• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.492-497
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• 2014

This study investigated removal characteristics of organic matters in pretreatment and reverse osmosis (RO) membrane processes for seawater desalination. Also, the influence of the changes in characteristics of organic matters on the membrane fouling was assessed. The pretreatment processes included dual media filtration (DMF), pressurized membrane filtration (MF), and submerged membrane filtration (SMF). Turbidity, UV absorption at 254 nm, dissolved organic carbon, size exclusion chromatography (SEC), fluorescence excitation emission matrix (FEEM), and transparent exopolymer particles (TEP) in raw and processed waters were analyzed. Ions and minerals were not removed by any pretreatment process tested, but were removed over 99% through the RO membrane process. Hydrophobic organics, which can play major role in organic membrane fouling, were relatively readily removed compared with hydrophilic ones. Membrane based pretreatment such as MF and SMF exhibited better removals of organics than conventional DMF. As the levels of organics in pretreated water decreased, the silt density index (SDI) decreased. MF treated water exhibited the lowest SDI value; this is possibly due to the lowest TEP ($0.1-0.4{\mu}m$) concentrations.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.355-367
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• 2016

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium ($Na^+$) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate (ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.131-137
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• 1998

The cellulase components were partially purified from the culture filtrate of the alkalophilic bacterium Pseudomonas sp. AC-711 and its enzymatic properties were characterized. The specific activity of the purified major enzyme component was 3.5 units/mg protein as carboxymethyl cellulase and the yield was 23% of the total activity of the culture broth. The molecular weight of the component was 46,000 and the Km and Vmax on CMC were determined as $15.4mg\;mL^{-1}$ and $4.17{\mu}moles\;mL^{-1}\;min^{-1}$, respectively. The enzyme was stable at the temperatures below $60^{\circ}C$ and at the pH range of 4.0~11.0, and the optimal temperature and pH were $60^{\circ}C$ and pH 8.0, respectively. The enzyme activity was not significantly affected by the common surfactants (concentration: 0.05%) such as ${\alpha}$-olefin sulfonate, linear alkylbenzene sulfonate, sodium dodecyl sulfonate, hexadecyltrimethylammonium bromide and Tween 80. The enzyme was activated by the metal ions such as $Ca^{2+}$, $Cu^{2+}$, $Co^{2+}$, whereas inhibited by $Hg^{2+}$ and $Zn^{2+}$. The enzyme exhibited relatively high activity toward amorphous CMC as compared with crystalline substrates such as filter paper and avicel.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.69-78
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• 1994

The acidic deposition (wet) was collected at three different locations; representative industrial (Kun-Jang industrial areas), semiindustrial (Kunsan City) and nonindustrial (Daeya areas) region between March, 1991 and June, 1993. Samples were analyzed for major chemical components along with pH. Also the responses of Hypnum filunzaeforme to the acidic deposition adjusted to pH 4.6, 3.6 and 2.6 with 1:4 molar ratio of nitric to sulfuric acid were investigated. Seasonal variation of pH showed the lowest in early spring and the highest in summer. The annual mean concentrations of $S0_4^{2-},\;NO_3^{-}\;and\;NH_4^{+}$ were 2.94 (81.0%), 0.48 (13.2%) and 0.21 (5.78%) mg/l in industrial region and 0.61 (64.21%), 0.25 (26.3%) and 0.9 (9.5%) mg /I in nonindustrial region, respectively. $S0_4^{2-}$ contents of industrial region was 4 times higher than those of nonindustrial region. The ratio of $S0_4^{2-}\;to\;NO_3^{-}$ was 4.75~7.35 in industrial region and 0.69-6.36 in nonindustrial region. The acidic deposition near industrial region was associated with excess ions, expecially $S0_4^{2-}$. Nitrate reductase activity(NRA) of mosses was inhibited by acidic deposition in both regions. The time required for the maximum NRA induction by 2mM $KNO_3$ was shortened in mosses collected from industrial region. Photosynthesis of H. plumaejorme began to decrease with acidic deposition by pH below 4.6, and was completely inhibited at pH 2.6 in both regions. Water potential of mosses treated with acidic deposition was almost constant during 18 days, however after withholding the supply of acidic deposition, it was rapidly decreased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.298-302
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• 1982

