Microbial phyto-power systems - A sustainable integration of phytoremediation and microbial fuel cells

Constructed wetland microbial fuel cells (CW-MFCs) or phyto-power systems are integrated bioelectrochemical systems (BES) that can sustainably harvest electricity from the anaerobic respiration of rhizospheric bacteria. This integration of techniques shows a promise in phytoremediation of wastewater along with bioenergy generation. In CW-MFCs, electrons harvested in anaerobic respiration of bacteria proliferating in the rhizospheric zone are electrochemically coupled with electron acceptors at the aerobic cathode submersed in water. Use of indigenous non-food plants in CW-MFCs has gained increasing interest primarily due to high yield of biomass that can be applied for other bioenergy purposes and bioaccumulation of pollutants. Furthermore, CW-MFCs can provide other benefits such as wastewater treatment, carbon dioxide assimilation, power generation and air purification. Microbial interaction with plant roots (rhizosphere), isolated species from the phyto-systems, with soil particles and pollutants are reviewed in this paper. In addition, successful applications of CW-MFCs are discussed with focus on power generation, the role of plant-microbe interactions as well as evaluating the critical operational parameters and their effect on power generation output efficiency.