CAREER: Inorganic-organic hybrid microreactors for fundamental study of cellulose hydrolysis by solid acids

摘要-蒂姆科，1554283-纤维素生物质是世界上最丰富的可再生碳来源，有望成为一种碳中性能源，可以减少对基于石油的交通燃料、化学品和材料的需求。尽管在许多不同生物燃料技术的开发方面取得了进展并带来了希望，但没有一项技术被证明在经济上是可行的。该项目的目的是使利用生物质资源生产燃料和化学品在经济上可行。生物质转化为燃料和化学品的经济性差，很大程度上是由于生物质对化学和生物攻击的抵抗力。已经提出了三个克服生物质顽固性的主要平台：生物油(通过热解或液化生产)、合成气(通过气化生产)和糖(通过预处理和酶解生产)。这项提议的重点是糖平台。生物质对化学和生物侵蚀的抗性使得单糖的回收成本高昂且能源密集型。这项工作的重点是从生物质中回收单糖，因为这一步骤是糖类平台的关键技术瓶颈。总体研究目标是了解固体酸催化剂破坏纤维素的基本机理。该方法包括构建聚合物刷修饰的无机颗粒(二氧化硅和沸石)作为催化微反应器，具有：1)明确的外部酸度，可由不溶基质获得；2)纤维素靶向/结合/增溶能力，提供不溶基质与固体酸外表面之间的相互作用；3)内部孔结构和酸性，可由小分子可溶底物获得。要解决的具体问题包括：1)控制催化剂-生物质相互作用的结构/性质-功能关系是什么？2)固体酸强度和纤维素水解活性之间的关系是什么？3)纤维素链断裂的外部酸度和可溶片段的内部酸度之间的平衡是多少？该项目将评估固体酸催化是由结合作用和强酸性介导的假说。在这项工作的研究部分，将研究潜在的机制：1)了解催化剂-纤维素结合的作用以及纤维素附着、催化剂表面组成和催化剂表面能之间的关系；2)量化酸度的作用，并回答表面需要多酸性才能催化水解的问题；3)区分转化不溶底物所需的外部酸性部位和能够转化可溶性碳水化合物的内部酸性部位。研究目标将与教育和推广相结合，目的是利用数据到音乐的工具来吸引来自未被充分代表的背景的学生进入STEM领域的职业，并吸引比工程课程中典型的本科水平更广泛的学习风格。在教育方面，使用音乐向大学工科学生传授困难的概念，可以改善对使用非典型工科课程学习方式的学生的培训。这有可能提高STEM领域更广泛的本科生的留存率。外展部分将为K-12学生提供一种引人入胜的STEM体验，增强而不是疏远。具体地说，研究数据将被转换为声音，并重新调制为音乐，这一过程模仿了推动嘻哈音乐创作的抽样做法。

Abstract - Timko, 1554283Lignocellulosic biomass, the world's most abundant source of renewable carbon, has promise as a carbon neutral energy source that can reduce the need for petroleum-based transportation fuels, chemicals, and materials. Despite progress and promise in the development of many different biofuel technologies, none have proven economically viable. The aim of this project is to make production of fuels and chemicals from biomass resources economically viable. The poor economics of biomass conversion to fuels and chemicals is due largely to biomass resistance to chemical and biological attack. Three primary platforms have been suggested for overcoming biomass recalcitrance: bio-oil (produced via pyrolysis or liquefaction), synthesis gas (produced by gasification), and sugars (produced by pretreatment and enzyme hydrolysis). This proposal is focused on the sugars platform. Biomass resistance to chemical and biological attack makes recovery of monosaccharides expensive and energy intensive. The focus of this work is on recovery of monosaccharides from biomass because this step represents the key technological bottleneck of the sugars platform.The overarching research objective is to understand the fundamental mechanisms underlying cellulose deconstruction by solid acid catalysts. The approach consists of constructing polymer-brush modified inorganic particles (silica and zeolites) as catalytic microreactors with: 1) well defined external acidity that can be accessed by insoluble substrates, 2) cellulose targeting/binding/solubilization capability to provide interactions between insoluble substrates and external surfaces of solid acids, and 3) internal pore structure and acidity that can be accessed by small molecule soluble substrates. Specific questions to be addressed include: 1) what is the structure/property- function relationship that governs the catalyst-biomass interaction? 2) what is the relationship between solid acid strength and cellulose hydrolysis activity? and 3) what is the balance between external acidity for cellulose chain breaking and internal acidity for hydrolysis of soluble fragments? The project will evaluate the hypothesis that solid acid catalysis is mediated by binding interactions and strong acidity. In the research component of this work, the underlying mechanism will be examined to: 1) understand the role of catalyst-cellulose binding and the relationship between cellulose adhesion, catalyst surface composition, and catalyst surface energy; 2) quantify the role of acidity and answer the question of how acidic the surface needs to be to catalyze hydrolysis; 3) differentiate between external acidic sites required to convert insoluble substrates and internal acidic sites capable of converting soluble carbohydrates.The research objectives will be integrated with educational and outreach aims to use data-to-music tools to attract students from under-represented backgrounds to careers in STEM fields and to appeal to a broader range of learning styles at the undergraduate level than are typical in the engineering curriculum. In terms of education, the use of music to teach difficult concepts to college engineering students could improve training for students that use learning styles that are not typical in engineering curricula. This has potential to improve retention of a broader range of undergraduate students in STEM fields. The outreach component will provide K-12 students with an engaging STEM experience that empowers rather than alienates. Specifically, research data will be converted into sounds and re-modulated into music, a process that mimics the practice of sampling that drives hip hop music composition.