Recently, researchers discovered two naturally occurring bacteria that can break down chlorinated “persistent chemicals”, also known as PFAS.

Scientists at the University of California, Riverside, specializing in chemical and environmental engineering, have discovered two types of bacteria in soil that can break down the persistent class of “forever chemicals” that hold promise for inexpensive biological treatment of industrial pollutants.

Associate Professor Yuji Meng of the Bourns College of Engineering and his team discovered that these bacteria can destroy a specific subset of per- and polyfluoroalkyl substances known as PFASs, particularly those containing one or more chlorine atoms in their chemical structure. Their findings were published in a scientific journal Nature Water .

Unhealthy chemicals stay in the environment for decades or even longer, due to extremely strong carbon-fluorine bonds. Remarkably, the UCR team discovered that the bacteria break down the pollutant’s chlorine-carbon bonds, initiating a chain of reactions that permanently destroys chemical structures, rendering them harmless.

University of California, Riverside, associate professor Yuli Man and graduate student Josen Jin. Credit: UCR photo, Shizhuo Zhang

“We found that the bacteria could first break the carbon-chlorine bond and form unstable intermediates,” Meng said. Said. “And then these unstable intermediates undergo spontaneous defluorination, which is the cleavage of the carbon-fluorine bond.”

Chlorinated PFASs are a large group in an endless chemical family of thousands of compounds. These include various non-flammable hydraulic fluids used in industry and compounds used to make chemically resistant films that act as moisture barriers in a variety of industrial, packaging and electronic applications.

Two types of bacteria – Desulfovibrio aminophylus And Sporomusa sphaeroides – They are known to live in subterranean microbiomes defined by the males group, occurring in nature and where groundwater can be contaminated with PFAS. For accelerated cleanup, an inexpensive nutrient such as methanol can be injected into the groundwater to encourage bacterial growth. Meng said this would greatly increase the presence of bacteria to more effectively destroy contaminants. If bacteria are not already present, contaminated water can be seeded with one of the bacterial strains.

Conceptual image of the biological treatment process. Image Credit: Evan Fields’ UCR Graphics

Meng is the corresponding author of the paper, and Bosen Jin, a graduate student in chemical and environmental engineering at UCR, is the lead author. Other UCR co-authors are postdoctoral Jinyu Gao; former postdoc Huaqing Liu; former graduate students Shun Che and Yaochun Yu; and Associate Professor Jinyong Liu.

The study expands on Meng’s previous work, which showed that microbes can break down a persistent class of PFASs called fluorinated carboxylic acids.

Microbes have long been used to biologically clean up oil spills and other industrial contaminants, including the industrial solvent Trichloroethylene, or TCE, that Maine is working on.

But what is known about using microorganisms to clear PFAS is still in its infancy, Meng said. Its discovery is promising because biological treatment is generally cheaper and more environmentally friendly than chemical treatment, if effective pollutant-eating microbes are present. Contaminant-feeding microbes can also enter hard-to-reach places underground.

The latest Men’s PFAS study comes with the U.S. Environmental Protection Agency introducing new guidelines to encourage the cleanup of PFAS-contaminated groundwater areas around the country because the chemicals have been linked to a host of harmful health effects, including cancer, kidney disease and hormone disruption. Source