Effect of treatment on electron transfer mechanism in microbial fuel cell

ABSTRACT

Untreated and treated (with chemical electron acceptors like Fe (III) oxide and Fumarate) sludge samples were subjected to microbial fuel cell (MFC) studies. The study focused on both anode biofilm as well as the anolyte consortia developed in the MFC reactor after treatment. Through impedance and voltammogram data, it was seen that untreated inoculum, when used in MFC followed a synergistic electron transfer mechanism (EET), dual EET (3.726 ± 0.130 mWm⁻³). The Fe (III) oxide treatment promoted the development of electrogenic biofilm that followed direct electron transfer (DET) mechanism (5.439 ± 0.009 mWm⁻³), whereas Fumarate treatment promoted the growth of electrogenic microbes in anolyte and followed mediator-based electron transfer (MET) mechanism (4.500 ± 0.0009 mWm⁻³). The microbial cultures like Alcaligenes sp. and Pseudomonas sp. were isolated from MFC reactors having Fe (III) oxide treated biofilm and Fumarate treated anolyte respectively. The occurrence of these microbes indicates their role in the EET mechanism adopted by various MFC reactors.

KEYWORDS:

• Direct electron transfer
• microbial consortia
• mediator electron transfer
• microbial fuel cell
• internal resistance

Acknowledgments

The authors are thankful Dr. M. S Dharne, Senior Scientist, National Collection of Industrial Micro-Organisms, CSIR-National Chemical Laboratory (NCL), Pune, India, for guidance during species-level identification of isolated microorganism and SAIF, Indian Institute of Technology-Bombay (IITB), Mumbai, India, for extending the facility of SEM.

Conflict of Interest Statement

All authors declare that there are no financial/commercial conflicts of interest.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

The study was funded by Department of Science and Technology, New Delhi, India, under the project code DST-WOS-A [SR/WOS-A/ET-1054/2014(G)].