E-wastExplor: Explorando estratégias para o tratamento sustentável de lixo eletrónico

The E-wastExplor project's ambitious approach distinguishes from other PCB bioprocessing approaches by focusing on a complete treatment, single-strain optimisation, and comprehensive sustainability assessment. For PCB bioprocessing optimisation, specific objectives involve 1) the identification of bacterial strains (Pseudomonas sp. Bacillus sp., among others) demonstrating the highest efficiency in degrading PCB plastics and mobilising metals (copper – Cu, nickel – Ni, and potentially others) through bioleaching; 2) optimisation of key process parameters (pH, temperature, nutrients availability, incubation time, biomass, among others) to maximise bioprocessing efficiency and predictability; 3) assessment of the potential of selected bacteria to break down or mitigate hazardous organic pollutants commonly found in PCB, such as brominated flame retardants and polychlorinated biphenyls, 4) resource recovery and valorisation. Metal recovery involves developing and refining methods, such as electrodeposition, for the selective recovery of metals (primary Cu, Ni, >80% recovery) from bioprocessing effluents. Biomass valorisation involves its thorough characterisation to identify valuable compounds with a focus on compounds with potential antimicrobial or antioxidant properties, otherwise used as feedstock for bioenergy production. Throughout the processes, chemical characterisation of the effluents and biomass is also aimed, along with a comprehensive ecotoxicological assessment, to evaluate the environmental impact of bioprocessing effluents and ensure the safety of the developed procedures. E-wastExplor objectives are ambitious and push the boundaries of current research in PCB bioprocessing through: 1) Innovative approach – beyond metal focus: Most PCB bioprocessing research prioritises metal recovery (including recent advances in biohydrometallurgy [2] By simultaneously targeting plastics degradation and further investigating biomass valorisation, E-wastExplor goes beyond the standard approaches. Maximising resource use from PCB bioprocessing is crucial for true circularity. 2) Single-strain control – selectivity and optimization: While bacterial consortia are used in e-waste bioprocessing, their complexity can hinder precise control, especially with complex materials like PCBs [3]. Individual strains allow fine-tuning conditions for specific metabolic pathways, increasing efficiency and scalability and exploring genetic modification options. 3) Emphasis on sustainability: targeting the broader spectrum of hazardous PCB constituents makes E-wastExplor more responsive to the real-world complexity of e-waste. Many studies focus on proving that bioprocess is possible, but this project aims to quantify its efficiency and ecotoxicity. 4) Interdisciplinary proposal: based on solid collaboration between (micro)biologists, analytical chemists, biotechnologists, and environmental geochemists who are leading the way in integrative, sustainable waste treatment methods, this project tackles the problem from many angles necessary when dealing with the complex nature of PCB. This comprehensive approach has the potential to pave the way for a paradigm shift in e-waste management. By addressing these critical challenges, E-wastExplor has the potential to not only revolutionise PCB recycling but also serve as a model for developing environmentally friendly solutions for e-waste management.