Biotechnological Strategies for the Recovery of Lithium and Other Metals from a Secondary Source: The Role of Microorganisms and Metal-Binding Peptides

The growing demand for lithium, driven by its key role in rechargeable batteries and its use in electric vehicles, highlights the need for sustainable and environmentally friendly recovery strategies. Conventional methods, such as pyrometallurgy and hydrometallurgy, are effective but costly and harmful as they emit toxic compounds. Biohydrometallurgy has emerged as a promising alternative, as it uses microorganisms and their metabolites to solubilize metals under milder conditions. Biohydrometallurgy has emerged as a promising alternative, as it relies on microorganisms and their metabolites to solubilize metals under mild operating conditions. Nevertheless, challenges related to process efficiency and selectivity remain, particularly for lithium recovery. In this context, recent advances in metal-binding peptides have attracted increasing attention due to their inherent selectivity and the possibility of rational design and heterologous expression in well-established microbial hosts such as Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae. This review critically analyzes current biotechnological strategies and explores the integration of microbial bioleaching with peptide-based approaches as a complementary and environmentally friendly framework for the selective recovery of lithium and other metals from spent batteries and waste electrical and electronic equipment. Overall, this review provides an integrative conceptual framework that highlights the potential of combining microbial processes with metal-binding peptides to guide the development of more selective and sustainable biotechnological strategies for lithium recovery from secondary sources.