School of Chemistry, National University of Ireland Galway, University Road, Galway, Ireland.
Enzyme Microb Technol. 2012 Mar 10;50(3):181-7. doi: 10.1016/j.enzmictec.2011.12.002. Epub 2011 Dec 24.
Enzyme electrodes show great potential for many applications, as biosensors and more recently as anodes and cathodes in biocatalytic fuel cells for power generation. Enzymes have advantages over metal catalysts, as they provide high specificity and reaction rates, while operating under mild conditions. Here we report on studies related to development of mass-producible, completely enzymatic printed glucose/oxygen biofuel cells. The cells are based on filter paper coated with conducting carbon inks containing mediators and laccase, for reduction of oxygen, or aldose dehydrogenase, for oxidation of glucose. Mediator performance in these printed formats is compared to relative rate constants for the enzyme-mediator reaction in solution, for a range of anode and cathode mediators. The power output and stability of fuels cells using an acidophilic laccase isolated from Trametes hirsuta is greater, at pH 5, than that for cells based on Melanocarpus albomyces laccase, that shows optimal activity closer to neutral pH, at pH 6. Highest power output, although of limited stability, was observed for ThL/ABTS cathodes, providing a maximum power density of 3.5 μWcm(-2) at 0.34 V, when coupled to an ALDH glucose anode mediated by an osmium complex. The stability of cell voltage above a threshold of 200 mV under a moderate 75 kΩ load is used to benchmark printed fuel cell performance. Highest stability was obtained for a printed fuel cell using osmium complexes as mediators of glucose oxidation by aldose dehydrogenase, and oxygen reduction by T. hirsuta laccase, maintaining cell voltage above 200 mV for 137 h at pH 5. These results provide promising directions for further development of mass-producible, completely enzymatic, printed biofuel cells.
酶电极在许多应用中显示出巨大的潜力，例如生物传感器，以及最近作为生物催化燃料电池中的阳极和阴极用于发电。与金属催化剂相比，酶具有优势，因为它们在温和条件下提供高的特异性和反应速率。在这里，我们报告了与开发大规模生产、完全酶促印刷葡萄糖/氧气生物燃料电池相关的研究。这些电池基于涂有导电碳油墨的滤纸，油墨中含有介体和漆酶，用于还原氧气，或醛糖脱氢酶，用于氧化葡萄糖。在这些印刷格式中，比较了介体的性能与溶液中酶-介体反应的相对速率常数，用于一系列阳极和阴极介体。在 pH 值为 5 时，从绒毛状 Trametes hirsuta 中分离出的嗜酸漆酶的燃料细胞的功率输出和稳定性大于基于 Melanocarpus albomyces 漆酶的燃料细胞，后者在接近中性 pH 值（pH 值为 6）时表现出最佳活性。使用 ThL/ABTS 阴极观察到最高的功率输出，尽管稳定性有限，为 3.5 μWcm(-2)，在 0.34 V 时，当与通过 Os 配合物介导的 ALDH 葡萄糖阳极耦合时，提供最大的功率密度。在适度的 75 kΩ负载下，超过 200 mV 的阈值的细胞电压稳定性用于基准印刷燃料电池的性能。使用 Os 配合物作为醛糖脱氢酶氧化葡萄糖和 T. hirsuta 漆酶还原氧气的介体的印刷燃料电池获得了最高的稳定性，在 pH 值为 5 时保持细胞电压高于 200 mV 137 h。这些结果为进一步开发大规模生产、完全酶促、印刷生物燃料电池提供了有希望的方向。
