• Korean Journal of Microbiology
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• v.54 no.1
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• pp.46-52
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• 2018

Biodegradation pathway of dibenzofuran (DBF) of Novosphingobium pentaromativorans US6-1, a high-molecular-weight polycyclic aromatic hydrocarbons degrading strain, was investigated via analysis of metabolic intermediates and transcriptome. As a result, 3(2H)-benzofuranone, a basic skeleton of the metabolic intermediates produced by lateral dioxygenation process, was detected as an intermediate. RNA-Seq analysis confirmed that most of the expressed genes upon exposure to DBF were related to the lateral degradation pathway. Based on these results, the biodegradation pathway of DBF by N. pentaromativorans US6-1 was proposed.

• Journal of the Korean Chemical Society
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• v.65 no.1
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• pp.9-14
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• 2021

In this study, the DFT calculation was performed using the B3LYP/6-31G(d,p) basis sets for the reaction process in which phenanthrene decomposes due to the chain reaction of two OH radicals on phenanthrene in the gaseous state of 298 K at 1 atm. As a result of the calculation, even when two OH radicals act on phenanthrene in a chain, the reaction for producing phenanthren-9-ol is predicted to be more advantageous than the reaction for producing phenanthren-1-ol. On the other hand, it was predicted that the OH addition process at room temperature would be advantageous for the priority of the OH addition and H abstraction process.

• Environmental Mutagens and Carcinogens
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• v.21 no.2
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• pp.149-155
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• 2001

Eighty-one workers including 38 employees directly incinerating industry wastes were recruited from a company located in South Korea. To evaluate the association between urinary 1-hydroxypyrene glucuronide (1-OHPG) levels, as internal dose of polycyclic aromatic hydrocarbon (PAH) exposure, and glycophorin A (GPA) mutation frequency, as an early biologic effect indicator. Urinary 1-OHPG levels were measured by synchronous fluorescence spectroscopy after immunoaffinity purification using monoclonal antibody 8E11. Erythrocyte GPA variant frequency (NN or NO) was assessed in MN heterozygotes with a flow cytometic assay. The GSTM1 and GSTT1 genotypes were assessed by a multiplex PCR method. The GPA NN phenotype frequency was higher in occupationally exposed group (n=14, mean$\pm$S.D. 6.6$\pm$12.0 in 10/SUP 6/ erythrocyte cells) than in non-exposed group (n=22, 2.1$\pm$3.5). Similarly, the GPA(NO or NN) phenotype frequency was higher in exposed group (n=14, 9.7$\pm$17.3) than non-exposed group (n=22, 4.2$\pm$6.3). The above differences failed to reach statistical significance, but a significant increase was seen in GPA variant frequency levels with increase in urinary 1-OHPG levels (Spearman's correlation: p=0.06 (NO), p=0.07 (NO or NN)). When this association was evaluated by GSTM1 genotype status, the association between GPA mutation and urinary 1-OHPG levels was stronger in individuals with GSTM1 present genotype (Spearmans correlation; r=0.50, p=0.02). These results suggest that the association between urinary 1-OHPG and GPA mutation is be modulated by the GSTM1 genotype.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.109-111
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• 2010

Recent studies have described various microorganisms that can degrade PAH, however, there are currently limited methods available to screen for PAH-degrading microorganisms. To screen for PAH-degrading microorganisms, a sublimation method (Alley, Jeremy F. and Lewis R. Brown. 2000. Appl. Environ. Microbiol. 66, 439-442) was modified to produce a simple screening system. In our results, there were several bacterial species capable of pyrene degradation including genera, Coryenbacterium, Gordonia, Rhodococcus, and Streptomyces, which have been screened from 350 bacterial isolates of commercial gasoline and oil-spilled sediment by the sublimation method. The main advantage of this method is that it (i) safely deposits an even, thin and visible layer of PAH onto the agar surface without the use of solvents and (ii) the quantity of PAH sublimed onto the agar can be easily controlled. Overall, this sublimation method may be an effective and simple technique to screen for PAH-degrading microorganisms.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.55-60
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• 2012

In order to investigate the effect of n-heptane mixing on PAH and soot formation, small amount of n-heptane has been mixed in counterflow ethylene diffusion flame. Laser-induced incandescene and laser-induced fluorescene techniques were employed to measure soot volume fraction and polycyclic aromatic hydrocarbon(PAH) concentration, respectively. Results showed that the mixing of n-heptane in ethylene diffusion flame produces more PAHs and soot than those of pure ethylene flame. However, signals of LIF for 20% n-heptane mixture flame were lower than that of pure ethylene flame. It can be considered that the enhancement of PAH and soot formation by the n-heptane mixing of ethylene can be explained by methyl($CH_3$) radical in the low temperature region. And it can be found that reaction rate of H radical for 10% n-heptane plays a crucial role for benzene formation.

