• 대한화학회지
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• 제57권3호
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• pp.357-360
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• 2013

Sustainable development is a balance between environment and development. Sustainable development requires sustainable supplies of clean, affordable, and renewable energy sources that do not cause negative impact to the society. This article introduces a green chemistry method to synthesize 2-amino-4H-chromenes that reduces or eliminates the use and generation of hazardous substances in the design, manufacture, and application of chemical products. This method is described using copper (II) sulfate pentahydrate, as a green and reusable catalyst on water. The products were obtained at very good yields, short reaction time, and at lower cost than other reported procedures.

• KSBB Journal
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• 제29권3호
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• pp.131-138
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• 2014

In this study, we isolated two novel chitinase producing bacterial strains from yellow loess samples collected from Jullanamdo province. The chitinase producing bacteria were isolated based on the zone size of clearance in the chitin agar plates. Both of them were gram positive, rod ($2{\sim}3{\times}0.3{\sim}0.4{\mu}m$), spore-forming, and motility positive. They were facultative anaerobic, catalase positive and hydrolyzed starch, gelatin, and casein. From the 16s rRNA gene sequence analysis, the isolates were labeled as Bacillus licheniformis KYLS-CU01 and B. licheniformis KYLS-CU02. The isolates showed higher extracellular chitinase activities than B. licheniformis ATCC 14580 as a control. The optimum temperature and pH for chitinase production were $40^{\circ}C$ and pH 7.0, respectively. Response Surface Methodology (RSM) was used to optimize the culture medium for efficient production of the chitinase. Under this optimal condition, 1.5 times higher chitinase activity of B. licheniformis KYLS-CU02 was obtained. Extracellular chitinases of the two isolates were purified through ammonium sulfate precipitation and anion-exchange DEAE-cellulose column chromatography. The specific activities of purified chitinase from B. licheniformis KYLS-CU01 and B. licheniformis KYLS-CU02 were 7.65 and 5.21 U/mg protein, respectively. The molecular weights of the two purified chitinases were 59 kDa. Further, the purified chitinase of B. licheniformis KYLS-CU01 showed high antifungal activity against Fusarium sp.. In conclusion, these two bacterial isolates can be used as a biopesticide to control pathogenic fungi.

• 한국환경과학회지
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• 제19권11호
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• pp.1385-1390
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• 2010

Repeated additions of untreated slurry to soil affected ecology and caused high levels of heavy metal in soil and ground water. The objective of this study was to evaluate heavy metal from hanwoo slurry with ferrous sulfate ($FeSO_4{\cdot}7H_2O$), aluminum sulfate [$Al_2(SO_4)_3{\cdot}14H_2O$, alum] and aluminum chloride ($AlCl_3{\cdot}6H_2O$) as a way to improve environmental management in hanwoo industry. The treatment rates, which were incorporated totally within the hanwoo slurry, were 1.0 g and 1.5 g of ferrous sulfate, alum and aluminum chloride/25 g of hanwoo slurry. The various rates of chemical additives significantly increased dry matter (9.98~13.94%) and decreased pH (3.48~6.52) compared with the controls. The use of chemical additives decreased Fe (11~29%), Al (7~12%), Zn (13~36%), and Cu (4~32%) contents, except for Fe in hanwoo slurry with ferrous sulfate and Al in hanwoo slurry with alum and aluminum chloride. In addition, the reduction in heavy metal should be associated with reduction in pH. In conclusion, the results of this study suggest that alum and aluminum chloride additives at rate of 1.5 g were cost-effective management practice that significantly reduces heavy metal from hanwoo slurry, while it may be improved environmental management.

• ALGAE
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• 제32권2호
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• pp.131-137
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• 2017

Although green algae of the genus Closterium are considered ideal models for testing toxicity in aquatic ecosystems, little data about the effects of toxicity on these algal species is currently available. Here, Closterium ehrenbergii was used to assess the acute toxicity of copper (Cu). The median effective concentration ($EC_{50}$) of copper sulfate based on a dose response curve was $0.202mg\;L^{-1}$, and reductions in photosynthetic efficiency ($F_v/F_m$ ratio) of cells were observed in cultures exposed to Cu for 6 h, with efficiency significantly reduced after 48 h (p < 0.01). In addition, production of reactive oxygen species significantly increased over time (p < 0.01), leading to damage to intracellular organelles. Our results indicate that Cu induces oxidative stress in cellular metabolic processes and causes severe physiological damage within C. ehrenbergii cells, and even cell death; moreover, they clearly suggest that C. ehrenbergii represents a potentially powerful test model for use in aquatic toxicity assessments.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.307-310
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• 2004

