CAS-Climate: Construction of a bacterium with optimized methane consumption at 10ppm for climate change mitigation

气候变化的迅速步伐使短期缓解战略变得非常紧迫，在这个项目中，获得了新的科学信息，以支持利用食用甲烷的细菌消除强效温室气体甲烷的战略。该项目的成功为开发温室气体减排技术奠定了基础，如果大规模部署，到2050年可以减缓全球变暖。这项技术将为开发和推出以二氧化碳为重点的干预措施赢得时间，同时阻止地球变暖带来的一些最具破坏性的短期影响。这个概念被引入到教育活动中，以增加对这些方法如何帮助地球的理解，本科生也在实验室中获得实践学习，作为这个项目的一部分。目前提议的甲烷减缓战略主要侧重于减少排放，这些都是重要的目标。然而，有人认为，为了到2050年减缓全球变暖，必须通过大气甲烷捕获来加强排放战略。由于甲烷的浓度很低（1.89 ppm），从大气中去除甲烷极具挑战性。然而，存在着成千上万的排放点，其上的甲烷含量在10- 100ppm范围内，这些排放点为利用消耗甲烷的细菌（甲烷氧化菌）从空气中捕获甲烷提供了机会。自然产生的甲烷氧化菌利用这些水平的甲烷，其甲烷消耗速度太慢，不切实际。然而，在研究者的培养收集中发现了一种甲烷化菌，它在500ppm下的生长明显好于文献中的其他菌株。在这个项目中，我们测试了特定的性状，以确定它们是否参与低甲烷条件下的生长，包括甲烷氧化系统的亲和力、饥饿反应调节基因rpoS和代谢网络中的关键分支点。通过对低甲烷条件下生长增强的菌株的生长、甲烷氧化、转录物和通量进行表征，了解与野生型相比，这些变化如何影响生长参数和代谢网络。使用适应性实验室进化方法对在100 ppm甲烷条件下生长增强的菌株进行选择，并对所确定的任何新性状进行表征。在100ppm或更低的浓度下，甲烷氧化菌能够更快地生长，未来可用于从空气中去除甲烷的新技术。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。

The rapid pace of climate change has created great urgency for short-term mitigation strategies and in this project, new scientific information is obtained to support strategies for removing the potent greenhouse gas methane using methane-eating bacteria. Success in this project lays the foundation for developing greenhouse gas mitigation technology that if deployed at scale, could slow global warming by 2050.This technology will buy time for the development and launch of CO2–focused interventions while keeping at bay some of the most devastating near-term impacts of a warming planet. This concept is brought to educational activities, to increase understanding of how such approaches can help the planet, and undergraduates also obtain hands-on learning in the laboratory as part of this project. Current proposed methane mitigation strategies are mainly focused on reducing emissions, and these are important goals. However, it has been argued that emission strategies must be augmented by atmospheric methane capture to slow global warming by 2050. Removing methane from the atmosphere is extremely challenging due to the low concentration (1.89 ppm). However, hundreds of thousands of emission sites exist in which the overlying methane is in the 10-100 ppm range, and these present opportunities for methane capture from air using bacteria that consume methane (methanotrophs). Naturally occurring methanotrophs that utilize methane at these levels have methane consumption rates that are much too slow to be practical. However, a methanotroph has been identified in the investigator's culture collection that grows at 500 ppm significantly better than other strains in the literature. In this project, specific traits are tested to determine whether they are involved in growth at low methane, including the affinity of the methane oxidation system, the starvation response regulatory gene rpoS, and key branchpoints in the metabolic network. Strains showing enhanced growth at low methane are characterized for growth, methane oxidation, transcripts, and fluxes at low methane, to understand how these changes affect growth parameters and the metabolic network compared to the wild type. Selection is carried out for strains with enhanced growth at 100 ppm methane, using adaptive laboratory evolution approaches, and any new traits that are identified are characterized. Methanotrophs capable of faster growth at 100 ppm and lower can be used in the future for new technology to remove methane from air.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.