• 유기물자원화
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• 제16권4호
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• pp.57-63
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• 2008

본 연구에서는 돈분을 이용한 열분해공정(pyrolysis)에 의한 바이오오일의 특성을 분석하여 보고하였다. 기본적으로 bio-oil 생산을 위한 pilot auger형 반응기는 $400^{\circ}C{\sim}600^{\circ}C$의 고온을 유지하였다. 바이오오일의 특성은 수질분석, 열량가, 원소분석, GC/MS를 이용한 마이오일의 원소, $^1H$ NMR분광기에 의한 functional group 구명 등을 포함한다. 돈분시료를 이용한 바이오오일 생산량은 pilot auger 반응기의 온도가 $550^{\circ}C$일 때 바이오일 생산율은 질량의 21%로서 최대를 나타내었다. 이 결과는 본 연구에서 연속 auger형 반응기의 이송이 편리하고 bio-oil 생산량이 적지 않아 대체 축분처리기술의 하나로 검토할 수 있음을 보였다. 그러나 auger 반응기의 원료로의 열전도가 유동상 반응조보다 낮아서 향후 이를 개선하기 위한 연구가 성공적으로 수행되면 바이오오일 생산량을 제고시킬 수 있을 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1440-1445
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• 2010

Rhodococcus sp. JDC-11, capable of utilizing di-n-butyl phthalate (DBP) as the sole source of carbon and energy, was isolated from sewage sludge and confirmed mainly based on 16S rRNA gene sequence analysis. The optimum pH, temperature, and agitation rate for DBP degradation by Rhodococcus sp. JDC-11 were 8.0, $30^{\circ}C$, and 175 rpm, respectively. In addition, low concentrations of glucose were found to inhibit the degradation of DBP, whereas high concentrations of glucose increased its degradation. Meanwhile, a substrate utilization test showed that JDC-11 was also able to utilize other phthalates. The major metabolites of DBP degradation were identified as monobutyl phthalate and phthalic acid by gas chromatography-mass spectrometry, allowing speculation on the tentative metabolic pathway of DBP degradation by Rhodococcus sp. JDC-11. Using a set of new degenerate primers, a partial sequence of the 3,4-phthalate dioxygenase gene was obtained from JDC-11. Moreover, a sequence analysis revealed that the phthalate dioxygenase gene of JDC-11 was highly homologous to the large subunit of the phthalate dioxygenase from Rhodococcus coprophilus strain G9.

• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1750-1759
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• 2020

The characterization of cytochrome P450 CYP125A13 from Streptomyces peucetius was conducted using cholesterol as the sole substrate. The in vitro enzymatic assay utilizing putidaredoxin and putidaredoxin reductase from Pseudomonas putida revealed that CYP125A13 bound cholesterol and hydroxylated it. The calculated K_D value, catalytic conversion rates, and Km value were 56.92 ± 11.28 μM, 1.95 nmol min^-1 nmol^-1, and 11.3 ± 2.8 μM, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis showed that carbon 27 of the cholesterol side-chain was hydroxylated, characterizing CYP125A13 as steroid C27-hydroxylase. The homology modeling and docking results also revealed the binding of cholesterol to the active site, facilitated by the hydrophobic amino acids and position of the C27-methyl group near heme. This orientation was favorable for the hydroxylation of the C27-methyl group, supporting the in vitro analysis. This was the first reported case of the hydroxylation of cholesterol at the C-27 position by Streptomyces P450. This study also established the catalytic function of CYP125A13 and provides a solid basis for further studies related to the catabolic potential of Streptomyces species.

• Environmental Analysis Health and Toxicology
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• 제13권1_2호
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• pp.43-53
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• 1998

