Strategies for biodegradation of fluorinated compounds

Environmental contamination by fluorinated organic compounds is an issue of major concern due to their widespread use and recalcitrance to degradation. The susceptibility of fluorinated pollutants to biodegradation, a major route for the removal of such pollutants from different environmental compartments, is affected by the molecule structure, namely, the number and position of fluorine atoms. In this chapter, the biodegradation of several fluorinated substrates is presented, highlighting the occurrence of mineralization versus biotransformation to dead-end metabolites, whose toxicity cannot be disregarded. Enrichment strategies to obtain degrading strains are addressed, as well as approaches to improve degradation efficiency. Frequently, in contaminated environments, autochthonous strains are not able to break the high-strength carbon-fluorine bond(s). Bioaugmentation, through the addition of specialized pollutant-degrading strains/genes to environmental matrices, is presented as a promising strategy to improve pollutant removal efficiency. Successful bioaugmentation processes applied to different reactor configurations are presented, and constraints to its implementation are also discussed.