• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.23-31
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• 1987

In land treatment systems for organic waste removal, especially rapid intiltration method is well known as less climatic restrictions and less field area requirements as against the others. Therefore the present study on rapid infiltration is aimed to survey the waste removal rate, infiltration rate, variation of dissolved oxygen due to biological oxygen absorption and pH decrement using pilot infiltration column filled with permeable soil(sand) as media, also to find the waste load(COD) per unit area and nitrate conversion ratio from TKN. The results obtained here are as follows. 1) When the depth of sand layer is more than 1 meter, the COD removal would be reached steadly to 90% or more under the infiltration rate below 15~20cm/day, and would be no problem due to leached organic pollutants considering the depth of ground water table. 2) The COD removal per unit area($m^2$) can readily be expected to 10~14g/day with proper operation, and the decomposition of substrate would be attained mostly at the surface layer of the media. 3) Generally the conversion of TKN to the $NO_3{^-}$-N is seemed to be proportional to the COD removal rate if provided proper retention time.

• Clean Technology
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• v.23 no.4
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• pp.345-356
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• 2017

The composting is a biological process that converts organic matter into useful resources such as fertilizers. It is a continuous transition of microbial communities to adapt changes in organic matter and environmental conditions (carbonation rate, temperature, humidity, oxygen supply, pH, etc.). Most of the composting plants are located in the proximity of the residential areas. It is a general scenario where government authorities receive complaints from the local residents due to release of odor from the composting, and has become a social problem in Korea. Identification of dominant microorganisms, understanding change in microbial communities and augmentation of specific microorganism for composting is vital to enhance the efficiency of composting, quality of the compost produced, and reduction of odor. In this paper, we suggest the optimum operation conditions and methods for compost depot to reduce odor generation. The selection of the appropriate microorganisms and their rapid increase in population are effective to promote composting. The optimal growth conditions of bacteria such as aeration (oxygen), temperature, and humidity were standardized to maximize composting through microbial degradation. The use of porous minerals and moisture control has significantly improved odor removal. Recent technologies to reduce odor from the composting environment and improved composting processes are also presented.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.12-17
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• 2000

For the enzymatic production of $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid (AA-2G) from ascorbic acid, rice seed was used as the source of ${\alpha}-glucosidase$ having transglucosylation activity. Among six rice varieties, cultivated in Korea, ${\alpha}-glucosidase$ activity of Oryza savita L. cv. Ilpumbyeo was the highest with 125.03 unit/ml and it had maximum specific activity with 8.52 unit/mg protein when rice seeds were grown for 3 days after germination. For the production of AA-2G using crude extract of O. savita L. cv. Ilpumbyeo, maltose was most effective glucose donor. The optimum concentration of maltose and ascorbic acid were 125 mM and 175 mM, respectively. The optimum concentration of ${\alpha}-glucosidase$ was 100 unit. The most effective buffer was 100 mM sodium citrate. The optimum pH and temperature were 5.0 and $60^{\circ}C$, respectively. Under the optimum condition, $108.43\;{\mu}M/unit$ of AA-2G was produced from ascorbic acid after 35 minutes of reaction, which corresponds to 6.2% of conversion ratio based on the amount of ascorbic acid used.

• Korean Journal of Food Science and Technology
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• v.44 no.2
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• pp.251-256
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• 2012

Stilbenes are known as antioxidants and some of them demonstrate anti-pigmentation activity. The purpose of the present study was to investigate whether two stilbene compounds produced by biotransformation of the extract of $Morus$ $alba$ root show skin irritation and sensitization. In skin irritation test, 1% oxyresveratrol (OXY), and 5% OXY, and 1% oxyresveratrol-3-$O$-glucoside (OXY-3) showed a P.I.I score of 0, 0.04, and 0, respectively. Accordingly, the two stilbenes were evaluated to be virtually 'non-irritant' materials. In a skin sensitization study by GPMT, 1% OXY, 5% OXY, and 1% OXY-3 did not cause edema and erythema at 24 h and 48 h after topical application and exhibited a sensitization score of 0 and a rate of 0%. Consequently, it was confirmed that OXY and OXY-3 had no contact allergic sensitization in GPMT. Therefore, OXY and OXY-3 might be potential candidates as skin-whitening agents without posing any serious side effects.

