An In Situ Evaluation of Different CAM Plants as Plant Microbial Fuel Cells for Energy Recovery in the Atacama Desert

Excess energy derived from photosynthesis can be used in plant microbial fuel cell (PMFC) systems as a sustainable alternative for the generation of electricity. In this study, the in situ performance of CAM (Crassulacean acid metabolism) plants in Calama, in the Atacama Desert, was evaluated for energy recovery using PMFCs with stainless steel AISI 316L and Cu as electrodes. The plant species evaluated included Aloe perfoliata, Cereus jamacaru, Austrocylindropuntia subulata, Agave potatorum, Aloe arborescens, Malephora crocea, and Kalanchoe daigremontiana. Among the plant species, Kalanchoe daigremontiana demonstrated significant potential as an in situ PMFC, showing a maximum cell potential of 0.248 V and a minimum of 0.139 V. In addition, the cumulative energy for recovery was about 9.4 mWh m^-2 of the electrode. The use of CAM plants in PMFCs presents a novel approach for green energy generation, as these plants possess an inherent ability to adapt to arid environments and water-scarce areas such as the Atacama Desert climate.