• Journal of Microbiology
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• 제42권2호
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• pp.94-98
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• 2004

Phenanthrene is a three-ring polycyclic aromatic hydrocarbon and commonly found as a pollutant in various environments. Degradation of phenanthrene by white rot fungus Trametes versicolor 951022 and its laccase, isolated in Korea, was investigated. After 36 h of incubation, about 46％ and 65％ of 100 mg/l of phenanthrene added in shaken and static fungal cultures were removed, respectively. Phenanthrene degradation was maximal at pH 6 and the optimal temperature for phenanthrene removal was 30$^{\circ}C$. Although the removal percentage of phenanthrene was highest (76.7％) at 10 mg/1 of phenanthrene concentration, the transformation rate was maximal (0.82 mg/h) at 100 mg/L of phenanthrene concentration in the fungal culture. When the purified laccase of T. versicolor 951022 reacted with phenanthrene, phenanthrene was not transformed. The addition of redox mediator, 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) or 1-hydroxybenzotriazole (HBT) to the reac-tion mixture increased oxidation of phenanthrene by laccase about 40％ and 30％, respectively.

• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.383-389
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• 2018

Degradation of the insecticide O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate (chlorpyrifos) in aqueous solution was investigated using iron salts and potassium persulfate during ZVI treatment through a series of batch experiments. The degradation rate of chlorpyrifos increased with increases in the concentrations of iron salts and potassium persulfate in the aqueous system. Ferric chloride was found to be the most effective iron salt for the ZVI-mediated degradation of chlorpyrifos in aqueous solution. Further, the iron salts tested could be arranged in the following order in terms of their effectiveness: $FeCl_3$> $Fe_2(SO_4)_3$> $Fe(NO_3)_3$. The persulfate-ZVI system could significantly degrade chlorpyrifos present in the aqueous medium. This revealed that chlorpyrifos degradation by treatment with $Fe^0$ was promoted on adding ferric chloride and potassium persulfate. The kinetics of the degradation of chlorpyrifos by persulfate-amended $Fe^0$ was higher than that for iron-salt-amended $Fe^0$. This suggests that using a sequential $Fe^0$ reduction-ferric chloride or $Fe^0$ reduction-persulfate process may be an effective strategy to enhance the removal of chlorpyrifos in contaminated water.

• Applied Biological Chemistry
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• 제40권1호
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• pp.1-11
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• 1997

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.337-345
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• 2005

The degradation of phenanthrene, a model PAH compound, by microorganisms either in the mixed culture or individual strain, isolated from oil-contaminated soil in oil refmery vicinity sites, was examined. The effects of pH, temperature, initial concentration of phenanthrene, and the addition of carbon sources on biodegradation potential were also investigated. Results showed that soil samples collected from four oil refinery sites in Korea had different degrees of PAH contamination and different indigenous phenanthrene-degrading microorganisms. The optimal conditions for phenanthrene biodegradation were determined to be 30$^{circ}C$ and pH 7.0. A significantly positive relationship was observed between the microbial growth and the rate of phenanthrene degradation. However, the phenanthrene biodegradation capability of the mixed culture was not related to the degree of PAH contamination in soil. In low phenanthrene concentration, the growth and biodegradation rates of the mixed cultures did not increase over those of the individual strain, especially IC10. High concentration of phenanthrene inhibited the growth of microbial strains and biodegradation of phenanthrene, but was less inhibitory on the mixed culture. Finally, when non-ionic surfactants such as Brij 30 and Brij 35 were present at the level above critical micelle concentrations (CMCs), phenanthrene degradation was completely inhibited and delayed by the addition of Triton X100 and Triton N101.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권6호
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• pp.553-556
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• 2006

A cis-1,2-dichloroethylene (cis-DCE)-degrading anaerobic bacterium, Clostridium sp. strain KYT-1, was isolated from a sediment sample collected from a landfill site in Nanji-do, Seoul, Korea. The KYT-1 strain is a gram-positive, endospore-forming, motile, rod-shaped anaerobic bacterium, of approximately $2.5{\sim}3.0\;{\mu}m$ in length. The degradation of cis-DCE is closely related with the growth of the KYT-1 strain, and it was stopped when the growth of the KYT-1 strain became constant. Although the pathway of cis-DCE degradation by strain KYT-1 remains to be further elucidated, no accumulation of the harmful intermediate, vinyl chloride (VC), was observed during anaerobic cis-DCE degradation. Strain KYT-1 proved able to degrade a variety of volatile organic compounds, including VC, isomers of DCE (1,1-dichloroethylene, trans-1,2-dichloroethylene, and cis-DCE), trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane. Strain KYT-1 degraded cis-DCE at a range of temperatures from $15\;to\;37^{\circ}C$, with an optimum at $30^{\circ}C$, and at a pH range of 5.5 to 8.5, with an optimum at 7.0.

