| Project/Area Number |
06680529
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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 |
環境保全
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| Research Institution | Yamagata University |
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Principal Investigator |
UEKI Katsuji Faculty of Agriculture, Yamagata University Prof., 農学部, 教授 (10111337)
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| Co-Investigator(Kenkyū-buntansha) |
UEKI Atsuko Faculty of Agriculture, Yamagata University Associate Prof., 農学部, 助教授 (60143088)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1994: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Acidic deposition / Method for measuring sulfate-reducing activity / Removal of sulfate / Sulfate-reducing bacteria / Sulfate reduction / 底泥層別硫酸還元能 / 底泥層別細菌分布 / 硫酸還元細菌 / 淡水環境 / 自己浄化機能 |
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| Research Abstract |
To assess the effect of acidic pollutants precipitated from the atmosphere on environments, estimation of the ability of environments to detoxicate the acidic pollutants is of importance. Major acidic pollutants in the precipitate are sulfuric and nitric acids. Nitric acid is relatively easily detoxicated by biological processes such as the denitrification and nitrate reduction, but sulfuric acid is not so easily metablized. Thus, sulfuric acid is one of the pollutants which should be especially paid attention to. In natural environments, dissimilatory sulfate reduction by sulfate-reducing bacteria is the main reaction removing sulfate. Determination of sulfate-reducing ability of the environment is of importance to estimate the ability of the environment to detoxicate acidic pollutants. Purposes of the present study are to establish a convenient method to measure the sulfate-reducing activity by following a decrease of sulfate concentration by HPLC analysis. Results in the present study are as follows.
1. An assay mixture containing sulfate, lactate and other carboxylates as electron donors, cysteine as a reducing reagent, resazurin as a redox-indicator, and MOPS buffer (pH7.0) was used for measuring the sulfate-reducing activity of samples. Sulfate reduction proceeded at a constant rate for at least 12 hours during the anaerobic incubation of samples with the assay mixture, and the sulfate-reducing activity could be reproduciblly estimated. The activity measured by incubation at 10 or 20ﾟC was about 10 or 30% of that at 30ﾟC.
2. In sulfate-reducing bacteria including type strains of Desulfovibrio desulfuricans and Desulfovibrio vulgaris, the sulfate-reducing activity per cellular protein (moles/h/mg protein) displayd strain-specific values.
3. The sulfate-reducing activity of sediments sampled from a freshwater lake was in the range of 3-26 mumol/h/1000cm^3. The ability of the lake to reduce sulfate was estimated to reach 46.7 mmol/day/m^2 in summer.
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