Researchers at the University of California, Riverside have discovered two species of bacteria with the potential to neutralize a group of resilient pollutants known as “forever chemicals” or PFAS. These naturally existing bacteria can dismantle the chemical bonds in these pollutants, thus rendering them harmless. This discovery provides a cost-effective, biological method for detoxifying industrial contaminants.
Recently, two naturally occurring bacteria have been found to be capable of decomposing chlorinated “forever chemicals,” otherwise known as PFAS.
Researchers in the fields of chemical and environmental engineering at the University of California, Riverside have identified two bacteria types within the soil that can break down this stubborn class of “forever chemicals,” presenting a promising prospect for a low-cost, biological method for removing industrial pollutants.
Under the leadership of Assistant Professor Yujie Men from the Bourns College of Engineering, the team discovered these bacteria are capable of eliminating a specific group of per- and poly-fluoroalkyl substances, or PFAS, especially those containing one or more chlorine atoms in their chemical makeup. Their groundbreaking research has been published in the scientific journal, Nature Water.
Forever chemicals pose a health risk and persist in the environment for decades or longer due to their remarkably strong carbon-to-fluorine bonds. Intriguingly, the team from UCR found that these bacteria can break the pollutant’s carbon-chlorine bonds, initiating a chain of reactions that dismantle the forever chemical structures and render them non-hazardous.
Yujie Men, Assistant Professor at the University of California, Riverside, and graduate student Josen Jin were instrumental in this research. (Credit: UCR photo by Sizhuo Zhang)
The team observed that bacteria initially cleave the carbon-chlorine bond, producing unstable intermediates. These intermediates then undergo spontaneous defluorination, or the breaking of the carbon-fluorine bond.
Forever chemicals or chlorinated PFAS comprise a vast group within the PFAS family, which contains thousands of compounds. These include various non-flammable hydraulic fluids utilized in industry and compounds used for creating chemically stable films that act as moisture barriers in multiple industrial, packaging, and electronic applications.
The two bacteria species identified by Men’s team—Desulfovibrio aminophilus and Sporomusa sphaeroides—are naturally occurring and are known to inhabit subterranean microbiomes where groundwater may be contaminated with PFAS. To accelerate cleanups, an affordable nutrient like methanol could be added to groundwater to stimulate bacterial growth. If these bacteria are not already present, the contaminated water could be treated with one of the bacteria species.
The research paper was authored by Yujie Men, with Bosen Jin, a UCR chemical and environmental engineering graduate student, as the lead author. Other UCR co-authors include postdoc Jinyu Gao; former postdoc Huaqing Liu; former graduate students Shun Che and Yaochun Yu; and Associate Professor Jinyong Liu.
Men’s research expands upon her earlier work, where she demonstrated microbes’ ability to decompose a stubborn group of PFAS called fluorinated carboxylic acids.
Microorganisms have long been utilized for the biological cleanup of oil spills and other industrial pollutants, a subject that Men has studied extensively. The use of microorganisms for PFAS cleanup, however, is still in its early stages. Nevertheless, Men’s discovery holds significant promise as biological treatments tend to be less expensive and more environmentally friendly than their chemical counterparts.
Men’s latest study on PFAS occurs at a time when the U.S. Environmental Protection Agency is introducing new regulations to encourage the cleanup of PFAS-contaminated groundwater sites nationwide. These chemicals are associated with various health hazards, including cancer, kidney disease, and hormonal disruptions.
The research was made possible through grants from the U.S. Department of Defense’s Strategic Environmental Research and Development Program and the National Institute of Environmental Health Sciences.
Reference: “Substantial defluorination of polychlorofluorocarboxylic acids triggered by anaerobic microbial hydrolytic dechlorination” by Bosen Jin, Huaqing Liu, Shun Che, Jinyu Gao, Yaochun Yu, Jinyong Liu, and Yujie Men, 15 May 2023, Nature Water.
DOI: 10.1038/s44221-023-00077-6
Table of Contents
Frequently Asked Questions (FAQs) about PFAS-degrading bacteria
What are “forever chemicals” or PFAS?
PFAS, or per- and poly-fluoroalkyl substances, are a class of man-made chemicals. They have been used in various industries around the globe since the 1940s. Because of their strong carbon-to-fluorine bonds, they persist in the environment for a long time, hence the nickname “forever chemicals.”
Who led the research on bacteria that can degrade “forever chemicals”?
The research was led by Assistant Professor Yujie Men and her team from the Bourns College of Engineering at the University of California, Riverside.
What are the two types of bacteria found to break down PFAS?
The two types of bacteria identified in this study are Desulfovibrio aminophilus and Sporomusa sphaeroides. These bacteria species can break the chemical bonds of a specific group of PFAS, rendering them harmless.
How does this bacterial breakdown of PFAS work?
The bacteria cleave the carbon-chlorine bond in the PFAS compounds first, creating unstable intermediates. These intermediates then undergo spontaneous defluorination, which involves breaking the carbon-fluorine bond, rendering the pollutants harmless.
How could this discovery help in cleaning up PFAS-contaminated groundwater?
By stimulating the growth of these bacteria in PFAS-contaminated groundwater, the breakdown process could be accelerated. This could be achieved by adding inexpensive nutrients like methanol or by introducing the bacteria species if they are not already present. This approach offers a cost-effective and environmentally-friendly method of dealing with industrial pollutants.
Why is this research significant?
This research is significant because PFAS compounds have been linked to a range of health problems, including cancer, kidney disease, and hormonal disruptions. By discovering a biological method to break down these harmful chemicals, it could help clean up contaminated sites and prevent further health risks.
More about PFAS-degrading bacteria
- University of California, Riverside
- Nature Water Journal
- U.S. Environmental Protection Agency on PFAS
- U.S. Department of Defense’s Strategic Environmental Research and Development Program
- National Institute of Environmental Health Sciences
