Iron Bio Reduction by Indigenous Bacteria From Red Mud

Red mud is solid waste from alumina processing containing more than 30 ferric oxide, Fe2O3. Iron is needed for biochemical and physiological pathways in plants. However, iron is absorbed by plants as ferrous ions, Fe (II). Bio reduction is a process to reduce the valence of ions using microorganisms or parts of the organisms. This research aimed to observe the ability of seven indigenous bacterial strains from red mud to reduce iron in synthetic precursors and study the effect of the addition of cysteine. This research uses FeCl3.6H2O and Fe2O3 as synthetic precursors and Luria Bertani media for bacterial growth. Bio reduction was carried out at room temperature, 200 rpm and an initial pH of 10. The results of this study were that the seven indigenous bacteria could reduce Fe (III) to Fe (II). The highest concentration of Fe (II) for each FeCl3.6H2O and Fe2O3 precursor was 0.3 mM by strain Ai7 and 0.47 mM by strain Ai3. The addition of cysteine could increase the formation of Fe (II) in strains As3, Ai7, and As 6. Indigenous bacteria from red mud have the potential to be applied as bioremediation of land with high ferric oxide content. © 2026 American Institute of Physics Inc.. All rights reserved.