Cultural and Molecular Studies of Methanogens in Paleocene Fort Union Formation Coal from the Powder River Basin of Wyoming and Montana

Donald A. Klein¹, Romeo M. Flores², Stacey McKinney³, Luciana P. Pereyra³, and Amy Pruden-Bagchi³. (1) Colorado State University, Fort Collins, CO 80523-1682, phone: 9704916947, fax: 9704911815, [email protected], (2) USGS, CO, (3) Colorado State University

The stimulation and replenishment of coalbed methane (CBM) in low-rank coals is of increasing interest in relation to managing this globally abundant and increasingly economically important unconventional energy resource. A critical first step in developing this technology is to document the presence and potential for methanogen development within the coal. Based on nested polymerase chain reaction (PCR) protocols, molecular analyses of coalbed materials have indicated that putative deep-rooted methanogen (PDRM) sequences are present in the Paleocene age Fort Union Formations coal from the Powder River Basin (PRB) in Wyoming and Montana. In this study, coal samples from beds in the Wyodak-Anderson coal zone have been incubated in specially designed polyethylene gas diffusion units, equilibrated in an anaerobic environment that should provide hydrogen and carbon dioxide at methanogen-permissive concentrations and flux rates. The samples used in the cultural analyses were recovered from freshly-exposed drill core faces using a flame-sterilized minidrill and aseptic sample trapping system. Diffusion sample units were assembled in 2-mil polypropylene using heat-sealed inner and outer packets containing the desired sample and filter-sterilized methanogen basal salts medium under controlled conditions. For analysis of responses after extended incubations (2-3 months), cultural expression of methanogens from these materials is being evaluated, together with quantitative and qualitative molecular signal responses. Understanding how methanogens function in Wyodak-Anderson coal beds, which produced 72 percent of the total CBM production from PRB as of the end of 2004, will be critical in terms of assuring the recyclability leading to longer-term productivity of this important resource.