• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.257-264
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• 2017

Mixed substrate oil cakes are known to emit sulfides, ammonia, and amines. Microorganisms capable of removing odorous gases related to these sulfur compounds were isolated from colonies enriched in vials containing oil cakes and water. Activity tests for hydrogen sulfide and methyl mercaptan reduction were performed to measure the sulfide reduction ratio of the isolates. Control groups were prepared with 0.25 g oil cakes and 10 ml water in a 100-ml vial without inoculation. The experimental groups were prepared similarly, albeit with an inoculum. Hydrogen sulfide removal efficiency of >90% was observed for an isolate, which was identified as Brevundimonas diminuta by 16S rDNA sequence analysis. The sequence was deposited in the Korean Collection for Type Cultures under the accession number KCTC11724BP. B. diminuta could remove up to 200 ppmv standard hydrogen sulfide in 24 hours and demonstrated a maximum hydrogen sulfide and methyl mercaptan removal efficiency of 100% at 453 ppmv and 98 ppmv, respectively, in vial tests. Furthermore, B. diminuta cells in 20% (v/w) medium showed removal efficiency of >85% for sulfur compounds in an odor emission chamber for swine manure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.4
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• pp.431-437
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• 1996

The efforts of removing the specific fresh water fishy odor were studied by inducing tilapia, Oreochromis niloticus, to sea water in the use of the flavoring chemicals such as pyrrolidine and piperidine as experimental flavors. The amines added to the grinded muscle of tilapia were recovered by $88\%$ for pyrrolidine and $90\%$ for piperidine. When live tilapia were retained in a tank containing 100 ppm solution of the flavor for 30 min and then begun to start the acclimation into sea water with daily increase of $5\%_{\circ}$ salinity within 7days, no amines in the skin and the muscle of tilapia were detected after 4 days of acclimation to sea water. For the purge effects of amino in the skin and the muscle of tilapia, the concentration of pyrrolidine and piperidine lost $73.4\%,\;83.7\%$ in the muscle and $93.6\%,\;90.6\%$ in the skin of tilapia after purging in fresh water for 72 hrs, while $66.2\%,\;73.6\%$ of amines were removed in the muscle and $90.1\%,\;87.7\%$ in the skin of tilapia acclimated to sea water after purging in on sea water for 72hr. Loss rates of pyrrolidine and piperidine were found to be $0.0231h-^{1}\;and\;0.0333\;h^{-1}$ from the muscle and $0.0652h-^{1}\;0.0413\;h^{-1}$from the skin of tilapia in the fresh water, while $0.0131h-^{1}\;and\;0.0354\;h^{-1}$ from the muscle, $0.0674h-^{1}\;and\;0.0549\;h^{-1}$ from the skin of tilapia in the sea water after 24hrs of exposure, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.743-750
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• 2008

In water treatment plant the Dissolved Ozone Flotation(DOF) System may be employed because this system has various abilities, such that it can remove SS using microbubbles, and it can exert strong oxidation power in removing taste and odor, color, and microbial agents. In order to investigate effectiveness of the DOF system in water treatment, removal characteristics of various water quality parameters were observed depending on the different levels of ozone concentrations. Removal efficiencies of water quality parameters in DOF system were compared with those in DAF(Dissolved Air Flotation) system and in CGS(Conventional Gravity Settling) system. Optimum ozone dose obtained in the pilot experiments was 2.7 mg/L. With increasing ozone dose higher than 2.7 mg/L, removal rates of turbidity, KMnO$_4$ consumption, UV$_{254}$ absorbance, and TOC were reversely lowered. High concentration of ozone dissociate organic matter in water, so that increasing dissolved organic level in effluent. Removal rates of water quality parameters at optimum ozone dose were obtained, such that removal rates of turbidity, KMnO$_4$ consumption, TOC, and UV$_{254}$ asorbance were 88.9%, 62.9%, 47%, and 77.3% respectively. Removal rate of THMFP was 51.6%. For all the parameters listed above, the DOF system was more effective than the DAF system or the CGS system. It is found that the DOF system may be used in advanced water treatment not only because the DOF system is more efficient in removing water quality parameters than the existing systems, but because the DOF system is also required smaller area than the CGS system for the treatment plant.

• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.637-643
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• 2015

This study has been carried out to provide the basic data obtained from the evaluation of the variation of water quality around the Chudong intake tower in Daechung resevoir, which may be able to help the establishment of a pure water supply policy. Five sites around the Chudong intake tower were selected, and the average data for recent ten years(from year 2004 to year 2013) were analysed. The average water quality around Chudong intake tower are as followed; pH 7.5, DO 8.7 mg/L, BOD 1.0 mg/L, COD 3.0 mg/L, SS 3.0 mg/L, TN 1.495 mg/L, TP 0.017 mg/L, and Chlorophyll-a 6.5 mg/m³ were matched the good class by comparing with the living environment standard of reservoir. COD values of higher than 3.0 mg/L after July were likely due to non-point pollutants and algae outbreak during rainy summer season. Total phosphorus rose sharply in the summer season, and then algae watch was issued consistently for average 40 days. Total nitrogen to total phosphorus ratio was average 90, and it is important to control the inflow phosphrous from small stream for proper management to block an algae growth according to eutrophication. It was recommended to operate the algae removing boats around intake tower from July to October, and was required advanced water treatment processes to remove NBD COD and bad odor and taste due to algae growth.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.1
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• pp.47-55
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• 2015

