Toward Artificial Enzyme Analogues for Cellulose Hydrolysis Using High-throughput Screening

1033017Lee智能优点用于运输燃料的可持续和环境友好的乙醇来源是纤维素，它是木质纤维植物生物质的主要成分。纤维素的水解会产生葡萄糖，葡萄糖可以发酵成乙醇。然而，总的来说，纤维素的水解是一个困难的过程，目前是纤维素转化为乙醇的限速步骤。纤维素酶具有非常特殊的催化结构，能够有效地进行纤维素酶的水解，而不会产生副产物。然而，酶的速度相对较慢，热不稳定，价格昂贵，因为它们必须是生物生产的，不容易重复使用。这项拟议的研究将开发和了解人造酶类似物可以水解纤维素及其亚单位的功能。基于溶胶-凝胶法，将纤维素低聚物分子印迹到有机-无机杂化固体催化剂载体上，从而形成人工酶结构。这一策略具有结合蛋白质酶的效率和专一性与多相固体催化剂的稳健性和成本效益的潜力。在拟议的研究中，将基于分子印迹溶胶凝胶技术和高通量合成和筛选方法合成用于纤维素低聚物和纤维素水解酶的人工酶类似物。印迹过程产生的分子空穴将为纤维素亚单位提供特定的结合域，以及糖苷键水解所需的固体酸中心。为了潜在地促进底物的水解和促进分子印迹催化剂与底物之间的诱导匹配，将通过在溶胶-凝胶基质中添加有机硅烷来调节溶胶-凝胶催化剂的柔韧性。假设分子印迹催化剂的专一性将阻碍导致葡萄糖降解的副反应，而这是传统固体酸催化剂的主要问题。高通量方法将能够筛选大量(~10,000)合成参数，以优化分子印迹催化剂的组成和结构。布罗德影响拟议的教育和推广活动旨在激发学生对生物质能源的兴趣和对科学和工程的基本想法。通过路易丝·斯托克斯少数民族参与联盟(AMP)夏季本科生研究计划招募的来自代表性不足群体的本科生将有机会参与研究。作为推广计划的一部分，PI将与当地一家有线电视接入电视台合作，制作关于能源现状和发展可再生能源技术的重要性的节目。这一科学节目将在费城大都会地区播出。

1033017LeeIntellectual MeritsA sustainable and environmentally friendly source of ethanol for transportation fuel is cellulose, which is the major component of lignocellulosic plant biomass. Hydrolysis of cellulose generates glucose, which can be fermented to ethanol. However, in general, the hydrolysis of cellulose is a difficult process, and is currently the rate-limiting step in the cellulose-to-ethanol conversion. Cellulase enzymes with very specific catalytic structures are capable of efficient cellulose hydrolysis without byproduct formation. However, enzymes are relatively slow, thermally unstable, and expensive, as they must be biologically produced are not readily reusable. The proposed research will develop and understand the function of artificial enzyme analogues that can hydrolyze cellulose and its subunits. Artificial enzyme structures will be created by molecular imprinting of cellulose oligomers onto organic-inorganic hybrid solid catalyst supports based on sol-gel methods. This strategy has the potential to combine the efficiency and specificity of protein-based enzymes with the robustness and cost effectiveness of heterogeneous solid catalysts.In the proposed research, artificial enzyme analogues for hydrolysis of cello-oligomers and cellulose will be generated based on a molecular-imprinting sol-gel technique combined with a high-throughput synthesis and screening method. Molecular cavities generated by the imprinting process will provide specific binding domains for sub-units of cellulose as well as solid acid sites required for hydrolysis of glycosidic bonds. To potentially enhance substrate hydrolysis and promote induced fit between the molecularly imprinted catalyst and substrate, the flexibility of the sol-gel catalysts will be tuned by adding organo-silanes to the sol-gel matrix. It is hypothesized that the specificity of the molecularly-imprinted catalysts would hinder side reactions that lead to degradation of glucose, which is a major problem with conventional solid-acid catalysts. The high throughput method will be able to screen a large number (~10,000) of synthesis parameters to optimize the composition and structure of the molecularly-imprinted catalysts.Broader ImpactsThe proposed education and outreach activities are designed to stimulate student interest in biomass energy and fundamental ideas in science and engineering. Undergraduate students from underrepresented groups recruited through the Louise Stokes Alliance for Minority Participation (AMP) Summer Undergraduate Research Program will be given opportunities to participate in the research. As part of the outreach plan, the PI will work with a local cable access TV station to develop programming on the current state of energy landscape and the importance of developing renewable energy technologies. This scientific program will be aired throughout the Philadelphia metro area.