• Journal of Life Science
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• v.20 no.6
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• pp.838-844
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• 2010

A fibrinolytic enzyme of Streptomyces corcohrussi from soil sediment was purified by chromatography using DEAE-Sephadex A-50 and Sephadex G-50. The analysis of SDS-polyacrylamide gel suggested that the purified enzyme is a homogeneous protein and the molecular mass is approximately 34 kDa. The purified enzyme showed activity of 0.8 U/ml in a plasminogen-rich fibrin plate, while its activity in a plasminogen-free fibrin plate was only 0.36 U/ml. These results suggested that the purified enzyme acts as a plasminogen activator. The fibrinolytic activity of the enzyme under the supplementation of protease inhibitors, $\varepsilon$-ACA, t-AMCHA and mercuric chloride in the enzyme reaction was less than 24%, indicating that it could be modulated by the plasmin and/or fibrinogen inhibitors involved in the fibrinogen-to-fibrin converting process. As time passed, $Zn^{2+}$, a heavy metal ion, inhibited the activity to 34.1%. The optimum temperature of the purified enzyme was approximately $50^{\circ}C$ and over 92% of the enzyme activity was maintained between pH 5.0 and 8.0. Therefore, our results provide a potential fibrinolytic enzyme as a noble thrombolytic agent from S. corcohrussi.

• Food Science and Preservation
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• v.23 no.6
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• pp.765-771
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• 2016

Omija-cheong, concentrated extracts from sugar-treated Omija fruit (Schisandra chinensis Baillon), is produced by traditional manner in Korea. The quality characteristics of Omija-cheong processed at low temperature with a pilot-scale were investigated to optimize the incubation time. With increasing incubation time in processing Omija-cheong, the pH level of Omija-cheong remained constant, while titratable acidity and organic acids increased. Fresh Omija fruits contained citric, malic and succinic acids, most of which were extracted into concentrated extracts after 37 days of incubation and reached to the stable concentration after 47 days of incubation. Titratable acidity in Omija-cheong gradually increased from 1.18% to 2.71%, and also was correlated with total concentration of organic acids. About 80% of supplemented sucrose for manufacturing Omija-cheong was converted into glucose and fructose until 68 days of incubation, and the composition of free sugars was maintained to be stable up to 138 days of incubation. The contents of total flavonoids and phenolic compounds in Omija-cheong were 24.1 mg-GAE/L and 1,635 mg-QE/L at 57 days of incubation, which were more than 9 and 5 times higher than those in Omija fruits, respectively. From the quality characteristics in processing Omija-cheong by low-temperature incubation, more than 60 days of incubation is required for the constant quality and value-added beverage.

• Food Science and Preservation
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• v.24 no.2
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• pp.237-245
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• 2017

Lactic acid fermentation of Flammulina velutipes (FV) powder was optimized to produce higher content of ${\gamma}-aminobutyric$ acid (GABA). FV powder (10%) was fermented with 0.5% yeast extract, 1% glucose, 5% mono sodium-L-glutamate (MSG) by Lactobacillus plantarum EJ2014 for 5 days at $30^{\circ}C$. The pH decreased from 6.1 to 4.4 for first 2 days after then increased to 6.2 for following 5 days. While the acidity increased from 0.5% to 1.3% for 2 days, after then decreased to 0.4% for 5 days. Viable cell count showed higher value of $2.2{\times}10^9CFU/mL$ after fermentation for 5 days. In particular, 3.54% MSG as a substrate was completely utilized during lactic acid fermentation, indicating higher 2.31% GABA content. The fermented FV powder showed higher antioxidant properties than that of un-fermented FV power. $IC_{50}$ values of DPPH radical scavenging and ABTS radical scavenging activities were 1.11 mg/mL and 2.58 mg/mL, respectively. Conclusively, natural fermented seasoning from the lactic acid fermentation of 30g of FV powder and 1 g of roasted wheat bran could provide the functional ingredients with 17% GABA, probiotics and dietary fiber, which is used for health food and functional seasoning.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.446-451
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• 1997

