Sub-toxic concentrations of volatile organic compounds inhibit extracellular respiration of Escherichia coli cells grown in anodic bioelectrochemical systems

Low-cost and rapid detection of volatile organic compounds (VOCs) is important for the control of water quality of used water and protection of downstream used water treatment processes. In this work, the effect of sub-toxic concentration of VOCs on the current output of Escherichia coli in bioelectrochemical systems (BES) is shown, in light of environmental sensing applications for sewage and used water networks. E. coli cells were grown on carbon felt electrodes in artificial used water, to increase sensitivity and decrease response time for detection. Extracellular electron transfer was promoted by the addition of a biocompatible redox mediator, 2-hydroxy-1,4-naphthoquinone (HNQ). Among the eight VOCs investigated, toluene is the most toxic to E. coli, with a detection limit of 50 ± 2 mg L^− 1 and current output of 32 ± 1 nA mg^− 1 L^− 1. This work offers a straightforward route to enhance the detection of organic contaminants in used water for environmental applications.