Grow-room studies of Switch Bioworks' engineered nitrogen-fixing microbes produced five times more nitrogen than "always-on" control strains — and now Bayer Crop Science is betting on the technology through a strategic collaboration announced with the California startup.

The deal pairs Switch's "switchable" microbes with Bayer's product development, formulation, field testing and commercialization muscle. Bayer, which has already chased engineered fertilizer microbes through its Joyn Bio joint venture with Ginkgo Bioworks, said its crop-genetics understanding will speed the work. "That's the only way we're going to accelerate progress," the company said.

How the technology works

Switch engineers soil microbes that first compete with the native microbiome and colonize corn roots. A genetic switch then turns on ammonia production several weeks into the season, triggered by a change in the soil environment. Farmers don't intervene. The trigger's precise mechanism remains undisclosed.

Founder and CEO Tim Schnabel, PhD, told AgFunderNews: "Initially the collaboration will bring together Switch's best strains with a variety of Bayer's leading hybrids." He added that Switch's platform "has the potential to be value-add to traits already developed by Joyn," and framed biological nitrogen fixation as "somewhat of a holy grail" that may need "strain stacking and trait stacking."

Because Switch built its microbes from the bottom up rather than selecting spontaneous mutants, Schnabel called the USDA and EPA field-trial approvals "first in class" for engineered biofertilizer organisms. Brazil's National Technical Biosafety Commission has also approved field releases there.

What does this change for growers' input costs?

Potentially $20 to $30 per acre. "Farmers have paper thin margins, so even just $20 to $30 in savings per acre on fertilizer would be a huge deal," Schnabel said. The microbes would be applied in-furrow at a small dose, and Switch's techno-economic analysis shows microbial production costs run well below the cost of 40 or 80 pounds of chemical nitrogen.

The timing matters. Fertilizer price spikes tied to the Iran conflict have added up to $35 per acre for US corn growers, sharpening the business case for biological alternatives.

Schnabel set realistic targets: replacing 25% of synthetic nitrogen while holding yields would be a major win, with biology's likely ceiling around 50%.

Trials: colonization first, yield later

Midwest corn field trials are testing three questions:

• Can the microbes establish and persist on corn roots?
• Does the genetic switch activate at the right time?
• Which microbes should form the eventual product?

Researchers are measuring root microbial community composition, engineered-strain abundance, switch activation — detectable via a DNA-sequence change — plant nitrogen-response indicators and yield.

"Although harvest is still over a month out, we're seeing some exciting early signals walking the plots and when it comes to drone data looking at leaf nitrogen," Schnabel said. "We've also been able to show that the switches turn on in the field."

He drew a hard line between development trials and proof: "These trials are for late stage product development, principally studying colonization and switching across many strains and conditions. They are not statistically powered enough to expect fertilizer replacement or yield in the first year."

Switch is targeting commercialization within two to three years. The Bayer collaboration, Schnabel said, "marks a pivotal milestone for our company." Whether switchable microbes can convert five-times greenhouse results into replicable field-level nitrogen savings is the question the next two harvests will have to answer.