Background: Microbial Fuel Cells (MFCs) are promising devices that enable the employment of discarded organic matter, typically gathered around food supply chains, to generate electricity. Aims: In this work, low-cost MFCs in the absence of a proton exchange membrane were fabricated. Methods: They were built on polyvinyl chloride (PVC) plastic tubes with square acrylic sheets at the ends serving as a framework of anode/cathode chambers and using zinc (Zn) and copper (Cu) metals as electrodes. Tomatoes, onions, and potatoes were used as substrates in MFCs and monitored for 21 days. Variables of interest such as voltage, current, pH, and volume were measured through a 100 Ω resistor. Results: The voltage measurements for the onion-based cell showed an upward trend that reaches a peak of 1.01 volts on the last day. Moreover, the greatest current generation was observed in onion cells, in w...