Search Results (9)

This review evaluates the feasibility of using microalgal culture for sustainable energy production, emphasizing microbial fuel cells (MFCs) and biophotovoltaics (BPVs). This study’s uniqueness is rooted in its thorough examination of recent developments (2014–present) in microalgal strain selection, bioreactor design, and electrode materials. Furthermore, this review combines microalga cultivation with wastewater treatment, highlighting its importance. Notably, it examines advanced methodologies, such as the use of genetic engineering to enhance microalgal traits, nanotechnology to optimize electrode efficacy, and artificial intelligence (AI) to optimize bioelectrochemical systems. In addition, this study identifies possible future research avenues by examining microalga–bacterium consortia and cascaded biobattery systems. Consequently, the incorporation of case studies illustrating microalga biobatteries’ practical applications in low-power devices and wastewater treatment underscores the technology’s promise. Similarly, this study examines significant problems with enhancing farming methods, reconciling cost and yield, and integrating renewable energy sources with the grid, offering vital insights for academics and policymakers. Ultimately, this review emphasizes the need for economical cultivation methods, waste stream utilization, and scalable bioreactor designs, thereby considerably advancing sustainable energy options. Full article

Human society annually produces nearly 100 billion gallons of wastewater, containing approximately 3600 GWh of energy. This study introduces a proof of concept utilizing graphene materials to extract and instantly store this energy. A hybrid device, mimicking a microbial fuel cell, acts as both a battery and supercapacitor. Wastewater serves as the electrolyte, with indigenous microorganisms on the graphene electrode acting as biocatalysts. The device features a capacitive electrode using a 3D nickel foam modified with a plasma-exfoliated graphene mixture. Compared to controls, the Gr/Ni configuration shows a 150-fold increase in power output (2.58 W/m²) and a 48-fold increase in current density (12 A/m²). The Gr/Ni/biofilm interface demonstrates outstanding charge storage capability (19,400 F/m²) as confirmed by electrochemical impedance spectroscopy. Microscopy, spectroscopy, and electrochemical tests were employed to elucidate the superior performance of Gr/Ni electrodes. Ultimately, the capacitive energy extracted from wastewater can power small electrical equipment in water infrastructure, addressing energy needs in remote regions without access to a typical power grid. Full article

Biofuel cells have been in the spotlight for the past century because of their potential and promise as a unique platform for sustainable energy harvesting from the human body and the environment. Because biofuel cells are typically developed in a small platform serving as a primary battery with limited fuel or as a rechargeable battery with repeated refueling, they have been interchangeably named biobatteries. Despite continuous advancements and creative proof-of-concept, however, the technique has been mired in its infancy for the past 100 years, which has provoked increasing doubts about its commercial viability. Low performance, instability, difficulties in operation, and unreliable and inconsistent power generation question the sustainable development of biofuel cells. However, the advancement in bioelectrocatalysis revolutionizes the electricity-producing capability of biofuel cells, promising an attractive, practical technique for specific applications. This perspective article will identify the misconceptions about biofuel cells that have led us in the wrong development direction and revisit their potential applications that can be realizable soon. Then, it will discuss the critical challenges that need to be immediately addressed for the commercialization of the selected applications. Finally, potential solutions will be provided. The article is intended to inspire the community so that fruitful commercial products can be developed soon. Full article

With the development of cross-fertilisation in various disciplines, flexible wearable sensing technologies have emerged, bringing together many disciplines, such as biomedicine, materials science, control science, and communication technology. Over the past few years, the development of multiple types of flexible wearable devices that are widely used for the detection of human physiological signals has proven that flexible wearable devices have strong biocompatibility and a great potential for further development. These include electronic skin patches, soft robots, bio-batteries, and personalised medical devices. In this review, we present an updated overview of emerging flexible wearable sensor devices for biomedical applications and a comprehensive summary of the research progress and potential of flexible sensors. First, we describe the selection and fabrication of flexible materials and their excellent electrochemical properties. We evaluate the mechanisms by which these sensor devices work, and then we categorise and compare the unique advantages of a variety of sensor devices from the perspective of in vitro and in vivo sensing, as well as some exciting applications in the human body. Finally, we summarise the opportunities and challenges in the field of flexible wearable devices. Full article

This work demonstrates the application of magnetic carbon-encapsulated iron nanoparticles (CEINs) for the construction of bioelectrodes in a biobattery and a biofuel cell. It has been shown that carbon-encapsulated iron nanoparticles are a suitable material for the immobilization of laccase (Lc) and 1,4-naphthoquinone (NQ) and fructose dehydrogenase (FDH). The system is stable; no leaching of the enzyme and mediator from the surface of the modified electrode was observed. The onset of the catalytic reduction of oxygen to water was at 0.55 V, and catalytic fructose oxidation started at −0.15 V. A biobattery was developed in which a zinc plate served as the anode, and the cathode was a glassy carbon electrode modified with carbon-encapsulated iron nanoparticles, laccase in the Nafion (Nf) layer. The maximum power of the cell was ca. 7 mW/cm² at 0.71 V and under external resistance of 1 kΩ. The open-circuit voltage (OCV) for this system was 1.51 V. In the biofuel cell, magnetic nanoparticles were used both on the bioanode and biocathode to immobilize the enzymes. The glassy carbon bioanode was coated with carbon-encapsulated iron nanoparticles, 1,4-naphthoquinone, fructose dehydrogenase, and Nafion. The cathode was modified with carbon-encapsulated magnetic nanoparticles and laccase in the Nafion layer. The biofuel cell parameters were as follows: maximum power of 78 µW/cm² at the voltage of 0.33 V and under 20 kΩ resistance, and the open-circuit voltage was 0.49 V. These enzymes worked effectively in the biofuel cell, and laccase also effectively worked in the biobattery. Full article

