• Journal of Nutrition and Health
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• v.27 no.2
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• pp.109-117
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• 1994

This study was conducted to evaluate dietary fat intake and its effect on the plasma lipids and fatty acids composition in plasma and red blood cells(RBC) in 96 healthy Korean female college student. Three-day food intakes were recorded, and fasting blood samples were collected and analyzed for plasma total cholesterol and triglyceride. Fatty acid compositions were determined in plasma and RBC membrane. Oleic acid was the most abundant in diet, followed by palmitic and linoleic acids. Mean daily intake of cholesterol was 219$\pm$127mg, mean plasma cholesterol was 160$\pm$24mg/이 and mean plasma triglyceride was 68$\pm$25mg/dl. Plasma fatty acids were mostly composed of linoleic, palmitic and oleic acids, while palmitic, stearic and arachidonic acids were high in RBC membrane. Plasma triglyceride showed positive correlation with BMI. Among dietary fatty acids, arachidonic acid, EPA and DHA showed negative correlation with plasma total cholesterol. Plasma triglyceride levels were negatively correlated with dietary arachidonic acid, plasma n-6 fatty acids and plasma polyunsaturated fatty acids. Dietary EPA and DHA levels were positively correlated with plasma EPA, dietary n-3/n-6 ratio were positively correlated with plasma n-3 fatty acids and n-3/n-6 ratio. Highly significant correlations were shown between the levels in plasma and RBC for several fatty acids.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.123-127
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• 2009

Weight loss and nutrient dynamics of Quercus mongolica leaf litter during decomposition were investigated from December 2005 through August 2008 in Mt. Worak National Park as a part of National Long-Term Ecological Research Program in Korea. The decay constant (k) of Q. mongolica litter was 0.26. After 33 months decomposition, remaining weight of Q. mongolica litter was 49.3$\pm$4.4%. Initial C/N and C/P ratios of Q. mongolica litter were 43.3 and 2,032, respectively. C/N ratio in decomposing litter decreased rapidly from the beginning to nine months decomposition, and then showed more or less constant. C/P ratio increased to 2,407 after three months decomposition, and then decreased steadily thereafter. N and P concentration increased significantly during decomposition. N immobilization occurred from the beginning through 18 months decomposition, and mineralization occurred afterwards in decomposing litter. P immobilized significantly from fifteen months during decomposition. K concentration decreased rapidly from the beginning to six months decomposition. However it showed an increasing pattern during later stage of decomposition. Remaining K decreased rapidly during early stage of decomposition. There was no net K immobilization. Ca concentration increased from the beginning to twelve months decomposition, and then decreased rapidly till twenty one months elapsed. However, it increased again thereafter. Ca mineralization occurred from fifteen months. Mg concentration increased during decomposition. There was no Mg immobilization during litter decomposition. After 33 months decomposition, remaining N, P, K, Ca and Mg in Q. mongolica litter were 79.2, 110.9, 36.2, 52.7 and 74.4%, respectively.

• Journal of Environmental Science International
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• v.16 no.11
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• pp.1271-1277
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• 2007

This study was conducted to investigate the ratios of phosphorus release to COD uptake, phosphorus release to nitrate removal, and phosphorus uptake to phosphorus release by DNPAOs(denitrifying phosphate accumulating organisms). In case $I{\sim}IV$, influent 1 were fed with synthetic wastewater with influent 2 $NO_3^--N$ injection to anoxic zone and the case V were fed with municipal wastewater with side stream oxic zone instead of influent 2 $NO_3^--N$ injection. As a result, the ratio of phosphorus release to carbon uptake was increased in accordance with nitrate supply. The DNPAOs simultaneously took up phosphate and removed nitrate from the anoxic reactor. In case $I{\sim}IV$, with above 20 mg/L of sufficient $NO_3^--N$ supply, phosphate was taken up excessively by the DNPAOs in anoxic condition. The large amount of both uptake and release of phosphorus occurred above 20 mg/L of nitrate supply, achieving the ratio of phosphorus uptake to phosphorus release to be 1.05. In case V, phosphate luxury uptake was not occurred in system due to 6.98 mg/L of insufficient $NO_3^--N$ supply and the ratio of phosphorus uptake to phosphorus release was 0.98. Consequently, if nitrate as the electron acceptor was sufficient in anoxic zone, the ratio was found to be high.

