• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.265-275
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• 2006

It is in its infancy to use bacteria as a novel biotechnology for leaching precious and heavy metals from raw materials. The objective of this study was to investigate biogeochemical processes of iron leaching from magnetite reduction by iron-reducing bacteria isolated from intertidal flat sediments, southwestern part of Korea. Microbial leaching experiments were performed using commercial magnetite, Aldrich magnetite, in well-defined mediums with and without bacteria. Water soluble Fe production was determined by ICP analysis of bioleached samples in comparison to uninoculated controls, and the resulting precipitated solids were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The extent of iron leaching from magnetite in the aerobic conditions (Fe = 107 ppm) was higher than that in the anaerobic environments (Fe = 94 ppm). In the anaerobic conditions, Fe(III) in commercial magnetite was also reduced to Fe(II), but no secondary mineral phases were observed. Amorphous iron oxides formed in the medium under aerobic conditions where there was sufficient supply of oxygen from the atmosphere. SEM observation suggests that the reduction process involves dissolution-precipitation mechanisms as opposed to solid state conversion of magnetite to amorphous iron oxides. The ability of bacteria to leach soluble iron and precipitate amorphous iron oxides from crystalline magnetite could have significant implications for biogeochemical processes in sediments where Fe(III) in magnetite plays an important role in the largest pool of electron acceptor as well as the tool as a novel biotechnology for leaching precious and heavy metals from raw materials.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.181-193
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• 2018

Nitrous oxide ($N_2O$) is a potent greenhouse gas as well as an ozone-depleting substance. $N_2O$ is emitted during the biological nitrogen removal process in wastewater treatment systems (WTSs), and has significant environmental impacts. In this study, $N_2O$ emission in WTSs was comprehensively reviewed to better understand the effects of key parameters on $N_2O$ emission and obtain useful guidelines for $N_2O$ mitigation strategies in WTSs. Three biological pathways leading to $N_2O$ emission are hydroxylamine oxidation, nitrifier denitrification, and heterotrohic denitrification. Measurements at lab-, pilot- and full-scale WTSs have shown large variations in $N_2O$ emission (0-95% of N-loaded) during wastewater treatment. In the full-scale WTSs (0-14.6% $N_2O$ of N-loaded), the average and median values were 1.95% and 0.2% of N-loaded, respectively. Dissolved oxygen, nitrite concentrations, and chemical oxygen demand (COD)/N ratio are the most important parameters leading to $N_2O$ emission. A variety of operational strategies have been suggested to minimize $N_2O$ emission from WTSs. A new $N_2O$ mitigation strategy involving the introduction of microorganisms with high $N_2O$ reductase activity or oxygenic denitrification ability has been proposed as an alternative canonical denitrification.

• Food Science and Preservation
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• v.14 no.4
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• pp.419-424
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• 2007

Fruits and vegetable extracts are well-known as healthy foods. Such foods have been used as herbal medicines or traditional therapies for centuries. To assess biological activities in grapes, we examined the immunomodulating activities of water extracts from four kinds of grapes (cultivars Kyoho, Delaware, Campbell, and Niagara). We explored possible antioxidant and anticancer activities using antioxidant assays such as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) reduction assay, the ferric iron reducing ability of plasma (FRAP) assay, a cell proliferation assay, an NO inhibition assay, a wound healing assay, and an IL-4/IL-13 elicitation assay. Methanol extracts of grapes were tested. The results showed that each grape extract had potent antioxidant activities. The grape extracts increased cell proliferation and NO production activities in tumor cell lines. IL-4 and IL-13 cytokine levels were decreased in mouse primary spleen cells by treatment with any extract. These results suggest that grape extracts can be used as biomaterials with immunomodulating activities.

• 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.

• The Journal of Korean Philosophical History
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• no.36
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• pp.173-202
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• 2013

In Korea The understanding about physical body contains several cultural and historical experiences. In the modern times several discussions bring about changes from moral training to physical education. Physical education shows clearly modern physical human being by destructions of confusional human being. In confusional philosophy human body contains moral facts such as moral training. Moral training shows right mind, so every physical acts target mental and cultural training. So in this capitalism, it is needed o training right moral training and right physical education.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.662-667
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• 2009

