2022 Fiscal Year Research-status Report
Development of a novel co-culture model of NH4-tolerant propionate-oxidizing bacteria and methane-producing archaea for the recovery of CH4 under high NH4+
| Project/Area Number |
22K12428
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| Research Institution | Osaka University |
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Principal Investigator |
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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| Co-Investigator(Kenkyū-buntansha) |
井上 大介 大阪大学, 大学院工学研究科, 准教授 (70448091)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Keywords | anaerobic digestion / high ammonium / propionate / propionate oxidizers / carbon recovery |
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| Outline of Annual Research Achievements |
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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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
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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| Strategy for Future Research Activity |
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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| Causes of Carryover |
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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[Journal Article] Aggregation and Dispersion Behaviours of Riverine Trace Metals (Fe, Al, V, Mn, Ni, and Zn) and Organic Matter in Freshwater and Estuarine Conditions: A case study in Shira and Midori Rivers, Kumamoto, Japan2023
Author(s)
Hiroaki Ito, Shinya Tsurumaki, Takehide Hama, Kei Ishida, Tsugihiro Watanabe, Luong van Duc, Yasunori Kawagoshi
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Journal Title
Aquatic Geochemistry
Volume: 29
Pages: 1-23
DOI
Peer Reviewed / Int'l Joint Research
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