Global warming and the increase in organic waste from agro-industries create a major problem for the environment. In this sense, microbial fuel cells (MFC) have great potential for the generation of bioelectricity by using organic waste as fuel. This research produced low-cost MFC by using zinc and copper electrodes and taking blueberry waste as fuel. A peak current and voltage of 1.130 ± 0.018 mA and 1.127 ± 0.096 V, respectively, were generated. The pH levels were acid, with peak conductivity values of 233. 94 ± 0.345 mS/cm and the degrees Brix were descending from the first day. The maximum power density was 3.155 ± 0.24 W/cm² at 374.4 mA/cm² current density, and Cándida boidinii was identified by means of molecular biology and bioinformatics techniques. This research gives a new way to generate electricity with this type of waste, generating added value for the companies in this area and helping to reduce global warming.

Power generation and wastewater treatment are two great challenges for sustainable development. Microbial fuel cells (MFCs) are a sustainable alternative that can generate bioelectricity in the bioremediation process of wastewater. For this reason, the objective of this research was to generate bioelectricity through double-chamber microbial-combustion cell systems from wastewater from the Covicorti Wastewater Treatment Plant (PTARC) in the anodic chamber and electrogenic bacteria such as Stenotrophomonas maltophilia, Acinetobacter bereziniae, and Achromobacteria xylosoxidans in the cathode chamber, respectively. Measurements of the voltage, current, power density, current density, and optical density of the bacteria and biochemical oxygen demand (BOD) were made. In addition, a metagenomic analysis of the wastewater sample was performed. It was shown that the MFC with A. xylosoxidans generated the highest voltage peak (1.01 ± 0.06 V) on day 24, while the MFC with S. maltophilia generated the highest current value (0.71 ± 0.02 mA). The pH levels were slightly alkaline, and the maximum anodic conductivity value was presented by the MFC with A. cerevisiae, with a peak value of 81 ± 2 mS/cm on day 24. On the other hand, a maximum power density and current density of 195,493 ± 4717 mW/m² and 4987 A/cm², respectively, were obtained in the MFC with A. xylosoxidans. Finally, the metagenomic analysis identified the predominant phyla of Proteobacteria present in wastewater samples capable of generating electrical energy as Bacillota, Pseudomonadota, Bacteroidota, Actinomyketone, and Campylobacterota.

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.

The use of organic waste as fuel for energy generation will reduce the great environmental problems currently caused by the consumption of fossil sources, giving agribusiness companies a profitable way to use their waste. In this research, tomato waste with different percentages of sucrose (0-target, 5, 10, and 20%) was used in microbial fuel cells manufactured on a laboratory scale with zinc and copper electrodes, managing to generate maximum peaks of voltage and a current of 1.08 V and 6.67 mA in the cell with 20% sucrose, in which it was observed that the optimum operating pH was 5.29, while the MFC with 0% (target) sucrose generated 0.91 V and 3.12 A on day 13 with a similar pH, even though all the cells worked in an acidic pH. Likewise, the cell with 20% sucrose had the lowest internal resistance (0.148541 ± 0.012361 KΩ) and the highest power density (224.77 mW/cm²) at a current density of 4.43 mA/cm², while the MFC with 0% sucrose generated 160.52 mW/cm² and 4.38 mA/cm² of power density and current density, respectively, with an internal resistance of 0.34116 ± 0.2914 KΩ. In this sense, the FTIR (Fourier-transform infrared spectroscopy) of all the substrates used showed a high content of phenolic compounds and carboxylate acids. Finally, the MFCs were connected in a series and managed to generate a voltage of 3.43 V, enough to light an LED (green). These results give great hope to companies and society that, in the near future, this technology can be taken to a larger scale.

The biosorption of arsenic (As) with macroalgae has aroused much interest as a clean and low-cost technology. To evaluate arsenic biosorption by Chondracanthus chamissoi and Cladophora sp., approximately 5 kg of algae was collected from Huanchaco’s beach and Sausacocha lake (Huamachuco), La Libertad. As biosorption was carried out in four column systems, with 2 g of algae pellets each, circulating As solutions of 0.25 and 1.25 ppm, respectively, at 300 mL/min cm². As concentration was determined at 3 and 6 h of treatment by flame atomic absorption spectrophotometry. Data were analyzed using Student’s t-test with 95% confidence. At 6 h, Chondracanthus chamissoi presented an As biosorption of 95.76% in a 0.25 ppm mg/L solution and 85.33% in a 1.25 mg/L solution. Cladophora sp., at 6 h, presented an As biosorption of 95.76% in a 0.25 mg/L solution and 42.03% in a 1.25 mg/L solution. It was concluded that Chondracanthus chamissoi achieves higher percentages of biosorption than Cladophora sp. in solutions of 1.25 mg/L As (p < 0.05), and that there is no significant difference between the biosorption percentages of Chondracanthus chamissoi and Cladophora sp. in a 0.25 mg/L solution of As at 6 h of treatment (p > 0.05).

The growing global energy demand drives the need to develop new clean energy technologies. In this context, microbial fuel cells (MFC) are one of the emerging technologies with great potential for eco-friendly energy generation; however, the correct choice of electrode material is a significant limitation in the optimal configuration of MFCs. Therefore, this research evaluated the efficiency of activated carbon (AC) anode electrodes for bioenergy production in MFC using synthetic wastewater as a substrate. Peak values of voltage (1120 ± 0.050 mV), current (4.64 ± 0.040 mA), power density (208.14 ± 17.15 mW/cm²), and current density (5.03 A/cm²) were generated, and the R_int obtained was 214.52 ± 5.22 Ω. The substrate was operated at pH values from 5.31 to 7.66, maximum ORP values (858 mV) were reached, and turbidity was reduced to 25.11 NTU. The SEM-EDS (scanning electron microscopy–energy-dispersive X-ray spectroscopy) analyses allowed us to observe the morphology and composition of the AC electrodes, revealing a predominance of O, C, Si, Al, Fe, K, and Ca. It is concluded that the AC electrodes have the potential to produce bioenergy at a laboratory by means of MFC.