Simplified Reactor Design for Mixed Culture-Based Electrofermentation toward Butyric Acid Production

Mixed microbial culture (MMC) electrofermentation (EF) represents a promising tool to drive metabolic pathways toward the production of specific compound. Here, MMC-EF process has been exploited obtain butyric acid in simplified membrane-less reactors operated by applying difference potential between two low-cost graphite electrodes. Ten values voltage difference, from −0.60 V −1.5 V, have tested and compared with experiment under open circuit (OCP). In all conditions, an enhancement rate (from synthetic mixture glucose, acetate, ethanol) was observed, ranging 1.3- 2.7-fold relative OCP. Smaller enhancements resulted higher calculated energy consumption. However, at applied voltages, low flow current detected one-chamber reactors, accounting for average value approximately −100 µA. These results hold substantial respect scalability technology, since they pinpoint possibility control MMC-based bioprocesses simply inserting polarized electrodes into traditional fermenters.