The Switch Bio partnership with Bayer will combine the startup’s engineered, nitrogen-fixing microbes with Bayer Crop Science’s development and commercialization capabilities, according to the companies. Switch Bioworks engineers microbes that colonize plant roots early in the season, then activate ammonia production several weeks later through a genetic switch.
Switch Bio partnership with Bayer focuses on nitrogen-fixing technology
Bayer, which has invested in microbe-based fertilizers through prior work with Ginkgo Bioworks via Joyn Bio, said it will bring product development, formulation, field testing, commercialization, and crop genetics expertise to complement Switch Bio’s platform.
Switch Bio founder and CEO Tim Schnabel, PhD, said the collaboration will initially match the startup’s top strains with several of Bayer’s leading hybrids. He added that Switch Bio’s approach could add value alongside traits developed in previous programs.
Schnabel described biological nitrogen fixation as a longstanding challenge that likely requires a systems strategy, including stacking multiple engineered strains and traits. He called the Bayer agreement a pivotal milestone for the company.
‘Switchable strains out-colonize always-on strains’
Switch Bio says competing solutions can struggle to establish on roots or fail to generate enough ammonia to offer clear economic benefit to growers. Its approach first focuses engineered microbes on root colonization, then triggers nitrogen production through a delayed genetic switch.
In controlled grow-room studies, the platform produced about five times more nitrogen than always-on control strains, according to the company. Field trials are underway on corn across the Midwest, and Switch has obtained authorization for field release in Brazil from the National Technical Biosafety Commission.
“Our work at Switch has shown that switching between growth and nitrogen production results in increased nitrogen fixation on plants because switchable strains out-colonize always-on strains,” Schnabel said. The firm has not disclosed the exact environmental signal that activates the switch, but noted it is triggered by changes in the soil environment after several weeks and requires no action from farmers.
The company deploys a consortium of nitrogen-fixing microbes that express nitrogenase, an enzyme that enables the conversion of nitrogen and hydrogen into ammonia, which can help reduce reliance on synthetic fertilizer.
Schnabel said that, unlike approaches centered on selecting spontaneously evolved mutants, Switch Bio has engineered its microbes from the ground up. He noted that recent approvals for field trials from the USDA and the EPA reflect the novelty and complexity of the design.
Field trials
Switch Bio’s field program is focused on three questions, according to Schnabel:
- Whether the microbes can establish and persist on corn roots.
- Whether the genetic switch activates at the intended time.
- Which microbial strains should comprise the final product.
Researchers are measuring the broader root microbiome, the abundance of engineered strains, switch activation as indicated by a DNA-sequence change, plant nitrogen response, and yield.
While harvest is more than a month away, Schnabel said early observations from plot walks and drone imagery assessing leaf nitrogen are encouraging, and the company has verified that the switches activate in the field. He emphasized that the current trials are designed for late-stage product development to study colonization and switching across many strains and conditions, and are not powered to demonstrate fertilizer replacement or yield impacts in the first year.
Regulatory and commercial outlook
Switch Bio is targeting commercialization within two to three years. Schnabel said the goal is not to eliminate synthetic nitrogen entirely. Replacing about 25% of applied nitrogen while maintaining yields would be a significant achievement, with biology’s probable ceiling around 50%.
He said the business case rests on delivering nitrogen at lower cost through a relatively small in-furrow application of microbes. Based on the company’s techno-economic analysis, the cost to produce the required microbes per acre is projected to be below the cost of supplying 40 to 80 pounds of chemical nitrogen. Given tight farm margins, Schnabel said savings of even 20 to 30 dollars per acre would be meaningful.
Switch Bio’s work continues amid fertilizer market pressures, with the company positioning its switchable biofertilizers as a complementary tool to reduce input costs while sustaining yields. Related efforts to protect crop performance, such as the Phaeosphaeria leaf spot spreads across Michigan corn coverage, highlight the broader push to support corn productivity.