• Journal of dental hygiene science
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• v.1 no.1
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• pp.7-11
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• 2001

Streptococcus mutans is one of the primary bacteria that cause dental caries which further result in plaque build up. Acid production resulted from carbohydrate metabolism can threaten survival of the bacteria. However some populations of S. mutans which are exposed to low acidic condition for a period of time would develop resistance and tolerance of cells to acidity that will enhance the chance of survival. Similar acid tolerances has been reported in case of Salmonella enterica serovar typhimurium, E. coli, Shigella flexneri. These acid tolerance responses(ATR) have been evolved in a similar manner as S. mutans. The protein produced in acidic condition has been proven to be important for ATR and confirmed by using chloramphenicol procedure. We hypothesize here that proteins synthesized in response to acid shock and other elements are important for ATR of cells. In this study we have confirmed that S. mutans developed acid tolerance and resistance against anaerobic condition. Mutational DNA analysis responsible for acid tolerance should be additionally required in the future. Since the development of acid tolerance that is essential for the survival of S. mutans and development of dental caries, ATR of S. mutans shoule be farther to prevent dental caries.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.194-200
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• 2000

The amount of swine wastewater reaches about $197,000m^3$ per day at live-stock houses in the whole country. A half of the swine wastewater resources are too small to be restricted legally. This untreated wastewater causes the eutrophication in the water bodies. In case of swine wastewater treatment, the solid-liquid separation must be performed because feces(solid phase) and urine(liquid phase) have large differences in nitrogen and phosphorus concentration. It is necessary to assess exactly the concentration of the pollutants in swine wastewater for planning the wastewater treatment facilities. A full-scale operation was carried out in K city and the plant is consists of conventional plant, the supplementary flocculation basin of chemical treatment process and $anaerobic{\cdot}aerobic$ basin for nitrogen removal. The improved full-scale swine wastewater treatment plant removed the $1,500{\sim}3,000mg/l$ of total-nitrogen(T-N) to 120mg/l of T-N and $131{\sim}156mg/l$ of total-phosphorus(T-P) to $0.15{\sim}1.00mg/l$ of T-N. Accordingly, as a results of operational improvement, the removal efficiencies of T-N and T-P were over $92{\sim}96%$, 99%, respectively. The continuous supply of organic carbon sources and the state of pH played important roles for the harmonious metabolism in anaerobic basin and the pH value of anaerobic basin maintained at about 9.0 for the period of the study.

• Korean Journal of Agricultural Science
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• v.34 no.2
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• pp.99-109
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• 2007

Cellulomanas sp. CS 1-1 was studied for its morphological, physiological and biochemical characteristics, together with DNA homology and fatty acid pattern to elucidate its taxonomical position in the species level. Colony morphology of CS1-1 exhibited circular form, opaque, convex, entire edge and pale yellow. Cells were of rod with the size of $0.3{\sim}0.5{\times}0.8{\sim}1.2{\mu}m$, while coryneforms were formed at the early stage of culture. D-ribose, raffinose, rhamnose, acetate, propionate, L-lactate, D-gluconate, aspartate and proline were not utilized as a sole source of carbon, whereas saccharose, arabinose, and amlyose were utilized. Biochemical characteristics of CS1-1 were Gram positive, catalase positive, oxidase negative, nonmotile, facultative anaerobic, mesophilic and G+C content of 74.7 mol %. The major fatty acid and menaquinone were 12-methyltetradecanoic acid(anteiso-$C_{15:1}$) and MK-$9(H_4)$, respectively. These results were correspondent with the characteristics reported for member of the genus Cellulomonas. The strain CS 1-1 exhibited a high level of DNA homology as 70% with C. uda ATCC491, compared to those of 54~59% with C. fimi ATCC 15724, 46~48% with C. biazotea, C. gelida and C. bibula. Finally, strain CS1-1 could be classified as a novel species belongs to C. uda.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.4
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• pp.111-116
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• 2001

As part of the recycling methods, residual food through the anaerobic fermentation process was decomposed into methane gas and fermentation liquid. The research was conducted to measure the effect of application of fermentation liquid on chemical properties of soil and plant growth according to application rate and separate manure at the base of nitrogen in fermentation liquid. The fermentation liquid contained 0.52% nitrogen was applied in treatments by standard fertilizer. The treatments were composed of the control only with chemical fertilizer and N-50, N-100-4, N-100-8 were each of applied with 50, 100(6 times), 100(3 times)% of fermentation liquid contrast to standard fertilizer. Properties of fermentation liquid was high EC because of waster soluble organic compounds as well as much of salts and also contained a lot of suspended solid. The changes of soil chemical properties little occurred in before and after of experiment but EC and content of ex. Ca in soil were increased. Fresh weigh in treatments applied with fermentation is high than that of control but the difference between treatments little showed. The above result means if fermentation liquid be used instead of chemical fertilizer the volume of used fermentation liquid will be reduced by 50% of present standard fertilizer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.25-33
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• 2018

