| Summary: | 碩士 === 國立成功大學 === 生物學系 === 87 === The nitrogen cycle sustained by microorganisms includes nitrification and denitrification. Nitrification is the oxidation of ammonia via nitrite to nitrate. Biological denitrification is the bacterial respiratory reduction of nitrate and nitrite to the gaseous end products nitrous oxide and dinitrogen. This reductive process is of environmental interest because a number of N-containing pollutants can be degraded under denitrifying conditions. In this study, we monitored the population of denitrifiers during several operation stages in biological denitrifying reactor.
There were 56 strains isolated from biological denitrifying reactor treated with ABS wastewater. 27 strains were able to denitrify with different carbon sources. Isolates from methanol as carbon source for denitrification had the broadest capability of utilizing six different carbon sources. However, most isolates from format、acetate、propionate and acrylic acid could not use methanol and methylamine as carbon sources for denitrification. The acetate-utilizing denitrifier was the dominant population in denitrifying bioreactor. The number of acetate-utilizing denitrifires was as high as 1014 MPN/g. The number of acryllic acid utilizing denitrifier was less than those of acetate-utilizing denitrifiers. The population of acrilamine-utilizing denitrifier is smaller then acrilonitrile-utilizing denitrifiers.
Nitrite reduction is the key point of biological denitrifying process. There are two different types of nitrite reductase in denitrifiers:heme-c,d1 containing nitrite reductase and copper-containing nitrite reductase. Specific primer sets were used to amplify the cd1 type nitrite reductase gene and Cu type nitrite reductase gene by polymerase chain reaction. Specific primers nirS1F-nirS6R could amplify the cd1 type nitrite reductase gene from 17 of 23 denitrifying isolates. The PCR product of Alcaligene eutrophus was used as probe to detect 7 isolates by southern blotting, 6 of them were recognized as cd1 type nitrite reductase containing denitrifiers. The population changes of nitrifiers and denitrifiers in biological denitrifying reactor were discussed in this study.
Key word: Denitrifiers、Nitrite reductase 、PCR 、primer
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