OPTIMIZATION OF RARE EARTH ELEMENT BIOLEACHING BY GLUCONOBACTER OXYDANS B58
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The sustainable energy transition requires an unprecedented increase in the supply of rare earth elements (REEs), essential for technologies like wind turbines, electric vehicles, and many other modern technologies. Traditional hydrometallurgical extraction methods pose significant environmental risks, fueling the search for cleaner alternatives.Bioleaching, which utilizes microbially produced lixiviants to solubilize metals from ores, concentrates, or recycled materials, presents an innovative solution. Gluconobacter oxydans has emerged as a promising candidate due to its ability to secrete organic compounds capable of solubilizing REEs. Advances in metabolic engineering can significantly improve yields, enabling bioleaching to compete effectively with traditional methods. The full potential of G. oxydans’ for REE bioleaching remains limited by an incomplete understanding of the biological processes that drive its metal solubilization capabilities. Gaining deeper insight into the genetic and metabolic factors involved is essential for developing strategies to improve its extraction efficiency. This thesis investigates the mechanisms underlying G. oxydans bioleaching capabilities with the aim of identifying targets for optimization and advancing its application in sustainable technologies. The characterization of G. oxydans’ metabolic profile and protein production uncovered metabolic pathways and organic compounds critical to metal solubilization. Genome-scale screening and high-throughput techniques identified key genes involved in the production of non-acid components of the biolixiviant, guiding engineering strategies to optimize REE bioleaching. G. oxydans strains engineered through site-directed mutagenesis successfully enhanced REE extraction efficiency. Additionally, evaluation of the biolixiviant’s potential for carbon mineralization demonstrated that electromicrobial production could enable microbially-accelerated mineral weathering, underscoring broader sustainability applications. This work provides a comprehensive framework for optimizing microbial systems for REE recovery, positioning G. oxydans as a sustainable and efficient extraction platform. These findings contribute to the broader understanding of microbial metal recovery and lay the foundation for further advancements in REE recovery with G. oxydans.