Anodic microbiota reassembly via cell-cell interactions confers oxygen resilience in microbial fuel cells

An anaerobic environment is typically optimal for electrochemically active microorganisms to generate current. Previous studies have created an integrated chamber-free microbial fuel cell (iMFC) that enables anaerobic sludge-sourced EAMs to function under high dissolved oxygen (DO) for the first time, although the mechanism remained unclear. This study examined the power output and anode microbiome dynamics under DO exposure in the iMFC. Multi-omics revealed a three-phase microbiome reassembly during aeration. Indole-3-acetic acid (IAA) and its precursors from anaerobes, together with streptozocin, phenazine, and rhamnolipid produced sequentially by aerobes, drove the anaerobic-aerobic transition. Initially, DO suppressed anaerobes, alleviating their IAA-mediated inhibition of facultative aerobes. Subsequent cell-cell signaling guided anodic microbiome succession from Acinetobacter to Stenotrophomonas, and finally to Pseudomonas. These findings elucidate the anode microbiome transformation mechanism and confirm with a reassembled synthetic consortium that iMFCs can operate aerobically, providing key insights for scaling the technology.