• Applied Biological Chemistry
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• 제40권6호
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• pp.459-464
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• 1997

Cyclodextrin glycosyltransferase 생산균주를 토양으로부터 분리하여 형태학적, 생화학적 그리고 균주의 세포벽 지방산 조성분석에 의해 Bacillus brevis로 동정하였고, Bacillus brevis CD162로 명명하였다. 또한 배지조성에 따른 cyclodextrin glycosyltransferase의 최적생산조건을 검토한 결과, 2.0% soluble starch, 0.75% yeast extract, 0.5% bacto peptone, 0.2% $K_2HPO_4$, 0.05% $MgSO_4{\cdot}7H_2O$, 1.5% $Na_2CO_3$ (pH 10.2)의 배지 조건에서 $30^{\circ}C$에서 96시간 배양하였을 때 가장 높은 효소생산인 0.9 unit/ml을 얻을 수 있었다.

• 에너지공학
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• 제26권4호
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• pp.45-56
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• 2017

Coal power plants produce electricity for the nation's power grid, but they also produce more hazardous air emissions than any other industrial pollution sources. The quantity is staggering, over 386,000 tons of 84 separate hazardous air pollutants spew from over 400 plants in 46 states. In South Korea also, annual coal ash generation from coal-fired power plants were about 6 million tons in 2015. Pollutants containing particulate matter 10, 2.5 (PM10, PM2.5), heavy metals and dioxins from coal-fired power plant. The emissions threaten the health of people who live near these power plants, as well as those who live hundreds of miles away. These pollutants that have long-term impacts on the environment because they accumulate in soil, water and animals. The present study is to investigate the physical and chemical characteristics of coal-fired power plant fly ash and bottom ash contains particulate matter, whose particulate sizes are lower than $PM_{10}$ and $PM_{2.5}$ and heavy metals. There are wide commercial technologies were available for monitoring the PM 2.5 and ultra-fine particles, among those carbonation technology is a good tool for stabilizing the alkaline waste materials. We collected the coal ash samples from different coal power plants and the chemical composition of coal fly ash was characterized by XRF. In the present laboratory research approach reveals that potential application of carbonation technology for particulate matter $PM_{10}$, $PM_{2.5}$ and stabilization of heavy metals. The significance of this emerging carbonation technology was improving the chemical and physical properties of fly ash and bottom ash samples can facilitate wide re use in construction applications.

• 한국대기환경학회지
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• 제27권4호
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• pp.395-404
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• 2011

Asian dust evens took place in Seoul on 27~28 March and 31 March~1 April 2007, during which the mass and chemical compositions of $PM_{10}$ were measured at urban area in Seoul, Korea. In conjunction with $PM_{10}$ compositions, the behaviors of gas precursors such as CO, $O_3$, $SO_2$, and $NO_2$ and meteorological parameters and air mass trajectories were thoroughly examined. The earlier case was a weak dust incidence which was characterized by elevated concentrations of CO, $SO_2$ and $NO_2$ as well as secondary aerosols. In contrast, the later showed the trait of the dust aerosols associated with high $PM_{10}$ mass and $Ca^{2+}$ concentrations. In general, the fractions of ionic species against mass decreased with increase in dust loading. The ratios of ${SO_4}^{2-}$ to ${NO_3}^-$ and $SO_2$ to $NO_2$ were similar in temporal variations, suggesting the concentrations of secondary aerosols were sensitive to the level of precursor gases. In this study, $Na^+$ and $Cl^-$ were also highly elevated during the heavy dust episode, which is thought to have originated from alkaline soils spreading through the northeast regions of China.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.189-195
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• 2002

Using Streptomyces sp. YU100 isolated from Korean soil, the fermentative production of phospholipase D was attempted along with its purification and characterization studies. When different carbon and nitrogen sources were supplemented in the culture medium, glucose and yeast extract were found to be the best. By varying the concentration of nutrients and calcium carbonate, the optimal culture medium was determined as 2.0% glucose, 1.5% yeast extract, 0.5% tryptone 0.3% calcium carbonate. During cultivation, the strain secreted most of the phospholipase D in the early stage of growth within 24 h. The phospholipase D produced in the culture broth exhibited hydrolytic activity as well as transphosphatidylation activity on lecithin (phosphatidylcholine). In particular, the culture broth showed 8.7 units/ml of hydrolytic activity when cultivated at $28^{\circ}C$ for 1.5 days. The phospholipase D was purified using 80% ammonium sulfate precipitation and DEAE-Sepharose CL-6B column chromatography, which produced a major band of 57 kDa on a 10% SDS-polyacrylamide gel with purity higher than 80%. The enzyme showed an optimal pH of 7 in hydrolytic reaction, and at pH 4 in a transphosphatidylation reaction. The enzyme activity increased until the reaction temperature was elevated to $60^{\circ}C$. The enzyme was relatively stable at high temperatures and neutral pH, but significantly unstable in the alkaline range. Among the detergents tested as emulsifiers of phospholipids, the highest enzyme activity was observed when 1.5% Triton X-100 was employed. However, no inhibitory effect by metal ions was detected. Under optimized reaction conditions, the purified enzyme not only completely decomposed PC to phosphatidic acid within 1 h, but also exhibited higher than 80% conversion rate of PC to PS by transphosphatidylation within 4 h.

