Wood- feeding insects are significant terrestrial sources of methane(1) (CH₄), but also host specialized methanotrophic bacteria capable of oxidizing the potent greenhouse gas(2–4), utilizing enzymes like CH₄ monooxygenases (MMOs)(5). Previous research has mainly focused on termites, known for their large colonies and substantial CH₄ production. The accumulated gas escapes the nest through tunnels and chimneys as it is oxidized by Type Ib or USCγ methanotrophs(6). This diversity of methanotrophs reflects the steep gradients of CH₄ within these tunnels, including pockets with atmospheric concentrations (~2 ppm)(5). However, the methanotrophic dynamics in smaller colonies of insects like wood-feeding beetles and cockroaches have been overlooked. These environments are likely to harbor high-affinity methanotrophs adept at oxidizing lower CH₄ concentrations, and represent an untapped resource with potential for scalable applications, aligned with Spark's criteria for viable climate solutions.

Our project explores how methanotrophic consortia in insect nests respond to and affect CH₄ dynamics, from high-concentration areas to normal atmospheric conditions. Insects forming small colonies will be our focus, in order to uncover more high-affinity methanotrophs for atmospheric methane oxidation applications. Key goals are to enrich methanotrophic consortia from the walls of nest tunnels using CH₄/oxidizer gradients(7), compare their ability to oxidize CH₄ at atmospheric levels, and identify bacteria and enzymes with biotech potential.

Key variables impacting outcomes include the accurate simulation of environmental conditions of tunnels using CH₄/O₂ countergradients, the depth of (meta)genomic and transcriptomic analysis, and the ability to apply findings to atmospheric CH₄ levels.

Success for our project will be gauged by the diversity and adaptability of methanotrophic consortia enriched from the tunnels, and their efficacy in the oxidation of CH₄ in the atmospheric range.

Focusing on wood-feeding insects, particularly those forming small colonies, allows us to tap into a rich, yet underexploited, ecological niche that harbors unique methanotrophic consortia, enhancing our pursuit of safe and natural atmospheric CH₄ removal strategies. By harnessing biological processes already at work in ecosystems, we leverage the specificity of these enzyme-catalyzed reactions to avoid the risks associated with intensive technological methods. This strategy not only promises effective CH₄ oxidation but also, aligns with the pressing need for sustainable, socially responsible climate solutions. Such solutions will be directly enabled by this project’s discovery of novel biological resources that overcome current barriers to scalable, organic CH₄ oxidation.