Dual detection of biochemical oxygen demand and nitrate in water based on bidirectional Shewanella loihica electron transfer. (August 2020) - Yi, Yue
Graphical abstract: Highlights: Establishes the relationship between the inward current of BES and nitrate. Reveals a new characteristic of ano-cathodophilic capability of S. loihica biofilm. Reports the first BES sensor for simultaneous detection of BOD and nitrate in water. Achieves a high accuracy of >80% and fast analysis within 1 h. Expands the application of bidirectional EET in water monitoring. Abstract: This study for the first time proposed a method for simultaneously measuring BOD and nitrate in water using electrochemically active bacteria. Firstly, the bidirectional extracellular electron transfer (EET) capability of a model electricigen Shewanella loihica PV-4 was revealed. Then, based on the respective outward and inward EET, S. loihica PV-4 was utilized to detection BOD and nitrate. The results demonstrated a positive correlation between the outward EET and BOD (from 0 mg/L to 435 mg/L) while a negative correlation between the inward EET and nitrate (from 0 mg/L to 7 mg/L); both the relationships were well fitted by the combination of traditional linear model and Michaelis-Menten model (R 2 > 0.96). Finally, a dual detection method for BOD and nitrate measurements was established based on the ano-cathodophilic capability of S. loihica PV-4 biofilm, and exhibited the characteristics of high accuracy (>80%) and fast analysis (<1 h), suggesting a promising prospect in water monitoring.