• Journal of Aquaculture
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• v.12 no.1
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• pp.47-56
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• 1999

Denitrification by anaerobic bacteria is one of the most common processes of removing nitrate from recirculating aquaculture systems. This process is affected by many factors such as external carbon sources, hydraulic retention time (HRT), and $COD/NO_3-N$ ratio. Although external organic carbon sources are essential for the denitrification process, these also contribute to increase dissolved organic carbon concentration in recirculating aquaculture systems. So these external organic carbons must be removed from the systems. This study was conducted to find out the optimum operating conditions for the removal of external organic carbons in a submerged denitrification biofilter. Combinations of two external carbon sources (glucose and methanol), two HRT (4- and 8-hour), and four different C:N ratios (3, 4, 5, and 6) were used in this experiment. The removal efficiencies of organic carbon sources at 8-hour HRT were always better than those at 4-hour's (P<0.05). Maximum removal efficiencies were achieved when C:N ratio was 5 in both glucose and methanol. The removal efficiencies of methanol were always better than those of glucose. The maximum removal efficiencies of glucose and methanol were 76.5% and 84.0%, respectively and the removal rates were 223.5 $g/m^2/day$ and 247.1$g/m^2/day$. The maximum removal rates of glucose (290.9 $g/m^2/day$) and methanol (355.6 $g/m^2/day$) were achieved at 4-hour HRT and 5 C:N ratio. But the concentrations of SCOD in the effluent of both glucose ($52.5 mg/\ell$) and methanol ($40.9 mg/\ell$) were too high for rearing fish. Therefore, the optimum operating conditions for the removal of external carbon in a submerged denitrification biofilter were 8-hour HRT and 5 C:N ratio. And methanol showed better efficiency as an external carbon sources.

• Journal of Environmental Science International
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• v.10 no.3
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• pp.247-252
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• 2001

This study was performed to evaluate the inactivation and microbial regrowth of heterotrophic and nitrifying bacteria using chloramine as a secondary disinfectant for drinding water distribution system. Three sets of the three reactors filled with the $Cl_2/NH_3-N$ ratio of 3:1, 4:1, and 5:1 were used in these experiments. Chloramine concentration were applied to each set of the reactors with $1mg/\ell$,\;2mg/\ell\;and\;3mg/\ell$, respectively. For the set with elapsed time and reached to zero level after 7 days. Heterotrophic bacteria remarkably increased and nitrification through the experimenatal period (21 day). Furthermore the regrowth of heterotrophic bacteria and nitrification were not found. More than $2mg/\ell$ of chloramine with $Cl_2/NH_3-N$ ratio of 3:1, the nitrification could be inhibited by 2 days of contact time.

• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.92-97
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• 2000

The treatment of the washout from small scale incinerator was performed physically, chemically and biologically. The results are as follows. 1. SS, FS removal efficiency of washout wastewater from incinerator was 67.4%, 37.4%, while SS, FS of sewage wastewater was removed 63.2% 35.4% respectively. 2. The optimal conditions for chemical coagulation turned out to be pH 7.5, alum(Al2O3 10%) 30ml/ι and polyelectrolyte(A-601P 0.1%) 4ml/ι. SS 86%, FS 89.5%, BOD 42.5% and CODMn, 63.5% was removed and the removal efficiency of some metals are shown as Pb 93.5%, Zn 86.5% and Fe 80.6%. The concentration of the effluent was SS 9mg/ι, BOD 98.4mg/ι, and CODMn 138.4mg/ι. 3. The removal efficiency in treating washout wastewater of incinerator through HBC-briquet media was getting higher with increasing HRT, and mixed wastewater with 1:1, 1:2 ratio could be met up to the standard limit with higher HRT than 12hr. Under the condition of 1:2 mix ratio and HRT 24 hr, removal efficiency of SS, BOD, CODMn, T-N and T-P was 92.1%, 90%, 87%, 48.2% and 48%, respectively, and the concentration of treated wastewater was SS 2.9 mg/ι, BOD 10.3mg/ι, CODMn 14.1mg/ι, T-N 11.6 mg/ι and T-P 1.3 mg/ι, respectively.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.107-113
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• 1999

A new biological nutrient removal system combining $A^2/O$ process with fixed film was developed in this work and the characteristics of denitrification were especially investigated in the combined fixed film reactor(CFFR). Media was added in the anaerobic, anoxic and aerobic reactors, respectively. Tests were made to establish the effluent level of $NO_x-N$, COD, DO and nitrite effects on $NO_x-N$ removal in the CFFR by decreasing hydraulic retention time (HRT) from 10.0 to 3.5 hours and by increasing internal recycle ratio form 0% to 200%. The influent was synthesized to levels similar to the average influent of municipal wastewater treatment plants in Korea. SARAN media with a porosity of 96.3% was packed 40% / 130% / 25% based on its reactor volume, respectively. It was found that COD rarely limited dentrification in the anoxic reactor because of high $C/NO_x/-N$ ratio in the anoxic reactor, while DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent inhibited denitrification in the anoxic reactor. It was proved that the critical points of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent were 0.15mg/L and 10%, respectively. As the internal recycle ratio increased, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent increased. Especially, at the condition of internal recycle ratio, 200%, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent exceeded the critical points of 0.15mg/L and 10%, respectively. Then, denitrification efficiency considerably decreased. Consequently, it was represented that the control of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent can assure effective denitrification.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.435-441
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• 1998

