Engineering FeoB-Mediated Iron Uptake Enhances Butyrate Fermentation in <i>Clostridium tyrobutyricum</i>

produced 67.6 g/L butyrate, significantly exceeding the levels reported for previously engineered strains (46.8-52.2 g/L). Carbon utilization was simultaneously improved, as indicated by a butyrate/acetate ratio of 10.1 and a butyrate yield of 0.43 g/g, corresponding to increases of 102.0% and 10.3%, respectively, relative to the wild type. These results establish engineering of iron uptake and homeostasis as an effective strategy for high-intensity butyrate biomanufacturing, supporting more efficient and low-carbon production of biobased chemicals.