Electroactive Geobacter bacteria drive critical environmental metal transformations that are of interest for metal bioremediation and recovery from wastes. Most of our understanding of these processes comes from laboratory-based studies under conditions that mimic the natural Geobacter environment. Our study identifies that small differences in the sodium ionic strength of cultivation media affect cell wall phenotypes and uranium detoxification mechanisms by Geobacter sulfurreducens. Quantitative proteomics revealed that proteins associated with the cell envelope and extracellular electron transfer functions were also differentially expressed in these media.