Renewable energy has been of interests in the area of modern alternative fuels. Biogas is produced in waste landfill sites through anaerobic digestion processes, including hydrolysis, acidogenesis, organic acid fermentation (acetogenesis), and methane fermentation (methanogenesis). High contents of fine dust and moisture limited its utilization for direct combustion, town gas and vehicle fuel. Thus, this study proposed a new design for a cooling device using a centrifugal cyclone for simultaneous removal of fine dust and moisture as a pretreatment in the purification processes. A heat exchanger and an ID fan, which are installed inside and outside of the cyclone, in order to cool the humid gas below the freezing point and form a foggy mist. Such an atmosphere enhanced to capture fine dust as recirculating the cold mist flow. The water removal rate was 80.8% at a relative humidity of 95%, and the particle removal efficiency was 98.3% for $2.5{\mu}m$. Simultaneous removal efficiency was 70.8% and 99.6% for particle and moisture respectively.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.171-180
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• 2002

The temporal and spatial distributions of phosphorus have been investigated in the Gomso Bay, Korea. TP, PIP, TOP and DIP in sediment were found 548.8mg P kg$^{-1}$ , 426.1mg P kg$^{-1}$ , 122.6mg P kg$^{-1}$ , and 0.217mg P kg$^{-1}$ , respectively with a decreasing order of PIP>TOP>DIP. Any temporal or spatial trend has not been found on the distribution of TP in the sediment, except the high TP values near the mouth of Julpo-chun. We found seasonal patterns high TOP(28.90% of TP) and low TIP(71.10% of TP) in August, but low TOP(15.63% of TP) and high TIP(84.38% of TP) in November. There were three times higher DIP concentration in August than in November. Such case is probably not only due to the enhanced supply of DIP directly from the decomposition of organic matter from overlying water in summer, but also the released phosphate from the adsorbed particulate matter such as PIP under the low pH and Eh conditions at the subsurface layers of the sediment induced by the active microbial respiration of increased organic materials in summer. Primarily, the source of phosphorous from municipal sewage strongly influenced the early stage of the distribution of all the phosphorous in the Gomso tidal flat. Notwithstanding, through the processes of diagenesis in sediment, water temperature and organic contents probably functioned as the key parameters to control the temporal distributions of TOP, TIP and DIP in the Gomso tidal flat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.472-479
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• 2012

The formation of volatile fatty acids(VFAs) and changes in pH, oxidation and reduction potential(Eh) and acid volatile sulfide(AVS) with the addition of yellow clay were investigated using microcosm systems to examine the effects of yellow clay dispersion on the anaerobic decomposition of Cochlodinium polykrikoides in marine sediments. The acetate concentration reached a maximum by day 4 and was 1.2-1.8 fold less in the sample treated with yellow clay compared to the untreated sample (224-270 vs. 333 uM). The formate concentration reached a maximum by day 1 and was 1.3-2.8 fold less in the sample treated with yellow clay compared to the untreated sample (202-439 vs. 563 uM). The propionate concentration reached a maximum by day 2 and was 1.5-1.8 fold less in the sample treated with yellow clay compared to the untreated sample (32.6 vs. 57.2 uM). After the amounts of acetate, formate and propionate peaked the levels dropped dramatically due to the utilization by sulfate reducing bacteria. The Eh of the samples treated with yellow clay was similar to the untreated sample on day 0 but was higher in the sample treated with yellow clay(140-206 mV) from days 4 to 17. AVS started to form on day 3 and this was sustained until day 6, and 1.2-2.2 fold less was produced in the sample treated with yellow clay compared to the untreated sample (40.2-69.3 vs. 83.2-93.8 mg/L). Accordingly, during the anaerobic decomposition of C. polykrikoides in marine sediments, yellow clay dispersal seems to suppress the reduction state of Eh and the formation of volatile fatty acids(acetate, formate and propionate) used as an energy source by sulfate reducing bacteria, indicating that this process controls the production of hydrogen sulfide that negatively affects marine organisms and the marine sediment environment.

