• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.231-239
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• 2000

This study was investigated to estimate optimal conditions and biological oxic denitrification to treat wastewater with low C/N ratio and high strength total inorganic nitrogen (TIN) concentration by using $A_2O$ fixed biofilm system. The lab-scale experimental system packed with media, which were composed of polyvinylidene chloride fiber (oxic basin) and ceramic ball (anaerobic and anoxic basin), was used. This system was operated with various influent alkalinities at the C/N(TOC/TIN) ratio of 0.5. The study results showed that TOC were removed over 96.0% at all operation conditions. The removal efficiencies over 93.5% for $NH_4{^+}-N$ and 81.8% for TIN were obtained at the alkalinity of about 1210mg/L(Run 5). Among the removal of TIN, 64.9% was occurred by biological denitrification at an oxic basin. It was confirmed through mass balance of alkalinity and nitrogen that the amount of alkalinity produced during biological denitrification at oxic basin was 2.49~3.46 mg Alkalinity/mg $NO_2{^-}-N$, ${\Delta}TOC/{\Delta}DEN$ of 0.34 (Run 5) was obtained at an oxic basin, which was less than the theoretical value of 1.22.

• Journal of Biomedical Engineering Research
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• v.16 no.3
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• pp.331-336
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• 1995

A composite material was produced as an artificial bone substitute which is gradually degrAded and replaced by the regenerated natural bones after implantation. To detect the effect of the material on the cell's activity, the composite specimens were placed in MEMs and incubated at $37^{\circ}C$ for one week. Human uterus cervical cancer origin HeLa 3 cells and mouse subcutaneous origin L929 cells were cul- tured in the specimen dissolved MEMs for 5 days to investigate cytotoxicity via cell growth rates. ${Na_2}^{51}CrO_4$ solution was added to the media, to label the HeLa 53 cells, and the released amount of $^{51}Cr$ was measured by a $\gamma$-counter. On the cell growth investigation, no significant cytotoxic phenomena were revealed in both HeLa S3 and L929 cell cultures. On the released 51CR from the incubated HeLa 53 cells, no significant cell degeneration was observed from the composite embedded MEMs.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.583-591
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• 2002

Biodegradation of fat, oil, and grease (FOGs) plays an Important role in wastewater management and water pollution control. However, many industrial food-processing and food restaurants generate FOG-containing waste waters for which there Is no acceptable technology for their pretreatment. To solve these problems, this study evaluated the feasibility of effective FOG-degrading microorganisms on the biodegradation of olive oil and FOG-containing wastewater. Twenty-two strains capable of degrading FOGs were isolated from five FOG-contaminated sites for the evaluation of their FOG degradation capabilities. Among twenty-two strains tested, the lipase-producing Pseudomonas sp. strain D2D3 was selected for actual FOG wastewater treatment. Its biodegradability was performed at 3$0^{\circ}C$ and pH 8. The extent of FOG removal efficiency was varied for each FOG tested, being the highest for olive oil and animal fat (94.5% and 94.4%), and the lowest for safflower oil (62%). The addition of organic nitrogen sources such as yeast extract, soytone, and peptone enhanced the removal efficiency of FOGs, but the addition of the inorganic nitrogen nutrients such as $NH_4$Cl and $(NH_4)_2SO_4$ did not increase. The $KH_2PO_4$ sources in 0.25% to 0.5% concentrations showed more than 90% degradability. As a result, the main pathway for the oxidation of fatty acids results in the removal of two carbon atoms as acetyl-CoA with each reaction sequence: $\beta$-oxidation. Its lipase activity showed 38.5 U/g DCW using the optimal media after 9 h. Real wastewater and FOGs were used for determining the removal efficiency by using Pseudomonas sp. strain D2D3 bioadditive. The degradation by Pseudomonas sp. strain D2D3 was 41% higher than that of the naturally occurring bacteria. This result indicated that the use of isolated Pseudomonas sp. strain D2D3 in a bioaugmentating grease trap or other processes might possibly be sufficient to acclimate biological processes for degrading FOGs.

