Impact of Opuntia species plant bio-battery in a semi-arid environment: Demonstration of their applications

The plant microbial fuel cell (P-MFC) is a novel bioelectrochemical device that is commonly used in highly water saturated ecosystems to produce sustainable energy. However, the use of this system in arid or semi-arid areas has been less well explored to date. This would involve, the use of plants such as prickly pear, which adapts to these adverse conditions and could be an alternative to expand the application of P-MFC. The objective of this research is to use four Opuntia species (succulent plants) for the generation of sustainable electricity via plant based biobattery design, under open environment and unsaturated water conditions. A Novel vertically integrated plug-in ceramic stick based P-MFCs was constructed, this could reduce the usage of the top-soil surface and aid the possible potential of scale-up design. For a long operating time (30 days), the results showed an average power density of 103.6 mW m(-3) with reactors using Opuntia albicarpa, followed by Opuntia ficus-indica (10.63 mW m(-3)) Opuntia robusta (7.46 mW m(-3)) > Opuntia joconostle (0.46 mW m(-3)), with 1000 Ohms resistance. Higher total electricity production of 285.12 J was achieved in Opuntia albicarpa over four weeks. In addition, the energy generation of 3.66 Wh m(-2) was achieved in this study. Notably, Opuntia ficus-indica and Opuntia albicarpa species showed a significant height in the first two months (P-value < 0.05). This finding opened the avenue for the electricity generation impact on plant growth. The P-MFC also shows the potential to be used in a semi-arid area.