• Journal of Applied Biological Chemistry
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• 제50권4호
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• pp.221-226
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• 2007

The high molecular-weight mucilage extracted and purified from cactus fruit of Opuntia ficus-indica var. Saboten was degraded by the cell-free culture filtrate of a fungus isolated from soil. TLC analysis of the polymeric mucilage after incubation with the fungal culture filtrate confirmed its degradation. When the degradation products were tested for their qualitative reactions with ninhydrin and phenol-sulfuric acid, only phenol-sulfuric acid gave positive development, and ninhydrin did not show any observable color reaction. This coloring reaction suggested the presence of a carbohydrate without an amino group within the mucilage. Analyses by HPLC and liquid gel permeation chromatography on sephadex G-100 also provided additional information on degradation of the mucilage by the fungal culture filtrate. The sequences of ITS-5.8S rDNA from the fungal isolate that was cultivated for the preparation of mucilage-degrading enzyme showed 99% similarity to those of Pestalotiopsis aquatica.

• 한국환경과학회지
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• 제7권3호
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• pp.393-400
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• 1998

A microorganism, Klebsiella gr. 47, capable of degrading BTX(benzene, toluene and xylene) was isolated from oil-contaminated soil and its characteristics of BTX degradation were investigated. When benzene and toluene were fed to Klebstella gr. 47 simulataneously, they showed competitive ingibition. The degradation rate of xylene was enhanced as much as 3 times when xylene was fed with benzene or toluene. Degradation rate of benzene and toluene was also enhanced by cocultured with Alcaligenes xylosoxidans. When benzene-adapted microorganism was used, each BTX compound was degraded efficiently within 5 hours.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1258-1266
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• 2005

The present study was carried out in order to assess the protective effects of calycosin-7-O-$\beta$-D-glucopyranoside, isolated from Astragali radix (AR), on hyaluronidase (HAase) and the recombinant human interleukin-$1\beta$ (IL-$1\beta$)-induced matrix degradation in human articular cartilage and chondrocytes. We isolated the active component from the n-butanol soluble fraction of AR (ARBu) as the HAase inhibitor and structurally identified as calycosin-7-O-$\beta$-D-glucopyranoside by LC-MS, IR, ${1}^H$ NMR, and ${13}^C$ NMR analyses. The $IC_{50}$ of this component on HAase was found to be 3.7 mg/ml by in vitro agarose plate assay. The protective effect of ARBu on the matrix gene expression of immortalized chondrocyte cell line C28/I2 treated with HAase was investigated using a reverse transcription polymerase chain reaction (RT-PCR), and its effect on HAase and IL-$1\beta$-induced matrix degradation in human articular cartilage was determined by a staining method and calculating the amount of degraded glycosaminoglycan (GAG) from the cultured media. Pretreatment with calycosin-7-O-$\beta$-D-glucopyranoside effectively protected human chondrocytes and articular cartilage from matrix degradation. Therefore, calycosin-7-O-$\beta$-D-glucopyranoside from AR appears to be a potential natural ant-inflammatory or antii-osteoarthritis agent and can be effectively used to protect from proteoglycan (PG) degradation.

• Journal of Microbiology
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• 제40권3호
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• pp.193-198
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• 2002

Several 2,4,6-trinitrotoluene (TNT) degrading bacteria were isolated from an activated sludge by an enrichment culture technique, and their TNT removal activities were examined. Among the isolates, strain C1 showed the highest degrading capability, and completely removed 100 or 200 mg I$\^$-1/ of TNT within 6 hours of incubation. This bacterium was identified as Klebsiella sp. The effects of different carbon sources on the removal of the parent TNT by Klebsiella sp. C1 were negligible, but the transformation rates of TNT metabolites such as amino-dinitrotoluenes and diamino-nitrotoluenes were higher with fructose addition compared to glucose addition. When nitrate was used as the nitrogen source, the degradation rates of TNT and hydroxylamino-dinitrotoluenes were higher than those with the ammonium addition. Although the TNT removal rate of Klebsiella sp. C1 was slightly higher in anaerobic conditions, the further transformations of TNT metabolites were more favorable in aerobic conditions.

• Applied Biological Chemistry
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• 제33권2호
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• pp.133-137
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• 1990

담수토양중(湛水土壤中)에 있어서 IBP의 분해(分解)에 미치는 각종(各種) 토양환경조건(土壤環境條件)의 영향(影響)에 대하여 연구검토(硏究檢討)하였다. IBP는 비담수조건(非湛水條件)에서 보다 담수조건(湛水條件)에서 느리게 분해(分解)되었다. 분해속도(分解速度)는 토양종류(土壤種類)에 따라 크게 변화(變化)되었으며, 유기물함양(有機物含量)이 높은 토양(土壤)에서보다 낮은 토양(土壤)에서 빨랐다. IBP는 저온(低溫)에서보다 고온(高溫)의 토양(土壤)에서, 고농도(高濃度)에서보다 저농도(低濃度) 첨가(添加)에서 빨리 분해(分解)되었다. 토양중(土壤中) 분해속도(分解速度)는 볏짚첨가에 의하여 현저히 저하(低下)되었으나, 복합비료(複合肥料)나 타농약(他農藥) fenitrothion과 butachlor의 첨가(添加)에 의하여는 영향(影響)을 받지 않았다. 토양중(土壤中) IBP는 호기적(好氣的) 미생물(微生物)에 의하여 분해(分解)되는 것으로 추정(推定)되었다.