Generation of a Gluconobacter oxydans knockout collection for improved extraction of rare earth elements

Bioleaching of rare earth elements using microorganisms offers an environmentally friendly alternative to thermochemical extraction. Here, Schmitz et al. generate a whole-genome knockout collection of mutants for one such microorganism, Gluconobacter oxydans, and identify genes affecting the production of acidic biolixiviant and thus bioleaching efficacy. Bioleaching of rare earth elements (REEs), using microorganisms such as Gluconobacter oxydans, offers a sustainable alternative to environmentally harmful thermochemical extraction, but is currently not very efficient. Here, we generate a whole-genome knockout collection of single-gene transposon disruption mutants for G. oxydans B58, to identify genes affecting the efficacy of REE bioleaching. We find 304 genes whose disruption alters the production of acidic biolixiviant. Disruption of genes underlying synthesis of the cofactor pyrroloquinoline quinone (PQQ) and the PQQ-dependent membrane-bound glucose dehydrogenase nearly eliminates bioleaching. Disruption of phosphate-specific transport system genes enhances bioleaching by up to 18%. Our results provide a comprehensive roadmap for engineering the genome of G. oxydans to further increase its bioleaching efficiency.

Automated summary

Researchers developed a whole-genome knockout collection of mutants for Gluconobacter oxydans, identifying genes influencing the efficacy of rare earth element bioleaching. Disruption of genes related to Pyrroloquinoline Quinone synthesis and glucose dehydrogenase significantly reduces bioleaching, while disruption of phosphate-specific transport system genes enhances bioleaching efficiency. This study offers a roadmap for engineering G. oxydans' genome to improve bioleaching efficiency.