Exploring Providencia rettgeri for application to eco-friendly paper based microbial fuel cell

Abstract

We report results of the studies relating to improved stability (40 days) of small sized microbial fuel cell (MFC) fabricated using agarose embedded paper-based proton exchange membrane. A fermentative bacterium Providencia rettgeri was isolated from rotten potato slurry and identified by 16S rRNA sequencing. The electroactivity of the bacteria was monitored via chronoamperometric and cyclic voltammetric studies using a three-electrode system which indicated the presence of bacterial redox mediator. The Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) and UV–Vis absorption spectroscopy provided the evidence that Providencia rettgeri synthesized folate (vitamin B9) during fermentation that was found to act for the first time as a redox mediator in an MFC. The paper based designed MFC fed with Providencia rettgeri yielded open circuit voltage of 787.9 mV with power and current density of 5.02 W/m3 and 11.26 A/m3, respectively when measured across 10 kΩ. The microbial re-chargeable battery comprising of an assembly of parallelly aligned four units of MFCs when connected in series (total 16 MFCs), generated 1.5 V that was used for powering a red-light emitting device (LED).