MINERAL EFFECTS ON HEADSPACE CO2-TO-CH4 CONVERSION RATIOS BY ARCHAELLATED AND NON-ARCHAELLATED METHANOGENS

Although the mechanisms are not completely understood, the need for both archaella and pili for attachment of Methanoccocus maripaludis to mineral surfaces has been well established. In addition, the uses for these pili and/or archaella are still not completely understood, but it has been proposed that they could function to preferentially attach to conductive surfaces allowing for electron shuttling. In reactors containing minerals of varying mineral electrical conductivity -pyrite >galena >kaolinite >quartz>limestone- wildtype M. maripaludis (Mm900) and non-archaellated mutant (∆flaB2) were examined in H₂-rich and H₂-limited environments to determine trends in early-stage methanogenesis. Building on these trends, a kinetic model of these early-stage trend was created based on the fitted parameters (c, k, and t_1/2).