Boosting microfluidic microbial fuel cells performance via investigating electron transfer mechanisms, metal-based electrodes, and magnetic field effect

Abstract

The presented paper fundamentally investigates the influence of different electron transfer mechanisms, various metal-based electrodes, and a static magnetic field on the overall performance of microfluidic microbial fuel cells (MFCs) for the first time to improve the generated bioelectricity. To do so, as the anode of microfluidic MFCs, zinc, aluminum, tin, copper, and nickel were thoroughly investigated. Two types of bacteria, Escherichia coli and Shewanella oneidensis MR-1, were used as biocatalysts to compare the different electron transfer mechanisms. Interaction between the anode and microorganisms was assessed. Finally, the potential of applying a static magnetic field to maximize the generated power was evaluated. For zinc anode, the maximum open circuit potential, current density, and power density of 1.39 V, 138,181 mA m-2 and 35,294 mW m-2 were obtained, respectively. The produced current density is at least 445% better than the values obtained in previously published studies so far. The microfluidic MFCs were successfully used to power ultraviolet light-emitting diodes (UV-LEDs) for medical and clinical applications to elucidate their application as micro-sized power generators for implantable medical devices.

Recent Advances in the Development of Sustainable Composite Materials used as Membranes in Microbial Fuel Cells

“…[124] Some studies report the benefit of applying a static magnetic field to MFC that can influence the bacteria and their deposition, thereby enhancing power production. [125] CNT-based composites have been reported as candidates for membranes because of their expansive surface area, high conductivity and chemical stability, and biocompatibility. CNTs also show reduced membrane swelling and biofouling.…”

“…Utilization of bacterial species that can work efficiently even within a biofilm deposition may increase the durability of MFC [124] . Some studies report the benefit of applying a static magnetic field to MFC that can influence the bacteria and their deposition, thereby enhancing power production [125] . CNT‐based composites have been reported as candidates for membranes because of their expansive surface area, high conductivity and chemical stability, and biocompatibility.…”

Sustainable circular biorefinery approach for novel building blocks and bioenergy production from algae using microbial fuel cell

“…The use of exoelectrogens as biocatalysts is favorable for generating electricity by organic substrate degradation [ 68 ]. Among exoelectrogen genera and species, the strain isolated from Clostridiaceae , Shewanellaceaae , Geobacteraceae , and Pseudomonadaceae genus, is of great interest phylum because of their capacity for extracellular electron transfer (EET) by direct electron transfer to the working electrode [ 102–104 ]. These exoelectrogens are usually negatively charged and generally known as Gram-negative microbes due to the presence of uronic acids and ketal-linked pyruvates in the cell plasma membrane, thereby supplying the anode with positive potential and divalent cations, including calcium and magnesium, which maximizes the scope of biofilm formation on the anode surface by involving electrostatic interactions [ 105 ].…”

“…In addition to the self-secreted (endogenous) mediators by the exoelectrogens, Shirkosh et al [ 102 ] explored bioelectricity production through EF from a glucose medium by using S. oneidensis with exogenetic riboflavin. Such endowment prompted an enhanced bioelectricity capacity and lifespan of the system, which yielded a maximum current density of 138,181 mA/m 2 with a prolonged operating duration of 50 days.…”

“…Such endowment prompted an enhanced bioelectricity capacity and lifespan of the system, which yielded a maximum current density of 138,181 mA/m 2 with a prolonged operating duration of 50 days. These results are nearly 445% better than the values obtained without exogenetic riboflavin, indicating that the exogenetic riboflavin is essential for the survival of S. oneidensis in anaerobic conditions by offering the ability to access insoluble electron acceptors [ 102 ]. This is attributed to the relatively slow production rate of endogenous mediators by S. oneidensis and will only produce limited concentrations in the stationary phase when the microbial cells are lysing [ 98 ].…”