Sequential flowing membrane-less microbial fuel cell using bioanode and biocathode as sensing elements for toxicity monitoring

Traditional microbial fuel cell based biosensor (MFC-Biosensor) utilizes bioanode as sensing element and delivers high sensitivity for single toxic shock but it fails to alert the combined shock of organic matter (OM)/toxic agent (TA). To address this limitation, this study developed a sequential flowing membrane-less MFC based biosensor (SMFC-Biosensor) using both bioanode and biocathode for toxicity monitoring. Results demonstrated the shocks of 1.5 mg/L Hg²⁺, 1.0 mg/L avermectin and 1.0 mg/L chlortetracycline hydrochloride to SMFC-Biosensor led to inhibition ratios of 36%, 15% and 9%, which were over twice higher than those of bioanode-based and biocathode-based MFC-Biosensors. The viabilities of anodic and cathodic biofilms were both inhibited by the toxic shock. Besides, the excessive organic matters caused a decay in the SMFC-Biosensor current and consequently the OM/TA combined shock could be successfully monitored. This study for the first time testified the feasibility of simultaneously using bioanode and biocathode as sensing elements for toxicity monitoring.