Toxic ‘forever chemicals’ are increasingly showing up in the environment, our food and drinking water, and throughout our bodies. But we might have a new weapon: scientists have identified a bacterium that can eat these chemicals, as well as their byproducts.
Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals that have been widely used for decades due to their handy water-repelling properties, including in non-stick cookware and waterproof clothing. The problem is, their strong chemical bonds mean PFAS can linger in the environment more or less indefinitely, raising health problems for the animals and humans who consume them – which is basically everyone now.
A new study, lead by researchers at the University at Buffalo, has found that a certain species of bacteria can break down at least three types of PFAS, and mop up some of the toxic byproducts created in the process.
The bacterium in question is known as Labrys portucalensis F11 (F11), which was isolated from a heavily polluted industrial site in Portugal. There, it seemed to have mutated to feed on common contaminants like PFAS, busting down those strong bonds to get to the carbon locked inside.
To test how well it might eat these chemicals, the researchers sealed populations of F11 into flasks where the only carbon source came from PFAS, at a concentration of 10,000 micrograms per liter. These were then incubated for between 100 and 194 days, then analyzed to see how much the bacteria had eaten.
After 194 days, F11 was found to have broken down up to 96% of one common chemical known as PFOS. It also managed to clear out other types of PFAS, including 58% of one called 5:3 fluorotelomer carboxylic acid and 21% of another known as 6:2 fluorotelomer sulfonate, after 100 days.
“The bond between carbon and fluorine atoms in PFAS is very strong, so most microbes cannot use it as an energy source,” said Diana Aga, corresponding author of the study. “The F11 bacterial strain developed the ability to chop away the fluorine and eat the carbon.”
Importantly, it didn’t stop there. F11 was also found to start chowing down on some of the by-products left behind after its first meal. These metabolites can have their own environmental issues, but the analysis found that after 194 days the bacteria had removed the fluorine from three PFOS metabolites.
While it’s an intriguing first step, F11 isn’t a silver bullet for the major environmental issue of PFAS. As the team points out, it takes a long time to work, and probably wouldn’t be that effective in real-world situations where the bacteria has other food sources. For the next tests, the researchers plan to add alternative food sources to boost the bacteria’s growth rate – but not too much.
“We want to investigate the impact of placing alternative carbon sources alongside the PFAS. However, if that carbon source is too abundant and easy to degrade, the bacteria may not need to touch the PFAS at all,” said Aga. “We need to give the F11 colonies enough food to grow, but not enough food that they lose the incentive to convert PFAS into a usable energy source.”
If all goes well, eventually the bugs could become a key step in wastewater treatment plants, removing PFAS before the water is released to the environment. It could be adjacent to a tank of bacteria that eat another major environmental issue of our time: microplastics.
The research was published in the journal Science of the Total Environment.
Source: University at Buffalo
