Date of Award

2020

Degree Type

Thesis

Degree Name

Master of Science in Chemical Engineering (MSChE)

Department

Chemical Engineering

First Advisor

Geoffrey D. Bothun

Abstract

Poly- and Perfluoroalkyl substances (PFAS) are a group of emerging contaminants which are persistent in nature and hazardous for living organisms. They have an anthropogenic origin and have unique properties which have the disadvantage of bioaccumulating in organisms.

This work aims at the investigation of the influence of different relevant PFAS on the membrane properties of A. borkumensis. This information is one important piece on the way to evaluate the overall response of the bacterium in the presence of these molecules. First, the lipids were extracted with a solvent-based method. Afterwards, they were spread at an air-water interface within a Langmuir trough while the water phase contained PFAS which can then interact with the lipid monolayer. Since PFAS are amphiphilic, their hydrophobic tail is drawn to the air phase just like the lipids’ tail. By evaluating different PFAS, the influence of the hydrophilic headgroup and the fluorinated tail length can be examined. To investigate the role of the lipid type, experiments with model membranes of known lipids were conducted, too.

In conclusion, all PFAS were found to have an impact on the monolayer increasing with the PFAS concentration. Very surface active components can even displace lipids. In all cases at least slight increases in fluidity could be observed which can be troubling for the live bacterium in the end since it relies on the mechanical stability of its membrane.

Available for download on Saturday, August 20, 2022

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