GRAND RAPIDS, Mich. (WOOD) — New research out of California has identified two types of naturally occurring bacteria that help break down certain forms of PFAS much more quickly than they would otherwise break down, potentially paving the way for a “low-cost biological” solution for the industrial pollutant.
The study, led by Dr. Yujie Men at the University of California-Riverside, was published in last month’s edition of the academic journal Nature Water.
Per- and polyfluoroalkyl substances are a large group of compounds first developed in the 1940s and incorporated into all sorts of products for waterproofing and heat resistance.
Research now shows that PFAS compounds take decades to break down organically and can build up in the human body, causing serious health problems.
PFAS compounds can last so long because they have unusually strong carbon-fluorine bonds. Some forms of PFAS are also chlorinated.
Men said two species of bacteria — Desulfovibrio aminophilus and Sporomusa sphaeroides — occur naturally in subterranean microbiomes and “cleave” the PFAS’ chlorine-carbon bonds in chlorinated PFAS, which kickstarts the process for breaking down the rest of the chemical structure.
“We observed a lot of defluorination for structures with several (chlorine-carbon) bonds. And in those bonds, the (chlorine) element, the chlorine can be replaced with (hydroxide) and that will trigger differentiation,” Men told News 8. “It will also trigger the breakdown of the chain, the long chain into shorter chains, shorter chain products.”
The hope is that the two bacteria could be introduced or reinforced into specific areas dealing with high PFAS contamination.
“Further studies are still needed in order to make sure the functionality stays the same and also the toxicity doesn’t increase,” she said.
Previous studies used mixed cultures to start the breakdown process, but Men’s study was able to identify the specific bacteria that do the work. In doing so, those bacteria can be isolated and studied to make them more efficient.
“Using those pure cultures to understand the mechanisms, understand the enzymes involved in this process and potentially manipulate the enzymes, the mechanism, the microorganisms in order to make them more versatile regarding PFAS degradation,” Men said.
In addition to maximizing the work done by these specific bacteria on chlorinated PFAS, her team hopes to find other bacteria that can help break down other forms of PFAS.
“There is no single bacteria that can do everything. It is structure-dependent and structure-specific,” she said. “But we can understand which bacteria are good at breaking down which type of PFAS so that we can tailor the design of variation.”