Indigenous biosensors for in situ hydrocarbon detection in aquatic environments

The use of microbial biofilms for the detection of hydrocarbon contamination in aquatic environments was investigated in this study. Two different microbial biofilms consisting of mixed culture bacteria and microalgae were used as biocatalysts and sensing organisms in the anode and cathode chambers of a bioelectrochemical system, respectively. A series of experiments were conducted to evaluate the potential of this method for sensing hydrocarbon contamination and to study the effect of gasoline (varied between 0.04% (v/v) and 1% (v/v)) and background chemical oxygen demand (COD) concentrations on the sensor response. A linear relationship was observed for gasoline concentrations between 0 and 0.1% (v/v), while an exponential relationship was noted for the gasoline concentration in the range of 0 to 1% (v/v). Reproducibility and resilience of the biosensor in detecting the presence of hydrocarbons were studied. Finally, the ability of the biosensor to remove COD (similar to 70%) indicated its possible use in the bioelectrochemical treatment of polluted waters.