Hypoiodous acid (HIO) represents a pivotal iodine species in global iodine cycling, yet microbial contributions to its transformation have remained poorly characterised. Here, we demonstrate that the metal‐reducing bacterium Shewanella oneidensis MR‐1 actively drive HIO reduction to iodide. Notably, genetic disruption of extracellular electron transfer components impaired HIO reduction activity in S. oneidensis MR‐1. Specifica...