Micellar enhanced ultrafiltration (MEUF) is a surfactant-based separation process and it can remove heavy metal ions from aqueous stream effectively. However, it is necessary to recover and reuse surfactants for economic feasibility because surfactant is expensive. Foam fractionation was investigated for both anionic and cationic surfactant recovery. Chelating agent such as ethylenediaminetetraacetic acid (EDTA) was studied for the separation of heavy metals from surfactant solution. Anionic surfactants bound with heavy metals can be recovered by lowering pH (acidification). In this study, citric acid and imminodiacetic acid (IDA) were applied to release copper from sodium dodecyl sulfate (SDS) micellar solution and compared with EDTA. Precipitation of copper by ferricynide and sodium sulfide were also investigated. As a result, ca. 100 % of copper was released from SDS micellar solution by 5 mM of EDTA and citric acid. And 3.3 mM of ferricyanide formed precipitate with 82.7 % of copper. 5 mM of IDA and sodium sulfide released or formed precipitate 82.5 % and 58.9 % of copper, respectively. Citric acid is harmless to environments and ferricyanide precipitates with Cu easily. Therefore, it is considered that citric acid and ferricyanide have competiveness over a famous chelating agent, EDTA, for the separation of Cu from SDS solution.

• 방사성폐기물학회지
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• 제19권4호
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• pp.469-477
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• 2021

Safe storage of spent nuclear fuel in deep underground repositories necessitates an understanding of the long-term alteration of metal canisters and buffer materials. A small-scale laboratory alteration test was performed on metal (Cu or Fe) chips embedded in compacted bentonite blocks placed in anaerobic water for 1 year. Lactate, sulfate, and bacteria were separately added to the water to promote biochemical reactions in the system. The bentonite blocks immersed in the water were dismantled after 1 year, showing that their alteration was insignificant. However, the Cu chip exhibited some microscopic etch pits on its surface, wherein a slight sulfur component was detected. Overall, the Fe chip was more corroded than the Cu chip under the same conditions. The secondary phase of the Fe chip was locally found as carbonate materials, such as siderite (FeCO₃) and calcite ((Ca, Fe)CO₃). These secondary products can imply that the local carbonate occurrence on the Fe chip may be initiated and developed by an evolution (alteration) of bentonite and a diffusive provision of biogenic CO₂ gas. These laboratory scale results suggest that the actual long-term alteration of metal canisters/bentonite blocks in the engineered barrier could be possible by microbial activities.

• Journal of Animal Science and Technology
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• 제47권4호
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• pp.537-546
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• 2005

양돈용 배합사료에 있어 사용빈도가 높은 첨가물질인 항생제(Chlortetracycline 110ppm), 황산동(Cu 125ppm) 및 생균제(Bacillus licheniformis and Bacillus subtilis)의 첨가가 육성돈의 생산성, 영양소소화율, 구리의 배출량, 분내 미생물 변화 및 분뇨의 숙성에 미치는 영향을 알아보기 위해 평균 체중 20.78kg(S.D.0.35) 및 평균 일령 50일($\pm$2.3)인 삼원교잡종(Landrace$\time$Yorkshire$\time$Duroc) 거세돈 50두를 완전임의로 각 돈방별 5처리 5반복으로 배치하여 40일간 실시하였다. ADG와 ADFI 및 F:G는 처리별로 통계적인 유의차를 나타내지는 않았으며(P>0.10), 전 시험기간에 걸친 영양소 소화율은 첨가물질에 의해 영향을 받지 않는 것으로 나타났으나(P>0.10), 무첨가구와 각 처리구의 비교에서는 생균제 0.1% 첨가구가 무첨가구에 비해 건물(P=0.093), 유기물(P=0.155), 조단백질(P=0.056) 및 열량(P=0.052) 소화율에서 크게 개선되는 경향을 보여주었다. 처리별 분으로의 구리 배출량은 황산동 첨가구가 1,514mg/kg으로 다른 구에 비해 뚜렷한 증가를 보였다(P<0.001). 분중 총균수 및 대장균군수는 첨가에 의한 영향이 나타나지 않았으며(P>0.10). 슬러리의 시간경과에 따른 암모니아 발생량은 처음 3주간은 황산동 첨가구가 다른 구에 비해 뚜렷한 감소를 보였으나(P<0.001), 시간이 경과할수록 다른 첨가구와 비슷한 발생경향을 나타내었다. 항생제 첨가구는 초기 2주간은 다른 첨가구에 비해서는 낮았으나 황산동 첨가구 보다는 암모니아 발생량이 높았다(P<0.001). 결론적으로 양돈사료에 대한 항생제, 황산동 및 생균제의 첨가는 환경조절이 잘 이루어진 상태에서의 육성돈에게는 생산성에 대한 영향을 크게 미치지 않는다고 볼 수 있으며, 환경측면에서 볼 때 황산동의 첨가는 슬러리의 초기발효를 억제시켜 암모니아 가스발생을 감소시킬 수 있으나, 배출량 과다로 인한 환경부담 요인으로 작용할 수 있기 때문에 이에 대한 종합적인 연구가 지속되어야 할 것으로 사료된다.

