FMSG: Bio: Merging electrochemistry and metabolic engineering for carbon neutral ammonia production

氨是氮基肥料的重要组成部分，对于养活不断增长的世界人口的集约化农业至关重要。分布式、可持续的氨制造，由可再生电力提供动力，并由电活性活微生物催化，可以对全球能源消耗和相关的碳排放产生巨大影响。该项目解决了关键的社会需求，即在农场或市政当局等使用场所实现分散的氨制造，同时降低碳排放。这种创新将在全国范围内实现更公平的粮食生产实践和基础设施，从而在全球范围内实现可持续的农业实践。这些外联活动将扩大这项工作的社会影响，并培训认识到可持续化学工业对环境影响的未来工作人员。在K-12的水平上，该项目将创造新的活动，展示生物和电化学结合的潜力，以实现燃料和能源的可持续生产。在社区大学层面，该项目将启动一个网络活动，将学生与专注于可持续性和循环性的创新创业公司联系起来。在本科生和研究生的水平上，本项目将在环境工程课程中整合环境电化学的新材料。目前的氨制造由碳和能源密集型的哈伯-博世工艺主导，该工艺在2021年排放了6亿吨二氧化碳，消耗了全球2%的能源。这项未来制造业种子基金将支持聚合电化学和代谢工程方法的基础研究，以实现氨的碳中性生产，将电化学合成的生产力和效率与固氮细菌产生氨的精细选择性和低成本结合起来。这种新方法基于一个环形零间隙电化学电池，将细菌产生的氨与非生物二氧化碳还原到阴极的有机酸结合起来。在电化学方面，该项目将(i)优化电子传递链，提高阳极的氮酶活性和选择性，（ii）最大化阴极的二氧化碳还原选择性。在代谢工程方面，该研究将(a)操纵代谢和调节途径以提高氨生产力，(b)增强氨排泄。这种方法的成功结果将通过开发和测试一个实验规模的高保真反应器来证明，该反应器可在商业相关条件下连续生产氨，该反应器可进一步扩大规模，作为单个农场的操作单元实施。这个未来制造项目由生物科学理事会的分子和细胞生物科学部、工程理事会的化学、生物工程、环境和运输系统部以及数学和物理科学理事会的化学部共同资助。该奖项反映了美国国家科学基金会的法定使命，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。

Ammonia is a critical component of nitrogen-based fertilizers, crucial in intensive agriculture to feed a continuously growing world population. Distributed, sustainable ammonia manufacturing, powered by renewable electricity and catalyzed by electroactive living microorganisms can have a tremendous impact on global energy consumption and related carbon emissions. This project addresses the critical societal need to enable decentralized ammonia manufacturing at the site of use such as a farm or municipality while simultaneously lowering carbon emissions. Such innovation will result in more equitable food production practices and infrastructure across the country, leading to sustainable agricultural practices across the globe. The outreach activities will broaden the societal impact of this work and train a future workforce aware of the impact of a sustainable chemical industry on the environment. On a K-12 level, this project will create new activities illustrating the potential of merging biology and electrochemistry for the sustainable production of fuels and energy. On a community college level, this project will launch a networking event, connecting students with innovative startups focusing on sustainability and circularity. On an undergraduate and graduate students level, this project will integrate new material on environmental electrochemistry in environmental engineering courses.Current ammonia manufacturing is dominated by the carbon and energy intensive Haber-Bosch process, which was responsible for the emission of 600 Mt of CO2 and the consumption of 2% of the global energy produced in 2021. This future manufacturing seed grant will support fundamental research on convergent electrochemistry and metabolic engineering approaches to enable carbon-neutral production of ammonia, merging the productivity and efficiency of electrochemical synthesis with the exquisite selectivity and low cost of ammonia generation by nitrogen-fixing bacteria. This novel approach is based on a looped zero-gap electrochemical cell, coupling ammonia production from bacteria with abiotic carbon dioxide reduction to organic acids at the cathode. On the electrochemistry side, the project will (i) optimize the electron transport chain and improve nitrogenase activity and selectivity at the anode and (ii) maximize carbon dioxide reduction selectivity at the cathode. On the metabolic engineering side, the research will (a) manipulate metabolic and regulatory pathways to increase ammonia productivity and (b) enhance ammonia excretion. The successful outcome of this approach will be demonstrated by developing and testing a bench-scale, high-fidelity reactor for continuous production of ammonia at commercially relevant conditions that can be further scaled up to be implemented as an operating unit on an individual farm.This Future Manufacturing project is jointly funded by the Division of Molecular and Cellular Biosciences in the Directorate for Biological Sciences, the Division of Chemical, Bioengineering, Environmental, and Transport Systems in the Directorate for Engineering, and the Division of Chemistry in the Directorate of Mathematical and Physical Sciences.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.