Teaming up With Soil Microbes to Fight Climate change
Written by Jürgen Eckhardt, Head of Leaps by Bayer
Nature is the source of many of our greatest inspirations and innovations. From the hooked barbs of thistles that inspired the design of Velcro to the discovery of CRISPR that is driving the Bio Revolution, transformative solutions to the world’s biggest problems are often discovered in the natural world around us.
Nowhere is innovation more important than in our existential fight against climate change. As evidenced by several important reports released as part of the UN Climate Change Conference, or COP26, a hotter planet is already inevitable. But just as science has pinpointed 1.5C as the limit to warming before we irreversibly damage our home, I’m hopeful that breakthrough innovation driven by biology will help enable us to meet this threshold.
One crucial front in the fight against climate change is agriculture — in particular, the use of nitrogen fertilizers. All living things need nitrogen, but the nitrogen gas that makes up almost 80% of the atmosphere is not a form that most crops can use. The development of synthetic nitrogen fertilizers in the early 1900s dramatically increased crop yields and our ability to feed a crowded planet. But making these fertilizers requires enormous amounts of energy: their use and production accounts for an estimated 1.5 gigatons, or 3%, of global greenhouse gas emissions.
For decades, one of the grand challenges of agriculture has been to engineer sustainable crops that can be grown without synthetic nitrogen fertilizers. Solving this problem is a major focus of Leap 03 / Reduce the environmental impact of agriculture.
In this quest, we can look to nature for possible solutions. Billions of years ago, ancient microbes evolved the ability to convert nitrogen from an atmospheric gas into a form that other living things can use, a process called nitrogen fixation. Today, the descendants of these microbes live in the soil and oceans, and their nitrogen fixation powers the rest of life on Earth.
Can we harness these extraordinary microbes to reduce our reliance on synthetic nitrogen fertilizers and shrink the carbon footprint of agriculture? Some plants, called legumes, have evolved close, symbiotic partnerships with nitrogen-fixing microbes, which live in specially shaped root nodules. But most other plants — including major crops like corn, wheat, and rice — need help to develop relationships with nitrogen-fixing bacteria, which is where bioengineering comes in.
We recognize that there will be no one-size-fits-all solution to the grand challenge of nitrogen fixation. With such a complex problem that affects farmers around the world, we want to build a flexible toolbox of potential solutions that can address the diversity of farming at a global scale
One of our most recent investments addressing nitrogen fixation is Andes. The innovative micropriming technology being developed by Andes delivers nitrogen-fixing microbes directly into the seeds, so they stay in the soil after crops are sown. Once in the ground, these microbes colonize the roots of the developing plant and supply the nitrogen the plants need to grow, reducing the need for synthetic fertilizers. Something I love about the technology that Andes is developing is that the microbes ride into the soil along with the seeds, a simple and scalable solution for farmers to put into place.
Sound Agriculture takes a different angle on the problem of nitrogen fixation. Instead of engineering or delivering microbes, as Andes does, Sound has launched a liquid product called SOURCE that stimulates the soil microbiome, helping plants recruit microbial partners and signaling the microbes to kickstart the process of nitrogen fixation. One advantage of Sound’s approach is that their product is in a form that farmers are already familiar with, making it easy to integrate into existing agricultural workflows. Yet scale matters. While farmers need to apply about 100kg of conventional fertilizer per acre, they need about 20 milliliters of SOURCE per acre.
Yet another innovative approach to nitrogen fixation comes from Joyn Bio, a joint venture between Leaps and our partners at the synthetic biology company Ginkgo Bioworks. Joyn Bio is using the bioengineering platform developed by Ginkgo to engineer nitrogen-fixing microbes that can associate with cereal crops like corn, wheat, and rice, helping them form the symbiotic partnerships that allow plants like legumes to grow without synthetic fertilizers. Joyn is also using this same platform to design, engineer, and test microbes that express other important agricultural traits like pest control and disease resistance, leveraging the Bio Revolution to expand the horizons of agriculture.
At scale, nitrogen fixation could reduce nitrogen fertilizer use by about 30%. By teaming up with microbes to make agriculture more sustainable, we hope we can create a future with healthier plants, healthier foods, and a healthier planet.