Key Takeaways
- Mafix raised a $5.4 million pre-seed funding round led by Azolla Ventures, with support from Astera Institute, Counteract VC, Impact Science Ventures, Plug and Play Ventures, and a Dutch family office.
- The company’s mineral conversion process uses cement kilns to accelerate silicate rock weathering, releasing plant nutrients within a single growing season instead of years.
- Mafix’s silicon fertilizer converts atmospheric carbon dioxide into stable bicarbonate, pairing agronomic benefits with carbon removal.
- The funding will help Mafix scale production to at least 1,000 tons of silicon fertilizer and move from small-plot to larger field trials.
- The company aims to use about 30% of currently idle global cement kiln capacity to keep scale-up costs down and the product affordable for farmers.
Mafix Raises $5.4 Million Pre-Seed Round
Mafix has closed a $5.4 million pre-seed funding round led by Azolla Ventures, with participation from Astera Institute, Counteract VC, Impact Science Ventures, Plug and Play Ventures, and a Dutch family office. The Stanford-linked startup develops silicon-based fertilizers designed to improve soil health while pulling carbon dioxide out of the atmosphere.
“We are fertilizer first, but we also can remove carbon dioxide from the atmosphere,” said Jade Marcus, CEO and cofounder of Mafix.
How Mafix’s Silicon Fertilizer Works
Mafix’s process accelerates the natural weathering of silicate rock using cement kilns, a method the company says releases plant-available nutrients within a single growing season rather than the years typical of untreated rock dust. As the silicate weathers, it converts atmospheric carbon dioxide into stable bicarbonate, giving the fertilizer a climate benefit alongside its agronomic one.
Mafix Plans to Scale Using Idle Cement Kilns
The new funding will support scaling production to at least 1,000 tons of silicon fertilizer, allowing Mafix to move from small-plot research into larger field trials. The company says it plans to draw on roughly 30% of currently idle global cement kiln capacity to lower the cost of scaling up while keeping the product affordable for farmers.
Silicon’s Growing Recognition as a Crop Nutrient
The raise comes as silicon gains formal recognition in the fertilizer industry: the Association of American Plant Food Control Officials classified silicon as an essential crop nutrient in 2026. Mafix joins a wave of capital flowing into agricultural carbon markets as it builds out a commercial-scale carbon removal business alongside its fertilizer line.
