Microbial biodegradation of the “unbreakable” fluorine-carbon bond

Abstract

Fluorinated molecules have been widely used in many industrial sectors. The most produced are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). These molecules are used for coatings to repel stain, grease and water in textiles and kitchen appliances. However, because of their specific molecular properties and the strong C-F bond they are extremely persistent. As a consequence, they accumulate in nature and in drinking water, which is harmful to humans and the environment in general. Current treatment techniques like granular activated carbon (GAC) and reverse osmosis (RO) are extremely expensive and have limitations. Therefore, other mechanisms need to be developed. One of these might be microbial bioremediation. In this thesis bacterial and fungal mechanisms are discussed that are involved in degradation of fluorinated molecules. These mechanisms have great potential for bioremediation of PFASs. However, it also shown that most PFAS species cannot be fully biodegraded by one organism or enzyme. Thus, this thesis also investigated other mechanisms like the use of catalyzed H2O2 propagation (CHP) and horseradish peroxidase (HRP). It can be concluded that the future of PFAS bioremediation will be in using mixtures of organisms and / or enzymes. CHP will be one of the most important mechanisms as it can completely degrade PFOA.