About This Project

To de-risk atmospheric methane removal (AMR) bioreactors, we will develop a techno-economic framework to assess their scalability and feasibility. Integrating process modeling, first-principles analysis, and literature review, we will create an open-access simulation tool for evaluating system-level and reaction-level performance metrics. The resulting simulation tool, peer-reviewed analysis, and stakeholder-informed perspective will provide actionable insights to guide AMR bioreactor research.

Ask the Scientists

Motivating Factor

Novel technology for methane removal at 1-100 MtCH4 scale is needed, particularly for oxidizing atmospheric concentrations (AMR, 2 ppm) (NASEM, 2024, Abernethy, 2024). One proposed strategy is the use of bioreactors, engineered systems which host methanotrophs or cell-free enzymes and actively contact them with air. In principle, bioreactors are more promising than thermal or photo-catalytic reactors, which are anticipated to have prohibitively high energy requirements (Abernethy et al., 2023). Recent discoveries of atmospheric concentration methane oxidation by methanotrophs (Tveit et al., 2019; Schmider et al., 2024) and methane monooxygenase enzymes (Tucci and Rosenzweig, 2024) confirm biological feasibility, yet non-biological system aspects are largely unexplored and anticipated to present significant challenges (e.g., air handling energy). This uncertainty limits the MR community’s ability to judge whether bioreactors should be earnestly pursued as a MR strategy.

Specific Bottleneck

Progress on atmospheric methane removal (AMR) bioreactor development is bottlenecked by uncertainty around the theoretical feasibility of climate-beneficial and cost-effective performance at scale. While bioreactors are currently used for point-source emissions at higher concentration (La et al., 2018), operating at 2 ppm presents significant challenges in biology, air contactor design, and process engineering (Yoon et al., 2009; Lidstrom, 2023),. Thus, the highest research priority is prospective life-cycle and techno-economic analyses that can both assess scalability and create a plausible vision of AMR bioreactor deployment to motivate development (Reginato, 2025). Such analyses will elucidate synergies and trade-offs between biological performance and system design across the range of potential process designs (cell-based versus cell-free, air contactor configurations, passive versus active), thus orienting research efforts to key constraints and high leverage activities.

Actionable Goals

An open-access techno-economic framework should be developed to further assess the scalability of proposed AMR bioreactor concepts. Such a framework could be built around a generalized model of surface-based methane oxidation. Considering the reaction mechanism and system-level operation as interacting but separate sub-models provides flexibility for accessing a range of process designs as well as methane oxidation mechanisms. This framework will achieve three action-inducing goals:

1. Allow the comparison of, e.g., a methanotroph defined by whole-cell specific affinity, a cell-free system, and a thermal catalyst by defining generalized performance metrics for the reaction mechanism.

2. Identify optimal component design, e.g., air contactor geometry, and upper bounds of performance with analogous system-level performance metrics.

3. Indicate targets to guide future research by quantitatively linking the above metrics to the cost, net climate impact, and resource use of a scaled system.