| Budget Amount *help |
¥3,710,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥210,000)
Fiscal Year 2007: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2006: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Research Abstract |
The anaerobic digestion system has become to be used for treating a wide range of organic wastes, wastewater, and aerobically digested sewage sludge, because of many advantages over more conventional aerobic processes, including low levels of excess sludge production, low space requirements and production of biogas. However, the digestion rate by this system is extremely low, especially in the reactions by methanogens. Meanwhile, eugenic methanogens that grow more rapidly compared to ones inhabiting usual anaerobic sludge have been found in extremobiospheres such as a deep-sea hydrothermal vent chimney.
Therefore, implanting such eugenic species to the ordinal anaerobic digestion system may improve the digestion and methane production processes. The present study was aimed at obtaining information about possible application of eugenic methanogens by performing co-cultures of different species of methanogens. Methanothermus fervidus and Methanothermocuccus okina wensis, which were isolated from Icelandic volcanic spring and mud holes and from deep-sea hydrothermal vent chimney, respectively, were used as model methanogens. A method used for quantifying each methanogen in a mixed system is real-time PCR. We designed a new DNA probe (primer), which could specifically anneal to 16S rDNA of M, okinawensis. M. fervidus was quantified by subtracting the amount of DNA of M. okinawensis, which was determined by the real-time PCR with the newly designed primer, from total amount of methanogen DNAs. The co-cultures of M. fervidus and M. okinawensis were carried out under various anaerobic conditions. As a result, we found a possibility that one species of methanogen that exists in minute quantities at the beginning of culture can predominantly grow and far surpass the other one by properly controlling cultural parameters (salt concentration and temperature).
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