Microbe chews through PFAS and other tough contaminants

By Princeton University | phys.org | September 18, 2019

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“In a series of lab tests, a relatively common soil bacterium has demonstrated its ability to break down the difficult-to-remove class of pollutants called PFAS, researchers at Princeton University said.

The bacterium, Acidimicrobium bacterium A6, removed 60% of PFAS–specifically perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)–in lab vials over 100 days of observation, the researchers reported in a Sept. 18 article in the journal Environmental Science and Technology. Because of their health concerns and ubiquity, EPA has recently opened a research effort into the chemicals impact in drinking water. Peter Jaffe, the lead researcher and a professor of civil and environmental engineering at Princeton, said the researchers were very encouraged to see these bacteria substantially degrade the famously recalcitrant class of chemicals but cautioned that more work was needed before reaching a workable treatment.

‘This is a proof of concept,’ said Jaffe, the William L. Knapp ’47 Professor of Civil Engineering. ‘We would like to get the removal higher, and then go and test it in the field.’

PFAS (Per- and polyfluoroalkyl substances) have been widely used in products from non-stick pans to firefighting foam, and the Environmental Protection Agency has said there is evidence that exposure to PFAS is harmful to human health. Because of this, U.S. manufacturers have phased out several versions of PFAS in their products. But the substance is long-lived and extremely difficult to remove from soil and ground water. In recent years, local governments have been seeking ways to reduce the amount of PFAS in water supplies.

Because of the strength of the carbon-fluorine bond, these chemicals are extremely difficult to remove through conventional means. But Jaffe and co-researcher, Shan Huang, an associate research scholar at Princeton, suspected that the Acidimicrobium A6 might be an effective remedy…

Acidimicrobium A6 thrives in low oxygen conditions, which makes it particularly effective for soil and groundwater remediation and allows it to function without expensive aeration. However, these bacteria also require iron and acidic soil conditions. Jaffe said this could limit their deployment, but adjusting soil conditions could also allow the bacteria to function in areas that do not naturally meet these requirements. Noting previous work on ammonium reduction by Acidimicrobium A6 in soil columns, constructed wetlands, and the electrochemical reactors, Jaffe said the researchers believe this could also be done for PFAS remediation.”

This content provided by the PFAS Project.