Bacteria Feed on Toxic and Persistent PFAS Chemicals

The so-called “forever chemicals” (PFAS) are increasingly present in the environment, food, drinking water, and even our bodies. However, researchers may have found a new solution to this problem: a bacterium capable of consuming these compounds and their toxic byproducts.

Per- and polyfluoroalkyl substances (PFAS) have been widely used for decades due to their water-repellent properties, appearing in products such as non-stick cookware and waterproof clothing. The main challenge is that their extremely strong chemical bonds make these compounds highly persistent in the environment, accumulating in living organisms and posing health risks to virtually the entire population.

A study conducted by researchers at the University at Buffalo identified a bacterial species capable of breaking down at least three types of PFAS while also reducing the toxicity of some byproducts generated in the process.

The Bacterium That Breaks Down PFAS

The bacterium, called Labrys portucalensis F11 (F11), was isolated from a highly polluted industrial site in Portugal. There, it appears to have evolved the ability to feed on these chemical compounds, breaking down their resistant bonds to access the carbon inside them.

To test its efficiency, scientists placed bacterial populations in flasks where the only carbon source came from PFAS, at a concentration of 10,000 micrograms per liter. These cultures were incubated for periods ranging from 100 to 194 days, and later analyzed to measure the degradation of the compounds.

After 194 days, researchers observed that F11 managed to break down up to 96% of PFOS, one of the most common PFAS. Additionally, in 100 days, it eliminated 58% of a compound known as 5:3 fluorotelomer carboxylic acid and 21% of another called 6:2 fluorotelomer sulfonate.

The Mechanism Behind the Degradation

“The bond between carbon and fluorine atoms in PFAS is extremely strong, so most microorganisms cannot use it as an energy source,” explained Diana Aga, corresponding author of the study. “The F11 bacterial strain developed the ability to remove fluorine and consume carbon.”

Even more interestingly, F11 did not just break down the primary PFAS compounds—it also started degrading some of the resulting byproducts. Many of these metabolites can also be harmful to the environment, but after 194 days, the analysis showed that the bacterium had removed fluorine from three PFOS metabolites.

A Promising Step, but Not a Definitive Solution

Although these results are promising, F11 is not yet a definitive solution to the environmental problem of PFAS. The degradation process is slow, and in natural conditions, where other food sources are available, the bacterium might not focus on breaking down these specific compounds.

Next, researchers plan to test adding alternative carbon sources to stimulate bacterial growth without diverting its focus from PFAS. “We want to investigate how different carbon sources might influence PFAS degradation,” said Aga. “But if we provide an easily degradable food source, the bacteria might ignore PFAS completely. We need to balance nutrient availability to ensure it continues converting these compounds into usable energy.”

If future tests succeed, scientists could use this bacterium in wastewater treatment to eliminate PFAS before releasing the water into the environment. Eventually, they could combine this process with other microorganisms that address equally concerning environmental issues, such as microplastics.

Read the original article on: New Atlas

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