CAS-CLIMATE: DIRECT METHANE CAPTURE IN AIR BY AEROBIC METHANOTROPHS

在100年的时间尺度上，甲烷的变暖影响是二氧化碳的34倍，在20年的时间尺度上是二氧化碳的86倍，而且甲烷在大气中相对较短的半衰期（~10年）为短期内减缓气候变化提供了机会。该项目的目标是创造一种技术，通过大规模去除空气中的甲烷，为减缓全球变暖奠定基础。由于甲烷浓度较低（1.89 ppm），从大气中去除甲烷具有挑战性。该项目的重点是开发一种技术，利用消耗甲烷的细菌（甲烷氧化菌），从垃圾填埋场、污水处理厂、煤矿、油气井、饲养场和水电站等排放甲烷的地方去除空气中的甲烷。许多甲烷氧化菌可以稳定地维持在500 ppm的甲烷浓度，使这一浓度成为反应堆部署的可能目标。在美国，预计数以万计的这样的地点在其上的空气中含有500ppm或更多的甲烷，为实现大规模的大气甲烷捕获提供了机会。虽然生物过滤技术已经存在，可以从气态废物流中去除甲烷，但它对更浓的甲烷进行了优化，在500 ppm的甲烷下是不可行的。该项目旨在建立一个实验室原型，用于从空气中浓度为500ppm或更高的地方消耗甲烷，目标是将目前的能力（甲烷消耗量/立方米处理量/年）提高10倍。该项目将从Lidstrom实验室发现的甲烷氧化菌开始，这些菌在500ppm时的甲烷消耗率比文献中任何一种都高2到4倍，并开发改进的菌株和优化的生长条件，包括财团。然后，该团队将使用优化的微生物群落对改进的生物过滤器配置进行建模、测试和优化，以减少甲烷的消耗。在进行实验工作的同时，该团队将开发一个综合建模框架，将过程模拟与影响评估相结合，以评估生物反应器系统在几种可能的运行情况下的情况。然后，该小组将进行相关的技术经济和环境生命周期评估研究，以说明广泛应用生物反应器系统的经济可行性和环境效益的潜力，并指导进一步的研究和发展工作。实验和建模团队将在迭代设计过程中密切合作，以构建最终框架并获得可行性的可靠评估。长期目标是使这些生物反应器成为垃圾填埋场、污水处理厂、饲养场、水电站、煤矿和其他地方的标准设备。这种甲烷捕获将对未来的气候产生强大的影响，特别是在同时努力减少甲烷排放的情况下。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。

Methane has a warming impact 34 times greater than CO2 on a 100-year timescale, and 86 times greater on a 20-year timescale, and its relatively short half-life in the atmosphere (~10 years) provides the opportunity for near-term climate mitigation. This project targets creation of a technology that would set the stage to slow global warming by removing methane from air at significant scale. Removing methane from the atmosphere is challenging due to the low concentration (1.89 ppm). This project focuses on creation of technology to remove methane from the air over sites where emissions result in locally higher concentrations in the air, such as many landfills, sewage treatment plants, coal mines, oil and gas wells, feedlots, and hydroelectric dams, using methane-consuming bacteria (methanotrophs). Many methanotrophs can be stably maintained at 500 ppm methane, making this concentration a possible target for reactor deployment. Tens of thousands of such sites in the United States are projected to contain 500 ppm or more methane in the overlying air, providing the opportunity to achieve atmospheric methane capture at scale. Although biofilter technology exists to remove methane from gaseous waste streams, it is optimized for more concentrated methane and is not practicable at 500 ppm methane. This project aims to result in a laboratory prototype for consuming methane from sites with 500 ppm or greater in the air, with a goal of a 10-fold increase over current capacity (methane consumed/m3 treatment volume/year).The project will start with methanotrophs identified in the Lidstrom lab that have 2- to 4-fold higher rates of methane consumption at 500 ppm than any in the literature, and develop improved strains and optimized growth conditions including consortia. The team will then model, test, and optimize for methane consumption a modified biofilter configuration using optimized microbial communities. Concurrently with experimental work, the team will develop an integrated modeling framework, coupling process simulation with impact assessment, to assess the bioreactor systems under several potential operating scenarios. The team will then conduct linked techno-economic and environmental life cycle assessment studies to illustrate the potential for economic feasibility and environmental benefit for widespread application of the bioreactor systems and guide further research and development work. The experimental and modeling teams will work closely and collaboratively, in an iterative design process to build the final framework and obtain a robust assessment of feasibility. The long term goal is to see these bioreactors as standard equipment at landfills, sewage treatment plants, feedlots, hydroelectric dams, coal mines, and elsewhere. This methane capture would have a powerful impact on the climate future, especially when coupled to parallel efforts to reduce methane emissions.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.