Pilot Proposal: Connecting methane oxidation rates to mineral sources of copper

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The proposed research will investigate linkages between mineral dissolution rates, concentrations of copper in minerals, and methane oxidation rates by methanotrophic microorganisms (e.g. bacteria that derive energy from the greenhouse gas methane). Previous research by the PIs has identified and characterized an extracellular copper-binding molecule, methanobactin, that has been shown in laboratory studies to influence mineral dissolution rates and the activity of methane oxidizing enzymes. These findings, suggest a compelling link between the availability of copper in soils, sediments, and water, and the biogenic regulation of the atmospheric concentrations of methane.This research will include controlled abiotic and biotic laboratory experiments using mineral phases (with differing concentrations of copper in their structure) a model methanotroph Methylosinus trichosporium OB3b (type II), and the copper-binding molecule methanobactin to investigate mechanisms and extent of mineral dissolution, and methane oxidation rates. Our specific research objectives for this pilot proposal are to determine how the presence of specific copper bearing mineral phases and methanobactin influences methanotroph growth and methane oxidation rates and if methanotrophic activity influences mineral dissolution rates.The broader impacts of this study will stem from a holistic understanding of biological and geological feedbacks controlling methane oxidation and in turn a major facet of the global carbon cycle. As part of our educational component of this pilot proposal the PIs will involve undergraduate students in a hands-on experiment related to the proposed research. Students will learn how to isolate and purify methanobactin, how to grow methanotrophs in continuous culture, and they will conduct their own incubation experiments. This study will elucidate controls on oxidation rates of methane a potent greenhouse gas and link methanotrophic activity to mineralogical controls in the environment.