Recently, the production of taste and odor (T&O) compounds is a common problem in water industry. Geosmin is one of the T&O components in drinking water. However, geosmin is hardly eliminated through the conventional water treatment systems. Among various advanced processes capable of removing geosmin, adsorption process using granular activated carbon (GAC) is the most commonly used process. As time passes, however GAC process changes into biological activated carbon (BAC) process. There is little information on the BAC process in the literature. In this study, we isolated and identified microorganisms existing within various BAC processes. The microbial concentrations of BAC processes examined were $3.5{\times}10^5$ colony forming units (CFU/g), $2.2{\times}10^6CFU/g$ and $7.0{\times}10^5CFU/g$ in the Seongnam plant, Goyang plant and Goryeong pilot plant, respectively. The dominant bacterial species were found to be Bradyrhizobium japonicum, Novosphingobium rosa and Afipia broomeae in each plants. Removal efficiencies of $3{\mu}g/L$ geosmin by the dominant species were 36.1%, 36.5% and 34.3% in mineral salts medium(MSM) where geosmin was a sole carbon source.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.17-25
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• 2012

To maintain good oral hygiene, plaque control is essential and the most common and effective method is appropriate brushing. However accurate brushing is so difficult for children that the importance of brush is getting higher. We investigated the effect of tooth brushing instruction in plaque control for 40 children who came to Kyunghee university dental hospital, department of pediatric dentistry. We examined basic information by self-assessment, evaluated plaque index, tooth & tongue cleanness, malodor index for 4 times and compared values before and after tooth brushing instruction. Plaque index decreased(p<0.01) and tooth & tongue cleanness increased(p<0.01). There were no significant differences in mal-odor index. In conclusion, tooth brushing instruction is effective in removing dental plaque and its beneficial role is highly expected in establishing children's good oral hygiene.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.2
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• pp.121-126
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• 2019

Trimethylamine (TMA) is a nitrogen-based aliphatic organic compound. It is a major odorous component of fish and fishery products and is often used as an indicator of fish quality. The efficacy of TMA removal by various yeast strains was investigated. The five yeast strains found to be most effective in removing TMA were isolated from fermented foods and were identified as Saccharomyces cerevisiae based on biochemical and 18S rRNA sequence analyses. These strains were designated as S. cerevisiae SK1511, SK1512, SK1513, SK1514 and SK1515. Yeast cultures were treated with a TMA solution (0.3%, v/v), and the level of TMA reduction was analyzed by headspace gas chromatography. The five S. cerevisiae strains removed 32.02-50.34% of the TMA from the solution. This study is the first to demonstrate TMA reduction by microbial treatment.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.56-65
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• 2011

Culture-independent microscopic observations and 16S rDNA analyses were applied to describe the bacterial community inherent to the biofilm structure of the RABC (Rotating Activated Bacillus Contactors) process for swine butchery wastewater treatment. The ratios of Gram-positive bacterial counts to total bacterial counts of the RABC process were significantly increased in the last aeration tank as well as returned sludge, while those of the existing A2O (Anaerobic-Anoxic-Oxic) process maintained constant from aeration tanks to returned sludge. Totally nine phyla were recovered by 16S rDNA analysis, two of which were major groups: the Proteobacteria (64.1%) and the Actinobacteria (18.4%). The third major group was the endospore-forming Firmicutes (5.4%). The remaining six minor groups are the Bacteroidetes (3.3%), the Chlorobi (2.2%), the Nitrospirae (1.1%), the Chlorofleix (1.1%), the Acidobacteria (1.1%), and the Fusobacteria (1.1%). The ratio of endospore-forming bacteria was 19.4%, which was composed of the members of the Firmicutes phylum (5.4%) and the Intrasporangiaceae family (14.0%) of the Actinobacteria phylum. Nitrifying and denitrifying related- and phosphorus accumulating related-sequences were composed of 6.5% and 5.4% of total community, respectively, these could mean the high capacity of the RABC process to remove odor compounds and reduce eutrophication by efficient removing inorganic nutrients.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.730-739
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• 2015

108 microorganism types (79 types of fungi and 29 types of bacteria) were isolated from 25 automobiles generating bad odor when the air conditioner was turned on, and 43 types of fungi and 23 types of bacteria were identified. The analysis of condensate generated by the air conditioners in the automobiles indicated pH 6.4~7.1, 12.5~34.2 mg/L carbon source, 0.9~18.6 mg/L nitrogen source, 0.5~27.8 mg/L ion contents, and 0.1~7.7 mg/L mineral contents. The biofilms were formed by the mesophiles under the summer temperature/humidity condition ($26^{\circ}C$, 70% R.H.), and they were regenerated when the environmental factors (nutritional contents and temperature/humidity) were appropriate even after they were artificially removed. Although the antimicrobials removed 99.9% of planktonic cells within 15 minutes, they were not effective in removing biofilm. Up to 1,950 ppmv of ethanol was observed in the automobile treated with the antimicrobials. Although the figure is lower than the acute toxicity level when inhaled by humans, the health safety of the chemical substances used in the antimicrobials needs to be reviewed.