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195368 https://hdl.handle.net/2286/R.2.N.195368 http://rightsstatements.org/vocab/InC/1.0/ All Rights Reserved 2024 114 pages Masters Thesis Academic theses Text eng Furedy, Julia Cadillo-Quiroz, Hinsby Rittmann, Bruce Xu, Jie Arizona State University Partial requirement for: M.S., Arizona State University, 2024 Field of study: Microbiology Methanotrophic bacteria play an important role in reducing methane emissions by consuming methane as their primary energy and carbon source. Thus, it is important to define the identity, diversity, and distribution of methanotrophic bacteria to understand their contributions to methane removal.To investigate methanotrophs from three geochemically distinct tropical peatlands of the Amazon, several treatments were applied to enrich methanotrophs. These enrichments varied in their pH, type of media used, single-carbon substrate(s) added, and the presence or absence of organic nitrogen. Conditions were selected based on the gradient of pH and nutrient concentrations characteristic of the three peatland sites of interest and combined to maximize the variety of culturable methanotrophs. Methanotrophic enrichments were then selected for isolation efforts, establishing various lineages that were purified and then identified by their DNA sequence. This study evaluated whether methanotrophs from geochemically distinct peatlands would prefer distinct culturing conditions under the hypothesis that various methanotrophs will grow best in conditions that mimic the selective pressure(s) of the environment that they arose from. The results show (a) the presence of multiple culturable species of methanotrophic bacteria, including strains of the species Methylosinus sporium, Methylocystis parvus, Methylocapsa acidiphila, Methylocystis hirsute, and Methyloferula stellata, as well as representatives of a potential novel species related to Methylocapsa acidiphila strain B2, (b) observable methanotrophic activity within enrichments from which no responsible organisms were isolated indicates unculturable methanotrophs from Amazon peats exist within the peat communities, and (c) the type of media and carbon sources used for enrichment and isolation of methanotrophs did not have a significant effect on the identity of methanotrophs isolated by traditional methods. Overall, the results show that Amazon peatlands contain a significant presence of culturable and yet-to-be-cultured methanotrophs. In addition to the progress achieved here, further variation in enriching and isolating strategies is still needed. Ecology Amazon Methanotrophic bacteria Microbial diversity Peatland Assessing the Culturable Diversity of Methanotrophic Bacteria from Amazon Peatlands Through Standard Isolation Methods