Japan Geoscience Union Meeting 2014

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[U-05_30PM2] Interrelation between Life, Water, Mineral, and Atmosphere

Wed. Apr 30, 2014 4:15 PM - 5:45 PM 419 (4F)

Convener:*Tsubasa Otake(Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University), Yohey Suzuki(Graduate School of Science, The University of Tokyo), Fumito Shiraishi(Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University), Ken Takai(Extremobiosphere Research Center, Japan Agency for Marine-Earth Science & Technology), Yuichiro Ueno(Department of Earth and Planetary Sciences, Tokyo Institute of Technology), Takeshi Naganuma(Graduate School of Biosphere Science), Takeshi Kakegawa(Graduate School of Science, Tohoku University), Tadashi Yokoyama(Department of Earth and Space Science, Graduate School of Science, Osaka University), Kentaro Nakamura(Precambrian Ecosystem Laboratory (PEL), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)), Chair:Yohey Suzuki(Graduate School of Science, The University of Tokyo), Takeshi Naganuma(Graduate School of Biosphere Science)

4:15 PM - 4:45 PM

★ [U05-17] Microbial methanogenesis in coal seams and diatomaceous formations: Topics and application prospects

*Satoru SHIMIZU1 (1.Horonobe Research Institute for the Subsurface Environment)

Keywords:Methane, Coal, diatomaceous rock, subsurface microorganisms, methanogenesis, Geo-bioreactor

1. Introduction Microbial methanogenesis occurs in diverse subsurface environments. For example, biogenic methane has been detected from all representative ecosystems of the world and has been reviewed1). However, the process of methanogenesis in those subsurface environments has yet to be revealed. Understanding the methanogenesis process is necessary for discerning the global-scale carbon-cycle and for a more effective utilization of biological methane as an energy resource from subsurface environments. 2. Methanogenic archaea from coal-beds and diatomaceous rockResearch topics on biogenic methanogenesis in the Ishikari (bituminous coal)2) and Tenpoku (brown coal) basin and the diatomaceous formations3, 4, 5) of northernmost Japan will be introduced in this presentation. We were successful in isolating and culturing methanogens from these habitats. In particular, the dominant methanogens isolated from diatomaceous shale formation4, 5) will help in understanding some of the processes of methanogenesis in subsurface environments.3. Biological methanogenic potential of coal-beds and diatomaceous rock formations as geobioreactorsThe bottleneck of methanogenesis in subsurface environments is the production of suitable substrates for methanogens from persistent geomacromolecules. One of our approaches for eliminating the bottleneck is a geobioreactor for methanogenesis using hydrogen peroxide. Oxidation of low-rank coal using hydrogen peroxide produces a high yield of small-molecule substrates for methanogenic microorganisms (e.g., methanol, acetate, formate)6). Substrate production from diatomaceous rock is considerably less than that from low-rank coal. However, the stratum thickness of diatomaceous rock (1 km or more) is much more than that of coal seams (several meters). Therefore, although the methanogenic potential of diatomaceous rock is low, by quantity, it constitutes an abundant resource. Furthermore, we have had success in microbial methanogenesis from small molecules produced from brown coal using hydrogen peroxide. References)1) Strapoc et al. (2011) Annu. Rev. Earth Planet Sci. 39, 617-656.2) Shimizu et al. (2007) Geobiology 5, 423-433.3) Shimizu et al. (2006) Geobiology 4, 203-213.4) Shimizu et al. (2011) Int. J. Syst. Evol. Microbiol. 61, 2503-2507.5) Shimizu et al. (2013) Int. J. Syst. Evol. Microbiol. 63, 4320-4323.6) Miura et al. (1996) Energy & Fuels 10, 1196-1201.