The primary alcohol groups of four kinds of polysaccharides (com starch, rice starch, sweet potato starch, and cellulose), with different structures and water solubilities, were oxidized to carboxyl groups using 2,2,6,6-tetramethyl-1-piperidine oxoammonium ion (TEMPO) at $25^{\circ}C$. The optimum pH, TEMPO content, and NaBr content for the TEMPO/hypobromite-catalyzed oxidation of the polysaccharides were $10.5{\sim}11.0$, 10 mmol/mol primary alcohol, and 0.49 mmol/mol primary alcohol, respectively. The oxidation degree for the primary alcohol group was more than 90% for all four kinds of the polysaccharides. The oxidation process greatly increased the water solubility of the polysaccharides. Water-insoluble polysaccharide such as cellulose became water-soluble to the extent of 8.42% (w/v). And also, the polysaccharides with very low water solubility (less than 0.10% (w/v)) such as com starch, rice starch, and sweet potato starch had high water solubility of approximately 45%(w/v). The gel-forming abilities with calcium ion were determined. The oxidized polysaccharides are new anionic polymers with unique structures that could have application as gums, gels, and films.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.2
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• pp.256-260
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• 2008

In this study, the composition of saponin and physico-chemical properties of Korean red ginseng extract was analyzed based on various extracting conditions. The total saponin and individual ginsenoside concentration of the red ginseng extract showed a decreasing trend as the extracting temperature and time increased; also, the extracting condition at $75^{\circ}C$ for 24 hours showed the highest concentration. In contrast, the concentration of $Rg_3$ increased as the extracting temperature and time increased within the particular range. It was suggested that a certain part of ginsenosides changes to $Rg_3$ according to extracting conditions; thus, the concentration of $Rg_3$ increased. Physico-chemical properties of Korean red ginseng extract based on the extracting conditions were different compared to those for saponin; so, as the extracting temperature and time increased, brix and color difference increased but pH decreased indicating stabilization of the overall quality of the product. Therefore, the most appropriate extracting condition for both the product quality of Korean red ginseng extract and stable extraction of saponin was $80^{\circ}C$ within 48 hours, minimizing the loss of ginsenosides.

• Journal of Life Science
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• v.20 no.5
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• pp.683-690
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• 2010

The yeast strains of Saccharomyces diastaticus produce one of three isozymes of an extracellular glucoamylase I, II or III, a type of exo-enzyme which can hydrolyse starch to generate glucose molecules from non-reducing ends. These enzymes are encoded by the STA1, STA2 and STA3 genes. Another gene, sporulation-specific glucoamylase (SGA), also exists in the genus Saccharomyces which is very homologous to the STA genes. The SGA has been known to be produced in the cytosol during sporulation. However, we hypothesized that the SGA is capable of being secreted to the extracellular region because of about 20 hydrophobic amino acid residues at the N-terminus which can function as a signal peptide. We expressed the cloned SGA gene in S. diastaticus YIY345. In order to compare the biochemical properties of the extracellular glucoamylase and the SGA, the SGA was purified from the culture supernatant through ammonium sulfate precipitation, DEAE-Sephadex A-50, CM-Sephadex C-50 and Sephadex G-200 chromatography. The molecular weight of the intact SGA was estimated to be about 130 kDa by gel filtration chromatography with high performance liquid chromatography (HPLC) column. Sodium dedecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed it was composed of two heterogeneous subunits, 63 kDa and 68 kDa. The deglycosylation of the SGA generated a new 59 kDa band on the SDS-PAGE analysis, indicating that two subunits are glycosylated but the extent of glycosylation is different between them. The optimum pH and temperature of the SGA were 5.5 and $45^{\circ}C$, respectively, whereas those for the extracellular glucoamylase were 5.0 and $50^{\circ}C$. The SGA were more sensitive to heat and SDS than the extracellular glucoamylase.