• Environmental Engineering Research
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• 제25권3호
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• pp.290-298
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• 2020

A large residual fraction of aliphatic components of diesel prevails in soil, which has adverse effects on the environment. This study identified the most bio-recalcitrant aliphatic residual fraction of diesel through total petroleum-hydrocarbon fractional analysis. For this, the strain Acinetobacter sp. K-6 was isolated, identified, and characterized and investigated its ability to degrade diesel and n-alkanes (C₁₈, C₂₀, and C₂₂). The removal efficiency was analysed after treatment with bacteria and nutrients in various soil microcosms. The fractional analysis of diesel degradation after treatment with the bacterial strains identified C₁₈-C₂₂ hydrocarbons as the most bio-recalcitrant aliphatic fraction of diesel oil. Acinetobacter sp. K-6 degraded 59.2% of diesel oil and 56.4% of C₁₈-C₂₂ hydrocarbons in the contaminated soil. The degradation efficiency was further improved using a combinatorial approach of biostimulation and bioaugmentation, which resulted in 76.7% and 73.7% higher degradation of diesel oil and C₁₈-C₂₂ hydrocarbons, respectively. The findings of this study suggest that the removal of mid-length, non-volatile hydrocarbons is affected by the population of bio-degraders and the nutrients used in the process of remediation. A combinatorial approach, including biostimulation and bioaugmentation, could be used to effectively remove large quantities of aliphatic hydrocarbons persisting for a longer period in the soil.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.297-300
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• 2004

The various microbial tests were performed to determine bioremediation agent capacity for eight strains isolated from the oil contaminated regions. Two tests for isolated strains were conducted such as cell hydrophobicity and emulsifying activity. The biodegradation of SHM (saturated hydrocarbon mixture) and AHM (aromatic hydrocarbon mixture) with the strains also was carried out. The strains having higher cell hydrophobicity and emulsifying activity degraded petroleum oil effectively. The degradation capacity for SHM was represented more than 90% in YS-7 and WLH-1 of isolated strains, and KH3-2 were capable of degrading AHM. Especially, WLH-1 as yeast was shown more than two or three times in the degradation capacity of automobile engine lubricants and the biomonitoring results of contaminated soil for residual oil degrading test showed that the hydrocarbon biodegradation was increased in the second treatment by this strain.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
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• pp.37-40
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• 1999

cDNAs for long- and short-chain acyl-CoA oxidases in fatty acid $\beta$-oxidation were isolated and were characterized their enzymatical and molecular properties. Both oxidases were exclusively localized in glyoxysomes, indicating that glyoxysomes can completely metabolize fatty acids to acyl-CoA by their cooperative action. In order to clarify the regulatory mechanisms underlying degradation of storage oil, we tried to obtain glyoxysome-deficient mutants of Arabidopsis. We screened 2,4-dichlorophenoxybutyric acid (2,4-DB) mutants of Arabidopsis which have defects in glyoxysomal fatty acid $\beta$-oxidation. Four mutants can be classified as carrying alleles at three independent loci, which we designated pedl, ped2, and ped3, respectively (where ped stands for peroxisome defective). The characteristics of these ped mutants are described.

• 한국조명전기설비학회지:조명전기설비
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• 제11권1호
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• pp.99-105
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• 1997

본 논문에서는 주상변압기 절연유의 가속열화반응을 수행하였다. 유중가스를 air bubbling 법으로 추출하여 가스크로마토크라프로 성분을 분석하였으며 가스농도는 각 가스의 추출율을 감안하여 보정하였다. 절연재료의 열화는 열분해반응과산화반응에의하여 진행되었으며 두 종류의 반응은 모두 0차반응의 특성을 보였고 탄화수소류, CO+{{{{ { CO}_{2 } }}}} 및 수소가스의 생성속도식을 얻었다. 유중가스 분석과 UV-Visible 분광광도법에 의하여 변압기내의 철심과 동코일이 열화과정에서 촉매역활을 함을 확인하였다.

• KSBB Journal
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• 제11권6호
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• pp.654-662
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• 1996

원유에 대한 분해능이 있는 균주를 분리하고, 이들 균주의 균체생육과 유화활성 및 원유 전환율을 검토하여 4균주 즉, A54, H17, H17-1 그리고 F6 를 선멸하였다. 이들 균주중 H17-1 균주를 최종선멸하여 형태학적 빛 생화학적 그리고 생리학적 특성 을 조사한 후 Nocardia sp. H 17-1로 명명하였다. Nocardia sp. H17-1의 배양 시간에 따른 균체생육, 유화도 그리고 원유 전환율을 측정한 결과, 균체수 는 $9.1\times109 CFU/mL$었고, 유화활성과 원유 전환율 은 각각 480 unit/mL와 약 83%로서 최대치에 도달하였다. 또한, 다양한 탄화수소를 탄소원으로 이용 하였다. 원유분해를 위한 배양조건 및 환경인자의 영향을 조사한 결과 배양온도는 $^30{\circ}C$, 초발 pH는 7.0, 염분농도는 2.0%이며, 5% 이상에서는 유화활 성이 현저히 감소하였다. 원유농도는 3%, 무기염류 의 농도는 12.5 mM $NH_4N0_3$, 0.057 mM $K_2HPO_4$로 나타났다. 또한, 잔류 원유의 GC 분석 결과 CI6(n­ hexadecane) 이상의 n-alkane peak가 현저히 감소하였다.

