Grantee Research Project Results
Final Report: Biodegradation of PFASs from Groundwater and Soil
EPA Grant Number: SU840169Title: Biodegradation of PFASs from Groundwater and Soil
Investigators: Goel, Ramesh , Dentinger, Bryn , Diaz, Ruby
Institution: University of Utah
EPA Project Officer: Spatz, Kyle
Phase: I
Project Period: December 1, 2020 through November 30, 2021 (Extended to November 30, 2023)
Project Amount: $24,978
RFA: P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet (2020) RFA Text | Recipients Lists
Research Category: P3 Awards , P3 Challenge Area - Safe and Sustainable Water Resources
Objective:
The objective of this project was to determine if the co-cultivation of bacteria and fungi could be used to achieve biodegradation of PFAS such as PFOA and PFOS. No intermediate compounds will be measured during the experiments, only PFOA, PFOS, and fluoride concentrations.
Summary/Accomplishments (Outputs/Outcomes):
The bacteria Streptomyces cattleya (SC) is known for the capacity to synthesize fluorinated metabolites and the bacteria bacillus amyloliquefaciens (BA) is known for the capacity to produce secondary metabolites that promote plant growth. White rot fungi are known for their capacity to mineralize lignin, a complex organic polymer difficult to biodegrade, in this experiment the species Pleurotus ostreatus (PO), Phanerochaete chrysosporium (PC), and Ganoderma lucidum (GL) were used in co-cultivation experiments. The objective of this project is to demonstrate that the selected fungi and bacteria can generate enzymes to break down the bond between carbon and fluorine. After the microorganisms break the bonds, they can use the carbon found in the PFASs compounds as the primary food source.
The initial experimental part of this project included co-cultivation of the two bacteria species with the three different white rot fungi species. The fungi-bacteria co-cultivation was evaluated by visual approach. The combination of fungi and bacteria that showed an enhancement on the growth of the white rot fungi was GL with SC. This combination was used for the subsequent per and polyfluoroalkyl substances (PFAS) biodegradation experiments of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).
The potential biodegradation of PFOA and PFOS using co-cultivation of the bacteria Streptomyces cattleya (SC) and the white rot fungi Ganoderma lucidum (GL) was explored The analytical data showed that no appreciable mineralization took place using the co-cultivated bacteria and fungi. All the experiments were performed in liquid media, using to enhance the growth of the fungi and polypropylene containers with polypropylene caps were used for all the batch experiments. Adsorption of the tested PFOA and PFOS was observed, potentially to the containers, carriers or fungi. The adsorption of PFAS to polypropylene have also being observed by other researchers. The cuantification of PFAS concentrations was performed using a high-performance liquid chromatography double mass spectrometry (HPLC/MS/MS) equipment.
The premise that enzymes generated by white rot fungi could mineralize PFAS was further evaluated using the enzyme manganese peroxidase produced by the white rot fungi Phanerochaete chrysosporium (PC). This enzyme is known for the capacity to degrade lignin, organic pollutants and dyes and was tested if it could degrade PFOA. Batch tests were used to determine the capacity of the enzyme to mineralize PFOA. During the batch experiments, the chemical compound 1-hydroxy benzotriazole (HBT) was used as a mediator during the test and hydrogen peroxide (H2O2) was used to activate the enzyme.
The batch experiments were run at a temperature of 27.5 oC and mixed at 130 rpm. The experimental results did not show any mineralization of PFOA. It was assumed that if the enzyme could break the carbon-fluoride bond, then fluoride concentations could be used as an indicator for mineralization of the tested PFOA. From all the experiments performed, none showed any concentrations of fluoride. All the experiments included triplicate tests as well as negative controls. The reduction of measured PFAS such as PFOA and PFOS during the experimental setting point out towards adsorption of the compound to surfaces such as filters, pipetes, containers but not to actual biodegradation of the compound.
The project team conducted educational outreach to high school students from local schools through in-class presentation and literature sharing. However only undergraduate and graduate students enrolled at the University of Utah will worked on this project. The project team will met with local communities located in areas affected by PFAs and explained the impact of PFAs in the environment, health, and people.
Supplemental Keywords:
White rot Fungi, PFAS, Flouride, RecalcitrantProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.