In order to elucidate the taste compounds of wild common carp, Cyprinus carpio, and Korean snakehead, Channa argus, organic acids, sugars ana minerals were analyzed as a part of the study on the taste compounds of fresh-water fishes. Among organic acids, the contents of succinic acid, butyric acid, propionic acid and valeric acid were fairly high, while those of oxalic acid, fumaric acid, maleic acid, tartaric acid and citric acid were trace. As for the sugars, glucose was found to be the most predominant monosaccharide of the species. Extremely small amounts of fructose and arabinose were also detected and inositol and ribose were trace in content. Among minerals, $K^{+},\;Na^{+},\;PO_{4}^{3-}\;and\;Cl^{-}$ were found to be the major ions and small amounts of $Ca^{2+}\;and\;Mg^{2+}$ were detected.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.689-693
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• 1993

${\alpha}-galactosidase$ releases galactoside from raffinose and stachyose which are the major sugars in soybean, Although raffinose and stachyose were known as flatulence factors, these sugars were recently claimed as bifidus factors. In this experiment we studied the properties of ${\alpha}-galactosidase$ and its production from Bifidobacterium sp. Int-57. Int-57 produced higher level of ${\alpha}-galactosidase$ than other intestinal bacteria. The production of ${\alpha}-galactosidase$ was greater when grown on raffinose compared with other carbohydrates tested. Partially purified ${\alpha}-galactosidase$ was obtained after sonication of harvested cell pellet followed by DEAE-cellulose chromatography and Sepharose CL-6B gel filtration, and assayed using PNP-${\alpha}-galactosidase$ as a substrate. Optimum pH for activity was 7.0 and optimum temperature was $40^{\circ}C$. At 5 mM concentration of metal ions, $CoCl_{2}\;and\;CuCl_{2}$ and inhibited the enzyme activity by 33% and 21% respectively. The enzyme was shown to hydrolyse genuine substrates, i.e. raffinose and stachyose.

• Journal of Ginseng Research
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• v.7 no.2
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• pp.102-107
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• 1983

The effects of saponin, one of major components (Panax ginseng C.A. Meyer), on the growth of E. coli K-12 and the formation of siderphore was observed The following results were obtained. 1. When E. coli was grown on medium containing 1${\times}$10-5%-11${\times}$10-1% of the saponin, the rate of growth was stimulated at 10-1% of the saponin significantly compared to that of control. 2. When E. coli K-12 was grown on medium containing 1${\times}$10-1% of the saponin, the amount of siderphore was two times as much as the control. 3. The growth of E. coli was observed to be dependent on the concentration of siderophore when siderophore was added to medium. 4. The effect of saponin on the formation of siderophore in vitro was observed to reach maximum at 1${\times}$10-3% of the saponin. Such results suggest that the growth rate of E. coli K-12 could be enhanced by ginseng saponin fraction through stimulation of siderphore formation. We have described the fast growth of E. coli, K-12 and B. subtilis, rapid uptake of 14C-glucose, and high level of other metabolites such as lipids and proteins of E. coli, and B. subtilis in medium containing saponing fraction compared to that of microorganisms without saponin fraction.1∼3Such differences were claimed to be due to rapid uptake of 14C-glucose by widened periplasmic region throught unknown mechanism in the prescence of saponin fraction in medium3 and have raised a question whether there is another possible factor, siderophore4(Greek for iron bears), since microorganisms must secure a sufficient amount of iron for normal growth. These are known to be synthesized by the cells under iron-deficient condition and in most case, excreted into the medium5, where they can complex and solubilize any iron present there. It is generally believed that these complexes are then taken into the cells presumably by specific transport systems, thus providing iron for cell metabolism. Within the group of enteric bacteria, only three species (E. coli, S. typhimurium, and A. aerogense) have, so far, been studied in a ny detail. The main iron-binding compound produced by these species is enterochelin, and its role in iron transport is now well established. And biosynthesis of enterochelin from 2, 3- dihydroxybenzoate and serine in the prescence of magnesium ions and ATP was reported6. 2, 3-dihydroxybenzoate was also shown to involve isochorismate and 2, 3-dihydro-2, 3-dihydroxybenzoate as intermediate.7∼11 The present paper deals with the effect of ginseng saponin fraction on growth, the level of enterochelin formation in vivo and the conversion of 2, 3-dihydroxybenzoate and serine into entrochelin in vitro, and entrochelin obtained on the growth in relation to possible explanation of ginseng saponin fraction on the rapid growth of E. coli, K-12.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.712-718
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• 2009

