Power production in MFCs inoculated with Shewanella oneidensis MR‐1 or mixed cultures

Abstract

Power densities and oxidation-reduction potentials (ORPs) of MFCs containing a pure culture of Shewanella oneidensis MR-1 were compared to mixed cultures (wastewater inoculum) in cube shaped, 1-, 2-, and 3-bottle batch-fed MFC reactor configurations. The reactor architecture influenced the relative power produced by the different inocula, with the mixed culture generating 68-480% more power than MR-1 in each MFC configuration. The mixed culture produced the maximum power density of 858 +/- 9 mW m(-2) in the cubic MFC, while MR-1 produced 148 +/- 20 mW m(-2). The higher power by the mixed culture was primarily a result of lower internal resistances than those produced by the pure culture. Power was a direct function of ohmic resistance for the mixed culture, but not for strain MR-1. ORP of the anode compartment varied with reactor configuration and inoculum, and it was always negative during maximum power production but it did not vary in proportion to power output. The ORP varied primarily at the end of the cycle when substrate was depleted, with a change from a reductive environment during maximum power production (approximately -175 mV for mixed and approximately -210 mV for MR-1 in cubic MFCs), to an oxidative environment at the end of the batch cycle ( approximately 250 mV for mixed and approximately 300 mV for MR-1). Mixed cultures produced more power than MR-1 MFCs even though their redox potential was less negative. These results demonstrate that differences between power densities produced by pure and mixed cultures depend on the MFC architecture.

Application of 3D Printed Porous Copper Anode in Microbial Fuel Cells

“…MFCs with 3D-PPC anodes and copper mesh anodes immediately generated high maximum voltages after being connected to the external resistors, which was consistent with the results obtained by Zhu and Logan (2014) The maximum voltage produced during the 3-day first cycle was 224.5 ± 32.4 mV for 3D-PPC anodes compared to 179.1 ± 22.8 mV from copper mesh anodes. This observation was abnormal since Shewanella MR-1 has never been reported to achieve such high maximum voltages in previous literature (Bretschger et al, 2007;Watson and Logan, 2010;Nourbakhsh et al, 2017;Bian et al, 2018). The peak voltages from copper anodes dropped dramatically to 95.2 ± 5.9 mV and 45.2 ± 9.4 mV, respectively, in the second cycle (Figure 2).…”

Microbial fuel cells in bioelectricity production

“…Geobacter (Lovley et al 1993;Rotaru et al 2011;Nevin et al 2008) and Shewanella (Gorby et al 2006;Watson & Logan 2010;) species account for the majority of the microbial population that have been utilized in MFC technology. Photosynthetic bacteria can also be used effectively in a MFC for electric power generation.…”

Electron transport phenomena of electroactive bacteria in microbial fuel cells: a review of Proteus hauseri

“…Regarding electrochemically active bacteria, species of genus Bacillus (Nimje et al 2009), Enterobacter (Rezaei et al 2009), Geobacter (Richter et al 2008), Proteus (Chen et al 1999), Shewanella (Watson and Logan 2010) have been explored to present practicability for bioelectricity generation. However, compared to pure microbial culture MFCs, mixed culture still exhibited the most promising stable power generation for longterm operation (Hassan et al 2017;Ishii et al 2017).…”