Ambient air levels of polycyclic aromatic hydrocarbons(PAHs) are of concern because of their potential for adverse health effects including transformation of some of these substances to mutagens and carcinogens by mammalian microsomal enzyme system. Airbone particulate samples were collected by a conventional high-volume sampler and by an Anderson cascade impactor on 2 to 3 days in each month over a period of 1 year at a representative site of the heavy traffic area of Seoul from beptember 1994 to August 1995. Ten individual PAHs in sizable air particulates of each stage of two months were separated and analyzed by gas chromatography/mass spectrometry. As a results of analysis, the gross concentrations of PAHs in the fine and coarse particles were higher in the winter month than in the spring, followed in descending order by in the fall and summer. In a study of dependency of 10 PAHs compounds on size distribution of particles at heavy traffic area found that about 85% of the total PAHs content was associated with particles less than 2.0um (fine particles) in diameter of winter sampling period. while 79% were associated with this size fraction during summer period. In according to the mean concentrations of the 10 PAHs in 7 size classification from < 0.38 to> 10.1, the 'size was the smaller, PAHs concentration was the higher. Thus it was found that PAHs concentration was greatly affected by air particle size. Annual mean benzo(a)pyrene equivalents was 5.88ng/m$^3$ and obtained by applying, toxic equivalency factor developed by Nisbet and Lagoy.

• 한국식품과학회지
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• 제22권1호
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• pp.7-12
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• 1990

산화촉진제 존재하에서의 트리글리세리드 분자종의 산화특성을 밝히기 위하여, 규산 컬럼으로 분획한 대두유 트리글리세리드에 $Fe^{2+}$와 heme 화합물인 myoglobin을 첨가하여 이들 산화촉진제가 트리글리세리드 각 분자종의 신화안정성에 미치는 영향을 조사하였다. 대두유 트리글리세리드에 대한 산화촉진효과는 본 실험의 조건에서는 myoglobin이 $Fe^{2+}$보다 켰으나, 트리글리세리드 분자종의 산화안정성에 있어서는 첨가한 산화촉진제의 종류에는 큰 영향을 받지 않았다. 또 산화촉진제의 효과는 분자종의 구성지방산의 불포화도가 낮은 경우는 뚜렷하였으나 불포화도가 높은 경우는 뚜렷하지 않았다. 그리고 산화촉진제를 첨가하였을 때 트리글리세리트 분자종의 산화안정성은 분자종의 이중결합수가 같은 경우는 구성지방산의 불포화도가 낮을수록 높았으나, 구성지방산의 불포화도가 같은 경우 공존하는 포화지방산 acyl기의 사슬길이에는 영향을 받지 않았다.

• 한국자원식물학회지
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• 제30권1호
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• pp.17-21
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• 2017

AChE 억제제는 알츠하이머 질환 치료에 이용될 수 있으므로, 본 연구는 더위지기 정유로부터 AChE 활성성분을 탐색하기 위하여 수행한 것이다. 더위지기로부터 얻은 정유를 GC-MS로 분석했을 때 camphor가 29.8%, borneol이 28.0%, eucalyptol이 5.81%, coumarin이 5.49%의 피크 면적 비율을 보였다. 이 중 camphor, borneol, coumarin을 사용하여 Anti-AChE 활성 검색을 수행하였다. 그 결과, $0.298mg/m{\ell}$, coumarin은 $0.236mg/m{\ell}$의 $IC_{50}$ 값을 나타내었다. 이러한 결과는 coumarin이 anti-AChE 활성을 나타내는 활성물질임을 나타내는 것이다.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.3049-3052
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• 2009

Methyl tert-butyl ether (MTBE) is added to gasoline to enhance the octane number of gasoline, tert-butyl alcohol (TBA) is major degradation intermediate of MTBE in environment, and benzene, toluene, ethyl benzene and xylene (BTEX) are also major constituents of gasoline. In this study, a simplified headspace analysis method was adapted for simultaneous determination of MTBE, TBA and BTEX in ground water samples. The sample 5.0 mL and 2 g NaCl were placed in a 10 mL vial and the solution was spiked with fluorobenzene as an internal standard and sealed with a cap. The vial was placed in a heating block at 85 $^{\circ}C$ for 30 min. The detection limits of the assay were 0.01 ${\mu}$g/L for MTBE and BTEX, and 0.02 ${\mu}$g/L for TBA. The method was used to analyze 110 ground water samples from various regions in Korea, and to survey the their background concentration in ground water in Korea. The samples revealed MTBE concentrations in the range of 0.01 - 0.45 ${\mu}$g/L (detection frequency of 57.3%), TBA concentrations in the range of 0.02 - 0.08 ${\mu}$g/L (detection frequency of 5.5%), and total BTEX concentrations in the range of 0.01 - 2.09 ${\mu}$g/L (detection frequency of 87.3%). The developed method may be used when simultaneously determining the amount of MTBE, TBA and BTEX in water.

