• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.202-208
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• 2006

Juice obtained from premature citrus fruits was deacidified by electrodialysis (ED), and its physicochemical and functional properties were evaluated. Total acidities decreased from 3.15 (Aug), 1.62 (Sep), and 1.45% (Oct) to 2.37 (Aug), 0.86 (Sep), and 0.74% (Oct) by electrodialysis for 100 min, respectively, whereas $^{\circ}Brix$ to acid ratio increased, and pH and color remained almost unchanged. Free sugar content of premature citrus juice remained almost unchanged, while organic acid content decreased significantly. Narirutin and hesperidin contents among flavonoids slightly, but not significantly, decreased. $K^+,\;PO_4\;^{2-},\;SO_42^-,\;and\;Cl^-$ contents decreased by ED, with $K^+$ content showing more than 60% decrease, while $Na^+$ content increased 2.5-3.5 times. Total polyphenol content and electron-donating ability decreased slightly by ED, while nitrite-scavenging ability remained almost constant. Sensory evaluation indicated juice (Sep) subjected to ED processing to $12^{\circ}Brix$ with sugar had the highest preference.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.98-104
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• 2001

Cultivation area of the plastic film-house has been continuously increased with the increase of consumers' income. Intensive land use without fallowing or crop rotation caused severe problem such as salt accumulation in soils and in turn retarded growth and low productivity. This study was carried out to solve them derived from longterm intensive farming practices. Seven farmers who are practicing plastic film-house cultivation were recommended for case study by municipal government and selected for their excellency of cultivation and soil management. The cultivation periods of these systems were in the range of 5 to 40 years in the regions mainly located in alluvial soil cultivated with cucumber, tomato and red pepper. The soils texture of the excellent farmers' fields were silt loam or sandy loam, ranged from 7 to 15 percents of clay contents. Soil bulk density, depth of plowing layer and soil aggregates contents of the farmers' soils were 0.89, 23.1 cm, 61.6% whereas those in neighboring soils were 1.10, 17.8 cm, 54.2 %, respectively. And pH, OM and $NO_3-N$ of the farmers' soils also were better than those of neighboring soils. There was no difference in population densities of nematode between the good farmers' and neighboring soils, but actinomyces and Fusarium densities of recommended farmers' soils were better than neighboring soils. The major farming practices by the good farmers were characterized by deep plowing with flooding, amendment of crude organic matter, and reduction of chemical fertilizer application before transplanting, and also drip irrigation and liquid manure application after planting. They also conducted solar sterilization with or without flooding, removal of plastic films during rainy days and culturing rice or corn as rotation crops to avoid the problems mentioned above.

• Journal of Life Science
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• v.26 no.7
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• pp.805-811
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• 2016

The present study was performed to evaluate the anti-oxidant and anti-proliferating activity of the water extract mixture of Cordyceps militaris (CM) and Allium tuberosum (AT). The water extract mixture rate of CM and AT was optimized by means of a sensory evaluation test. The optimized mixture rate were decided at 70% of CM, 30% of AT, and 10% of apple concentrate as an additive. The values of total acidity, pH, sugar contents, and turbidity of the water extract mixture were 0.1%, 4.28, 9.10 °Brix, and 1.48 respectively. The water extract mixture had effective DPPH radical scavenging activity, reducing power effect, and ABTS radical activity. DPPH radical activities of the water extract and the water extract mixture were 43.2% and 51.7% respectively; their reducing power (OD₇₀₀) was 1.14 and 1.43 respectively; and ABTS^.+ radical activities were 47.1% and 62.2% respectively. Also, the water extract mixture showed a higher anti-proliferating effect than the AT extract on human prostate cancer cells. These results provided experimental evidence that the water extract mixture of CM and AT is a better source of anti-oxidant and anti-cancer ingredients than a single extract of CM. In conclusion, the water extract mixture of CM and AT will be beneficial in development of a functional drink.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.520-520
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• 2016

