Microbial Conversion of Lignocellulosic Biomass into 1-Propanol and 2-Butanol

该项目将设计基于二醇脱水酶的新型1-丙醇和2-丁醇途径，在大肠杆菌中设计这些途径，并开发将木质纤维素生物质转化为液体生物燃料1-丙醇和2-丁醇的生物过程。研究工作包括从木质纤维原料中微生物释放可发酵糖，设计和构建代谢途径和微生物生产平台，将释放的糖转化为所需产品，以及开发从木质纤维资源中提取1-丙醇和2-丁醇的集成工艺。本研究的关键内容是利用二醇脱水酶进行蛋白质工程以促进2，3-丁二醇的脱水，以及利用大肠杆菌的代谢工程来高效地利用Caldicellulosiruptor Bescii处理过的木质纤维生物质生产1-丙醇和2-丁醇。最终，该项目的长期目标是开发可扩展和可持续的技术，以有效地从可再生资源中生产正丙醇和异丁醇，特别是1)改善大肠杆菌菌株的特性以高效地生产正丙醇；2)通过蛋白质工程改善二醇脱水酶的特性以满足工艺指标；3)开发菌株和集成工艺以从木质纤维生物质中生产正丙醇和异丁醇。正丙醇和异丁醇都具有高能量密度、低蒸汽压和低水分的物理化学性质，这使它们成为比目前广泛使用的生物乙醇更好的液体生物燃料。这项研究的结果将加深我们对微生物代谢的了解，并导致通过微生物发酵从木质纤维生物质中生产1-丙醇和2-丁醇的实用技术的开发，代表着扩大自然代谢用于生物能源应用的努力，并影响到化学、生物科学和工程学科。研究和教育工作将整合如下：1)将在拟议研究的基础上开发代谢工程与合成生物学课程和代谢工程与合成生物学实验室，以加强佐治亚大学(UGA)的生化工程计划，该计划将为本科生和研究生提供化学、生物科学和工程学的跨学科培训。2)拟议的研究将通过乔治亚大学现有的合作扩展项目，包括佐治亚州4-H组织和佐治亚州植物园的教育方案，与社区教育相结合，优先鼓励少数群体和教育或经济上处于不利地位的群体参与。3)拟议的研究将与加州大学生物能源系统研究所现有的项目相结合，为学生提供培训、实习、交流和奖学金。

This project will design novel 1-propanol and 2-butanol pathways based on a diol dehydratase, to engineer the pathways in Escherichia coli, and to develop biological processes to convert lignocellulosic biomass into liquid biofuels 1-propanol and 2-butanol. The research work consists of the efforts in releasing fermentable sugars from lignocellulosic materials microbially, designing and constructing metabolic pathways and microbial production platforms to convert the released sugars into the desired products, and developing integrated processes to deliver 1-propanol and 2-butanol from lignocellulosic resources. The key elements of this research work are the protein engineering of a diol dehydratase to enhance dehydration of 2,3-butanediol and metabolic engineering of E. coli to enable the efficient production of 1-propanol and 2-butanol from Caldicellulosiruptor bescii treated lignocellulosic biomass. Eventually, the long-term objective of the proposed project is to develop scalable and ustainable technologies to efficiently generate 1-propanol and 2-butanol from renewable sources, specifically 1) improving E. coli strain properties for efficient 1-propanol production; 2) improving the properties of the diol dehydratase to meet process metrics via protein engineering; 3) developing strains and integrated processes for the generation of 1-propanol and 2-butanol from lignocellulosic biomass.Both 1-propanol and 2-butanol have the physicochemical properties of high energy density, low vapor pressure, and low water content, which make them better liquid biofuels than currently widely-used bioethanol. The outcome of this research will advance our understanding of microbial metabolism and lead to the development of practical technologies for the production of 1-propanol and 2-butanol from lignocellulosic biomass through microbial fermentation, representing the efforts of expanding natural metabolism for bioenergy applications and impacting the disciplines of chemistry, biological sciences, and engineering. The research and education efforts will be integrated as the following: 1) A Metabolic Engineering & Synthetic Biology Course and a Metabolic Engineering & Synthetic Biology Laboratory will be developed based on the proposed research to strengthen the BioChemical Engineering Program at the University of Georgia (UGA), which will provide undergraduate and graduate students with the interdisciplinary training of chemistry, biological sciences, and engineering. 2) The proposed research will be integrated with community education through the existing cooperative extensions at UGA including the Georgia 4-H organization and the educational programs at the State Botanical Garden of Georgia with the priority of encouraging the participation of minority and educationally or economically disadvantaged groups. 3) The proposed research will be integrated with the existing programs of Bioenergy Systems Research Institute at UGA to provide students with training, internships, exchanges, and scholarships.