Production of electrical energy from living plants in microbial fuel cells

Abstract

Growing energy demand is a current problem with greater incidence in the future. The research objective is to establish seed bases to give a leading role to plants used in anthropogenic production activities and consumption, and even plants belonging to wildlife in terms of energy production. The use of living plants to obtain electrical energy through a microbial-vegetable fuel cell is proposed as a mechanism to supply the energy demand with easy access worldwide, especially in areas far from urban centres. In this work, the voltage produced by microbial-vegetable fuel cells was measured using graphite electrodes and plants belonging to the species of aloe (Aloe vera), corn (Zea mays), black beans (Phaseolus vulgaris), tomato (Solanum lycopersicum) and moss (Dicranidae). They were selected for their presence in everyday life and their great commercial and agricultural value, reaching a maximum voltage of 884 mV from moss. There is evidence that all plants can be a source of energy to a greater or lesser extent and that their performance is given by the plant root interactions at the electrodes. However, an extensive root system can favour the accumulation of substrate after the hydrolysis of dead roots, provided that their presence does not interfere with microbial activity on the anodic surface. For this, using plants with low resistance to thermal stress can lead to a substrate richer in substances that can be decomposed. Therefore, it is recommended to use plants according to their life cycle and the morphology of their roots, and plants that can grow in waterlogged conditions or without direct contact with the Sun.