Scientists identify microbes that may destroy “forever chemicals” in groundwater

19 Jul 2024 --- Microorganisms of the genus Acetobacterium, commonly found in wastewater environments, can destroy certain kinds of PFAS “forever chemicals.” The researchers note the discovery is a step toward low-cost treatments of contaminated drinking sources.

The University of California in Riverside (UCR), US team explains that the microorganisms can cleave the stubborn fluorine-to-carbon chemical bonds in PFAS. 

“This is the first discovery of a bacterium that can do reductive defluorination of PFAS structures,” says Yujie Men, corresponding study author and an associate professor at UCR’s Bourns College of Engineering in the Department of Chemical and Environmental Engineering.

However, the identified bacteria were only effective on unsaturated PFAS compounds with double carbon-to-carbon bonds in their chemical structures. 

Responsible enzymes 
Moreover, the researchers identified the specific enzymes in these bacteria essential for cleaving the carbon-fluorine bonds. Enzymes are specific proteins that act as catalysts for biochemical reactions. 

The study, published in Science Advances, thus “opens the door” for bioengineers to improve these enzymes to work on other PFAS compounds. 

“If we can understand the mechanism, maybe we can find similar enzymes based on the identified molecular traits and screen out more effective ones,” explains Men. “Also, if we can design some new enzyme or alter this known enzyme based on the mechanistic understanding, we could make it more efficient and work with a broader range of PFAS molecules.”

The discovery is a step toward low-cost treatments of contaminated drinking sources.The discovery builds on a study by Men last year, expanding the number of PFAS compounds that can be destroyed biologically. Her earlier research identified other microorganisms that can cleave the carbon-chlorine bond in chlorinated PFAS compounds, which triggers substantial spontaneous defluorination and destroys this group of pollutants. 

Addressing health risks 
The researchers note that using bacteria to treat groundwater is cost-effective, as the microorganisms destroy pollutants before the water reaches wells. The groundwater would be injected with the preferred bacteria species and nutrients to help them grow. 

PFAS compounds are linked to cancer and other diseases. Research recently revealed that the majority of the chemicals in food packaging are unregulated and untested for health hazards. 

Earlier this year, the US Environmental Protection Agency imposed water-quality limits to restrict certain “forever chemicals” to only four parts per trillion in the country’s tap water, spurring water providers to look for PFAS cleanup solutions. 

Meanwhile, a survey by Sapio Research found that 80% of consumers are not familiar with “forever chemicals” and the term PFAS, nor are they aware of the health risks of the compounds in food packaging.