The enormous environmental problems that arise from organic waste have increased due to the significant population increase worldwide. Microbial fuel cells provide a novel solution for the use of waste as fuel for electricity generation. In this investigation, onion waste was used, and managed to generate maximum peaks of 4.459 ± 0.0608 mA and 0.991 ± 0.02 V of current and voltage, respectively. The conductivity values increased rapidly to 179,987 ± 2859 mS/cm, while the optimal pH in which the most significant current was generated was 6968 ± 0.286, and the ° Brix values decreased rapidly due to the degradation of organic matter. The microbial fuel cells showed a low internal resistance (154,389 ± 5228 Ω), with a power density of 595.69 ± 15.05 mW/cm² at a current density of 6.02 A/cm²; these values are higher than those reported by other authors in the literature. The diffractogram spectra of the onion debris from FTIR show a decrease in the most intense peaks, compared to the initial ones with the final ones. It was possible to identify the species Pseudomona eruginosa, Acinetobacter bereziniae, Stenotrophomonas maltophilia, and Yarrowia lipolytica adhered to the anode electrode at the end of the monitoring using the molecular technique.

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.

La educación virtual, implica el uso de estrategias didácticas adecuadas para lograr una enseñanza de calidad. Se realizó una revisión sistemática con el objetivo de identificar las estrategias en la educación virtual universitaria. Las búsquedas se realizaron en las bases de datos Scielo, Redalyc, ERIC y Google Scholar. Los descriptores fueron: “Educación virtual”, “comunicación” “perspectivas”, “estrategias. Se incluyeron artículos de acceso libre, de texto completo, artículos de los últimos 7 años, en idiomas inglés, español y portugués. Se excluyeron los resúmenes, los artículos duplicados y aquellos que no tenían información relevante sobre las variables en estudio. Después del proceso de selección, quedaron 14 artículos. En cuanto a las estrategias didácticas para la educación virtual destacan la planeación y control, la motivación, la comunicación, la confianza, la empatía, innovación, el diseño, formas de evaluación, trabajo colaborativo, metodología constructivista, y estrategias de autorregulación. Se resalta la importancia del conocimiento del idioma inglés y de las TIC. Se concluye que las estrategias didácticas utilizadas en educación virtual universitaria son de gran utilidad y deben adaptarse para responder al modelo educativo.

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).

Pollution generated by the misuse of large amounts of fruit and vegetable waste has become a major environmental and social problem for developing countries due to the absence of specialized collection centers for this type of waste. This research aims to generate electricity in an eco-friendly way using red dragon fruit (pitahaya) waste as the fuel in single-chamber microbial fuel cells on a laboratory scale using zinc and copper electrodes. It was possible to generate voltage and current peaks of 0.46 ± 0.03 V and 2.86 ± 0.07 mA, respectively, with an optimum operating pH of 4.22 ± 0.09 and an electrical conductivity of 175.86 ± 4.72 mS/cm at 8 °Brix until the tenth day of monitoring. An internal resistance of 75.58 ± 5.89 Ω was also calculated with a maximum power density of 304.33 ± 16.51 mW/cm² at a current density of 5.06 A/cm², while the FTIR spectra showed a decrease in the initial compounds and endings, especially at the 3331 cm⁻¹ peaks of the O–H bonds. Finally, the yeast-like fungus Geotrichum candidum was molecularly identified (99.59%). This research will provide great opportunities for the generation of renewable energy using biomass as fuel through electronic devices with great potential to generate electricity.

The self-healing of concrete through the use of bacteria is an ecological, sustainable, and environmentally friendly method that can replace time-consuming and costly repairs. The aim of this research was to isolate and select spore-forming bacilli with potential for concrete self-healing. Soil samples from the limestone mines of Simbal, Trujillo, La Libertad, Peru were used. These samples were processed to primarily isolate spore-forming bacteria. The self-healing potential of these bacteria was evaluated through their ability to produce the urease enzyme, grow at an alkaline pH, and produce calcium carbonate crystals in a culture medium with urea and CaCl₂ at pH 8.0. The produced crystals were visualized with scanning electron microscopy and their calcium content was confirmed through EDS analysis. The isolated bacteria were identified by 16 S rRNA gene amplification by PCR as Bacillus sp and Streptomyces sp. It was observed that Bacillus sp. produces CaCO₃ crystals with vaterite morphology, while Streptomyces sp. produces rhombohedral calcite crystals. It is concluded that the isolated bacteria have the potential to be used in concrete self-healing processes.