Plant microbial fuel cells for recovering contaminated environments

Plant Microbial Fuel Cells (PMFCs) are bioelectrochemical systems able to convert solar energy into bioelectricity with the support of rhizosphere microbial populations. The simultaneous bioelectricity and biomass production makes PMFCs an interesting nature-based solution for promoting not only energy production, but also soil decontamination. This review reports the main bacterial groups involved in microbial fuel cell systems and key factors influencing their performances in plant presence. In detail, to implement PMFCs for remediation of contaminated soils, it is firstly necessary to know chemical characteristics of pollutants, their concentrations, soil physico-chemical characteristics and soil microbial community structure and functioning. Then, based on characterization data of the contaminated soil, a plant species able to resist pollutant toxicity and promote soil phytoremediation processes (e.g. phyto-extraction, phyto-stabilization, phyto-degradation) can be selected, also based on the climatic characteristics of the study area. Finally, electrode materials and their configurations need to be designed to ensure an efficient plant growth, adequate electron transfer and the best possible generation of bioelectricity and at the same time promoting the degradative activity of microorganisms.