Microbial Fuel Cell-Based Biosensors

Abstract

The microbial fuel cell (MFC) is a promising environmental biotechnology that has been proposed mainly for power production and wastewater treatment. Though small power output constrains its application for directly operating most electrical devices, great progress in its chemical, electrochemical, and microbiological aspects has expanded the applications of MFCs into other areas such as the generation of chemicals (e.g., formate or methane), bioremediation of contaminated soils, water desalination, and biosensors. In recent decades, MFC-based biosensors have drawn increasing attention because of their simplicity and sustainability, with applications ranging from the monitoring of water quality (e.g., biochemical oxygen demand (BOD), toxicants) to the detection of air quality (e.g., carbon monoxide, formaldehyde). In this review, we summarize the status quo of MFC-based biosensors, putting emphasis on BOD and toxicity detection. Furthermore, this review covers other applications of MFC-based biosensors, such as DO and microbial activity. Further, challenges and prospects of MFC-based biosensors are briefly discussed.

Keywords: BOD; biosensors; environmental monitoring; microbial fuel cells; toxicity.

Figure 1

Schematic diagrams of (A) a biosensor [20], (B) a dual-chamber microbial fuel cell (MFC) and (C) an MFC-based biosensor.

Figure 2

(A) Schematic diagram of the membrane-less single-chamber MFC-based BOD sensor [25]. (B) Schematic diagram of the three-stage MFCs as BOD sensor and compliance of predicted BOD₅ values with five-day BOD test (BOD₅). y = x is shown as the “ideal” prediction [57].

Figure 3

Photographs or schematics of MFC toxicity sensors: (A) membrane-based electrodes [77], (B) abiotic cathode sensing element [78], (C) miniature MFC with air bubble trap [79], (D) paper MFC [80], and (E) shared cathode [81].