Fertilizer production accounts for roughly 2% of global greenhouse-gas emissions, and the Iran war has driven up costs for farmers. Startup Switch Bioworks is engineering microbes with a genetic switch to fix nitrogen for crops like corn, potentially reducing reliance on the energy-intensive Haber-Bosch process. Founder and CEO Tim Schnabel says the microbes first establish healthy colonies around roots before shifting into nitrogen-producing mode, triggered by dropping soil nitrogen levels.

This approach addresses a key challenge: nitrogen fixation is energetically expensive for microbes and can hamper their growth. Dan Blaustein-Rejto of the Breakthrough Institute notes that genetic switches could help microbes thrive before fertilizing crops. Switch is trialing its product in six US states, focusing on corn — the most-planted US crop with over 90 million acres in 2026 — but remains two to three years from a commercial product.

Early August trials showed treated corn plants looked visibly healthier. The company continues developing products for broader deployment.