Determination of antibiotic toxicity using a microbial fuel cell (MFC) based biosensor

Antibiotics are antimicrobial drugs commonly used in the treatment of bacterial infections in humans and animals. As a result of the increase in usage of antibiotics worldwide, these compounds reach wastewater treatment plants and affect the performance of the activated sludge process. The early warning device has a critical importance to detect the existence of toxic substrances in biologic wastewater treatment plants. In this thesis study, the detection of the toxic effect of three different antibiotics (tetracycline, chlortetracycline and oxytetracycline) on the microorganism were investigated by using microbial fuel cell (MFC) based biosensors. Different antibiotic concentrations in the ranges of 0.25 to 30 mg/L were injected to the MFC reactors. The performance of the MFCs were investigated in detail under these concentrations. The results showed that there is correlation between antibiotic concentration and the inhibition ratio in power density of MFC. The highest toxic effect was observed with chlortetracycline antibiotic. On the other hand, the biofilm resistance increased with increasing antibiotic concentration. It was seen from the SEM images that a few bacteria present on the surface of the anode at the end of the operation period. Additionally, a thick precipitation layer was observed on the proton exchange membrane surface. The results showed that the MFC based biosensors can be used to detect antibiotics.