Different species of bacteria have been shown to be electroactive and able to oxidize organic compounds releasing electrons that can be transferred to a conductive solid support which is known as a bioanode. In biocathodes, electrons transferred to the bacteria can be coupled with oxygen reduction (ORR) generating water. The combined activities of bioanodes and biocathodes can couple the degradation of organic compounds to the production of useful electricity and water such as in the alternative and cost effective bioelectrochemical systems including microbial fuel cells (MFCs). Such MFCs have shown progress as components of self-sustainable wastewater treatment systems. Understanding the bioelectrocatalytic nature of the metabolism of electrically active bacteria, particularly their internal and external electron transfer, is of great importance for the further development of MFCs and a key component in their future application. In this work, an artificial approach for enhanced microbial bioelectrocatalysis was explored along with the study of the parameters promoting bacterial extracellular electron transfer (EET). This approach consisted of chemical modification of smooth electrode gold surfaces by introducing various functional groups (-CH3, -OH, -N(CH3)3 and -COOH) in the form of self-assembled monolayers (SAMs). Biofilm growth and electrochemical performance have been studied in both pure bacterial culture models and mixed environmentally obtained cultures. Power curves and single electrode polarization data have been gathered to evaluate the performance of these MFCs. XPS analysis of electrodes was used to study the influence of each functional group on the electrochemical results. Confocal and SEM microscopy were used to study the bacterial biomass and biofilm development tracked over time. In addition, small bacterial metabolites were monitored using chromatographic techniques in order to correlate their emergence in response to different conditions such as SAM chemistry and applied electrical potential.

Surface chemistry enhanced microbial electrodes: Biofilm modeling and characterization

249th National Meeting (2015)

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