Publications by Colleges and Departments (MSU - Bozeman)
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Item High Selectivity Reactive Carbon Dioxide Capture over Zeolite Dual-Functional Materials(American Chemical Society, 2024-05) Crawford, James M.; Rasmussen, Matthew J.; McNeary, W. Wilson; Halingstad, Sawyer; Hayden, Steven C.; Dutta, Nikita S.; Pang, Simon H.; Yung, Matthew M.Reactive carbon dioxide capture (RCC) is a process where carbon dioxide (CO2) is captured from a mixed gas stream (such as air) and converted to products without first performing a separation step to concentrate the CO2. In this work, zeolite dual-functional materials (ZFMs) are introduced and evaluated for simulated RCC. The studied ZFMs feature high surface area, crystalline, microporous zeolite faujasite (FAU) as the support. Sodium oxide (“Na2O”) is impregnated as an effective capture agent capable of scavenging low concentration CO2 (1,000 ppm). Exchanged and impregnated sodium on FAU chemisorbs CO2 as carbonates and bicarbonates but does not promote the conversion of sorbed CO2 to products when heated in hydrogen. The addition of Ru promotes the formation of formates, while the addition of Pt generates carbonyl surface species when heated in hydrogen. The active metal then promotes extremely high selectivity for CO2 hydrogenation to either methane on Ru catalyst (∼150 °C) or carbon monoxide on Pt catalyst (∼200 °C) when heated in reducing atmospheres.Item Oxic methane production from methylphosphonate in a large oligotrophic lake: limitation by substrate and organic carbon supply(American Society for Microbiology, 2023-11) Peoples, Logan M.; Dore, John E.; Bilbrey, Evan M.; Vick-Majors, Trista J.; Ranieri, John R.; Evans, Kate A.; Ross, Abigail M.; Devlin, Shawn P.; Church, Matthew J.While methane is typically produced under anoxic conditions, methane supersaturation in the presence of oxygen has been observed in both marine and fresh waters. The biological cleavage of methylphosphonate (MPn), which releases both phosphate and methane, is one pathway that may contribute to this paradox. Here, we explore the genomic and functional potential for oxic methane production (OMP) via MPn in Flathead Lake, a large oligotrophic freshwater lake in northwest Montana. Time series and depth profile measurements show that epilimnetic methane was persistently supersaturated despite high oxygen levels, suggesting a possible in situ oxic source. Metagenomic sequencing indicated that 10% of microorganisms in the lake, many of which are related to the Burkholderiales (Betaproteobacteria) and Actinomycetota, have the genomic capacity to cleave MPn. We experimentally demonstrated that these organisms produce methane stoichiometrically with MPn consumption across multiple years. However, methane was only produced at appreciable rates in the presence of MPn when a labile organic carbon source was added, suggesting that this process may be limited by both MPn and labile carbon supply. Members of the genera Acidovorax , Rhodoferax , and Allorhizobium , organisms which make up less than 1% of Flathead Lake communities, consistently responded to MPn addition. We demonstrate that the genomic and physiological potential for MPn use exists among diverse, resident members of Flathead Lake and could contribute to OMP in freshwater lakes when substrates are available. IMPORTANCE Methane is an important greenhouse gas that is typically produced under anoxic conditions. We show that methane is supersaturated in a large oligotrophic lake despite the presence of oxygen. Metagenomic sequencing indicates that diverse, widespread microorganisms may contribute to the oxic production of methane through the cleavage of methylphosphonate. We experimentally demonstrate that these organisms, especially members of the genus Acidovorax , can produce methane through this process. However, appreciable rates of methane production only occurred when both methylphosphonate and labile sources of carbon were added, indicating that this process may be limited to specific niches and may not be completely responsible for methane concentrations in Flathead Lake. This work adds to our understanding of methane dynamics by describing the organisms and the rates at which they can produce methane through an oxic pathway in a representative oligotrophic lake.Item Algal amendment enhances biogenic methane production from coals of different thermal maturity(Frontiers Media SA, 2023-03) Platt, George A.; Davis, Katherine J.; Schweitzer, Hannah D.; Smith, Heidi J.; Fields, Matthew W.; Barnhart, Elliott P.; Gerlach, RobinThe addition of small amounts of algal biomass to stimulate methane production in coal seams is a promising low carbon renewable coalbed methane enhancement technique. However, little is known about how the addition of algal biomass amendment affects methane production from coals of different thermal maturity. Here, we show that biogenic methane can be produced from five coals ranging in rank from lignite to low-volatile bituminous using a coal-derived microbial consortium in batch microcosms with and without algal amendment. The addition of 0.1 g/l algal biomass resulted in maximum methane production rates up to 37 days earlier and decreased the time required to reach maximum methane production by 17–19 days when compared to unamended, analogous microcosms. Cumulative methane production and methane production rate were generally highest in low rank, subbituminous coals, but no clear association between increasing vitrinite reflectance and decreasing methane production could be determined. Microbial community analysis revealed that archaeal populations were correlated with methane production rate (p = 0.01), vitrinite reflectance (p = 0.03), percent volatile matter (p = 0.03), and fixed carbon (p = 0.02), all of which are related to coal rank and composition. Sequences indicative of the acetoclastic methanogenic genus Methanosaeta dominated low rank coal microcosms. Amended treatments that had increased methane production relative to unamended analogs had high relative abundances of the hydrogenotrophic methanogenic genus Methanobacterium and the bacterial family Pseudomonadaceae. These results suggest that algal amendment may shift coal-derived microbial communities towards coal-degrading bacteria and CO2-reducing methanogens. These results have broad implications for understanding subsurface carbon cycling in coal beds and the adoption of low carbon renewable microbially enhanced coalbed methane techniques across a diverse range of coal geology.