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EAGER Electrically Driving the Microbial Conversion of Nitrogen Gas into Ammonia

EAGER 电力驱动微生物将氮气转化为氨

基本信息

批准号：
1840956
负责人：
Douglas Call
金额：
$ 13.35万
依托单位：
North Carolina State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-15 至 2020-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1840956&HistoricalAwards=false
关键词：
EAGER Electrically Driving Microbial Conversion

项目摘要

Ammonia is a critical resource for farming and industrial activities. The majority of ammonia is generated through an industrial process called the Haber-Bosch process. This paradigm changing method was a significant factor driving the agricultural green revolution and helped ammonia become one of the most produced chemicals in the world. This success has come at a high cost in terms of dollars and environmental impact. Requiring extremely high temperature and pressure conditions to produce the ammonia, the process consumes 1-2% of global energy and generates 2.5% of all carbon dioxide emissions annually. There is, therefore, a critical need to find sustainable and low-cost alternatives to the Haber-Bosch process. Naturally occurring microorganisms can convert atmospheric nitrogen gas into ammonia and can do so at ambient temperature and pressure. Challenges preventing industrial-scale microbial ammonia production include the sensitivity of the nitrogen-converting enzyme to oxygen, the inability to drive high ammonia production rates, and ammonia recovery from the microorganisms. Accordingly, this project will combine the fields of electrochemistry and microbiology to characterize and optimize an electrically-driven ammonia production biotechnology. The research team will use model electricity-generating bacteria to understand the response of their nitrogen conversion pathways to an electrical driving force and then use that information to engineer highly efficient ammonia-generating bacteria. The results will expand our knowledge of microbial nitrogen conversion processes and lead to the foundation of an ammonia production technology that can be scaled in size for small farms to large, industrial-scale processes. The team will also engage underrepresented undergraduate and graduate students in the research by leveraging the established Research Internship Summer Experience (RISE) program at their institution. These students will have a unique opportunity to conduct research spanning electrochemistry, microbiology, and engineering.Several emerging ammonia production technologies utilize electrochemical and microbial methods separately. They have had limited success and face inherent scalability challenges. These limitations may be overcome by combining electrochemical and biological processes, rather than treating them separately. Research in electromicrobiology has demonstrated that microbial metabolisms can be electrically driven with inputs of less than one volt of electricity. Several electricity-generating bacteria, known as exoelectrogens, are also vigorous nitrogen-fixing microorganisms. By exploiting and optimizing their unique physiology, microbial electrochemical technologies (METs) may be developed to electrically drive nitrogen fixation into ammonia. The overall objective of this project is to identify nitrogen fixation regulatory changes in response to electrical driving forces and to use that information to optimize ammonia-generating strains. This work has three main tasks: (1) determine the impact of MET operational variables on the completeness and rates of nitrogen fixation; (2) identify regulatory changes in nitrogen fixation and ammonia generation pathways during MET operation using whole transcriptome RNA sequencing; and (3) engineer new exoelectrogenic strains that excrete ammonia using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) genome editing tools. It is expected that this work will yield new insight into nitrogen fixation pathways that will be relevant to an array of biotechnological platforms. Modulating CRISPR in exoelectrogenic microorganisms will also provide a new tool for applications ranging from wastewater treatment to bioelectrosynthetic chemical production.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

氨是农业和工业活动的重要资源。大多数氨是通过一种称为哈伯-博世工艺的工业过程产生的。这种改变模式的方法是推动农业绿色革命的重要因素，并帮助氨成为世界上生产最多的化学品之一。这一成功在资金和环境影响方面付出了高昂的代价。该工艺需要极高的温度和压力条件来生产氨，每年消耗全球1-2%的能源，产生2.5%的二氧化碳排放量。因此，迫切需要找到可持续和低成本的哈伯-博施工艺替代品。自然存在的微生物可以将大气中的氮气转化为氨，并且可以在环境温度和压力下进行。阻止工业规模微生物氨生产的挑战包括氮转化酶对氧气的敏感性，无法驱动高氨生产速率，以及从微生物中回收氨。因此，本项目将联合收割机结合电化学和微生物学领域，以表征和优化电驱动的氨生产生物技术。研究小组将使用模型发电细菌来了解它们的氮转化途径对电驱动力的反应，然后利用这些信息来设计高效的氨生成细菌。研究结果将扩大我们对微生物氮转化过程的了解，并为氨生产技术奠定基础，该技术可以从小型农场扩展到大型工业规模工艺。该团队还将通过利用其机构的既定研究实习暑期体验（RISE）计划，让代表性不足的本科生和研究生参与研究。这些学生将有一个独特的机会进行研究跨越电化学，微生物学和工程。几个新兴的氨生产技术分别利用电化学和微生物方法。他们取得了有限的成功，并面临着固有的可扩展性挑战。这些限制可以通过结合电化学和生物过程来克服，而不是单独处理它们。电微生物学的研究已经证明，微生物的代谢可以用小于一伏的电力输入来驱动。几种发电细菌，称为外生产电菌，也是活跃的固氮微生物。通过利用和优化其独特的生理学，可以开发微生物电化学技术（MET）以电驱动固氮成氨。该项目的总体目标是确定响应于电驱动力的固氮调节变化，并使用该信息来优化产氨菌株。这项工作有三个主要任务：（1）确定MET操作变量对固氮的完整性和速率的影响;（2）使用全转录组RNA测序确定MET操作期间固氮和氨生成途径的调控变化;（3）使用重复的规则间隔短回文重复序列（CRISPR）基因组编辑工具设计新的分泌氨的外生电菌株。预计这项工作将对固氮途径产生新的见解，这将与一系列生物技术平台有关。在产电微生物中调控CRISPR还将为从废水处理到生物电合成化学品生产的应用提供新工具。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。