Toxicity monitoring signals analysis of selenite using microbial fuel cells

Microbial fuel cells (MFCs) based biosensors are widely studied to environmental monitoring. The suitable responsive signal is important for microbial electrochemical sensors. However, the responsive signals of toxins have not been investigated in detail. Using sodium selenite as a toxic substance, the different response signals are analyzed over a concentration range from 0 to 150 mg/L in the double chambered. The output voltage and power density had the opposite trend between 0 and 2.5 mg/L and 2.5-150 mg/L. To analyze the reasonable signal of Se(IV) monitoring sensor, correlation analysis of concentrations and responsive signal data (maximum voltage, maximum power density, coulombic recovery, coulombic efficiency, and normalized energy recovery, etc.) has been accomplished. The high concentration of exogenous selenite (2.5-100 mg/L) is negatively correlated with maximum voltage (r = -0.901, p < 0.01) and max power density (r = -0.910, p < 0.01). The low concentration of exogenous selenite is positively correlated with average voltage, max power density, coulombic yield (r = 0.973, 0.999 and 0.975, respectively. p < 0.05). Furthermore, Illumina sequencing results indicate that the addition of sodium selenite solution changes the anode community structure, thereby affecting the removal efficiency of organic matter, which may be the reason why coulombic efficiency and normalized energy recovery are not suitable as sensing signal. Overall, based on the analysis of experimental data, the maximum power density is the best response signal, which provides a reference for the selection of sensor response signal based on microbial fuel cells.

Automated summary

Microbial fuel cells (MFCs) based biosensors are widely studied for environmental monitoring. However, the responsive signals of toxins in microbial electrochemical sensors have not been extensively researched. This study analyzed the different response signals of sodium selenite over a concentration range of 0 to 150 mg/L. Correlation analysis revealed that high concentrations of exogenous selenite were negatively correlated with maximum voltage and maximum power density, while low concentrations were positively correlated with average voltage, maximum power density, and coulombic yield. The addition of sodium selenite solution also affected the anode community structure, resulting in changes in the removal efficiency of organic matter. Based on the analysis of experimental data, the maximum power density was identified as the best response signal for microbial fuel cell-based sensors.