Molecular basis of enzyme-catalyzed pehydrolysis of acetate esters for pretreatment of lignocellulosic biomass

酶催化醋酸酯脱水预处理木质纤维素生物质的分子基础

• 批准号: 0932762
• 负责人: Romas Kazlauskas
• 金额: $ 30万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0932762&HistoricalAwards=false
• 关键词: Molecular; basis; enzyme; catalyzed; pehydrolysis

0932762KazlauskasSummary Replacing the current biofuels feedstock - corn - with lignocellulosic biomass such as wood, switchgrass or agricultural wastes is a key current goal of bioenergy research. Recalcitrance - inefficient release of sugars from lignocellulosic biomass - is the key problem that must be solved to make this replacement. The proposed solution is an unnatural enzyme-catalyzed reaction to make a strong oxidant peracetic acid. The objective for this application is a molecular-level understanding of an unnatural enzyme-catalyzed reaction - perhydrolysis of esters to form peracetic acid. The central hypothesis is that precise positioning of hydrogen bond donors or acceptors within the active site selectively deactivates water, thus favoring hydrogen peroxide. The PIs have formulated this hypothesis based on the comparison of x-ray crystal structures of enzymes with different abilities to make peracetic acid. The test for this hypothesis will be to correlate the structure and kinetics of perhydrolysis and to design new enzyme variants that make high concentrations of peracetic acid for pretreatment of lignocellulosic biomass. Intellectual Merit: The intellectual merit includes first the molecular-level understanding of how to design enzyme catalyzed non-natural reactions. It will contribute to the research frontier catalytic promiscuity where enzymes catalyze several distinct chemical reactions. Learning how to favor one or another reaction gives insight into the natural process of divergent enzyme evolution and will deepen our understanding of the subtleties of enzymatic catalysis.Broader Impact: The proposed research will generate new fundamental knowledge on the molecular basis of how catalytic activity of enzymes can evolve to new catalytic activities and contribute to the understanding of the mechanisms of oxidation of proteins. The proposed research will contribute to the discovery of efficient routes to peracetic acid to remove lignin to convert lignocellulosic biomass to fuels. The proposed research will educate and train undergraduate students, graduate students and postdoctoral fellows, including students from underrepresented groups in chemical sciences. For the last three years, the PI participates in the Common X-Change program in Saint Paul public schools, which teaches experimental science at the elementary school level. The science teacher partner in this project over the last four years, Ms. Henriette Ngo-Bissoy, an African-American woman, and many of the students in the classes are from underrepresented groups in science. The co-PI, Tschirner, teaches a two week all day summer workshop titled "Topics in Natural Resources: Renewable energy and Bioproducts" for twenty high school teachers. About half of the class is hands-on experiments, inquiry based teaching that is suitable for classroom teaching. The proposed research will also support international cooperation of visitors from Europe and Asia to the PI's laboratories.

0932762KAZLAUSKASSUMMARY用木质纤维素生物量（例如木材，开关草或农业废物）代替当前的生物燃料原料 - 玉米 - 是生物稳态研究的关键目的。顽固性 - 从木质纤维素生物质中释放糖的效率低下 - 是必须解决此替代品必须解决的关键问题。提出的溶液是一种不自然的酶催化反应，使氧化剂二乙酸具有较强的氧化剂。这种应用的目的是对酯类不自然酶催化反应的分子级别理解 - 酯的polhydrolsyss形成了乙酸。中心假设是，在活性位点，精确定位氢键供体或受体选择性地停用水，从而有利于过氧化氢。 PI是根据具有不同能力的X射线晶体结构的比较来提出了这一假设的。该假设的检验将是将钙解析的结构和动力学相关联，并设计新的酶变体，使高浓度的过乙酸用于预处理木质纤维素生物量。智力优点：智力优点首先包括对如何设计酶催化非天然反应的分子水平的理解。它将有助于研究边界催化性滥交，酶催化了几种不同的化学反应。学习如何偏爱一个或另一种反应可以深入了解酶演化的自然过程，并将加深我们对酶促催化的细胞的理解。Broader的影响：拟议的研究将对酶的催化活性产生分子基础的新基本知识，可以使酶的催化活性能够进化为新的催化活性和对这种机制的贡献，从而有助于这种催化剂的理解。拟议的研究将有助于发现有效的过乙酸途径以去除木质素以将木质纤维素生物量转化为燃料。拟议的研究将教育和培训本科生，研究生和博士后研究员，包括来自化学科学领域代表性不足小组的学生。在过去的三年中，PI参加了圣保罗公立学校的共同X-Crange计划，该计划在小学一级教授实验科学。在过去的四年中，该项目的科学老师合作伙伴是非裔美国妇女Henriette Ngo-Bissoy女士，班级中的许多学生来自科学的代表性不足的群体。 Tschirner的Co-Pi为二十名高中教师提供了一个为期两周的夏季研讨会，标题为“自然资源的主题：可再生能源和生物产品”。全班大约一半是动手实验，基于询问的教学，适合课堂教学。拟议的研究还将支持来自欧洲和亚洲与PI实验室的国际游客合作。