Characterization of electrodes and influence of phenazines on the performance of pseudomonas aeruginosa catalyzed fuel cell

Abstract

Microbial fuel cells (MFCs) have a great potential as catalysts for utilization of a variety of organic wastes and renewable biomass to electricity. Several factors affect the operation of an MFC, including the microbes, the availability and form of substrate, the proton-conducting material, the material of the electrodes, the cathode/anode catalyst, the electrode spacing and the system configuration. Each of these parameters offers unique opportunities for system development. One of the objectives of the present work was to develop modified carbon electrodes with enhanced active surface area, conductive surface, and redox behavior suited to microbial metabolism and conducive to biofilm formation which may lead to increase in efficacy of MFCs. Two strategies were adopted. In the first strategy based on bulk doping, graphite/epoxy composite electrode (GECE) was modified with seven metal ion which were prepared through a wet impregnation procedure. In the second approach, immobilization of redox dyes on carbon cloth and graphite sheet was carried out using N,N dicyclohexylcarbodiimide for surface modification. Crystallinity, morphology, surface chemistry and electrochemical properties of all modified electrodes were investigated. With Cu2+- GECE as anode in oxychloraphin and tubermycin supplemented MFC, power density generated was 22.9 and 7.8 fold higher, respectively when compared with unsupplemented MFCs. Doping with other metal ions such as Mn2+, Mg2+ , Co2+ and Zn2+ in GECE for use as anode also enhanced the power density in oxychloraphin supplemented MFC. The addition of phenazines pyocyanin and pyorubin that are normally produced by the P.aeruginosa MTCC 2474, however was not very helpful to the performance of the MFC. The addition of these phenazines inhibited the growth of bacteria as well. Thus, choice of an appropriate secondary metabolite can have a positive influence as a mediator of electron transfer in the working of MFCs. newline newline newline