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Super-cutting-edge Grand and Advanced Research (SUGAR) Program



Establishing a new record for organism's maximum proliferation temperature and discovering unusually heavy isotopic methane compositions

We succeeded in breaking the record of upper temperature limits of life and biosphere by isolating a hyperthermophilic methanogen from Kairei Field, in Indian Ocean. This achievement enabled us to know more about the possibilities and conditions of life in the universe. SUGAR (Subsurface Geobiology and Advanced Research Program) and Precambrian Ecosystem Laboratory at JAMSTEC have developed a high temperature & pressure cultivation method (Takai method), and verified cell proliferation at 122‹C. Another evolutionary achievement was to find out methane composition made in the deep-sea condition by microorganisms are actually isotopically heavy, rather than the commonly known fact in Earth Science that often said the opposite. These achievements will surely lead us to further search for origin of methane on Earth and Mars.

Takai, K., Nakamura, K., Toki, T., Tsunogai, U., Miyazaki, M., Miyazaki, J., Hirayama, H., Nakagawa, S., Nunoura, T., & Horikoshi, K. (2008) Cell proliferation at 122°C and isotopically heavy CH4 production by a hyperthermophilic methanogen under high-pressure cultivation. Proc. Natl. Acad. Sci. USA, 105:10949-10954.

Electron microscopic photograph of strain 116@of Methanopyrus kandleri.

History of fifty years record on upper temperature limit of life (Left). Classification scheme of carbon isotope ratio for methane in natural environment, on organic geochemistryfs textbook (Right). We used to believe that all organisms on Earth can be gkilledh at 121‹C, however, this organism proved that our belief was wrong (Left). The conventional statement, gMethane made by microorganisms is isotopically lighth also begged us to think once more and prove it again (Right).