1992 Fiscal Year Final Research Report Summary
Study on the interaction between pesticide-degrading and -nondegrading microorganisms upon degradation of the pesticide in soil
| Project/Area Number |
02660060
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
土壌・肥料
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SATO Kyo Institute of Genetic Ecology,Tohoku University, 遺伝生態研究センター, 助教授 (80006006)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Gram-negative Bacteria / Microbial Nutrient / Optimum PCP Concentration / Pentachlorophenol(PCP) / Pesticide-Degradation / Pesticide-Degrading Microorganism / Pesticide-Tolerance / Soil Microorganisms |
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| Research Abstract |
As pesticide-degrading microorganisms in soil decompose not only the pesticide applied but also common nutrients present in soil, degradation of the pesticide is possibly affected by the presence of nutrient. In this work, therefore, degradation of the pesticide, PCP (pentachlorophenol)and the population changes of the PCP-degrading microorganisms in soil were investigated in connection with the decomposition of some kinds of added nutrient and the population change of bacteria which may proliferate utilizing the nutrients. The main results obtained were as follows:
1. The population changes of several bacteraial groups as well as the dissipation of amino acids, glycine and glutamic acid were followed; (1)Total viable bacterial counts increased in all cases even though high PCP concentration(200ppm) delayed the increase a little. Gram-negative bacterial population which was present at low level in the soil increased abruptly and their change went on the same pattern as that of the total
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viable counts. (2) Amino acids decreased in accordance with the increase in the bacterial population. (3) PCP was not degraded during 5 weeks experiment period. These results suggest that PCP did not markedly affect degradation of nutrients by microorganisms in soil.
2. Optimum PCP concentration was followed for the increases in the population of microorganisms degrading, and/or tolerant to, PCP in soil; (1) The higher the PCP concentration, the stronger the PCP-tolerance of bacterial cells. (2) PCP-degrading microorganisms proliferated well only under low concentration(5-10ppm) of PCP. These results mean that the microorganisms degrading, and tolerant to, the pesticide behave differently in soil.
3. Effect of the nutrient addition on degradation of PCP was investigated following dissipation of the nutrients as well as the increase in the population of PCP-degrading microorganisms in soil; (1) PCP degradation was retarded by the addition of amino acids and glucose and started after dessipation of the nutrients. The increase in the population of the degrading microorganisms also delayed. (2) Cellulose did not affect the degradation as well as the increase in the microbial populations. These results indicate that microbial degradation of the pesticide is affected differently depending on the kind of nutrient which coexists with the pesticide. Less
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