Poultry Residual Biomass as Substrate to Generate Bioelectricity using a dual Chamber Microbial Fuel Cell “MFC” with Graphite and Copper Electrodes

Abstract

Microbial fuel cells (MFC) are electrochemical systems through which sustainable energy can be produced due to the degradation of organic matter using substrates with a varied chemical composition. The bioprocess that takes place inside the MFC takes advantage of the oxidation of organic matter. This process releases protons and electrons extracellularly, and the latter are transferred from the anode to the cathode generating bioelectricity. The MFC operating system produces energy due to the bacterial metabolism, through an electron transfer phenomenon that reflects into a bio energy conversion with minimal impacts on the environment. With the MFC system, it is possible to investigate the use of new residual substrates for energy production, the types of native microbial communities that develop during the degradation of specific compounds and the design of more efficient cells. In this research, copper and graphite were evaluated as low-cost electrodes using batch microbial fuel cells for 208 hours of operation, a data logger was used, and physicochemical parameters were taken during this period. The maximum power density presented was 14 mW/m2 with the graphite electrode and 6.7 mW/m2 with the copper electrode. Electrogenic bacteria were identified through biochemical and molecular tests such as bacterial culture, strain purification, DNA extraction and sequencing of microorganisms. The bacteria were uploaded to the NCBI gene data bank and the identity of these strains was identified: avian graphite 1 “Av_A1” (Pseudomonas aureginosa), avian graphite 2 “Av_A2” (Bacillus cereus) and avian copper 1 “AV_C1” (Bacillus tropicus). A dual chamber MFC was assembled, so each microbial cell can contain the residual substrate and the corresponding electron acceptor, both for the anodic and cathodic cell. These cells were separated by a Nafion® or Ultrex® membrane cation exchange membrane. The results showed us that optimal conditions for the generation of bioelectricity can be established in MFC cells, adding information to the literature on the behavior of bacteria that thrive in stressful environments such as copper and simple materials such as the graphite.