Development of an Osmium Redox Polymer Mediated Bioanode and Examination of its Performance in Gluconobacter oxydans Based Microbial Fuel Cell

Abstract

Gluconobacter oxydans (G. oxydans) cells together with an osmium redox polymer (ORP) [Osmium (2,2’‐bipyridine)2(poly‐vinylimidazole)10Cl]Cl were combined with a glassy carbon paste electrode (GCPE) to form a bioanode for a microbial fuel cell (MFC) based on G. oxydans. Although there are G.oxydans/ ORP combined bioanode in the literature, as far as it is known, this system is the first one where G.oxydans/ORP bioanode is combined with a cathode and a MFC is formed. After the optimization of experimental parameters, analytical characteristics of ORP/G. oxydans/GCPE bioanode were investigated. ORP/G. oxydans/GCPE showed two linear ranges for ethanol substrate as 1.0–30 mM (R2=0.902) and 30–500 mM (R2=0.997) and analytical range as 1.0–1000 mM. Limit of detection (3.0 s/m) and limit of quantification (10 s/m) values were calculated as 1.29 mM and 4.30 mM respectively where the RSD value was 1.16 % for n=5. Combining the developed bioanode in the presence of 5.0 mM K3Fe(CN)6 mediator with a Pt wire cathode a double compartment MFC was obtained via a salt bridge. G. oxydans/GCPE bioanode based MFC had maximum power density of 0.133 μW cm−2 (at 33.5 mV), maximum current density as 8.73 μA cm−2 and OCP value of 156 mV. On the other hand, ORP/G. oxydans/GCPE based MFC showed maximum power density as 0.26 μW cm−2 (at 46.8 mV), maximum current density as 15.079 μA cm‐2 and OCP value of 176 mV.

Development of a Bioanode for Microbial Fuel Cells Based on the Combination of a MWCNT‐Au‐Pt Hybrid Nanomaterial, an Osmium Redox Polymer and Gluconobacter oxydans DSM 2343 Cells

“…GCPE has widely been used by our group in many applications including biosensor and biofuel cell systems ,,. However, CFE, another type of carbon based electrode, is reported to be a good alternative as bioanode and/or biocathode supporting electrode for various MFC systems ,,,,,. According to these studies, CFE provides a biocompatible environment with a large accommodation space and effective immobilization for bacterial cells.…”

“…Zhu and Ni (2009) utilized CFE both as bioanode and biocathode in a MFC system and with this system, they manage to remove the refractory (heat resistive) pollutants from water successfully. From this point of view, as the first step in our study, the electrochemical performance of GCPE and CFE is compared in a 5.0 mM K 3 Fe(CN) 6 solution using linear sweep voltammetry (LSV). The GCPE electrode showed a peak current value equal to 115±3 μA ( Figure Aa) whereas the CFE showed a peak current of 185±2 μA ( Figure Ab) .…”

“…In a previous study, a significant electrocatalytic effect of MWCNT‐Au‐Pt hybrid nanostructure has been demonstrated in comparison with non‐hybrid nanostructures which lead us to use this structure in our system . Because of the bioconversion capability of Gluconobacter oxydans DSM 2343 (G. oxydans) cells on a variety of organic compounds, these cells have been used for decades for both biosensor and MFC applications . It is possible to grow G. oxydans DSM 2343 cells specifically on a certain substrate like ethanol.…”

“…By means of this “wiring” process, the redox centers of the OsRP facilitate the electron transfer between a series of different redox proteins localized on the periplasmic membrane of the bacteria and the electrode surface. The membrane localized dehydrogenases are able to oxidize a diverse range of substrates and thus produce electrons that can be picked up by the flexible OsRP ,,,,. The OsRP serves also another purpose, i. e., as an immobilization matrix for the cells on the electrode surface.…”

“…Although there are many works in the literature covering the usage of G. oxydans strains in bioanodes,,, our group developed a combined OsRP and G. oxydans based MFC for the first time . In this previously reported OsRP/ G.oxydans work a glassy carbon paste electrode (GCPE) based bioanode (where the anolyte solution also contained K 3 Fe(CN) 6 as an additional external mediator to further facilitate the electron transfer from the G. oxydans cells to the electrode,) and a salt bridge MFC system were presented. In the present work the electrode of the bioanode was changed from GCPE to CFE after careful voltammetric examination of these two different electrode materials.…”