Synthetic Shewanella-Bacillus Microbial Consortia for Enhanced Metal Oxide Leaching From Spent Lithium-Ion Batteries Using Brewing Wastewater as Leaching Agent.

The rapid proliferation of lithium-ion batteries (LIBs) underscores the need for recycling, yet existing methods are costly, inefficient, and environmentally challenging. This work developed a spent LIBs recycling approach using brewing wastewater and designed a microbial consortium as a biocatalyst for facilitating metal oxide leaching. The Shewanella oneidensis reduces spent LIBs cathode LiNixCoyMn1-x-yO2 (NCM) via extracellular electron transfer (EET) by feeding with brewing wastewater's organics, and the Bacillus subtilis removes residual ethanol to eliminate inhibition on EET. The catalytic performance is further enhanced via boosting EET, increasing metal oxide leaching, which, however, impairs cell viability. To bolster resistance, the global transcriptional factor IrrE is introduced, achieving a leached metal ion concentration of 102.4 mg L-1, 30.12 times higher than in brewing wastewater. Cellular electrophysiology analyses reveal that S. oneidensis utilizes c-type cytochromes MtrC and OmcA, and riboflavin to transfer electrons to NCM. This study proposes a sustainable "treating waste with waste" technology for recycling spent LIBs.