The role of the combination of Shewanella oneidensis MR-1 and Bacillus cereus bacteria in the performance of microbial fuel cell (MFC) series

Indonesia is the world's second largest food waste producer after Saudi Arabia, with an estimated waste disposal of 300 kg/person/year. This problem needs to be addressed to prevent the spread of disease. One way to utilize food waste is to convert it into electrical energy using the Microbial Fuel Cells (MFC) method. MFC has undergone several developments, from dual chamber MFC to Upflow MFC and stacked MFC. Stacked MFC has the advantage of increasing the generated electrical current by stacking several MFC chambers in series or parallel. Power density produced by MFC operating in batches with operating conditions Shewanella oneidensis MR-1, cobalt micronutrients 1 μg/L and operating for 20 days is 29.007 W/m2. This research aims to maximize electrical energy with the help combination of Shewanella oneidensis MR-1, Bacillus cereus, and micronutrients. The experimental procedure used Shewanella oneidensis MR-1, cobalt micronutrients 1 μg/L and Bacillus cereus in amounts of 5 ml and 10 ml. The output results of this research are in the form of a comparison of power density, current, and voltage against time read by an integrated computer. Data obtained from this research shows that the addition of Bacillus cereus increases electricity production, where the total voltage during 15 days of operation of the control variable, the variable of adding 5 ml Bacillus cereus, and the variable of adding 10 ml Bacillus cereus are 90.269 V, 118.961V, 123.195 V,respectively. Then the total current is 6024.56 A, 5822.09 A, 5876 A, respectively. And power density is 119.74 x 108 W/m2, 153.35 x 108 W/m2, 155.85 x 108 W/m2, respectively. There is a decrease in pH due to biofilm formation activity, but the pH decrease is insignificant. It's still in the range of 6.8-7.1 because micronutrients affect the production of extracellular substances that can act as a buffer.