Switchover of electrotrophic and heterotrophic respirations enables the biomonitoring of low concentration of BOD in oxygen-rich environment

However, there is still no technique to directly measure BOD at low concentrations in oxygen-rich environments. Here, we propose a new scheme using facultative electrotrophs as the sensing element, and confirmed aerobic Acinetobacter venetianus RAG-1 immo_x0002_bilized on electrode was able to measure BOD via the switchover between electrotrophic and heterotrophic respirations.

The hybrid binder of Nafion and polytetrafluoroethylene (PTFE) maximized the baseline current (127 ± 2 A/m2) and sensitivity (2.5 ± 0.1 (mA/m2)/(mg/L)). The current decrease and the BOD5 concentration fitted well with a linear model in the case of known contaminants, verified with both lab samples of acetate and glucose (R2 >0.96) and in standard curves of real environmental samples collected from the lake and the effluent of wastewater treatment plant (R2>0.98).