Journal of Energy Bioscience 2024, Vol.15, No.5, 314-325 http://bioscipublisher.com/index.php/jeb 319 6.3 Case study 3: portable power systems for remote areas The development of portable power systems using enzyme-catalyzed biofuel cells is another area of successful implementation. These systems are particularly valuable in remote areas where conventional power sources are unavailable. A study on mediatorless high-power glucose biofuel cells based on compressed carbon nanotube-enzyme electrodes achieved a power density of up to 1.3 mW cm-2 and an open circuit voltage of 0.95 V. The biofuel cell remained stable for one month and delivered 1 mW cm-2 under physiological conditions, making it a viable option for portable power systems (Zebda et al., 2011). Another research effort focused on the assembly and stacking of flow-through enzymatic bioelectrodes for high-power glucose fuel cells, which allowed for the convenient assembly of multiple cells to reach the necessary voltage and power for portable electronic devices without the need for additional energy management systems (Abreu et al., 2017). 6.4 Key insights from case studies and lessons learned The case studies presented highlight several key insights and lessons learned from the successful implementations of enzyme-catalyzed biofuel cells: Long-term stability: Achieving long-term stability is crucial for the practical application of EBFCs, particularly in medical devices and portable power systems. Innovations such as the use of bacterial surface-displayed enzymes and optimized electrode materials have shown promise in enhancing stability (Shao et al., 2013; Hou et al., 2014). Power output optimization: The power output of EBFCs can be significantly improved through the optimization of enzyme immobilization techniques, electrode materials, and cell configurations. Studies have demonstrated that the use of advanced materials like carbon nanotubes and macroporous gold films can lead to higher power densities (Zebda et al., 2011; Hou et al., 2014). Scalability and integration: For environmental applications and portable power systems, the ability to scale up and integrate multiple biofuel cells is essential. Flow-through designs and the stacking of bioelectrodes have been effective strategies to achieve higher power outputs and meet the energy demands of larger systems (Abreu et al., 2017). Sustainability and biodegradability: The environmental benefits of EBFCs, such as their ability to operate under mild conditions and their biodegradability, make them suitable for sustainable applications in wastewater treatment and other environmental processes (Barelli et al., 2021). These insights underscore the potential of enzyme-catalyzed biofuel cells in various applications and highlight the ongoing advancements needed to overcome current limitations and enhance their practical viability. 7 Performance Optimization Strategies 7.1 Improving enzyme longevity and stability One of the primary challenges in the development of enzyme-catalyzed biofuel cells (EBFCs) is the limited operational stability and longevity of the enzymes used. Various strategies have been explored to address this issue. For instance, the encapsulation of enzymes within protective matrices has shown promise. A study demonstrated that using single-walled carbon nanotubes (SWCNTs) and metal-organic frameworks (MOFs) to encapsulate glucose oxidase (GOx) and horseradish peroxidase (HRP) significantly enhanced enzyme stability, even in the presence of molecular inhibitors and high temperatures (Yimamumaimaiti et al., 2020). Additionally, covalent immobilization techniques on commercial polymers have been employed to improve enzyme durability, resulting in biofuel cells that maintain power output over extended periods (Pelosi et al., 2022). These approaches are crucial for the practical application of EBFCs in wearable and implantable devices. 7.2 Enhancing power density and energy efficiency Enhancing the power density and energy efficiency of EBFCs is essential for their viability as power sources. Multi-enzyme catalysis systems have been identified as a key strategy to achieve this goal. For example, the use of enzyme cascades, where multiple enzymes work sequentially to fully oxidize the fuel, has been shown to significantly increase power density. A study utilizing a DNA scaffold to organize an invertase/glucose oxidase enzyme cascade reported a 75% increase in power density compared to free enzyme systems (Nguyen et al., 2014). Furthermore, the integration of advanced nanomaterials, such as carbon nanodots and carbon nanotube (CNT) sponges, has been shown to enhance electron transfer and improve overall cell performance (Huang et al., 2019). These innovations are critical for developing high-performance EBFCs.
RkJQdWJsaXNoZXIy MjQ4ODYzMg==