• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.323-326
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• 2002

To detect whole ammonia-oxidizing bacteria in the activated sludge, group-specific primers targeting the 16S-rRNA gene of ammonia-oxidizing bacteria were used. The electrophoresis pattern of the PCR products seemed to produce a single band of approximately 1.0 k bp for the bacteria in activated sludge and Nitrosomonas europaea. No band was observed for nitrite-oxidizer Nitrobacter winogradskyi and heterotrophs such as Pseudomonas putida. Then direct measurement of the PCR product was made by fluorometry using the reagent Hoechist 33258, so that the fluorescent intensity was in proportional to the cell number of the sample up to 240. Total time required for the test was about 4 h including DNA extraction. The DNA fragments produced were cloned and their sequences showed high similarity to those of Nitrosomonas spp. This study showed the feasibility to detect ammonia-oxidizing bacteria and to esti-mate their population rapidly for the control of the nitrogen elimination process.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.146-153
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• 2000

To elucidate succession of bacterial populations, especially nitrifying bacteria during the composting of cattle manure with apple pomace, fluorescent in situ hybridization(FISH) using rRNA targeted oligonucleotide probes were applied. The density of ammonia-oxidizing bacteria was ranged from $3,3{\times}10^6cells/g$ dw to $13,4{\times}10^6cells/g$ dw with the peak value after 26 composting days whereas that of nitrite-oxidizing bacteria varied between $6.0{\times}10^6cells/g$ dw and $17.2{\times}10^6cells/g$ dw with the peak value after 7 composting days. And the tendency that the numbers of nitrite-oxidizing bacteria were higher than those of ammonia-oxidizing bacteria, and the peak-time of their densities were the same as that of data determined by the ratio of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria to eubacteria. The peak of ammonia-oxidizing bacteria followed the peak of nitrite-oxidizing bacteria, at the late phase of composting process could be probably caused by the depletion of volatile ammonia of composting materials. Besides these results indicate that FISH method is a useful tool for detection of slow growing nitrifying bacteria.

• Journal of Korean Society on Water Environment
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• v.24 no.2
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• pp.214-220
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• 2008

Nitrifying bacteria were detected by fluorescent in situ hybridization (FISH) method at 6 sampling sites with different eutrophication degree in the Nak-Dong River and their tributaries. And conventional physico-chemical parameters including $NH_4-N$, $NO_3-N$, and TN were determined concurrently. In rainy period (July), there was no noticeable difference between the number of ammonia/nitrite-oxidizing bacteria detected at each site except Sang-Ju and the ratio of nitrifying bacteria to total counts stained by DAPI varied in 6~33%. By contrast, in the dry period (October), both of bacterial population was increased differently and the ratio of nitrifying bacteria to total counts ranged more widely from 6% in heavily polluted water zone, Hwa-Won to 60% in upper tributary with high agricultural land use. Byung-Sung-Chun. In January, the numbers of ammonia-oxidizing bacteria was reduced up to one tenth, while those of nitrite-oxidizing bacteria was apparently increased maybe due to high DO and low DOC.

• Journal of Korean Society on Water Environment
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• v.31 no.4
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• pp.399-406
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• 2015

A sequencing batch reactor was operated under different pH conditions to see the influence of free ammonia (FA) and free nitrous acid (FNA) to microbial community on ammonium partial nitrification. Long-term influences of FA and FNA were evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis and fluorescence in situ hybridization. Nitrite accumulation was successfully achieved at pH 8.2 and 6.3. The shifts in the microbial community were observed when influent ammonia concentration increased to 1 g $NH_4$-N/L at pH 8.2, and then when pH was dropped to 6.3. Both Nitrosomonas and Nitrosospira were selected during the startup of the reactor, and eventually became dominant members as ammonia-oxidizing bacteria. The results of molecular microbiological analysis strongly suggested that the composition of microbial community was changed according to the method used to control nitrite-oxidizing bacteria.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.33-36
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• 2007

In this study, an antibiosis of antimicrobial mortar developed to reduce biochemical corrosion of sewage facilities concrete was evaluated. First, artificial acceleration test reflecting similarly biochemical corrosion of mortar was developed. Antimicrobial mortar specimen were experimented in this test and antibiosis of it was evaluated by SEM and EDX. As a results of the study, sulfur-oxidizing bacteria on the plain specimen were survived for 20 weeks in this test. But sulfur-oxidizing bacteria on antimicrobial specimen were survived less than the plain, and sulfur-oxidizing bacteria were externally distorted and destroyed. So the antibiosis of an antimicrobial mortar was verified by it.

