Power generation potential of plant microbial fuel cells as a renewable energy source

The global energy demand has increased interest in the development of new technologies that offer alternative, cost-effective energy solutions with minimal environmental impact. Among these technologies, is microbial fuel cell (MFC), which takes advantage of the electrical energy produced through the metabolic reactions of microorganisms when they encounter a substrate. This study assesses the electric power generation potential of MFC configured using as a substrate and source comprising a mixture of soil, sand, organic fertilizer, and ash in a proportion of 3:2:1:1/2. Native plants (Torenia fournieri, Kalanchoe blossfeldiana, Pentas lanceolata, Nephrolepis exaltata, Begonia semperflorens, or Asplenium nidus) were planted to promote the exchange of organic chemical species and nutrients for renewable electrical energy generation. The configuration, constituting a system of fuel cells with microorganisms and plants (Plant Microbial Fuel Cell, PMFC), demonstrated varying whose efficiency levels, determined by measuring the potential between the cell electrodes. The highest voltage obtained in the PMFCs was 0.609 V for the Begonia semperflorens plan, while the lowest was 0.069 V for Asplenium nidus. Torenia fournieri and Asplenium nidus presented the highest voltage peaks at 1.782 and 1.587 V, respectively. Of the plants studied, Nephrolepis exaltata and Asplenium nidus were the only surviving plants after the measurements. When all were connected in series, excluding Asplenium nidus due to its instability, it resulted in an average voltage of 1.856 V. The minimum recorded voltage was 1.540 V, and the maximum electrical potential reached 2.050 V. Analysis of the soil samples, along with the substrate before and after the experiment, identified six electrogenic bacteria: Escherichia coli, Pseudomonas sp., Erwinia sp., Lactobacillus sp., Enterococcus sp., and Clostridium sp. The Escherichia coli was only present in the soil and substrate sample before the experiment, while the concentration of Pseudomonas sp. and Erwinia sp., increased. This study confirmed that PMFCs with low-cost substrates and native Caribbean plants, represent a promising technology that could drive energy development in developing countries, especially in remote areas lacking access to electricity. This implementation of PMFCs aligns with sustainable energy practices, offering a cost-effective strategy, that can be replicated globally, contributing to the achievement of Sustainable Development Goal 7: Ensure access to affordable, reliable, sustainable, and modern energy for all.