Optimizing Biofuel Cell Performance Using a Targeted Mixed Mediator Combination

Abstract

A study of how mediators might interact with the catabolic pathways of yeast was undertaken with a view towards improving the performance of microbial fuel cells. This work suggests that no single mediator is ideally suited to the task, and that a carefully selected mixture of two targeted mediators (Methylene Blue and Neutral Red) might be optimal. To test this hypothesis a yeast-catalyzed microbial fuel cell was built and empirically evaluated under different mediation conditions. The results clearly show that a judicious mix of the two mediators can indeed achieve significantly superior performance, in terms of power-density, than when either mediator is used singly at the same overall concentration.

Yeast as a Biocatalyst in Microbial Fuel Cell

“…This increase in the performance was related to the role of the MB in the enhancement of the anaerobic respiration, while NR involved with fermentation only. This study [44] showed that the addition of the MB was effective than NR, which is in contradiction to that reported by Najafpour et al [49]. This might be related to the difference in the operation conditions, and/or any other reasons that is not clear for the authors right now.…”

“…These mediators whether internal or external will be responsible for the electron transfer from the bulk microorganisms to the anode surface. The electron transfer in the mediated electron transfer is higher than that in the DET [4,[44][45][46][47][48][49][50][51].…”

“…Several yeast strains have been studied as biocatalysts in MFC with or without external mediator such as Saccharomyces cerevisiae (S. cerevisiae) [41][42][43][44][45][46][47][48][49][50][51][52], Candida melibiosica 2491 (C. melibiosica) [53][54][55][56], Hansenula anomala (H. anomala) [40], Hansenula polymorpha (Hansenula polymorpha) [57], Arxula adeninivorans (A. adeninivorans) [58] and Kluyveromyces marxianus (K. marxianus) [59].…”

“…These results showed that NR served as a suitable mediator and enhanced the electrical energy by 5 folds compared to that of MB [49]. When NR (0.5 mM) was added to the MB (0.5 mM), the S. cerevisiae yeastbased MFC showed a maximum power output of 500 mW/m 2 compared to 400 mW/m 2 in case of 1 mM of MB [44]. This increase in the performance was related to the role of the MB in the enhancement of the anaerobic respiration, while NR involved with fermentation only.…”

Improved Performance of a Microbial Fuel Cell with Polypyrrole/Carbon Black Composite Coated Carbon Paper Anodes

“…Figure 6A shows that the phenothiazine-type mediators are better than phenazinetype mediators as also reported by Ieropoulos et al who tested different types of mediators for a prototype MFC using E. coli. 25 It may be due to the fact that different types of mediators act to the different parts of a metabolic pathway. 26 According to Wilkinson, NR most likely interacts with fermentation pathway, not with respiration pathway, which leads to less production of electrons.…”