Metal-containing enzymes (metalloenzymes) hold tremendous promise for sustainable chemistry because they perform challenging reactions under mild conditions. However, known metalloenzymes are limited in substrate scope or have complicated structures that are recalcitrant to engineering, which poses a major constraint on biocatalyst development. Excitingly, microbial genomes harbor a wealth of unexplored enzymes that can serve as alternative starting points for engineering. My group unleashes this synthetic potential by discovering new metalloenzymes, characterizing their structures and functions, and engineering them for new chemistry using cutting-edge evolution technologies. By integrating enzyme discovery and evolution into one research program, our work will provide fundamental insights into the chemistry of underexplored metals (e.g. nickel) in biological systems like the human microbiome and accelerate the critical development of sustainable organometallic catalysts.