• The Korean Journal of Mycology
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• v.27 no.2 s.89
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• pp.94-99
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• 1999

For the purpose of utilizing cellulose resources by cellulolytic enzymes of Stropharia rugosoannulata, it's cultural conditions for the prodution of cellulolytic enzymes in synthetic media were investigated. The optimum pH for the production of Avicelase and ${\beta}-glucosidase$ was pH 5.0, while that of CMCase was pH 4.0. The optimum temperature for the production of Avicelase, CMCase and ${\beta}-glucosidase$ was $40^{\circ}C$. Among the carbon sources, xylose was good for the production of CMCase and ${\beta}-glucosidase$, but maltose was good for the production of Avicelase. The optimum concentration of the carbon sources for the production of CMCase, Avicelase and ${\beta}-glucosidase$ was 1.0, 0.8 and 1.1%, respectively. As inorganic nitrogen sources, $NH_4Cl$ was good for the production of all the three cellulolytic enzymes. The optimum concentration of $NH_4Cl$ for the production of CMCase was 0.3% while that of Avicelase and ${\beta}-glucosidase$ was 0.4%. As organic nitrogen sources, malt extract was good for the production of all the three cellulolytic enzymes. The optimum concentration of organic nitrogen for the production of ${\beta}-glucosidase$ was 1.3% while that of CMCase and Avicelase was 1.0%. As the mineral sources, $CoCl_2$ good for the was good for the production of all the three cellulolytic enzymes. The optimum concentration of $CoCl_2$ for the production of all the three enzymes was 0.35%.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.55-58
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• 2004

The objective of this study was to get information about water retention characteristics of horticultural substrates used in Korea determined by European standard method. Water retention curves were prepared at water volume (v/v, %) in relation to -10 cm, -50 cm, -100 cm water pressure head. Water retention curves showed different properties depending upon the type, the place of origin, particle size, and manufacturing processes of substrates. Peat and coir had easily available water content in the range of 30-40% and showed high water holding capacity, water buffering capacity, and aeration for plant growth. However, bark, sawdust and rice hull showed low water holding capacity about below 10%. The easily available water content of perlite and clay ball was low about 0.1-13.8%, whereas that of vermiculite and rockwool granulate was high about 25.9-52.0%. Understanding water retention characteristics of growing substrates is very important in cstablisliing optimum condition for plant growth. Further study on water retention curves for more substrates, mixture and growing media is needed.

• Microbiology and Biotechnology Letters
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• v.37 no.1
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• pp.62-68
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• 2009

The culture conditions to maximize the production of laccase (EC 1.10.3.2) from Fomitopsis pinicola mycelia were investigated. Among the tested media for the enzyme production, mushroom complete medium (MCM ; 2% dextrose, 0.2% peptone, 0.2% yeast extract, 0.05% $KH_2PO_4$, and 0.05% $MgSO_4{\cdot}7H_2O$) showed the highest activity of the enzyme. To optimize the culture condition for the laccase activity, influence of various carbon and nitrogen sources was investigated in MCM. Among various carbon and nitrogen sources, 2% glucose and 0.4% peptone showed the highest production of the enzyme, respectively. For the phosphorus and inorganic source, 0.05% $NaH_2PO_4$ and 0.05% $CaCl_2$ were best for the enzyme activity. The enzyme production was reached to highest level after the cultivation for 8 days at $25^{\circ}C$. Native polyacrylamide gel electrophoresis (PAGE) followed by the laccase activity staining using 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as the substrate was performed to identify the laccase under culture conditions studied. Zymogram analysis of the culture supernatant showed a laccase band with molecular mass of 52 kDa. The optimum pH and temperature for the enzyme activity were $80^{\circ}C$ and pH 3.0.

• Journal of Conservation Science
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• v.33 no.6
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• pp.467-483
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• 2017

In this study, the degradation properties by temperature stress of $Araldite^{(R)}$ rapid-curing epoxy resin used for inorganic cultural heritages, was identified. The tensile and tensile shear strength of durability decreased for 12,624 hours at temperatures of $40{\sim}60^{\circ}C$. In terms of stability of external stress and temperature, the slow-curing epoxy was superior to the rapid-curing epoxy, and cultural heritage conservation plans should therefore consider the strength and stress properties of restoration materials. Color differences increased for 12,624 hours at temperatures of $40{\sim}60^{\circ}C$, and glossiness decreased. Both color and gloss stability were weak, which necessitates the improvement of optical properties. Thermal properties (weight loss, decomposition temperature, and glass transition temperature) of adhesives are linked to mechanical properties. Interfacial properties of the adherend and water vapor transmission rates of adhesives are linked to performance variation. For porous media (ceramics, brick, and stone), isothermal and isohumid environments are important. For outdoor artifacts on display in museums, changes in physical properties by exposure to varying environmental conditions need to be minimized. These results can be used as baseline data in the study of the degradation velocity and lifetime prediction of rapid-curing epoxy resin for the restoration of cultural heritages.