• Journal of Soil and Groundwater Environment
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• v.21 no.4
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• pp.50-59
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• 2016

Spatial and temporal changes in nitrification activities and distribution of microbial population of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) in paddy soils were investigated. Soil samples were collected in March and October 2015 from rice paddy with and without the presence of confined animal feeding operations. Incubation experiments and quantitative polymerase chain reaction showed that AOA's contribution to nitrification kinetics was much higher in locations where organic nitrogen in animal waste is expected to significantly contribute to overall nitrogen budget, and temporal variations in nitrification kinetics were much smaller for AOA than AOB. These differences were interpreted to indicate that different microbial responses of two microbial populations to the types and concentrations of nitrogen substrates were the main determining factors of nitrification processes in the paddy soils. The copy numbers of ammonium monooxygenase gene showed that AOA colonized the paddy soils in higher numbers than AOB with stable distribution while AOB showed variation especially in March. Although small in numbers, AOB population turned out to exert more influence on nitrification potential than AOA, which was attributed to higher fluctuation in AOB cell numbers and nitrification reaction rate per cells.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.287-287
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• 2000

As a method to control the bacteria number in adequate level, a real time control system based on microscope image processing measurement for the bacteria is adopted. For the experiment, Ammonia-oxidizing bacteria such as Acinetobacter sp. are used. This paper proposed hybrid method combined watershed algorithm with adaptive automatic thresholding method to enhance segmentation efficiency of overlapped image. Experiments was done to show the effectiveness of the proposed method compared to traditional Otsu's method, Otsu's method with adaptive automatic thresholding method and human visual method.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.44-52
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• 2006

Bio-filtration processes using honeycomb tubes (process 1) and aeration and manganese-sand filtration (process 2) were evaluated for the biological manganese removal efficiency. The concentration of manganese at effluent was stabilized after 20days operation in process 1. It was estimated the required time for attaching and growing microorganisms to honeycomb tubes. In long term of operation periods, manganese removal efficiency was dropped for the excessively attached biofilm and manganese dioxide to honeycomb tubes. It took several days for normal operation in process 2, after that manganese removal efficiency was increased to 98% and stabilized for 1.5 years. Microorganisms in process 1 and 2 were isolated and cultured to characterize manganese-oxidizing bacteria. Among the four types of colony, light brown colony was turned blue color by leuco crystal violet spot test. Stenotropomonas genus, known as manganese-oxidizing bacteria, was identified by 16S rDNA partial sequencing analysis which was isolated in process 1 and 2. For the biological treatment to remove manganese, these two considerations are important. One is to choose the proper media attaching manganese oxidant, another one is to define the cultural condition of isolated manganese-oxidizing bacteria.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.282-285
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• 2001

The microbial community structure and in situ spatial distribution of ammonia oxidizing and nitrite oxidizing bacteria in nitrifying biofilm of an upflow biological aerated filter system were investigated. The reactor had been continuously operated under high free ammonia concentration and low DO concentration for nitrite accumulation more than 2 years before the experiment. Fluorescence in situ hybridization

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.9-17
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• 2008

The presence of thiosulfate oxidizing bacteria was examined in rhizosphere soils of 19 economically important plant species belonging to 10 different families. The results showed that the thiosulfate oxidizing bacteria were present in all the tested rhizosphere soils, and the total 32 thiosulfate oxidizing bacteria were recovered. Furthermore, the biochemical characterization revealed that 56% and 44% of the isolates belonged to the obligate chemolithoautotrophs and facultative heterotrophs, respectively. The isolates ATSR15P utilized 19.17 mM of thiosulfate and accumulated 11.65 mM of sulfate in the medium. Concurrently, the decrease in pH of the medium was observed. This study comprehensively demonstrates that the active sulfur oxidation is a ubiquitous phenomenon in the rhizosphere of crop plants in Korea.