Geochemical Journal, Vol. 50 (No. 6), pp. 453-460, 2016
Masanori Kaneko,1* Yoshinori Takano,2 Nanako O. Ogawa,2 Yuki Sato,3 Naohiro Yoshida3 and Naohiko Ohkouchi2
1National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8567, Japan
2Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
3Department of Environmental Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
(Received April 10, 2015; Accepted December 2, 2015)
Coenzyme F430 is the hydrocorphinoid nickel complex which acts as active site in methyl-coenzyme M reductase (MCR). The MCR-F430 complex catalyzes the last step of methanogenesis: reduction of methyl-coenzyme M to methane. Since F430 is a common enzyme for mathanogens, it can be a function-specific biomarker to estimate biomass and activities of methanogens in environmental samples. A recently developed high sensitive method for coenzyme F430 analysis and a further purification step revealed F430 concentrations at 69 and 88 meters below seafloor (mbsf) off Shimokita Peninsula (529 and 31.3 fmol g-wet–1) and at 60 and 275 mbsf at Nankai Trough (31.4 and 26 fmol g-wet–1). Estimated methanogenic biomass and activities based on reported F430 content and activities in methanogens and prokaryotic cell weight, were ranging from 3.9 × 106 to 2.7 × 106 cells g-wet–1 and from 1.7 to 11 μmol d-1 g-wet–1.
Key words: coenzyme F430, methane hydrate, methanogens, function-specific compound analysis, marine sediment