석유 화학공장에서 발생하는 spent sulfidic caustic (SSC) 폐수는 액화석유가스(LPG)나 천연가스(NG)의 정제과정에서 발생되는 것으로 고농도의 sulfide와 cresylic, phenolic 그리고 mercaptan 등이 포함된 독성과 냄새를 유발하는 물질이다. 이러한 물질들은 LPG나 NG의 정제과정에서 높은 산도를 가진 휘발성 황화합 물질들을 제거하기 위해 사용된 NaOH가 $H_2S$와 반응하여 발생하는 것이다. 진한 갈색 또는 검은색을 띄는 SSC 폐수는 12 이상의 높은 pH를 가지고 있으며 5~12 wt%의 높은 염분도를 가지고 있다. 또한 강한 부식성과 독성을 가진 황화합물의 농도가 1~4 wt%이며, 방향족 탄화수소 물질 (i.e. methanethiol, benzene, tolune and phenol)들도 다량 함유되어 있다. 따라서 이러한 유해 물질들은 기존의 하수처리 공정으로 방류하기 전에 완벽하게 처리해야만 하수처리 공정의 오염 부하량을 줄일 수 있다. 습식산화공정은 SSC 폐수를 처리하기 위해 흔히 사용되고 있는 물리-화학적 처리 공정이지만 고비용, 고에너지가 필요하며, 고온 및 고압에서만 작동되어 안전상의 문제점을 갖고 있다. 또한 습식산화공정을 거친 폐수는 배출허용기준을 만족하기 위해 생물학적 2차 처리가 반드시 필요하다. 철-과산화수소를 이용하는 펜톤산화 공정, 그리고 sulfide를 sulfate로 전환시키는 생물학적 처리 공정은 황화합물의 완전한 무기물화가 힘들며, 현장 적용 시 기술적 경제적 부담이 크다. 이러한 단점을 극복하고, SSC 폐수를 효과적으로 처리하기 위해 본 연구는, 높은 흡착력과 광산화력을 가진 흡착광산화 반응 시스템(Adsorption Photocatalysis System, APS)을 개발하였다. APS는 SSC 폐수를 시스템 내부로 유입하여 수중의 오염물질을 흡착광산화제로 구성된 반응구조체가 흡착하고, 흡착된 오염물질을 UV에너지와 이산화티타늄 광촉매의 광화학반응에 의해 최종적으로 무해한 물질로 환원시키는 폐수처리시스템이다. APS의 반응구조체는 태양에너지 및 인공에너지원에 의해 활용 가능하며, 난분해성 유기화합물질을 물과 이산화탄소로 분해할 수 있는 친환경적이고 경제적인 소재로서 널리 쓰이고 있는 이산화티타늄 광촉매와 화력발전소의 높은 소성온도에 의해 연소된 후 발생되는 bottom ash를 이산화티타늄의 지지체로 사용하여 높은 흡착력과 광촉매 산화력을 가진 복합물이다. 개발된 APS에 의해 SSC 폐수를 처리한 결과, COD 86.1%, 탁도 98.4%, sulfide 99.9%의 높은 처리효율을 보여주고 있다. 따라서 본 연구를 통해 개발된 APS는 강한 부식성과 독성 그리고 높은 농도를 가지고 있는 SSC 폐수를 효과적으로 처리할 수 있다.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.506-514
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• 2020

4-Hydroxybenzyl alcohol (4-HB alcohol) is one of the major active components of Gastrodia elata Blume, with beneficial effects on neurological disorders such as headache, convulsive behavior, and dizziness. Here, we developed a metabolically engineered Corynebacterium glutamicum strain able to produce 4-HB alcohol from 4-hydroxybenzoate (4-HBA). First, the strain APS963 was obtained from the APS809 strain via the insertion of aroK from Methanocaldococcus jannaschii into the NCgl2922-deleted locus. As carboxylic acid reductase from Nocardia iowensis catalyzes the reduction of 4HBA to 4-hydroxybenzaldehyde (4-HB aldehyde), we then introduced a codon-optimized car gene into the genome of APS963, generating the GAS177 strain. Then, we deleted creG coding for a putative short-chain dehydrogenase and inserted ubiCpr encoding a product-resistant chorismate-pyruvate lyase into the pcaHG-deleted locus. The resulting engineered GAS355 strain accumulated 2.3 g/l 4-HB alcohol with 0.32 g/l 4-HBA and 0.3 g/l 4-HB aldehyde as byproducts from 8% glucose after 48 h of culture.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.1
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• pp.39-47
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• 2024

