Influence of Shewanella oneidensis MR-1 Bacterial Metabolism Process on Waste Treatment of Cr and Mn Metals in Reactor Microbial Fuel Cell (MFC)

Chromium (Cr) and manganese (Mn) are heavy metals which have high oxidation potential and cause mutagenesis and carcinogenic to living organisms. Microbial Fuel Cell (MFC) appears as one of the applications in the processing of Cr and Mn metals. MFC is bioreactor which converts chemical energy of organic compounds into electrical energy through the catalytic reaction of microorganisms in anaerobic conditions. The aim of this research are to find out the role of Shewanella oneidensis MR-1 bacteria on manufacture electrical energy by utilizing organic wastes, and to find out the concentration of Shewanella oneidensis MR-1 on the most influential anode side for the reduction of metallic Cr, Mn, and its mixed metal on the cathode side by using a MFC. The research method used molasses with bacteria concentration of 10%; 12.5%; 15% (v/v) on the anode side, while on the cathode side was used Cr(VI), Mn(VII) solutions, and mixtures of Cr and Mn solutions with the ratio of 1:0; 0:1; 1:1 (w/w). 15% bacteria concentration on mixture of metal solution resulted the highest electricity production, which was 46.33 (mW/m²), and the best reduction of Cr⁶⁺ to Cr³⁺ 82.15%, while for the reduction of Mn⁷⁺ to Mn² was 61.17%.