Microbial Fuel Cell Transformation of Recalcitrant Organic Compounds in Support of Biosensor Research

摘要

Microbial fuel cells (MFCs) have the potential to be used as low- cost, real-time biosensors for drinking water sources. MFCs have been shown to produce current through oxidation of readily degradable organic substrates and the current can be correlated to the substrate concentration. The purpose of this research was to evaluate the transformation of recalcitrant organic compounds, such as aldicarb, in MFCs and to determine if the current generation and current metrics are related to the transformation, through the measured concentrations, of these recalcitrant organic compounds. Partial transformation of aldicarb was observed over two days in the presence of aerobic bacteria when aldicarb was initially at 1 mg L-1 (average concentration difference 13.8%). The aldicarb concentration changed very little when in the presence of anaerobic bacteria, or when added to deionized water or feed media (average concentration difference anaerobic bacteria 0.7%, feed solution 1.8%, deionized water 2.0%). Aldicarb transformation was greater in MFCs than in the aerobic bacteria solution but only partial transformation was observed (average concentration difference MFC1 15.9%, MFC3 28.8%). These data confirm that biotransformation of aldicarb does not occur readily. Aldicarb does not serve as a substrate for the bacteria that generate current in MFCs. This finding was supported by the fact that No. (1) there were no strong linear regression correlations between the change in aldicarb concentration and the current metrics generated from the MFC, No. (2) cyclic voltammetry profiles show very little oxidation potential for aldicarb, No. (3) the majority of current generation from the aldicarb feed cycles was most likely due to the acetonitrile solvent, and No. (4) MFCs did not show a tendency to acclimate to aldicarb.