• 한국지역사회생활과학회지
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• 제22권4호
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• pp.615-621
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• 2011

This study was conducted to evaluate of the protection efficiency in each part of developed pesticide-proof clothes by repeated washings. We investigated the effect of repeated laundering on mechanical properties of pesticide-proof clothes (not washed vs 5 times washed). We also examined pesticide infiltration rate into the pesticide-proof clothes by repeated laundering. The patches(TCL paper, surface area 50cm2)were attached to the inside of pesticide-proof clothes(head, chest, right upper-arm, right forearm, left thigh, left calf, back) which subjects had dressed in during pesticide spraying. The patches were detached from working clothes after work. For the extraction of pesticide in pesticide-proof clothes, sonication was applied for 30 min with methanol. The gas chromatography/mass spectrometry (GC/MS) was applied to identify the pesticide component. The results of this study are as follows: The force strength, water-vapour resistance and surface wetting resistance of pesticide-proof clothes decreased 5 times more in washed clothes. The concentration of pesticide was the highest in the head area of pesticide-proof clothes. In seven parts of TLC paper attached to the pesticide proof clothes, the concentration of pesticide was higher in the left thigh. The penetration part and concentration of pesticide increased as washing was repeated. Therefore the conclusion which can be drawn from this study is this: protection efficiency of pesticide-proof clothes decrease by repeated washings.

• Journal of Microbiology and Biotechnology
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• 제25권8호
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• pp.1299-1306
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• 2015

This study aims to investigate the mechanism of action of the cinnamon bark essential oil (CB), when used singly and also in combination with piperacillin, for its antimicrobial and synergistic activity against beta-lactamase TEM-1 plasmid-conferred Escherichia coli J53 R1. Viable count of bacteria for this combination of essential oil and antibiotic showed a complete killing profile at 20 h and further confirmed its synergistic effect by reducing the bacteria cell numbers. Analysis on the stability of treated cultures for cell membrane permeability by CB when tested against sodium dodecyl sulfate revealed that the bacterial cell membrane was disrupted by the essential oil. Scanning electron microscopy observation and bacterial surface charge measurement also revealed that CB causes irreversible membrane damage and reduces the bacterial surface charge. In addition, bioluminescence expression of Escherichia coli [pSB1075] and E. coli [pSB401] by CB showed reduction, indicating the possibility of the presence of quorum sensing (QS) inhibitors. Gas-chromatography and mass spectrometry of the essential oil of Cinnamomum verum showed that trans-cinnamaldehyde (72.81%), benzyl alcohol (12.5%), and eugenol (6.57%) were the major components in the essential oil. From this study, CB has the potential to reverse E. coli J53 R1 resistance to piperacillin through two pathways; modification in the permeability of the outer membrane or bacterial QS inhibition.

• 한국미생물·생명공학회지
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• 제48권2호
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• pp.148-157
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• 2020

Eucalyptus oil is a rich source of bioactive compounds with a variety of biological activities and is widely used in traditional medicine. Eucalyptus citriodora is cultivated for the production of essential oils. However, the mode of antibacterial action of essential oils from E. citriodora is not well-known. This study aimed to determine the chemical components, microbial inhibitory effect, and mechanism of action of the essential oil from E. citriodora. The oil was extracted from E. citriodora leaves by hydro-distillation and the chemical components were analyzed using gas chromatography-mass spectrometry. The antibacterial activities of eucalyptus oil against gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus intermedius) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were screened by disc diffusion method and quantitative analysis was conducted by the microdilution method. The mechanism of action of the extracted essential oil was observed using SEM and analyzed by SDS-PAGE. The major components of E. citriodora oil were citronellal (60.55 ± 0.07%), followed by dl-isopulegol (10.57 ± 0.02%) and citronellol (9.04 ± 0.03%). The antibacterial screening indicated that E. citriodora oil exhibited prominent activity against all tested strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against B. subtilis were 0.5% and 1.0%, respectively. The MIC and MBC concentrations against S. aureus, S. intermedius, E. coli, and P. aeruginosa were 1% and 2%, respectively. As observed by SEM, the antibacterial mechanism of E. citriodora oil involved cell wall damage; SDS-PAGE revealed decrease in protein bands compared to untreated bacteria. Thus, E. citriodora oil showed significant antimicrobial properties and caused cellular damage.