To look into the degree of the long distance movement of the air pollution within Mt. Kyebang, Hongcheon, one of the clean regions, major ions, components of collected wet precipitation, were analyzed by using the ion chromatography after measuring pH and electrical conductivity. The quality assurance of chemical composition data was checked by considering the ion balance and electrical conductivity. Also, the pH of precipitation showed in the pH5.0~5.5 range, less than the pH5.6 in which the standards of the acid precipitation. On the whole, the more precipitation got, the less ion concentration became.: It could showed what it influenced on the fluctuation of the precipitation pH according to fluctuation and neutralization of the according materials. In the meantime, as composition ratios of wet deposition, ${SO_4}^{2-}$ and $nss-{SO_4}^{2-}$, ${NH_4}^+$ and $nss-Ca^{2+}$ accounted for high percentage. Especially, as the concentration of ${SO_4}^{2-}$, the artificial pollutant, and $Ca^{2+}$, the soil substance, showed high, Mt. Kyebang, Hongcheon having barely fixed air-pollutants sources was most likely to be influenced by the pollutants moved from long distances.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.4
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• pp.275-288
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• 2009

The Korean government strengthened the environmental polices to manage and enhance Metropolitan Area air quality, and also has enforced "Special Act on Seoul Metropolitan Air Quality Improvement (SASMAQI)" issued in Dec. 2004. Recently government expanded the Seoul Metropolitan Air Quality Management District (SMAQMD) to the outskirts satellite cities of Seoul area through the "Revised Law Draft of SASMAQI". The SMAQMD has been alloted the allowable emission loads to the local governments on the basis of the carrying $PM_{10}$ capacity. However, in order to establish the effective air quality control strategy for $PM_{10}$, it is necessary to understand the corresponding sources which have a potential to directly impact ambient $PM_{10}$ concentration. To deal with the situations, many receptor methodologies have been developed to identify the origins of pollutants and to determine the contributions of sources of interests. The objective of this study was to extensively identify $PM_{10}$ sources and to estimate their contributions at the metropolitan area. $PM_{10}$ samples were simultaneously collected at the 3 semi-industrialized local cities in the Seoul metropolitan area such as Hwasung-si, Paju-si, and Icheon-si sites from April 15 to May 31, 2007. The samples collected on the teflon membrane filter by one $PM_{10}$ cyclone sampler were analyzed for trace metals and soluble ions and samples on the quartz fiber filter by another sampler were analyzed for OC and EC. Source apportionment study was then performed by using a positive matrix factorization (PMF) receptor model. A total of 6 sources were identified and their contributions were estimated in each monitoring site. Contribution results on Hwasung, Paju, and Icheon sites were as follows: 33%, 27%, and 27% from soil source, 26%, 26%, and 21% from secondary aerosol source, 11%, 11%, and 12% from biomass burning, 12%, 6%, and 5% from sea salt, 7%, 15%, and 19% from industrial related source, and finally 11%, 15%, and 16% from mobile and oil complex source, respectively. This study provides information on the major sources affecting air quality in the receptor sites and thus it will help to manage the ambient air quality in the metropolitan area by establishing reasonable control strategies, especially for the anthropogenic emission sources.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.501-511
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• 2008

The Objective of this study is to examine the characteristic of fine aerosol $(PM_{2.5})$ obtained at Ieodo Ocean Research Station, which lies between the eastern part of China and the south western part of Korea. The average mass concentration of $PM_{2.5}$ was $21.5{\pm}17.0{\mu}g/m^3$ during June $2004{\sim}June 2006$. The concentration was the highest in winter $(34.8{\mu}g/m^3)$ and lowest in summer $(16.5{\mu}g/m^3)$. Water soluble ions were measured for samples collected from December 2004 to September 2005. Among them, $SO_4^{2-}\;and\;NH_4^+$ were the most abundant species and accounted for 32.2% and 14.2% of the $PM_{2.5}$ mass, respectively. The mass fraction of $SO_4^{2-}$ was higher in winter (42%) than in spring (26%). Nitrate concentrations were much lower than those of sulfate due mainly to evaporation during sampling period. The cluster analysis of backward airmass trajectories showed that the high mass loadings $(26.9{\mu}g/m^3\;on\;average)$ were associated with air originating inland China. Also, the seasonal variation of $PM_{2.5}$ mass was well correlated with the frequency of westerly winds passing through the western part of China. During the ABC-EAREX2005 (March 2005), $PM_{2.5}$ mass and major ionic concentrations were higher at Ieodo, compared with $PM_{2.5}$ measurements at Gosan while they were similar in variation pattern. These results suggested that $PM_{2.5}$ mass and its ionic composition of Ieodo Ocean Research Station were greatly influenced by continental outflows from China.