The fight against “forever chemicals” known as PFAS has received a potential boost with the discovery of a bacteria strain capable of breaking down these persistent pollutants—and even some of their toxic byproducts. This finding offers new hope for more effective environmental cleanup.
PFAS (per- and polyfluoroalkyl substances) are notorious for their strong carbon-fluorine bonds, which prevent them from naturally degrading in the environment. Most current remediation efforts focus on containing rather than destroying these chemicals. However, certain microbes possess the rare ability to break these bonds.
A team led by Diana Aga at the University at Buffalo has identified a bacterial strain, Labrys portucalensis F11 (F11), that can metabolize several types of PFAS. Crucially, the study, published in Science of the Total Environment, shows that F11 can break down over 90% of PFOS (perfluorooctane sulfonic acid), a particularly persistent and hazardous PFAS designated as such by the U.S. EPA. The bacteria also degraded substantial amounts of two other PFAS compounds: 58% of 5:3 fluorotelomer carboxylic acid and 21% of 6:2 fluorotelomer sulfonate within 100 days.
Unlike previous research, this study also tracked the breakdown products, or metabolites, of PFAS degradation. The F11 bacteria not only broke down the original PFAS but also continued to degrade some of these resulting metabolites, even removing fluorine from them in some cases. This is a significant finding, as these metabolites can also be toxic.
The F11 strain was originally isolated from contaminated soil in Portugal and had previously shown an ability to break down other pollutants. The researchers incubated F11 with high concentrations of PFAS as its sole carbon source. Analysis revealed that the bacteria effectively detached fluorine atoms from the PFAS molecules, allowing them to metabolize the carbon.
While promising, the biodegradation process was relatively slow, taking 100 days to achieve significant breakdown. The researchers are now investigating methods to accelerate this process, such as introducing alternative carbon sources that encourage bacterial growth without diminishing their appetite for PFAS. Future research will explore deploying F11 in real-world settings, such as wastewater treatment plants or directly at contaminated sites through a process called bioaugmentation.