PFAS, or per- and polyfluoroalkyl substances, are among the most persistent pollutants known. Used for decades in products from firefighting foams to non-stick coatings, they accumulate in groundwater, soil and the human body and have been linked to a range of health and environmental harms. Destroying them is difficult: the dominant disposal route is high-temperature incineration, which is energy-intensive, costly and capacity-constrained. Other emerging methods are expensive, work only on liquids, or struggle with the short- and ultra-short-chain compounds that are hardest to treat.

CellX Biosolutions is a spinoff from ETH Zurich, founded in 2024 by Estelle Clerc, Fabienne Kurt and Geoffrey Besnier. The company’s approach to decontamination uses naturally occurring bacteria that break down PFAS. The solution grew out of Clerc's doctoral research in marine microbiology, which used microfluidics to study how bacteria break down complex molecules in the ocean. 

CellX’s core technology is a patent-pending microfluidic "trap" that isolates high-performing strains directly from contaminated or remote environments. The company has built a library of more than 50 strains with confirmed PFAS degradation and combines them into cocktails tailored to different contamination profiles, then deploys them in standard bioreactors. CellX says the breadth of its collection lets it address a wide range of sites and PFAS types. 

The company has secured eight pilot projects to date. The pilots are split evenly between water and soil, addressing either industrial wastewater treatment, contaminated groundwater or contaminated soil. Half of the pilots are running with clients in Switzerland, and half international clients in Belgium, France, the Netherlands and the United States. 

Two of the Swiss projects have public backing. Armasuisse, the federal defence-procurement agency, has published a tender allowing it to unlock a budget of up to CHF 400,000 for its collaboration with CellX. A separate project supported by the Federal Office for the Environment (BAFU), is screening bacteria to degrade PFAS found on a site polluted by fire-fighting foam, with the aim of advancing the technology towards a field trial. The remaining six pilots are with private companies testing whether CellX's technology works on their own contaminated water or soil, five paying for the work and one contributing in kind.

“We are running lab pilots with prominent wastewater treatment and soil remediation companies as well as large chemical producers. This allows us to prove that our bacteria can destroy PFAS in real world applications. It is a key milestone to bring to the market the world's first bacterial solution for PFAS destruction,” says Geoffrey Besnier, co-founder and COO of CellX. 

Alongside the pilots, CellX says it has raised over CHF 4.8 million non-dilutive funding from backers including Innosuisse, the Migros Pionier Fonds, BAFU, KlimaStiftung Schweiz, the Zurich Klimup program, and the W.A. De Vigier Stiftung Award, as well as other foundations and startup prizes. The company also raised a pre-seed round in early 2025 including CHF 1.45 million in convertible loans, led by Positron Ventures. This brings the total funding raised to around CHF 6.3 million. 

CellX is growing its team from 10 to 13 people by October 2026. Further, the company plans to raise a seed round at the end of 2026 to fund its scale-up to larger industrial pilots over the following two years. Longer term, the company intends to license its bacterial consortia to large water-treatment and remediation firms to reach customers worldwide.

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Photo: Estelle Clerc filling an ISCA chip for bacterial sampling. Photo provided by CellX, credits to Nicole Davidson, ETHZ for the image.