Intensification of bioelectricity generation in microbial fuel cells using Shewanella oneidensis MR-1 mutants with increased reducing activity

Hassett

2015

Analyst

There is a large global effort to improve microbial fuel cell (MFC) techniques and advance their translational potential toward practical, real-world applications. Significant boosts in MFC performance can be achieved with the development of new techniques in synthetic biology that can regulate microbial metabolic pathways or control their gene expression. For these new directions, a high-throughput and rapid screening tool for microbial biopower production is needed. In this work, a 48-well, paper-based sensing platform was developed for the high-throughput and rapid characterization of the electricity-producing capability of microbes. 48 spatially distinct wells of a sensor array were prepared by patterning 48 hydrophilic reservoirs on paper with hydrophobic wax boundaries. This paper-based platform exploited the ability of paper to quickly wick fluid and promoted bacterial attachment to the anode pads, resulting in instant current generation upon loading of the bacterial inoculum. We validated the utility of our MFC array by studying how strategic genetic modifications impacted the electrochemical activity of various Pseudomonas aeruginosa mutant strains. Within just 20 minutes, we successfully determined the electricity generation capacity of eight isogenic mutants of P. aeruginosa. These efforts demonstrate that our MFC array displays highly comparable performance characteristics and identifies genes in P. aeruginosa that can trigger a higher power density.

Section: Introductionmentioning

confidence: 99%

A paper-based microbial fuel cell array for rapid and high-throughput screening of electricity-producing bacteria

Hassett

2015

Analyst

Phys. Chem. Chem. Phys.

“…5). 14,15,26,29,48,49,55,61,[63][64][65][66] According to PCA, the design parameters having the highest influence over the operational characteristics were: the surface area of the electrodes and the membrane, the volume of the compartments, carbon paper and carbon cloth as electrode materials and AMI or the Nafion 117 membrane. Regarding the anodic solution and conditions, PIPES was again the preferred buffer with lactate or even glucose as carbon sources under aerobic conditions, or in the presence of ferric citrate after a longer adaptation period.…”

Section: Resultsmentioning

confidence: 99%

Innovative statistical interpretation of Shewanella oneidensis microbial fuel cells data

Babanova

Bretschger

Roy

et al. 2014

The last decade of research has made significant strides toward practical applications of Microbial Fuel Cells (MFCs); however, design improvements and operational optimization cannot be realized without equally considering engineering designs and biological interfacial reactions. In this study, the main factors contributing to MFCs' overall performance and their influence on MFC reproducibility are discussed. Two statistical approaches were used to create a map of MFC components and their expanded uncertainties, principal component analysis (PCA) and uncertainty of measurement results (UMR). PCA was used to identify the major factors influencing MFCs and to determine their ascendency over MFC operational characteristics statistically. UMR was applied to evaluate the factors' uncertainties and estimate their level of contribution to the final irreproducibility. In order to simplify the presentation and concentrate on the MFC components, only results from Shewanella spp. were included; however, a similar analysis could be applied for any DMRB or microbial community. The performed PCA/UMR analyses suggest that better reproducibility of MFC performance can be achieved through improved design parameters. This approach is exactly opposite to the MFC optimization and scale up approach, which should start with improving the bacteria-electrode interactions and applying these findings to well-designed systems.

“…Smaller volume of chamber (5 ml) used in the present equipment would also reduce the amount of cells used for each experiment. In our laboratory, we have observed if the variation caused by the hardware was well controlled, correlation between the change of MFC measurement and cellular biochemical change induced by the experimental conditions might be observed , for example, correlation between reducing activity of the cells and the current density in MFC (Voeikova et al 2013) and between columbic efficiencies and temperature . Therefore, the biological change of cells induced by experimental conditions could be well reflected in electric current measurement in MFC.…”

Section: Introductionmentioning

confidence: 93%

UCP2- and non-UCP2-mediated electric current in eukaryotic cells exhibits different properties

Wang

MoYung

Zhang

et al. 2015

Environ Sci Pollut Res

Using live eukaryotic cells, including cancer cells, MCF-7 and HCT-116, normal hepatocytes and red blood cells in anode and potassium ferricyanide in cathode of MFC could generate bio-based electric current. Electrons and protons generated from the metabolic reaction in both cytosol and mitochondria contributing to the leaking would mediate the generation of electric current. Both resveratrol (RVT) and 2,4-dinitrophenol (DNP) used to induce proton leak in mitochondria were found to promote electric current production in all cells except red blood cells without mitochondria. Proton leak might be important for electric current production by bringing the charge balance in cells to enhance the further electron leak. The induced electric current by RVT can be blocked by Genipin, an inhibitor of UCP2-mediated proton leak, while that induced by DNP cannot. RVT could reduce reactive oxygen species (ROS) level in cells better than that of DNP. In addition, RVT increased mitochondrial membrane potential (MMP), while DNP decreased it. Results highly suggested the existence of at least two types of electric current that showed different properties. They included UCP2-mediated and non-UCP2-mediated electric current. UCP2-mediated electric current exhibited higher reactive oxygen species (ROS) reduction effect per unit electric current production than that of non-UCP2-mediated electric current. Higher UCP2-mediated electric current observed in cancer cells might contribute to the mechanism of drug resistence. Correlation could not be established between electric current production with either ROS and MMP without distinguishing the types of electric current.