Microbial Mineralization\nwith Lysinibacillus\nsphaericus for Selective Lithium Nanoparticle Extraction

Lithium is a critical mineral in a wide range of current\ntechnologies,\nand demand continues to grow with the transition to a green economy.\nCurrent lithium mining and extraction practices are often highly ecologically\ndamaging, in part due to the large amount of water and energy they\nconsume. Biomineralization is a natural process that transforms inorganic\nprecursors to minerals. Microbial biomineralization has potential\nas an ecofriendly alternative to current lithium extraction techniques.\nThis work demonstrates Lysinibacillus sphaericus biomineralization of lithium chloride to lithium hydroxide. Quantitative\nanalysis of biomineralized lithium via the 2-(2-hydroxyphenyl)-benzoxazole\nfluorescence assay reveals significantly greater recovery with L. sphaericus than without. Furthermore, L. sphaericus biomineralization is specific to lithium\nover sodium. The nanoparticles produced were further characterized\nvia Fourier transform infrared and transmission electron microscopy\nanalysis as crystalline lithium hydroxide, which is an advanced functional\nmaterial. Finally, ESI–LC/MS was used to identify several proteins\ninvolved in this microbial biomineralization process, including the\nS-layer protein. Through the isolation of L. sphaericus ghosts, this work shows that the S-layer protein alone plays a critical\nrole in the biomineralization of crystalline lithium hydroxide nanoparticles.\nThrough this study of microbial biomineralization of lithium with L. sphaericus, there is potential to develop innovative\nand environmentally friendly extraction techniques.