Nitrogen fertilizer helps feed the world. Without its yield-boosting magic, it’s possible that almost half of the global population wouldn’t be alive today.
But the benefits of synthetic nitrogen fertilizer have steep environmental and, increasingly, financial costs, lending new urgency to the production of sustainable, affordable alternatives.
Not only is synthetic nitrogen fertilizer a major greenhouse-gas contributor and potential water pollutant, but over the last year, its price has skyrocketed as the cost of natural gas—a key input to fertilizer production—has surged. In 2020, well before these price hikes, American farmers alone spent over $24 billion on fertilizer, lime, and soil conditioner, per the USDA. In addition to rising prices, some countries, like Sri Lanka and the Netherlands, have taken steps to restrict or ban the use of synthetic nitrogen fertilizer, which has sparked an ongoing, intense backlash from some farmers who say the moves will hamper food production and ruin their livelihoods.
A group of startups, including Pivot Bio and Joyn Bio, are leveraging the promise of synthetic biology to try and produce affordable, environmentally friendly alternatives at scale. The push for these bio-based fertilizers is in its early stages—although Pivot has a product on the market, Joyn said it may not have its technique refined for at least five years—but experts told us the concept holds promise in the long-term.
“The fundamental advantage of synthetic nitrogen fertilizers would be the convenience of buying nitrogen instead of growing it or doing other things to make it more available,” Richard L. Mulvaney, professor of soil fertility at the University of Illinois Urbana-Champaign, told us. “In the present economic climate, that advantage is turning into a liability, because we’re currently looking at record prices for fertilizers. And this is bound to make some farmers reconsider how they might make use of other options in terms of fertility.”
Teaching old crops new tricks
Jonathan Margolis, chief scientific officer at JoynBio, told Emerging Tech Brew that the company is attempting to augment and imitate a natural process called nitrogen fixation. Fixation is caused when legumes like soybeans naturally partner with bacteria in a symbiotic relationship: the legumes provide nutrients to bacteria, while bacteria takes nitrogen from the air and converts it into ammonia, which in turn helps crops grow.
While this process occurs naturally in legumes, like soybeans, peas, beans, or lentils, it doesn’t for other staple crops like corn, rice, or wheat. That’s where fertilizer comes in.
“What we’re trying to do is find microbes which will associate with the corn plant, and which naturally have that same biochemical capability, but where we want to dramatically improve the efficiency and the specificity,” Margolis said.
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The science behind engineering microbes isn’t entirely new—it was first achieved in the 1970s—but the idea of applying it at a wide scale in agriculture is newer.
Relying on biological processes eliminates the nitrous-oxide emissions that occur in synthetic fertilizer production, which have 300x the warming potential of carbon dioxide and accounted for 7% of all US GHG emissions in 2020, according to the EPA. It can also prevent nitrogen from leaching into and contaminating nearby water sources, a common side effect of using synthetic nitrogen fertilizers.
Pivot Bio, which raised $430 million in Series D funding in July 2021, engineers microbes in the soil to extract naturally occurring nitrogen in the atmosphere and convert it into ammonia, which cereal crops like corn use to grow faster. Pivot’s products are applied in the planting process and stay in the soil throughout the cycle of plant growth. The company works entirely within the existing DNA of a given microbe, rearranging it to optimize ammonia production, which fertilizes plants.
“The benefits of working within a strain is that we can take what’s best about that strain already…we can make our reprogramming changes to it and get it out and test it and find out if it does work better,” Ernie Sanders, VP of product development at Pivot Bio, told Emerging Tech Brew.
In contrast, Joyn, which has raised $100 million as a joint venture between Ginkgo Bioworks and Leaps by Bayer, modifies and combines the DNA of different microbes to create new ones. It won’t have a product for several years, but Joyn Bio CEO Mike Millie said the company is targeting a 30%–40% reduction in farmers’ reliance on synthetic nitrogen fertilizers.
Ultimately, although experts told us the potential and appetite for bio-based alternatives is there, it will take time to phase out synthetic fertilizers entirely.
“At some point, we’re going to be able to grow crops just using biological processes with engineered microbes,” Vander Luis Novais Nunes, postdoctoral researcher at the University of Illinois at Urbana-Champaign, told Emerging Tech Brew. “I believe that one day we are going to get there, but I don’t know how far away we are from that point. I assume that it’s going to take quite a while.”
Correction: A previous version of this piece stated that Joyn Bio had raised $200 million to date. It has raised $100 million. We've updated the piece to reflect this and apologize for the error.