In the ongoing battle against PFAS, or “forever chemicals,” bacteria may hold the key to solving one of the most persistent environmental challenges of our time. While traditional remediation methods often focus on containing or capturing these chemicals, a breakthrough discovery by a research team led by the University at Buffalo reveals that certain bacteria can actually dismantle the chemical bonds that make PFAS so indestructible.
The researchers found that a strain of bacteria, Labrys portucalensis F11 (F11), is capable of breaking down and transforming at least three types of PFAS. More impressively, this strain also has the ability to degrade some of the toxic byproducts produced during the breakdown process. Published in Science of the Total Environment, the study demonstrates that F11 can metabolize more than 90% of perfluorooctane sulfonic acid (PFOS) in just 100 days, one of the most widely used and hazardous PFAS compounds. PFOS was officially classified as hazardous by the U.S. Environmental Protection Agency (EPA) in 2022.
PFAS are a group of human-made chemicals that have been used for decades in products like nonstick cookware, stain-resistant fabrics, and firefighting foam. Due to their strong carbon-fluorine bonds, PFAS are notoriously difficult to break down, earning them the nickname “forever chemicals” because they persist in the environment for an exceptionally long time.
The F11 bacteria studied in this research were able to degrade not only PFOS but also two other types of PFAS: 58% of 5:3 fluorotelomer carboxylic acid and 21% of 6:2 fluorotelomer sulfonate, after 100 days of exposure. According to Dr. Diana Aga, the study’s lead author, “The bond between carbon and fluorine in PFAS is so strong that most microbes cannot use it as an energy source. But the F11 bacteria developed the ability to break that bond—removing the fluorine and metabolizing the carbon.”
This breakthrough is significant because previous studies on PFAS-degrading bacteria typically focused only on the initial breakdown of PFAS. In contrast, this study accounted for the metabolites produced during the breakdown process, including those with or without fluorine. Some of these breakdown products were further degraded by F11 to undetectable levels, revealing the bacteria’s ability to not just break down PFAS, but to continue eliminating its toxic remnants.
The bacteria behind this discovery are far from picky eaters. PFAS are not a natural food source for most microorganisms, but some bacteria living in contaminated environments have evolved the ability to “consume” chemical pollutants for energy. F11, for example, was originally isolated from soil at a contaminated industrial site in Portugal, where it had previously shown the ability to strip fluorine from pharmaceutical contaminants.
“It’s likely that bacteria that survive in polluted environments do so because they have adapted to use the surrounding chemical pollutants as food sources, preventing starvation,” says Dr. Aga. Through evolution, some bacteria can develop effective mechanisms to metabolize these contaminants and use them to grow. This adaptation has allowed certain strains, like F11, to thrive in environments laden with PFAS.
In collaboration with researchers from the Catholic University of Portugal, the University of Pittsburgh, and the Waters Corp., the team placed the F11 bacteria in sealed flasks with no carbon source other than 10,000 micrograms per liter of PFAS. After incubation periods of 100 to 194 days, the samples were sent to the University at Buffalo for analysis. The results were clear: F11 had successfully degraded a significant portion of the PFAS.
What makes this discovery even more notable is that the elevated levels of fluoride ions detected in the samples indicate that F11 had removed the fluorine atoms from PFAS molecules, allowing it to metabolize the carbon. This step is crucial, as the carbon-fluorine bond is what makes PFAS so persistent in the environment.
“We’re not just chopping PFOS into smaller pieces,” says Mindula Wijayahena, a PhD student and first author of the study. “We’re actually removing the fluorine from those smaller pieces, which is a critical step in breaking down PFAS.”
While this discovery is a promising start, there are still challenges ahead. The F11 bacteria took 100 days to degrade a significant portion of the PFAS in the study, and no alternative carbon sources were provided. The researchers are now exploring ways to encourage the bacteria to degrade PFAS more quickly, even in the presence of competing carbon sources that could spur their growth rate.
“We want to understand how F11 performs when alternative carbon sources are available,” says Dr. Aga. “But we also have to be careful. If the bacteria have access to an abundance of easy-to-degrade carbon, they might lose the incentive to break down the PFAS.”
Future research will focus on creating the ideal conditions for F11 to grow faster and more efficiently while still focusing on PFAS breakdown. One potential application of this research is bioaugmentation, a process in which specific bacteria are introduced to contaminated environments to enhance the removal of pollutants.
In practical terms, F11 could be deployed in contaminated water and soil to help remediate PFAS pollution. This could involve growing the bacteria in activated sludge systems at wastewater treatment plants, or even directly introducing the bacteria into contaminated sites through bioaugmentation.
“By adding F11 to existing bacterial populations in wastewater treatment plants, we could accelerate the removal of PFAS and other harmful chemicals,” says Dr. Aga. “Bioaugmentation is a promising method that could help mitigate PFAS contamination in the environment.”
While further research is needed, the discovery of bacteria capable of breaking down PFAS offers hope for a future where these dangerous chemicals are no longer a permanent part of our environment. As scientists continue to refine these microbial processes, they could lead to more efficient, sustainable, and cost-effective solutions for cleaning up PFAS pollution on a global scale.
By Impact Lab