• Microbiology and Biotechnology Letters
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• v.41 no.2
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• pp.145-152
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• 2013

The culture conditions to maximize the production of endoglucanase (EC 3.2.1.4) from the brown rot fungus Fomitopsis pinicola MKACC 54347 mycelia were investigated. Among the tested media for endoglucanase production, Mandel's mineral salts medium (MSM; 1% cellulose, 0.1% peptone, 0.14% $(NH_4)_2SO_4$, 0.03% urea, 0.2% $KH_2PO_4$, 0.03% $MgSO_4{\cdot}7H_2O$, 0.03% $CaCl_2$, and 0.1% trace metal solution (19.8 mM $FeSO_4$, 13.0 mM $MnSO_4$, 12.2 mM $ZnSO_4$, and 15.4 mM $CoCl_2$)) produced the highest activity of the enzyme. To optimize the medium composition for enzyme activity, the effects of various carbon, nitrogen, phosphorus, and inorganic sources were investigated in MSM. Maximal enzyme production was accomplished using a medium containing 2% carboxymethyl cellulose (CMC), 2% yeast extract, 0.2% $KH_2PO_4$, 0.03% $MnSO_4$, and 0.3% trace metal solution. Different physiological conditions, like incubation period and temperature, were also examined to assess their influence on enzyme production. Enzyme production from F. pinicola reached its highest level after cultivation for 8 days at $25^{\circ}C$. Nondenaturing polyacrylamide gel electrophoresis (PAGE), followed by the endoglucanase activity staining using CMC as the substrate, was performed to identify the endoglucanase under the culture conditions studied. Zymogram analysis of the culture supernatant revealed an endoglucanase band with a molecular mass of 52 kDa. The optimum pH and temperature for enzyme activity were $55^{\circ}C$ and pH 5.0, respectively.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.239-244
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• 1987

This studies was carried out to find the effect of inorganic matters of Apple Leaves on the occurrence of Alternaria leaf spot and calicium compounds on mycelial growth of Alternaria mali. Diseased leaf rate of Alternaria leaf spot of susceptible apple varieties was 84.8%, moderate resistant 8.1% and resistant 0.3% respectively and in No. of lesion per leaf, the tendency was same. CaO contents of apple leaves was contained much in the resistant varieties than susceptible one. It was estimated that calcium is one of factors on resistance to apple leaf spot by the results of relations among CaO contents and diseased leaf rate from July to August and No. of lesion per leaf was correlated significantly as r=-0.551, r=-0.585, -0.485 but in T-N, $P_2O_5,\;K_2O,\;MgO,\;Na_2O$, there was no difference among varieties. Then, growth of Alternaria mali was possible in the media of which pH ranged up to $11{\sim}13$, and calcium has effect of inhibition on growth of Alternaria mali.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.1
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• pp.43-50
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• 1986

A research was performed to examine the applicability of aerobic fixed-biofilm reactors for removal of biodegradable organics in raw waters. Crushed briquette ashes or granite were utilized as media. Experiments were carried out by feeding packed bed reactors with a synthetic raw water prepared by dissolving phenol in tap water with other inorganic nutrients. Results of the research showed that the effluent TBOD concentrations were lower than 6 mg/l when the influent BOD concentrations were kept below 50 mg/l and a detention time of about 2.7 hours was provided. The SBOD concentrations of the treated waters should be less than 5 mg/l since the effluent SS could be removed by conventional water treatment methods such as coagulation and filtration. It was also found that most of the SS in the effluents were humic materials since the effluent SS caused little BOD. This means the biofilm in the reactor was in endogenous respiration phase due to low F/M ratio. According to the results of this study, it is recommended to pretreat any raw water contaminated with biodegradable organics in an aerobic fixed biofilm reactor with a detention time of 2 to 3 hours.