane, into higher-value products.

In the early part of the 2010s, there was a surge in hydraulic fracking, which made the price of methane fall significantly, reinforcing the potential business case of using it to make products, not just fuel.

In 2010, Silverman co-founded Calysta, which specializes in creating protein with fermentation. There, he had his first commercial experience with methane-eating bacteria.

"They were known in the literature and described, so you can find papers on them. But they were not sexy, they were not well known — it was a few Earth science professors literally in the basement of their geology departments who had looked at these," Silverman told CNBC.

While methane-eating microbes are naturally occurring, the scientific literature at the time said they were very slow to grow and not easy to work with. But with further investigation, Silverman started to realize that those ideas were built on old research, and without modern technology.

"It turns out, most of the dogma was completely wrong," Silverman said.

With proper techniques to feed them and the right kind of environments, methane-eating microbes can be genetically modified and grown quickly, just like most other kinds of bacteria.

"They're just able to eat a different food than most other bacteria. And once you deal with that, then the rest is actually pretty easy," he told CNBC.

For his next move, Silverman wanted to use all of his combined experience — his knowledge that methane could be a building block for other useful products, and that methane-eating microbes can scale — to address climate change, which he calls "the big elephant in the room."

"Who cares about making a little bit of impact here and there? You have got to swing for the fences, right? This is a 'go big or go home' story," Silverman said.

Silverman knew he wanted to see if methane-eating bacteria could help fight climate change, but first needed to figure out a business case. "That was really the core problem," Silverman told CNBC.

Because these microorganisms eat methane and put the resulting nutrients into the soil, cow farms were a logical entry point. Using the bacteria could save them money they'd normally have to spend on fertilizer.

The benefits can all be measured clearly, which helped Silverman make the business case.

"We measure methane into the compost pile, we measure methane coming out of the compost pile, we measure carbon and nitrogen left over in the compost pile," Silverman told CNBC. "There's no modeling or uncertainty associated with it. It's 100% quantifiable with the highest certainty of any type of climate impact that we do have today."

That business model got Mayfield investors on board.

"By converting methane into an effective organic fertilizer through methane-eating microbes, Windfall can dramatically lower costs and turn the challenges faced by these industries into advantages," said Arvind Gupta, a partner at Mayfield. "Windfall's innovative methane capture and conversion solution has garnered the attention and investment of dairy and agronomy leaders, such as Grupo Lala, Wilbur Ellis, and TetraLaval, as well as an experienced syndicate venture capital firms," Gupta said.

Gupta also drew confidence from Silverman's previous entrepreneurial experience. Since 2002, Silverman has co-founded four companies and helped grow two others.

"We are proud to partner with Josh, the world's foremost expert in commercializing methane-eating microbes and a successful entrepreneur," Gupta told CNBC.

While farmers are a first set of customers, Silverman's goals are to let these microbes loose on many other sources of methane emissions in years to come.

First, they will move to other types of livestock farms, like cows, pigs and chickens, Silverman told CNBC. From there, Windfall Bio will move to other sources of dilute methane emissions, like landfills and wastewater treatment facilities.

"Our goal is not to be just for cows, it is to be for everything," Silverman said.