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

气候变化的快速步伐为短期缓解战略创造了巨大的紧迫性，在该项目中，获得了新的科学信息，以支持使用甲烷食菌去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，可以在2050年之前减缓全球变暖。该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，同时保持一些最具破坏性的近期影响变暖的星球。这一概念被带到教育活动中，以增加对这些方法如何帮助地球的理解，作为该项目的一部分，本科生还可以在实验室中获得动手学习。目前提出的甲烷减排战略主要集中在减少排放，这些都是重要的目标。然而，有人认为，排放战略必须通过大气甲烷捕获来加强，以在2050年之前减缓全球变暖。由于甲烷浓度低（1.89 ppm），从大气中去除甲烷极具挑战性。然而，存在数十万个排放点，其中上覆甲烷在10-100 ppm范围内，并且这些为使用消耗甲烷的细菌（甲烷氧化菌）从空气中捕获甲烷提供了机会。以这些水平利用甲烷的天然存在的甲烷氧化菌具有太慢而不实用的甲烷消耗速率。然而，在研究者的培养物收集中已经鉴定出甲烷氧化菌，其在500 ppm下生长显著优于文献中的其他菌株。在这个项目中，测试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。在低甲烷下表现出增强生长的菌株的特征在于在低甲烷下的生长、甲烷氧化、转录物和通量，以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甲烷下生长增强的菌株进行选择，并对所鉴定的任何新性状进行表征。在100 ppm及更低浓度下能够更快生长的甲烷氧化菌将来可用于去除空气中甲烷的新技术。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。

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.