1999 Fiscal Year Final Research Report Summary
Influence of NiィイD12+ィエD1 and CoィイD12+ィエD1 on activity of microorganisms related to methanogenesis
| Project/Area Number |
10680549
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
環境保全
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| Research Institution | Kumamoto University |
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Principal Investigator |
KIDA Kenji Kumamoto University, Faculty of Engineering, Professor, 工学部, 教授 (00195306)
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| Co-Investigator(Kenkyū-buntansha) |
SHIGEMATSU Toru Kumamoto University, Faculty of Engineering, Assistant Professor, 工学部, 助手 (10315286)
MORIMURA Shigeru Kumamoto University, Faculty of Engineering, Associate Professor, 大学院・自然科学研究科, 講師 (20230146)
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| Project Period (FY) |
1998 – 1999
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| Keywords | methane fermentation / aceticlastic methanogen / coenzyme / FィイD2420ィエD2 / corrinoid / FィイD2430ィエD2 / methanogenic pathway |
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| Research Abstract |
The influence of NiィイD12+ィエD1 and CoィイD12+ィエD1 on methanogenic activity and the coenzymes involved in methanogenesis were investigated in an anaerobic continuous cultivation with synthetic wastewater containing acetate as the sole carbon source. Addition of NiィイD12+ィエD1 and CoィイD12+ィエD1 to the synthetic wastewater increased the concentrations of coenzymes corrinoids and FィイD2430ィエD2 in biomass. Their concentrations were approximately constant, being 0.55-0.62 and 0.56-0.67 nmol/g-VSS at a dilution rate of more than 0.12 dィイD1-1ィエD1. Methanogenic activity of biomass also increased with an increase in dilution rate. However, without addition of NiィイD12+ィエD1 and CoィイD12+ィエD1, corrinoids and FィイD2430ィエD2 were not detected in biomass and the methanogenic activity was zero at a dilution rate of 0.025 dィイD1-1ィエD1. These results suggest that NiィイD12+ィエD1 and CoィイD12+ィエD1 accelerated the methane-producing reactions via increases of coenzymes coninoids and FィイD2430ィエD2.
The effects of NiィイD12+ィエD
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1 and CoィイD12+ィエD1 limitation on methanogenesis from acetate were investigated using a mesophilic anaerobic continuous cultivation. A significant inhibition in methanogenic activity and degradation rate of acetate in response to a decrease in coenzymes corrinoids and FィイD2430ィエD2 contents in biomass was observed with a decrease of metal ion concentrations added. An increase of coenzyme FィイD2420ィエD2 and improvement in the degradation rate of acetate was observed with a decrease in dilution rate under metal ion limitation. These results suggest that an alternative pathway from acetate to methane via syntrophic conversion by acetate oxidizing bacteria and hydrogenophilic methanogens occupied a considerable portion of the whole bioconversion at a low dilution rate under metal ion limitation. The populations of aceticlastic and hydrogenophilic methanogens estimated by the most probable number (MPN) method also supported this suggestion.
A mesophilic anaerobic continuous cultivation with synthetic wastewater containing propionate and acetate (3 : 1 in molar ratio) was constructed. This cultivation is under stable conditions. We are now trying to investigate the mechanisms of anaerobic degradation of propionate. Less
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