• Journal of the Korean Chemical Society
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• v.62 no.5
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• pp.344-351
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• 2018

The IR spectra of gaseous phenanthrene, phenathrenols, phenanthrenyl radicals, and hydroxylphenanthrene radicals have been obtained using the BLYP/6-311++G(d,p) method. A comparison of these spectra shows that the measurements of IR spectra can be valuable to identify the reaction pathway(s) of the phenanthrene decomposition reaction by ${\cdot}OH$. We have found that the H atom abstraction reaction process can be easily identifiable from the $650-850cm^{-1}$ (CH out-of-plane bending) region and the ${\cdot}OH$ addition reaction process from the CH stretching and bending modes region of IR spectra. In addition, the calculated IR spectra of all five phenanthren-n-ols (n = 1, 2, 3, 4, 9) have also given in this work.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.292-299
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• 2004

This study is intended to check a temperature of the flame to raise by burning A heavy oil in a boiler. to measure the concentration of DS and SOF after collecting the PM(Particulate Matters). and to analyze the components ingredients of SOF by G.C Mass for presupposing the generation of particulate matters(soot). It is thought that the methyl(CH3) of the cyclic compound is changed to the materials of 2 cycles and 3 cycles after becoming CH by dehydrogenation and also mixing with the CH of a chain compound. form H-$\cdot$C=C$\cdot$-H that is mentioned before. in order to become Polycyclic Aromatic Hydrocarbon.

• Korean Journal of Pharmacognosy
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• v.53 no.3
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• pp.170-180
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• 2022

Polycyclic aromatic hydrocarbons(PAHs) contents were analyzed by measuring benz(a)anthracene(BaA), chrysene(Chr), benzo(b)fluoranthene(BbF) and benzo(a)pyrene(BaP), and the related risk characterization was conducted for 113 samples out of 14 different agricultural products used for food and medicine. Detection rate of PAHs was 90.3% as a whole, and the highest one was 80.5% for BaP. The detection rate of BaP exceeding the maximum permitted concentration of Rehmanniae Radix Preparata and Rehmanniae Radix, 5.0 ㎍/kg was 1.8%, and the detection rates of BaA, Chr and BbF were within the range of 2.7~10.6%. The highest average concentration of BaA was 3.41 ㎍/kg detected from Lycii Fructus, while those of Chr, BbF, BaP and PAH4(sum of detected BaA, Chr, BbF and BaP) were 5.00, 1.79, 2.36, 12.36 ㎍/kg, respectively, detected from Rehmanniae Radix Preparata. As for the risk characterization on PAHs, the overall MOE(Margin of Exposure) values were measured within the range of 10⁵~10⁷, which is unlikely to cause direct health concerns, but the worring values of MOE were measured 6.57×10⁴ for BaP and 6.10×10⁴ for PAH4 from Rehmanniae Radix Preparata, which may require an improvement plan to reduce BaP contents.

• Journal of Ginseng Research
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• v.33 no.4
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• pp.355-360
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• 2009

Phenanthrene ($C_{14}H_{10}$) is a polycyclic aromatic hydrocarbon with three aromatic rings, and it can be produced by incomplete combustion of fossil fuels. Comet assay was used to examine the oxidative DNA damage of lymphocytes by phenanthrene and to measure the suppressive effects of ginseng extract on the DNA damage in this investigation. The in vitro oxidative DNA damage by phenanthrene increased in a dose-dependent manner in the lymphocyte. However, the DNA damage was significantly inhibited by ascorbate. Moreover, pretreatment, cotreatment and posttreatment with ginseng extract enhanced lymphocyte resistance to the phenanthrene-induced DNA damage. Phenanthrene enhanced the generation of intracellular reactive oxygen species, and the elevated reactive oxygen species level was reduced by treatment with ginseng extract.

• Environmental Engineering Research
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• v.24 no.4
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• pp.591-599
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• 2019

To convert sewage sludge to energy, drying-gasification characteristics during microwave heating were studied. During the gasification of carbon dioxide, the main products were gas, followed by char, and tar in terms of the amount. The main components of the producer gas were carbon monoxide and hydrogen including a small amount of methane and light hydrocarbons. They showed a sufficient heating value as a fuel. The generated tar is gravimetric tar, which is total tar. As light tars, benzene (light aromatic tar) was a major light tar. Naphthalene, anthracene, and pyrene (light polycyclic aromatic hydrocarbon tars) were also generated, but in relatively small amounts. Ammonia and hydrogen cyanide (precursor for NO_x) were generated from thermal decomposition of tar containing protein and nitrogen in sewage sludge. In the case of sludge char, its average pore diameter was small, but specific area, pore volume, and adsorption amounts were relatively large, resulting in superior adsorption characteristics.