• 한국미생물·생명공학회지
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• 제10권4호
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• pp.275-281
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• 1982

Trypsin에 대한 강한 저해물질을 생성하는 Streptomyces속 균주 AS-707을 토양으로부터 얻어 그 배양액에서 Trypsin inhibitor를 분리정제하여 저해물질의 안정성과 여러가지의 protease에 대한 저해성 여부를 검토한 결과는 다음과 같다. 배양액을 Amberlite IRC-50에 흡착 methanol추출. 2차 Amberlite IRC-50, CM-cellulosecolumn chromatography로 정제하여 active amorphous powder를 얻었는데 이 때의 비율은 26%였다. 분리정제된 물질은 trypsin 이외에 papain, $\alpha$-chymotrypsin, Azotobacter vineiandi protease와 Bacillus subtilis protease 등에 대해서도 저해작용을 나타내었으며, 안정성은 비교적 커서 10$0^{\circ}C$에서 120분간 가열해도 잔존활성이 약90%였으며, pH처리에 대해서는 37$^{\circ}C$에서 처리하면 산에서 Alkali에 걸치는 대단히 넓은 pH범위 (pH 2.0~12.0)에서 안정하였으나 6$0^{\circ}C$에서 처리하면 산에서는 안정하였으나 Alkali에서는 불안정하였다.

• Environmental Engineering Research
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• 제19권3호
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• pp.241-245
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• 2014

The As accumulation in part of roots, shoots, husks and grains of rice plants was significantly decreased with the increasing dosage of kaolin addition from 0.5% to 10% w/w. Kaolin addition could reduce As accumulation in rice plants, which mainly could be attributed to the formation of stable crystalline Al oxides bound As that decreased the available As in soil with decreased As accumulation in rice plants. The pH values of the soils did not change significantly when amended with kaolin. The pH values of the soils was neural that proper to adsorb of arsenic with $Al_2O_3$. Arsenic tends to adsorb with $Al_2O_3$ at acid neutral pH and with desorbing at alkaline pH. The dry weight of rice plant was significantly increased with the increasing dosage of kaolin addition from 2.5% to 10% w/w. The highest dry weight of rice plants was 6.67 g/pot achieved at kaolin addition of 10% w/w with about 13% increasing over the control, which was probably attributed to the highest As concentration formation with kaolin at this dosage. The results of this study indicated that kaolin has the potential to reduce As accumulation in rice plants and enhance the dry weight of rice plants.

• Applied Biological Chemistry
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• 제38권6호
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• pp.534-540
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• 1995

토양에서 분리된 호알칼리성 coryneform bacteria TU-19는 적어도 세종류의 단백질분해효소(Protease I, II, III)를 생성분비하였다. 이 균주의 효소생산과 관련된 배양조건을 조사해본 결과 최적온도 및 pH는 각각 $30^{\circ}C$와 10.0인 것으로 나타났다. 이틀 배양된 배양액으로부터 이 효소들을 정제하기 위해서 ammonium sulfate fractionation, gel filtration 및 QAE-Sephadex column chromatography 등을 순차적으로 행하였다. 그 결과 이들 세종류의 효소는 SDS-PAGE pattern으로 평가했을 때 single band로 순수 정제되었으며, 각각의 분자량은 120, 80, 45 kDa이었다. 정제된 효소의 특성을 살펴보면 Pretense I과 II의 최적 pH와 온도는 각각 $10.5,\;45^{\circ}C$이었으며, Protease III는 11.0과 $50^{\circ}C$로 나타났다. 또한 이들 세효소는 10 mM PMSF 농도에서 효소활성을 완전히 상실하였으며, pCMB, 1,10-phenanthroline, IAA, EDTA에는 별 영향이 없는 것으로 보아 serine protease의 일종으로 생각된다.

