SummaryGlobally, sustainable provision of high-quality safe water is a major challenge of the 21st century. Various chemical and biological monitoring analytics are presently utilized to guarantee the availability of high-quality water. However, these techniques still face some challenges including high costs, complex design and onsite and online limitations. The recent technology of using microbial fuel cell (MFC)-based biosensors holds outstanding potential for the rapid and realtime monitoring of water source quality. MFCs have the advantages of simplicity in design and efficiency for onsite sensing. Even though some sensing applications of MFCs were previously studied, e.g. biochemical oxygen demand sensor, recently numerous research groups around the world have presented new practical applications of this technique, which combine multidisciplinary scientific knowledge in materials science, microbiology and electrochemistry fields. This review presents the most updated research on the utilization of MFCs as potential biosensors for monitoring water quality and considers the range of potentially toxic analytes that have so far been detected using this methodology. The advantages of MFCs over established technology are also considered as well as future work required to establish their routine use.
Fundamentals and limitations of microbial fuel cellsCurrently, eco-friendly bioelectrochemical systems (BESs) have shown outstanding potential to be a promising process for the recovery of valuable resources from wastewater (Wang and Ren 2013; Bajracharya et al. 2016). The bestknown example of this technology is the microbial fuel cell (MFC). The MFC operates by utilizing micro-organisms as a biocatalyst to oxidize organic matter and generate electrical current at the anode chamber, which when coupled to the oxygen reduction, occurring at the cathode chamber, produces electrical power (Fig. 1) (Modin et al. 2017). In principle, BESs can be employed to turn wastewater, including organic matter, into energy in self-sufficient wastewater treatment plants. Actually, all the energy consumption process for activated sludge treatment, which is usually utilized to eliminate organic matter, can be minimized by BESs (ElMekawy et al. 2013(ElMekawy et al. , 2017. The scientific concept is very attractive, and numerous research investigations have been conducted in this field.Nevertheless, there are some challenges facing the commercial application of these systems including huge capital costs. BESs comprise electrodes, current collectors, wiring and membranes, which increase the costs compared with conventional reactors used in wastewater treatment. If a BES is to completely or partially substitute the activated sludge system, it is expected that the value of generated product and the cost reduction resulting from decreased aeration requirements should be high enough to cover the system capital investment (Escapa et al. 2012;