• Applied Biological Chemistry
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• v.41 no.7
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• pp.527-532
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• 1998

This study was aimed at the development of the rice product by fermentation of saccharified rice solution with Bifidobacterium. To optimize the preparation of saccharified rice solution for Bifidobacterium fermentation, various pretreatment conditions were established. Grinding for 30seconds by an impact mill was more efficient than any other grinding schemes tested. The preheating before gelatinization showed a positive effect for efficient saccharification, and its optimal conditions were at $60^{\circ}C$ for 45 min. The optimum gelatinization conditions were at $100^{\circ}C$ for 40 min. The optimum levels of enzymes for saccharification of rice were 0.135 unit/g rice powder for ${\alpha}-amylase$ and 3.375 unit/g rice powder for glucoamylase, respectively. The physico-chemical properties of the fermented product by a fastidious Bifidobacterium showed a great potential for a functional rice product. However, an improvement on its flavor was required, which might be achieved by the addition of various fruits and vegetables.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.67-73
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• 2019

We carried out basic research to evaluate covering material for improving and managing contaminated benthic environments in coastal areas. Changes in nutrient concentration such as phosphate, hydrogen sulfide of contaminated sediment, and pH, Oxidation Reduction Potential (ORP) were investigated through mesocosm experiments for 6 months by covering contaminated sediment with granulated coal ash. Calcium oxide eluted from the granulated coal ash was confirmed to neutralize acidified sediment by increasing pH through hydrolysis. Also, calcium oxide and silica eluted from the granulated coal ash adsorbed and precipitated with phosphate in the sediment. The concentration of phosphate in the sediment investigated decreased by ca. 84.31 %. Similarly, the concentration of hydrogen sulfide decreased by 133.5 mg/L in one month. The hydrogen sulfide is considered to have reacted with substances such as manganese oxide which were eluted from the granulated coal ash and precipitated. Also, it was concluded that the hydrogen sulfide was reduced since anaerobic conditions in the sediment weakened. According to the results of these mesocosm experiments, granulated coal ash was found to be effective to remediate and manage benthic environments by covering the surface layer of sediment.

• Korean Journal of Poultry Science
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• v.29 no.3
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• pp.213-223
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• 2002

This study was conducted to investigate the influence of feeding various Lactobacillus on production performance, nutrients digestibility, intestinal microflora, and fecal $NH_{3}$ gas emission in laying hens. Three hundred and sixty ISA Brown layers, 21 weeks of age, were randomly allotted to nine treatments, with low replicates per treatment. Nine treatments consisted of Control(no Lactobacillus), Lactobacillus crispatus avibrol(LCB: KFCC-11195), Lactobaciilus reuteri avibro2(LRB: KFCC-11196), Lactobacillus crispatus avihenl(LCH: KFCC-11197), Lactobacillus vaginalis avihen2(LVH: KFCC-11198). Each Lactobacillus was added at two levels ($10^{4}$and $10^{7}$ cfu/g diets). Egg production, and egg weight were measured daily. A metabolism trial was conducted following the 12-week feeding trial, during which egg qualities, intestinal microflora and fecal $NH_{3}$ gas emission were examined. Egg production and daily egg mass improved significantly by the addition of various Lactobacillus(P<0.05), of which effect was more notable during the latter part of the feeding trial. But, no significant differences were found among Lactobacillus strains and between two levels of supplementation. Egg weight and feed intake showed no difference among all treatments. Feed conversion ratio of birds fed lactobacillus was significantly improved compared to that of the Control(P<0.05), but not different among lactobacillus treatments. Digestibility of crude protein, ether extract and crude ash improved significantly in lactobacillus treatments(P<0.05). However, there were not statistically different by adding levels and strains. Total counts of Lactobacillus spp. in ileum of layers fed Lactobacillus were significantly higher than that of the control, but no consistent trend was found in cecum. There were no significant differences in intestinal yeast and anaerobes counts among all treatments. The Lactobaciilus supplementation did not exert my effect on the eggshell quality and Haugh unit. Fecal $NH_{3}$ gas emission decreased significantly in Lactobacillus treatments, and showed no difference between the two supplementation levels. From the result of this study, it could be concluded that dietary supplementation of Lactobacillus, regardless of their species, Improves the laying performance and decreases the fecal ammonia gas emission. The proper level of supplementation appears to be $10^{4}$ cfu/g of diet.