• 미생물학회지
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• 제47권3호
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• pp.194-199
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• 2011

알칼리성 protease를 생산하는 호알칼리성 균주를 분리하여 Bacillus pseudofirmus HS-54로 동정하였고, HS-54가 생산하는 알칼리성 protease를 ammonium sulfate 침전, DEAE cellulose chromatography, sephadex G-100 gel filtration을 통과시켜 정제하였는데, 정제된 protease의 분자량은 27 kDa이었다. 정제된 효소의 반응최적 pH는 10.0이었고 pH 7.0-11.0에서 비교적 안정하였다. 또한 정제된 효소의 반응최적 온도는 $50^{\circ}C$이었고 $10-55^{\circ}C$에서 안정하였다. 금속이온에 대한 영향은 $Ca^{2+}$와 $Mg^{2+}$ 등에 의해 효소활성이 촉진되었으나, $Hg^{2+}$, $Zn^{2+}$, $Cu^{2+}$, $Al^{3+}$ 등에 의해서 효소활성이 저해되었다. 본 효소는 PMSF에 의해 강하게 저해를 받는 것으로 보아 serine protease에 속하는 것으로 판단된다.

• 한국수산과학회지
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• 제34권5호
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• pp.502-508
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• 2001

병원성 비브리오 속인 Vibrio furnissii의 용혈소를 분리정제하고 그 물리화학적 특성, 생물학적인 그리고 면역학적인 상호관련성을 검토하여, 다음과 같은 결과를 얻었다. 용혈소의 정제는 ammonium sulfate precipitation, DEAE-Sephadex A-50 (1st와 2nd)와 Sephaedx G-100 gel permeation chromatography를 거쳐 738배로 정제되었으며 회수율은 각각 $11.6\%$ 와 $5.2\%$로 나타났다 전기영동법으로 용혈소의 정제를 확인한 결과 단일 밴드의 형성을 관찰할 수 있었다. 분자량은 61 kDa이였으며 또한 SDS-PAGE 결과 subuint는 존재하지 않았다. 정제된 용혈소는 열에 불안정한 이열성 용혈소이며 $Cu^{2+},\;Zn^{2+}$와 cholesterol에 의해 용혈활성이 모두 저해되었다. 용혈기작에 있어서는 온도의존성 용혈기작으로서 최적 용혈의 온도는 $37^{\circ}C\sim47^{\circ}C$로 나타났다. 정제용혈소의 pH 안정성은 pH 6.0, 6.5, 10.0에서 각각 불안정하였다. 용혈활성에 있어서 최적 혈구 농도는 $1.0\sim2.0\%$였다. 또한 각종 동물 혈구의 감수성 시험 결과 두 용혈소 모두 토끼에서 가장 감수성이 높았으며 사람의 혈구에서는 B형 혈액형에서 다소 높은 감수성을 나타내었다.

• 한국미생물·생명공학회지
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• 제26권5호
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• pp.427-434
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• 1998

Xanthomonas sp. YL-37 이 생산하는 alkaline protease를 정제하기 위하여 ammonium sulfate로 침전시켜 회수하여 CM-cellulose ion exchange resin column에 주입한 후 Sephadex G-100 column에 2회 통과시켜 단일효소를 얻었으며 분자량은 약 62,000 dalton으로 단일 subunit로 되어있다. 정제효소의 반응최적온도는 5$0^{\circ}C$였으며 특히 2$0^{\circ}C$에서도 최적활성의 약 40%를 유지하였다. 금속염에 대한 영향은 MnSO$_4$, MgSO$_4$, CaCl$_2$,등에 의해서 효소활성이 촉진되었으나 HgCl$_2$, ZnSO$_4$, CuSO$_4$ 등에 의해서 효소활성이 저해되었다. 본 효소는 EDTA, EGTA에 의해서 강하게 저해를 받는 것으로 보아 metal ion을 갖고 있는 metaloenzyme으로 보이며 효소에 결합된 cofactor는 $Mn^{2+}$이었으며 정제한 alkaline protease의 NH$_2$-말단 아미노산은 alanine이었다. 본 효소의 Km값은 4.0 mg/$m\ell$이 었고 Vmax는 5,500 unit/$m\ell$이었다.