Performance of stacked microbial fuel cells with Barley–Shochu waste

Cellulose-fueled microbial fuel cells equipped with a bipolar membrane using hydrogen phosphate as the final electron acceptor

OBJECTIVES

A bipolar membrane microbial fuel cell (bMFC) is used to generate electricity using cellulose in phosphate buffer solution as fuel, and the mechanism of electricity generation is elucidated from five reference experiments.

RESULTS

The bMFC was operated for 20 days using cellulose as fuel and Cellulomonas fimi. In the first reference experiment, no microorganism was used. In the second experiment, a cation-exchange membrane was used instead of a bipolar membrane. In the third experiment, the bipolar membrane was used in the opposite orientation as in the main experiment. In the fourth experiment, D2O was used instead of H2O in the cathode chamber. In the final experiment, the tris-maleate buffer was used instead of a phosphate buffer. Sufficient power generation did not occur in either reference experiment.

CONCLUSIONS

The bMFC continuously generated electricity for 20 days, and elucidated H+ and OH- react in bipolar membrane, where the counter cation of dihydrogen phosphate served as the final electron acceptor.

An Overview of Microbial Fuel Cell Technology for Sustainable Electricity Production

The over-exploitation of fossil fuels and their negative environmental impacts have attracted the attention of researchers worldwide, and efforts have been made to propose alternatives for the production of sustainable and clean energy. One proposed alternative is the implementation of bioelectrochemical systems (BESs), such as microbial fuel cells (MFCs), which are sustainable and environmentally friendly. MFCs are devices that use bacterial activity to break down organic matter while generating sustainable electricity. Furthermore, MFCs can produce bioelectricity from various substrates, including domestic wastewater (DWW), municipal wastewater (MWW), and potato and fruit wastes, reducing environmental contamination and decreasing energy consumption and treatment costs. This review focuses on recent advancements regarding the design, configuration, and operation mode of MFCs, as well as their capacity to produce bioelectricity (e.g., 2203 mW/m2) and fuels (i.e., H2: 438.7 mg/L and CH4: 358.7 mg/L). Furthermore, this review highlights practical applications, challenges, and the life-cycle assessment (LCA) of MFCs. Despite the promising biotechnological development of MFCs, great efforts should be made to implement them in a real-time and commercially viable manner.

Electric Current Generation by Increasing Sucrose in Papaya Waste in Microbial Fuel Cells

The accelerated increase in energy consumption by human activity has generated an increase in the search for new energies that do not pollute the environment, due to this, microbial fuel cells are shown as a promising technology. The objective of this research was to observe the influence on the generation of bioelectricity of sucrose, with different percentages (0%, 5%, 10% and 20%), in papaya waste using microbial fuel cells (MFCs). It was possible to generate voltage and current peaks of 0.955 V and 5.079 mA for the cell with 20% sucrose, which operated at an optimal pH of 4.98 on day fifteen. In the same way, the internal resistance values of all the cells were influenced by the increase in sucrose, showing that the cell without sucrose was 0.1952 ± 0.00214 KΩ and with 20% it was 0.044306 ± 0.0014 KΩ. The maximum power density was 583.09 mW/cm² at a current density of 407.13 A/cm² and with a peak voltage of 910.94 mV, while phenolic compounds are the ones with the greatest presence in the FTIR (Fourier transform infrared spectroscopy) absorbance spectrum. We were able to molecularly identify the species Achromobacter xylosoxidans (99.32%), Acinetobacter bereziniae (99.93%) and Stenotrophomonas maltophilia (100%) present in the anode electrode of the MFCs. This research gives a novel use for sucrose to increase the energy values in a microbial fuel cell, improving the existing ones and generating a novel way of generating electricity that is friendly to the environment.