Promovendo a saúde do solo através de biorremediação sustentável usando microrganismos eletrogeradores

This proposal aims at the protection of the environment and natural resources. The main objective is to develop a bioelectrochemical degradation process as a tool for bioremediation of contaminated soil. The focus will be the contamination by phenolic compounds and PFAS due to the high concern posed by their widespread contamination and negative impacts in soil health and safety. Nowadays, electrochemical technologies are considered pivotal for the elimination of recalcitrant contaminants in the environment, while producing clean energy as a byproduct. Particularly electrochemical devices using biological material, known as biofuel-cells, have shown to provide bioenergy based on the controlled breakdown of suited organic compounds. However, there are crucial variables that influence the feasibility and performance of the solution. In this project, we will address these variables by optimizing each component in the device. Our first focus will be on the special development of the bioanode and biocathode as the key components of bioelectrochemical devices. The process will entail the comparative evaluation and meticulous selection of optimal electrode materials exhibiting favorable redox characteristics, alongside the cultivation and enrichment of electroactive bacterial consortia tailored for implementation in both the bioanode and biocathode configurations. Concerning the anode, the objective is to obtain an electrode surface coated with a biofilm containing active bacteria responsible for transferring electrons extracted during the oxidation of the phenolic and PFAS compounds to the cathode, the latter enriched with electroactive bacteria capable of accepting electrons. The western and southern coastal regions of Portugal, characterized by high anthropogenic activities, where five distinct types of soils can be identified. These soils range from medium/fine textured organic-rich humic cambisols to clay-rich luvisols, all of which will be addressed in this project. Another specific objective is to overcome the low electrical conductivity observed in various types of soils, harnessing the ability of microorganisms to engage in long-distance interspecies electron transfer through the incorporation of conductive biochar. This approach will be complemented by the objective of efficiently immobilizing specific bacteria from the UCP bacterial collection with proven capacity to degrade the target recalcitrant compounds within the biochar matrix as biocatalysts, as well as establish the conditions for the stability, viability, and activity of the immobilized biocatalyst. The soil bioaugmentation with these bacteria will be a plus to increasing the efficiency of bioremediation, coupling the pollutant oxidation capacity of electroactive bacteria with the ability of specialized degrading strains for the complete biodegradation of the target pollutants. This comprehensive approach aims to enhance the remediation efficiency by leveraging the amendment properties of biochar in both functioning as a microorganism carrier in bioaugmentation and to increase soil conductivity to potentiate electrochemical processes. Finally, we aim to construct and operate a bioelectrochemical device for soil remediation. We will combine all the developed and optimized components to achieve the goal of complete biodegradation of phenolic compounds and PFAS in soil microcosms. This will promote bioremediation while generating green electricity.