| 研究課題/領域番号 |
22K12428
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| 研究機関 | 大阪大学 |
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研究代表者 |
Luong Van・Duc 大阪大学, 大学院工学研究科, 特任研究員(常勤) (60815174)
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| 研究分担者 |
井上 大介 大阪大学, 大学院工学研究科, 准教授 (70448091)
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| 研究期間 (年度) |
2022-04-01 – 2025-03-31
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| キーワード | anaerobic digestion / high ammonium / propionate / propionate oxidizers / carbon recovery |
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| 研究実績の概要 |
We have successfully enriched NH4-tolerant propionate-oxidizing bacteria by batch transfers. The enrichment culture can oxidize propionate under 5 gNH4-N/L. Next-generation sequencing showed the dominance of propionate-oxidizing bacteria, including Pelotomaculum and Cryptanaerobacter. In addition, the increase of hydrogenotrophic methanogens Methanoculleus was also observed, indicating the syntrophic relationship between NH4-tolerant propionate-oxidizing bacteria and hydrogenotrophic methanogens.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
Because the activity of NH4-tolerant propionate-oxidizing bacteria is unstable after several transfers. Therefore, the enrichment period is extended more than expected to optimize the enrichment culture and increase biomass. The extended period is necessary to maintain the activity of propionate-oxidizing bacteria before proceeding to the following steps.
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| 今後の研究の推進方策 |
Higher concentrations of propionate and NH4+ will be introduced to test the tolerance of the enriched culture. Next, different combinations of propionate-oxidizing bacteria and archaea will be considered for stable and effective production of CH4 under high NH4+ concentrations.
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| 次年度使用額が生じた理由 |
Because the activity of propionate-oxidizing bacteria is unstable after several transfers. In addition, the enriched amount of biomass is inadequate for testing the tolerance of the enriched culture to high propionate and NH4+. Therefore, the enrichment period is extended longer than those in the expected plan to optimize the enrichment culture and accumulate biomass amount of propionate-oxidizing bacteria. For optimizing the enrichment culture, periodical observation of CH4 production is required in addition to optimizing the culture conditions. Therefore, the remaining amount of the fund in the first year (2022) will be transferred to the second fiscal year (2023) for purchasing Helium gas which is necessary for the periodical measurement of CH4 production. In addition, the transferred fund will be used for testing the tolerance of the enriched culture to higher propionate and NH4+ which could not be performed in the first fiscal year (2022).
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