Collaborative Proposal: DNA guided assembly of enzyme cascades for biocatalytic fuel cell applications

酶燃料电池由于其将丰富的原材料直接转化为电能的潜力而受到相当大的关注。多酶级联的使用是特别有吸引力的，因为它们提供了通过燃料的顺序氧化实现更高电流密度的可能性。然而，有效的底物和电子通道是提高多酶燃料电池功率输出的两个最重要的瓶颈。美国国家科学基金会催化生物催化计划授予特拉华州大学的Wilfred Chen教授和加州大学河滨分校的Nosang Myung教授的奖项将支持对克服这些障碍的方法的研究。本提案的总体目标是研究使用遗传控制的基于DNA的模块化支架方法，用于增强底物和电子通道的多酶级联的空间定义的自组装。将开发一种简单且可扩展的静电纺丝方法来合成具有非常高表面积的电纺电极。然后，基因设计的介体将组装体连接到电极垫。所提出的设计的模块化性质允许容易地改变酶、介质和电极之间的间距，用于以合理的方式研究最佳底物和电子通道。纳米工程和生物工程方法的独特结合将使Chen和Myung能够系统地研究影响多酶燃料电池整体性能的因素。这一概念的初步测试将在纤维素转化为葡萄糖酸的过程中进行演示，随后将研究其他反应。拟议的研究具有科学意义，因为这一概念是建立在从生物学延伸到全新工程应用的思想基础上的。由于设计的模块化性质，预计所提出的框架将对其他多酶级联的组装产生巨大影响。所提出的方法将提供一个未来的平台，用于燃料电池应用的广泛的多酶系统的自组装。从教育的角度来看，参与这项研究的研究生将获得连接生物化学，电化学和纳米技术的重要接口和协同作用的综合视角。PI计划通过加州大学滨江的数学工程科学成就计划和在特拉华州建立家庭学校日计划来推广计划。

Enzymatic fuel cells have received considerable attention because of their potential for direct conversion of abundant raw materials to electricity. The use of multi-enzyme cascades is particularly attractive as they offer the possibility of achieving a higher current density by the sequential oxidization of fuels. However, efficient substrate and electron channeling are two of the most important bottlenecks in improving the power output of multi-enzyme fuel cells. An award from the National Science Foundation Catalysis & Biocatalysis Program to Professors Wilfred Chen of the University of Delaware and Nosang Myung of the University of California-Riverside will support investigation of approaches to surmount these obstacles. The overall objective of this proposal is to investigate the use of a genetically controlled, DNA-based modular scaffold approach for the spatially-defined self-assembly of a multi-enzyme cascade for enhanced substrate and electron channeling. A simple and scalable electrospinning method will be developed to synthesize nanofiber mat electrodes with a very high surface area. A genetically designed mediator will then connect the assembly to the mat electrode. The modular nature of the proposed design allows easy alteration of spacing between the enzymes, mediators and the electrodes for investigating the optimal substrate and electron channeling in a rational manner. The unique combination of nanoengineering and bioengineering approaches will enable Chen and Myung to systematically investigate the factors affecting the overall performance of the multi-enzyme fuel cell. The initial testing of the concept will be demonstrated for the conversion of cellulose to gluconic acid, with other reactions to be studied subsequently.The proposed research is scientifically significant because the concept is built on ideas from biology extending to an entirely new engineering application. Because of the modular nature of the design, it is anticipated that the proposed framework will have a huge impact on the assembly of other multi-enzyme cascades. The proposed methodology will provide a future platform useful for the self-assembly of a wide range of multienzyme systems for fuel cell applications. From an educational perspective, graduate students participating in this research will gain an integrated perspective of the important interfaces and synergies connecting biochemistry, electrochemistry, and nanotechnology. The PIs plan outreach programs through the Mathematics Engineering Science Achievement Program at UC Riverside and the establishment of a Homeschoolers Day program in Delaware.