Optimal conditions for the production of natural color, betacyanin were investigated by varying light intensity, C/N ratio, concentrations of phosphate and kinds of elicitors. Batch cultivation was employed to characterize cell growth and betacyanin production of 32 days. The maximum specific growth rate, ${\mu}$$\sub$max/, was 0.3 (1/day) for batch cultivation. The maximum specific production rate, q$\^$max/$\sub$p/, was enhanced 0.11 (mg/g-cell/day) at 3 klux. A light intensity of 3 klux was shown to the best for both cell growth and betacyanin production. The maximum specific production rate was 0.125 (mg/g-cell/day) at 0.242 (1/day), the maximum specific growth rate. The dependence of specific growth rate on the light lintensity is fit to the photoinhibition model. The correlation between ${\mu}$ and q$\sub$p/ showed that the product formation parameters, ${\alpha}$ and ${\beta}$$\sub$p/ were 0.3756 (mg/cell) and 0.001 (mg/g-cell/day), respectively. The betacyanin production was partially cell growth related process, which is different from the production of a typical product in plant cell cultures. In C/N ratio experiment, high carbon concentration, 42.1 (w/w) improved cell growth rate while lower concentration, 31.6 (w/w) increased the betacyanin production rate. The ${\mu}$$\sub$max/ and q$\^$max/$\sub$p/ were 0.26 (1/day) and 0.075 (mg/g-cell/day), respectively. Beta vulgaris L. cells under 1.25 mM phosphate concentration produced 10.15 mg/L betacyanin with 13.46 (g-dry wt./L) of maximum cell density. The production of betacyanin was elongated by adding 0.1 ${\mu}$M of kinetin. This also increased the cell growth. Optimum culture conditions of light intensity, C/N, phosphate concentration were obtained as 5.5 klux, 27 (w/w), 1.25 mM, respectively by the response surface methodology. The maximum cell density, X$\sub$max/, and maximum production, P$\sub$max/, in optimized conditions were 16 (g-dry wt./L), 12.5 (mg/L) which were higher than 8 (g-dry wt./L), 4.48 (mg/L) in normal conditions. The ${\mu}$$\sub$max/ and q$\^$max/$\sub$p/ were 0.376 (1/day) and 0.134 (mg/g-cell/day) at the optimal condition. The overall results may be useful in scaling up hairy root cell culture system for commercial production of betacyanin.

• Environmental Engineering Research
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• v.23 no.4
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• pp.374-382
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• 2018

Petroleum hydrocarbons pollutants, such as diesel fuel, have caused ecosystem damage in terrestrial and aquatic habitats. They have been recognized as one of the most hazardous wastes. This study was designed to optimize the effect of Tween 80 concentration, nitrogen (N)/phosphorus (P) ratio and salinity level on diesel biodegradation by Vibrio alginolyticus (V. alginolyticus). Response surface methodology with Box-Behnken design was selected with three factors of Tween 80 concentration (0, 5, 10 mg/L), N/P ratio (5, 10, 15) and salinity level (15‰, 17.5‰, 20‰) as independent variables. The percentage of diesel degradation was a dependent variable for 14 d of the remediation period. The results showed that the percentages of diesel degradation generally increased with an increase in the amount of Tween 80 concentration, N/P ratio and salinity level, respectively. The optimization condition for diesel degradation by V. alginolyticus occurred at 9.33 mg/L of Tween 80, 9.04 of N/P ratio and 19.47‰ of salinity level, respectively, with percentages of diesel degradation at 98.20%. The statistical analyses of the experimental results and model predictions ($R^2=0.9936$) showed the reliability of the regression model and indicated that the addition of biostimulant can enhance the percentage of diesel biodegradation.

• Korean Journal of Microbiology
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• v.39 no.1
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• pp.21-26
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• 2003

Ninety strains of photosynthetic bacteria were isolated from a local stream at Kyonggi-do, Korea and were further screened. Using these isolated strains, experiments were performed under various light and oxygen conditions in order to select strains with high nitrogen $(NH_3-N,\; NO_3^--N)$ removal efficiencies. Results showed that all the strains screened removed $NH_3-N$, the light had no effect on nitrogen removal, and the nitrogen removal rate was higher aerobically than anaerobically. The removal of $NO_3^--N$ was showed up to 35.3% in some specific strains. Results of batch experiments using Rhodocyclus gelatinosus, an isolated strain with a superior removal rate of $NH_3--N$ and $NH_3-N$, under the anaerobic condition, showed that the removal rate of organics and $NH_3-N$ was the highest (98.2 and 89.0%, respectively) at the CODcr (mg/L)/biomass (mg/L) ratio of 0.2, and the $NH_3-N$ concentration did not increase with the decreasing $NH_3-N$ concentration. Experimental results from various C/N ratios confirmed that the effective removal rate (75.8%) of $NH_3-N$ occurred even at the low (5:1) C/N ratio as well as high ratios, and the simulataneous removal of $NO_3^--N$ (96.0%).