• 한국산림과학회지
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• 제7권1호
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• pp.28-34
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• 1968

식물생육(植物生育) 특(特)히 임목(林木) 생육(生育)함에 있어서 필수(必須) 양료외(養料外)에 여러 가지의 미량요소(微量要素)가 있는데 기중(其中) Na 함량(含量)이 내산성(耐酸性)에 대(對)하여 어떠한 효용(效用) 및 영향(影響)이 있는가를 구명(究明)하기 위(爲)하여 실험(實驗)하였다. 대체적(大體的)으로 가흡태(可吸態) Ca 분(分)이 적다고 인정(認定)되는 산성역(酸性域)에서 중성역간(中性域間)에 그 함량(含量)이 많았고 수종간(樹種間)에 함량(含量)의 차이(差異)가 컸는데 이것은 Hammer & Benne의 결과(結果)와도 같이 각(各) 수종(樹種)의 특성(特性)이라 본다. 또한 이의 함량(含量)은 수종(樹種)을 통(通)하여 시찰(視察)할 때 내산도(耐酸度)가 높은 수종(樹種)일수록 산성역(酸性域)에서 Sodium 함량(含量)이 많았고 Alkali 역(域)에서 Ca함량(含量)과 상관(相觀)을 가지며 산성역(酸性域)에서 부상관(負相關)을 나타내는 것으로 보아 토양산도(土壤酸度)에 대(對)한 적응성(適應性)에 유관(有關)한 인자(因子)로 인정(認定)된다. 특(特)히 Na는 K의 생리적(生理的) 작용(作用)을 일부(一部) 보충(補充)한다는 미확인설(未確認設)에 비추어서 앞으로 임목내(林木內)의 K함량(含量)을 추적(追跡)하여 본(本) 실험(實驗)을 보충(補充)하겠다.

• 인간식물환경학회지
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• 제24권6호
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• pp.585-593
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• 2021

Background and objective: Illegal open-air incineration, which is criticized as a leading source of air pollutants among agricultural activities, currently requires constant effort and attention. Countries around the world have been undertaking studies on the emission of heavy metal substances in fine dust discharged during the incineration process. A precise analytical method is required to examine the harmful effects of particulate pollutants on the human body. Methods: In order to simulate open-air incineration, the infrastructure needed for incineration tests complying with the United States Environmental Protection Agency (EPA) Method 5G was built, and a large-area analysis was conducted on particulate pollutants through automated scanning electron microscopy (SEM)-energy-dispersive X-ray spectroscopy (EDS). For the test specimen, high-density polyethylene (HDPE) waste collected by the DangJin Office located in Choongcheongnam-do was used. To increase the identifiability of the analyzed particles, the incineration experiment was conducted in an incinerator three times after dividing the film waste into 200 g specimens. Results: Among the metal particulate matters detected in the HDPE waste incineration test, transition metals included C (20.8-37.1 wt%) and O (33.7-37.9 wt%). As for other chemical matters, the analysis showed that metal particulate matters such as metalloids, alkali metals, alkaline earth metals, and transition metals reacted to C and C-O. Si, a representative metalloid, was detected at 14.8-20.8 wt%, showing the highest weight ratio except for C and O. Conclusion: In this study, the detection of metal chemicals in incinerated particulate matters was effectively confirmed through SEM-EDS. The results of this study verified that HDPE waste adsorbs metal chemicals originating from soil due to its own properties and deterioration, and that when incinerated, it emits particulate matters containing transition metals and other metals that contribute to the excessive production and reduction of reactive oxygen species.

• 유기물자원화
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• 제28권2호
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• pp.15-29
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• 2020

본 연구는 하수슬러지와 침출수 공정슬러지를 건조연료와 혼합하여 물리적 특성을 개선하고 악취를 저감하는 중성고화제를 개발하여 매립 복토재로 재활용하기 위한 연구이다. 슬러지와 건조연료의 배합비율(W/W)은 1:1이 적정하며 기계 혼합시험에서도 균질하게 혼합되었다. 슬러지는 건조연료와 혼합되면서 함수율과 점성은 저감되고, 입자와 입자사이에 공극이 생겨 통기성을 가지게 된 것을 알 수 있었다. 다양한 혼합시험과 악취시험 결과, 중성고화제는 악취저감에 효과적인 것을 알 수 있었으며, 주 원료는 하수슬러지 소각재로 폐기물의 재활용과 생산비용에 있어 경쟁력이 있다. 중성고화제를 적용하여 고화복토재를 생산하면 압축강도 등 물리적인 특성이 향상되고 복토재 사용 품질기준도 만족하다. 또한, 알칼리성 고화복토제 대비 복합악취는 1/3 (3,000 → 1,000), 고화제 사용량은 1/8 (50% → 6%)로 낮춘다는 것이 입증되었다. 그리고 이것은 토사와 혼합하여 식물재배를 위한 토지개량제로 활용이 가능함을 입증하기 위해 추가 연구가 진행되고 있다.