In this study, four Korean black raspberry wines were developed using raspberries from different regions in Korea; Gochang (G), Hoengseong (H), Jeongeup (J), Sunchang (S). Sample wines were monitored for titratable acidity, ethanol, pH, reducing sugar content, color intensity, hue, total phenolic content, and organic acids during alcoholic fermentation and aging. After fermentation was complete, the pH levels in the four wines were in a similar range (3.43-3.52), while total acidity levels ranged from 9.98 to 16.2 g/L, which were significantly different among the four wines. During 120 days of aging, the ethanol content ranged from 15.8 to 16.40% which corresponds to a good conversion rate of sugars. Among the four samples tested, the wine made with Jeongeup raspberries showed the highest levels of total phenolic content, and other color values such as hue and intensity. The predominant organic acids were citric acids (3.30-4.89 mg/mL) and succinic acids (1.92-3.48 mg/mL). Overall the wine made with Jeongeup raspberries showed differences in physico-chemical compositions compared to the other wines made with Gochang, Hoengseong, and Sunchang raspberries, respectively.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.207-211
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• 1995

In order to determine the mechanism of cold tolerance in crops, changes in biochemical factors related with the biological reduction of molecular oxygen upon cold shock treatment were analyzed at an early stage of Brassica germination. As the cold shocked seedlings were recovered under the normal growth condition for 24 hours, the peroxidase activities in cold sensitive rape(B. napus) and cold tolerant 'Sandongchae'(B. campestris) were considerably increased by 33% and 87% in root fraction and, 84% and 206% in hypocotyl, respectively. The content of superoxide($H_2O_2$) in hypocotyl fraction was dramatically accumulated until 8 hours after recovery and then gradually decreased. The extent of superoxide accumulation was severer in B. napus than B. campestris. At 24 hours after cold shock, $H_2O_2$ content was decreased to the nearly control level in B. campestris but still remained by 38%, in E. napus. Even though $H_2O_2$ content in hypocotyl fraction was decreased only 2% in B. napus during cold shock, while in B. campestris it was severely decreased about 15%. On the other hand, the cold shock at 3 days after Uniconazole treatment was more effective in increase of peroxidase activity than each separate treatment.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.2
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• pp.79-89
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• 1995

Changes of microbial activity and physicochemical environment during composting of papermill sludge(PMS) in the pilot plant equipped with an agitated bed reactor were monitored for establishing the efficient composting system. Microbial activity determined as the evolution of $CO_2$ increased for the first 10 days after introduction of PMS to the reactor and decreased thereafter. Population changes of microorganisms in the reactor-PMS were not typical as in windrow system. The ratio of thermophilic bacteria to mesophilic bacteria, however, increased slowly even 23 days after introduction. Temperature of PMS increased rapidly from the first day and reached $62^{\circ}C$ at 7 days after introduction and decreased slowly thereafter. The acidity of PMS was pH 6.8 initially, increased to pH 8.0 after 7 days and decreased to pH 7.4 after 23 days. Redox potential(Eh) of PMS was -320mV at the beginning of composting, but it was increased with time to reach -15mV after 23 days composting. However, Eh of PMS pre-sterilized before measurement was average 50mV, regardless of composting periods indicating the major role of microorganisms during composting process. Water content of PMS was 67% initially and decreased to about 50% after 23 days composting in the reactor. Less than 13 days-old compost inhibited growth of radish in the container mixture with bed soil. Based on statistical analysis of microbial and physicochemical parameters of PMS during composting, an equation was developed for determining compost maturity. A number of experiments using various organic wastes are required before application of the formular to the practical use.

• Journal of Animal Environmental Science
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• v.18 no.2
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• pp.99-110
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• 2012

The purpose of the study is to collect basis data for to establish standard administrative processes of liquid fertilizer treatment. From this survey we could make out the key point of each step through a case of effective liquid manure treatment system in pig house. It is divided into six step; 1. piggery slurry management step, 2. Solid-liquid separation step, 3. liquid fertilizer treatment (aeration) step, 4. liquid fertilizer treatment (microorganism, recirculation and internal return) step, 5. liquid fertilizer treatment (completion) step, 6. land application step. From now on, standardization process of liquid manure treatment technologies need to be develop based on the six steps process.

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.154-161
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• 2010

In the study, the effect of acid and salt concentrations during the production of bio-ethanol from various brwon-algae raw materials was investigated. Especially, the possibility of the conversion of various polysaccarides contained in Laminaria japonica was studied. Bio-ethanol was produced by Saccharomyces cerevisiae KCCM1129 strains in Laminaria japonica. The maximum bio-ethanol production of 2.09 g/L using heat-treatment of Laminaria japonica was achieved. The optimum concentration for reducing sugar conversion by Laminaria japonica was found to be 3.95 g/L at the HCl concentration of 0.1 N. But bio-ethanol production was higher than the case without the non-acid pretreatment. Among the various polysaccharides, only mannitol produced maximum 3.09 g/L bio-ethanol. In case of laminaran, the ethanol was produced only at 0.15 g/L only in 0.1 N HCl pretreatment medium and cell growth was higher than other pretreatment.