In this study, LiDAR-detective black material is synthesized by recycling silicon sludge (SS) that is generated from semiconductor manufacturing process, and its recognition is confirmed using two types of LiDAR sensors (MEMS and Rotating LiDAR). In detail, metal impurities on the surface of SS is removed, followed by coating of titanium dioxide (TiO₂) and subsequent chemical reduction to obtain SS-derived black TiO₂ (SS/bTiO₂) material. As-prepared SS/bTiO₂ is mixed with transparent paint to prepare hydrophilic black paints and applied to a glass substrate using a spray gun. SS/bTiO₂-based paint shows similar blackness (L^*=15.7) compared to commercial carbon black-based paint, and remarkable NIR reflectance (26.5R%, 905nm). Furthermore, MEMS and Rotating LiDAR have successfully detected the SS/bTiO₂-based paint. This is attributed to the occurrence of high reflection of light at the interface between the black TiO₂ and the silicon sludge according to the Fresnel's reflection principle. Hence, the new application field to effectively recycle silicon sludge generated in the semiconductor manufacturing process has been presented.

• Journal of Life Science
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• v.24 no.10
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• pp.1110-1117
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• 2014

Tidal flats are continuously contaminated by human activities. This study assessed the bioremediation efficiency of tidal flat soil using microcosm reactors and microorganisms originating from the tidal area. We screened 135 bacterial strains that produce extracellular enzymes from the tidal area located in the North port of Incheon bay. Two bacterial strains (Pseudoalteromonas sp. and IC35 Halothiobacillus neapolitanus IC_S22) were selected and used in the microcosm reactors, which were specially designed to functionally mimic the ecological conditions of the tidal flats. Pseudoalteromonas sp. IC35 was selected based on its relatively high activity of the enzymes amylase, cellulose, lipase, and protease. Halothiobacillus neapolitanus IC_S22 was selected for oxidation of sulfur. The M1 and M2 microcosm reactors were operated by continuous feeding of seawater under the same conditions, but M2 was first inoculated with Pseudoalteromonas sp. IC35 before the seawater feeding. The initial COD in both the M1 and M2 microcosm reactors was 320 mg/l. The final COD was 21 mg/l (M1) and 7 mg/l (M2). The M3 and M4 microcosm reactors were operated by continuous feeding of seawater under the same conditions, but M4 was first inoculated with H. neapolitanus IC_S22. The initial sulfate concentration in both the M3 and M4 microcosm reactors was 660 mg/l, and the maximum sulfate concentration was 1,360 mg/l (M3) and 1,600 mg/l (M4).

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.517-523
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• 2008

The degradation mechanism of Triclosan(TCS), which is a potent broad-spectrum antimicrobial agent and has been considered as an emerging pollutant, was investigated in the Fenton and the hybrid reaction with Fe$^{2+}$ and UV-C. The results show that the Fe$^{2+}$ is oxidized to 30% by $H_2O_2$, 28% by UV-C, and 15% by UV-A for 10 min. The degradation rate of TCS for beginning time(10 min) was higher in UV-C only reaction than that in hybrid reaction, which of the order was inverted according to the lapse of reaction time. The effect of methanol was the greatest in Fenton reaction, in which the degradation rate of TCS decreased from 90% to 5% by the addition of methanol. Chloride, ionic intermediate, was produced to 77% for 150 min of hybrid reaction(Fe$^{2+}$ + UV-C), which was the greatest. In case with methanol, the generation rate of chloride for 15 min was ignorable in all reactions($\leq$2%) but the hybrid reaction with Fe$^{2+}$ and UV-C(12%). Additionally, the removal rate of TOC in each reaction was estimated as the followed orders; Fe$^{2+}$ + UV-C > Fe$^{2+}$ + $H_2O_2$ > Fe$^{2+}$ + UV-A > UV-C > UV-A. However, the Fenton reaction was almost stopped after 90 min because the reaction between Fe$^{2+}$ and $H_2O_2$ cannot be kept on without adding the oxidant. The phenomena was not observed in the hybrid reaction. In view of generating chloride, the reductive degradation of TCS may be in the hybrid reaction with Fe$^{2+}$ and UV-C, which is favorable to mineralize halogenated organic compounds such as TCS. Consequently, the hybrid process with Fe$^{2+}$ and UV-C may be considered as the alternative treatment method for TCS.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.201-206
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• 2003