Energy production in constructed wetlands is a little-known field, as is the operation of vertical partially saturated constructed wetlands (VPS-CWs) that promote both aerobic and anaerobic microbial interactions. By doing so, bacterial degradation is increased, becoming the main mechanism of pollutant removal in constructed wetlands (CWs). For the first time, the generation of bioelectricity, together with the production of ornamental plants in vertical partially saturated constructed wetlands during the treatment of domestic wastewater, was evaluated. Six VPS-CW systems functioned as bioelectricity generators, where the systems were filled with red volcanic gravel and activated carbon as anode and cathode. Three systems were planted with Zantedeschia aethiopica and three with Canna hybrids plants. The development was measured through mother plants and shoots produced every 60 days. The input and output of each VPS-CW was monitored using control parameters such as BOD₅, phosphates (P-PO₄), and total Kjeldahl nitrogen (TKN). Bioelectricity, power, voltage, and current measurements were performed every 15 days for a period of 7 months. It was found that the VPS-CWs used as biobatteries in combination with the use of domestic wastewater as a substrate improved the development of the two evaluated plant species and stimulated growth and germination of new shoots. No significant differences were found between the different treatments (p ≤ 0.05). Likewise, an average efficient removal of BOD₅ (98%) for both systems without statistical differences was observed (p ≤ 0.05), but for TKN and P-PO₄, significant differences (p ≤ 0.05) were found between systems planted with Z. aethiopica (TKN: 65%; P-PO₄: 20%) and Canna hybrids (TKN: 69%; P-PO₄: 27%). This method of water treatment and bioelectricity production with Canna hybrids was an efficient system that generated a great electric current (140 mA/m²), voltage (750 mV), and electric power (15 mW/m²), compared with those observed in systems with Z. aethiopica (60 mA/m², 500 mV, 9 mA/m²). Full article

This study describes a novel approach for real-time energy harvesting and performance diagnostics of a solid anolyte microbial fuel cell (SA-MFC) representing a prototype smart biobattery. The biobattery power output was maximized in real time by combining intermittent power generation with a Perturbation-and-Observation algorithm for maximum power point tracking. The proposed approach was validated by operating the biobattery under a broad range of environmental conditions affecting power production, such as temperature (4–25 °C), NaCl concentration (up to 2 g L⁻¹), and carbon source concentration. Real-time biobattery performance diagnostics was achieved by estimating key internal parameters (resistance, capacitance, open circuit voltage) using an equivalent electrical circuit model. The real time optimization approach ensured maximum power production during 388 days of biobattery operation under varying environmental conditions, thus confirming the feasibility of biobattery application for powering small electronic devices in field applications. Full article

One of the problems with the use of enzymes as catalysts in biofuel cells is to achieve good contact between the enzyme and the electrode surface. One solution to this problem is the use of various nanostructures such as carbon nanotubes, fullerenes, graphene derivatives, gold nanoparticles, as well as mediators for the construction of electrodes. Acetosyringone and promazine adsorbed on glassy carbon electrodes (GCEs) covered with multiwall carbon nanotubes (MWCNTs) and laccase were used as biocathodes. These mediators showed very efficient adsorption on modified glassy carbon electrodes covered with MWCNTs and enabled efficient and stable adsorption of laccase, which acts as the bioelectrocatalyst. Very good electrical contact between the electrode surface and the laccase enzymatic active sites made it possible to increase the catalytic current density of oxygen-reduction by about 82% compared to electrodes without mediators. Application of acetosyringone and promazine used in the construction of biocathode also improved the current and power of the biobattery ca. twice comparing to the system without mediators. The device output reached the power that equaled approximately 2 mW/cm² at 0.8 V and open circuit potential (OCP) was 1.6 V. The systems elaborated proved also useful in oxygen sensing and allowed to determine lower oxygen concentrations in solution compared to the GCE modified with MWCNTs and laccase alone. The electrode showed also better stability in long-timescale measurements. Full article

We use origami to create a compact, scalable three-dimensional (3-D) biobattery stack that delivers on-demand energy to the portable biosensors. Folding allows a two-dimensional (2-D) paper sheet possessing predefined functional components to form nine 3-D microbial fuel cells (MFCs), and connect them serially within a small and single unit (5.6 cm × 5.6 cm). We load the biocatalyst Pseudomonas aeruginosa PAO1 in predefined areas that form the MFCs, and freeze-dry them for long-term storage. The biobattery stack generates a maximum power and current of 20 μW and 25 μA, respectively, via microbial metabolism when the freeze-dried cells are rehydrated with readily available wastewater. This work establishes an innovative strategy to revolutionize the fabrication, storage, operation, and application of paper-based MFCs, which could potentially make energy available even in resource-limited settings. Full article