Proof of Concept
Hypothetically, the Defluorinator prevents entry of PFAS into active water sites that supply municipal water systems through the use of enzymatic degradation. We tested incorporating FaCD and HaCD into NEB 3 alpha, a strain of Ecoli, to breakdown PFOA compounds in LB Broth and Water cultures. We tested them between average concentrations found in municipal systems (100ng/L). The next step in determining the efficacy of both dehalogenases would be exposing them (via P. Putida) to different environmental conditions to determine the relationship between degradation efficiency and behavior in alternative environments. Furthermore, the growth conditions of the modified P. Putida (in varying ranges of PFAS concentration) should be compared to the growth curves of alternative chassis such as E. Coli to maximize efficiency of the Defluorinator (in future development). Degradation efficiency can be further modeled by the use of ordinary differentials, to calculate the average rate of enzymatic reactions. The constants for modeling the ODEs, however, require further experimental data on the enzymatic reactions of the tested enzymes as well as on the natural reactions between wild P. Putida and PFAS. The rate constants for the differential (of degradation efficiency) can be caculated using Density Functional Rate theory (DFT), which helps calculate the predicted rate constants between enzymes and PFAS. In the following year, the next step in developing the Defluorinator would be to determine the rate constants of fluoroacetate and haloacid dehalogenase respectively to determine their distinct efficiencies. Another continuation of this project would be in installation, creating a standardized means of installation to integrate Defluorinator systems into private water management facilities (such as in waste water treatment). With further research, the Defluorinator would increase in efficiency and become a stronger competitor aganst expensive water treatment techniques such as pyrolysis and reverse osmosis.
Fig.1. Wastewater treatment facilities cause residual buildup of PFAS during treatment, resulting in the introduction of PFAS compounds into active water sites that sustain municipal water systems. The filtration methods that are used to disinfect this water do not affect the PFAS compounds in the water, resulting in the accumulation of PFAS in humans (via drinking water)
In further iterations of experimental testing, various PFAS-contaminated liquids would be placed in a saline solution containing the modified P. Putida to determine the variation in degradation across various chemicals. One such site where the Defluorinator would be tested is in Waste water facilities, where the bacterial cultures would be exposed to various contaminants such as sewage sludge and contrast the data to filtration methods such as pyrolysis. In the setting of a private water facility, the Defluorinator would need to be tested in varying pressures and concentration gradients of liquids requiring treatment. In addition, further investigation regarding the limits of the filtration measures of the Defluorinator would be required. Lastly, future experimentation should include data for the capacity of the activated carbon and sodium bicarbonate to absorb byproducts of the enzyme reactions between the modified P. Putida and PFAS compounds.