An apple wine was prepared by fermentation at $25^{\circ}C$ for 2 weeks using Saccha개myces cerevisiae KCCM 12224, followed by aging at $15^{\circ}C$ for 14 weeks, and its physicochemical and microbiological changes were investigated. The viable bacterial cell numbers, increased from $1.4{\times}10^3\;CFU/ml$ at the beginning of fermentation, to $2.8{\times}10^6\;CFU/ml$ after 2 weeks, but decreased to $1.0{\times}10^5\;CFU/ml$ after aging. The viable yeast cell numbers changed from $4.3{\times}10^4\;CFU/ml$ to $1.2{\times}10^7\;CFU/ml$ during the fermentation, and decreased to $1.2{\times}10^4\;CFU/ml$ after aging. Sugar content changed from $20.0^{\circ}Brix$ to $8.5{\circ}Brix$, and reducing sugar content was changed from 9.66% to 6.44%. Alcohol content and acidity increased to 7.0% and from 0.19% to 0.24%, respectively. No changes in acidity, pH, and sugar content were observed during the aging, but reducing sugar and solid contents decreased. When apple wine was fultered through $0.45\;{\mu}m$ nitrocellulose membrane followed by various ultrafiltration membranes with different molecular weight cut-off values, the initial flux $(121.2\;liter/m^2/h)$ and the average flux of Biomax 100k membrane were the highest among the membranes used. These membrane filtration treatments resulted in complete removal of microorganisms as well as decrease in turbidity and solid content without changes in other chemical properties. No changes in the physicochemical properties of the apple wine and no microorganisms were detected during the storage at $156{\circ}C$ for 6 weeks.

• Journal of Soil and Groundwater Environment
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• v.14 no.3
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• pp.40-46
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• 2009

The applicability of a well-type autotrophic sulfur-oxidizing reactive barrier (L $\times$ W $\times$ D = $3m\;{\times}\;4\;m\;{\times}\;2\;m$) as a long-term treatment option for nitrate removal in groundwater was evaluated. Pilot-scale (L $\times$ W $\times$ D = $8m\;{\times}\;4\;m\;{\times}\;2\;m$) flow-tank experiments were conducted to examine remedial efficacy of the well-type reactive barrier. A total of 80 kg sulfur granules as an electron donor and Thiobacillus denitrificans as an active bacterial species were prepared. Thiobacillus denitrificans was successfully colonized on the surface of the sulfur granules and the microflora transformed nitrate with removal efficiency of ~12% (0.07 mM) for 11 days, ~24% (1.3 mM) for 18 days, ~45% (2.4 mM) for 32 days, and ~52% (2.8 mM) for 60 days. Sulfur granules attached to Thiobacillus denitrificans were used to construct the well-type reactive barrier comprising three discrete barriers installed at 1-m interval downstream. Average initial nitrate concentrations were 181 mg/L for the first 28 days and 281 mg/L for the next 14 days. For the 181 mg/L (2.9 mM) plume, nitrate concentrations decreased by ~2% (0.06 mM), ~9% (0.27 mM), and ~15% (0.44 mM) after $1^{st}$, $2^{nd}$, and $3^{rd}$ barriers, respectively. For the 281 mg/L (4.5 mM) plume, nitrate concentrations decreased by ~1% (0.02 mM), ~6% (0.27 mM), and ~8% (0.37 mM) after $1^{st}$, $2^{nd}$, and $3^{rd}$ barriers, respectively. Nitrate plume was flowed through the flow-tank for 49 days by supplying $1.24\;m^3/d$ of nitrate solution. During nitrate treatment, flow velocity (0.44 m/d), pH (6.7 to 8.3), and DO (0.9~2.8 mg/L) showed little variations. Incomplete destruction of nitrate plume was attributed to the lack of retention time, rarely transverse dispersion, and inhibiting the activity of denitrification enzymes caused by relatively high DO concentrations. For field applications, it should be considered increments of retention time, modification of well placements, and intrinsic DO concentration.