• 청정기술
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• 제22권4호
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• pp.292-298
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• 2016

본 연구에서는 인도네시아 현지로부터 수급된 지층 자원에 포함된 역청성 오일의 경질화를 위하여 열분해 공정이 적용되었다. 이러한 자원 내에 포함된 역청성 오일에 대한 조성 및 기초성상을 조사하기 위하여 공업분석, 원소분석 등이 수행되었으며, 열중량분석을 통해 역청성 오일의 전환에 대한 열분해반응 기초특성이 조사되었다. 이러한 결과를 바탕으로 원료 내에 포함된 역청성 오일을 경질화하기 위하여 필요한 열분해 온도 등의 운전조건 범위가 선정되었으며, 실험실 규모의 고정층 반응기를 이용하여 반응온도에 따른 역청성 오일의 전환율 및 열분해 오일의 회수율을 확인하였다. $550^{\circ}C$에서 수행된 열분해 공정에서 원료 내 포함된 역청성 오일의 전환율은 약 21%였으며, 경질화된 열분해 오일의 회수율은 약 80%였다.

• 공업화학
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• 제34권6호
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• pp.649-659
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• 2023

This study was initiated to evaluate the phosphorus (P) removal and diesel oil degradation by bacteria isolated from industrial wastewater. The bacteria isolated were identified as Bacillus sp. The P removal efficiencies by Bacillus sp. were 99% at the initial 20 mg/L P concentration. The diesel degradation efficiencies by Bacillus sp. were 86.4% at an initial 1% diesel concentration. Lipophilicity by bacteria was the highest in the log phase, whereas it was the lowest in the death phase. As the diesel was used as a carbon source, P removal efficiencies by Bacillus sp. were 68%. When glucose, acetate, and a mixture of glucose and acetate as second carbon sources were added, the diesel degradation efficiencies were 69.22%, 65.46%, and 51.46%, respectively. The diesel degradation efficiency was higher in the individual additions of glucose or acetate than in the mixture of glucose and acetate. When P concentration increased from 20 mg/L to 30 mg/L, the diesel degradation efficiency was increased by 7% from 65% to 72%, whereas when P concentration was increased from 30 mg/L to 40 mg/L, there was no increase in diesel degradation. One of the five proteins identified by proteome analysis in the 0.5% diesel-treated samples may be involved in alkane degradation and is known as the cytochrome P450 system. Also, two of the sixteen proteins identified in the 1.5% diesel-treated samples may be implicated in the fatty acid transport system and alcohol dehydrogenation.

• Tribology and Lubricants
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• 제19권5호
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• pp.280-284
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• 2003

High performance characteristics are required for rolling bearings and the various functions of bearing are greatly influenced by grease. Recently, higher performance is being demanded of rolling bearing greases for bearing lubrication. Four special greases with different composition such as lithium soap/ester oil, urea/ester oil, urea/ether oil and PTFE/fluorine oil were synthesized to compare the performance of these greases with that of the conventional lithium soap/mineral oil grease. The grease properties were investigated using a series of typical grease testing methods and grease life test. After the life test, the greases were charaterized by FTIR analysis and a microscope. And the iron amount in the greases was analyzed by AAS after ashing. The composition and manufacturing process determined the grease performance. The grease with a base oil of synthetic oil showed higher performance and the urea/ester oil and PTFE/fluorine oil showed about three times longer life as compared with conventional lithium grease.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.179-185
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• 2001

High performance characteristics are required for rolling bearings and the various functions of bearing are greatly influenced by grease. Recently, higher performance is being demanded of rolling bearing greases for bearing lubrication. Four special greases with different composition such as lithium soap/ester oil, urea/ester oil, urea/ether oil and PTFE/fluorine oil were synthesized to compare the performance of these greases with that of the conventional lithium soap/mineral oil grease. The grease properties were investigated using a series of typical grease testing methods and grease life test. After the life test, the greases were charaterized by FTIR analysis and a microscope. And the iron amount in the greases was analyzed by AAS after ashing. The composition and manufacturing process determined the grease performance. The grease with a base oil of synthetic oil showed higher performance and the urea/ester oil and PTFE/fluorine oil showed about three times longer life as compared with conventional lithium grease.

• Journal of Microbiology
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• 제37권3호
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• pp.128-135
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• 1999

Among oil-degrading microorganisms isolated from oil-polluted industrial areas, one yeast strain showed high degradation activity of aliphatic hydrocarbons. From the analyses of 18S rRNA sequences, fatty acid, coenzyme Q system, G+C content of DNA, and biochemical characteristics, the strain was identified as Yarrowia lipolytica 180. Y. lipolytica 180 degraded 94% of aliphatic hydrocarbons in minimal salts medium containing 0.2% (v/v) of Arabian light crude oil within 3 days at 25$^{\circ}C$. Optimal growth conditions for temperature, pH, NaCl concentration, and crude oil concentration were 30$^{\circ}C$, pH 5-7, 1%, and 2% (v/v), respectively. Y. lipolytica 180 reduced surface tension when cultured on hydrocarbon substrates (1%, v/v), and the measured values of the surface tension were in the range of 51 to 57 dynes/cm. Both the cell free culture broth and cell debris of Y. lipolytica 180 were capable of emulsifying 2% (v/v) crude oil by itself. They were also capable of degrading crude oil (2%). The strain showed a cell surface hydrophobicity higher than 90%, which did not require hydrocarbon substrates for its induction. These results suggest that Y. lipolytica has high oil-degrading activity through its high emulsifying activity and cell hydrophobicity, and further indicate that the cell surface is responsible for the metabolism of aliphatic hydrocarbons.