Biosynthesized Iron Sulfide Nanocluster Enhanced Anodic Current Generation by Sulfate Reducing Bacteria in Microbial Fuel Cells. Issue 24 (15th October 2018)

• Record Type: Journal Article
• Authors: Murugan, Muralidharan; Miran, Waheed; Masuda, Takuya; Lee, Dae S.; Okamoto, Akihiro
• Is Part Of: ChemElectroChem. Volume 5:Issue 24(2018)
• Page Start: 4015
• Page End: 4020
• Publication Date: 2018-10-15
• Subjects: Desulfovibrio vulgaris -- electron transfer -- in vivo electrochemistry -- microbial fuel cells -- voltammetry; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201801086
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: The anodic oxidation of sulfide metabolically generated from sulfate is considered to be the primary mechanism of sulfate reducing bacteria (SRB) to contribute to the current generation in Microbial Fuel Cells (MFCs). However, the other redox active metabolic by‐product of conductive iron sulfide (FeS) has been seldomly studied in the context of anodic current generation. Here, we demonstrate that the biomineralized FeS increased the anodic current production in Desulfovibrio vulgaris Hildenborough, compared with that mediated by diffusive sulfate. Chronoamperometry on indium tin‐doped oxide electrodes (ITO) poised at +0.4 V (vs SHE) in the presence of lactate and sulfate showed that the presence of ferrous ion caused twice more anodic current than that in the absence of the iron. Linear Sweep Voltammetry (LSV), Scanning Electron Microscopy (SEM) and X‐ray Photoelectron Spectroscopy confirmed that the aggregation formation of cells with FeS and FeS2 particles on the surface of the ITO electrode. These iron sulfur precipitates were more oxidized on the anode surfaces once lactate was depleted as electron source. The presented data suggests that biosynthesized FeS mediates the electron transport from D. vulgaris Hildenborough to the electrode surface. Given microbial capability of FeS biosynthesis is general among SRB, the FeS‐mediated mechanism may dominate anodic current generation of SRB in MFCs. Abstract : Bio‐boost for microbial fuel cells : biomineralized FeS particles enhance the rate of extracellular electron transport (EET) to the electrode surface in sulfate reducing bacteria (SRB), Desulfovibrio vulgaris Hildenborough. While the anodic oxidation of sulfide metabolically generated from sulfate is considered as primary mechanism of SRB for EET, the presented results indicate that the FeS‐mediated mechanism may dominate anodic current generation of SRB in microbial fuel cells.