• Journal of Life Science
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• 제9권2호
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• pp.76-81
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• 1999

216 microorganisms which able to degrade wasted lubricant were isolated in the region of contaminated with wated lubricant such automobile repair shops, garages and gas stations in Taejon. Most activated strain among them is selected and used in this research. The microorganism in identified as Acinetobacter lwoffii 16C-1, which shows active growth and hydrocargon utilization withnormal alkane such as tetradecane, hexadecane and octadecane, and do not grow aromatic hydrocargons, cycloalkane, and branched alkane. In addition, A. lwoffii 16C-1 has resistance to heavy metals such as Ba, Li, Cr, and Mn more than 6.4mg/ml, and showed negligible tolerance against antibiotics. Effects of environmental conditions including concentration of wasted lubricnt, pH, NaCl concentration, nitrogen source and phosphate on microorganism growth and emulsification were studied. 2% of wasted lubricant, pH 7.0, 0-1% of NaCl, 0.2% of peptone, and 0.01% of K2HPO4 is turn out to be optimum condition. By the analysis of remaining oils, almost of hydrocarbons added to the media are removed by A. lwoffii 16C-1 at 30$^{\circ}C$ after 2 days of culture, which showed excellent oil degradation characteristics.

• 한국응용과학기술학회지
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• 제31권1호
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• pp.1-6
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• 2014

Gemini type of cationic surfactant, namely ${\alpha},{\omega}$-alkane-bis(N-lauroyloxyethyl-N,N-dimethyl)-diammonium bromide was synthesized and confirmed by FT-IR and $^1H$-NMR spectroscopy. Their inhibition effect on corrosion of mild steel in 1 M HCl solution was tested by weight loss method. Surface tensions were measured by surface tensiometer Sigma 70. Their c.m.c. values evaluated by surface tension method was $4.01{\times}10^{-5}{\sim}4.99{\times}10^{-5}mol/L$. The Krafft point of the these surfactants were < $0^{\circ}C$. The emulsifying properties of synthesized cationic gemini surfactants and sodium dodecyl sulfate (SDS), tetradecyl trimethyl ammonium bromide (TTAB) was investigated. Of these, ${\alpha},{\omega}$-alkane-bis(N-lauroyloxyethyl-N,N-dimethyl)-diammonium bromide has been confirmed as a good emulsifier. The inhibition efficiency increases by increasing cationic gemini surfactant concentration. As a result, these surfactants are expected to be applied as corrosion inhibitors.

• Bulletin of the Korean Chemical Society
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• 제7권5호
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• pp.367-371
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• 1986

Dynamic and equilibrium properties of n-alkane chains immersed in solvent molecules have been investigated by a molecular dynamics method. The n-alkane chain is assumed to be a chain of elements (CH$_2$) interconnected by bonds having a fixed bond length and bond angle, but each bond of the chain is allowed to execute hindered internal rotation. We studied the effect of the number of the chain elements (N$_c$ = 10, 15 and 20) on the equilibrium properties of the system, e.g., the pair correlation functions between a chain element and solvent molecules, g$_{cs}$(r), and between the chain elements, g$_{cc}$(r), and the configurational properties such as the mean-square end-to-end distance < R$^2$ >, the mean-square radius of gyration < S$^2$ >, and the eigenvalues of the moment-of-inertia tensor < S$_i^2$ > / < S$^2$ > (i = 1, 2 and 3). We also studied the dynamic properties of the system, e.g., the autocorrelation function C(A;t) where A = R$^2$(t), = S$^2$(t), or = ${\vec{V}}(t)({\vec{V}}$ = velocity of the center of mass), and the diffusion coefficient D. The g$_{cs}$(r)'s are almost equal irrespective of the change of Nc while g$_{cc}$(r) becomes larger as N$_c$ increases; The MD computed configurational properties < R$^2$2 > and < S$^2$ > were found to be a little different from the values calculated from the statistical equations of < R$^2$ > and < S$^2$ >, it may be due to the fact that our model for the MD simulations includes a long-range volume effect. From the < S$_i^2$ > / < S$^2$ >, it is found that the chain molecule has a nearly spherical shape irrespective of the variation of N$_c$. For the dynamic properties we found that the C(R$^2$;t) and C(S$^2$;t) of lower N$_c$ decay faster than those of higher N$_c$, while the C($\vec V$;t) of the center of mass in the chain is weakly dependent on the N$_c$. The center of mass diffusion coefficient D$_c$ decreases as N$_c$ increases while the end point diffusion coefficient D$_e$ is nearly equal irrespective of the change of N$_c$.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.1009-1010
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• 2003

• Bulletin of the Korean Chemical Society
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• 제20권1호
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• pp.7-15
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• 1999

The present paper is a review of the current studies of quantum beats in recombination of spin-correlated radical pairs in solutions as well as of future applications of quantum beats technique for studying these pairs. Examples are given of the use of this method for determining the hfi constants and relaxation times of short-lived radical ions, for finding the rate constants of the reactions of alkane radical cations and for estimating a fraction of singlet-correlated pairs in the pairs in the tracks of ionizing particles. The potentialities of this method, its advantages and limitations are discussed.

• Bulletin of the Korean Chemical Society
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• 제16권5호
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• pp.427-432
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• 1995

A model based on two coupled generalized Langevin equations is proposed to investigate the trans-stilbene photoisomerization dynamics. In this model, a system which has two independent coordinates is considered and these two system coordinates are coupled to the same harmonic bath. The direct coupling between the system coordinates is assumed negligible and these two coordinates influence each other through the frictional coupling mediated by solvent molecules. From the Hamiltonian which is equivalent to the coupled generalized Langevin equations, we obtain the transition state theory rate constants of the stilbene photoisomerization. The rates obtained from this model are compared to experimental results in n-alkane solvents.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.339-345
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• 2009

We evaluated the activity and abundance of the crude-oil-degrading bacterium Nocardia sp. H17-1 during bioremediation of oil-contaminated soil, using real-time PCR. The total petroleum hydrocarbon(TPH) degradation rate constants(k) of the soils treated with and without H17-1 were $0.103\;d^{-1}$ and $0.028\;d^{-1}$ respectively. The degradation rate constant was 3.6 times higher in the soil with H17-1 than in the soil without H17-1. In order to detect and quantify the Nocardia sp. H17-1 in soil samples, we quantified the genes encoding 16S ribosomal RNA(16S rRNA), alkane monooxygenase(alkB4), and catechol 2,3-dioxygenase(23CAT) with real-time PCR using SYBR green. The amounts of H17-1 16S rRNA and alkB4 detected increased rapidly up to 1,000-folds for the first 10 days, and then continued to increase only slightly or leveled off. However, the abundance of the 23CAT gene detected in H17-1-treated soil, where H17-1 had neither the 23CAT gene for the degradation of aromatic hydrocarbons nor the catechol 2,3-dioxygenase activity, did not differ significantly from that of the untreated soil($\alpha$=0.05,p>0.22). These results indicated that H17-1 is a potential candidate for the bioaugmentation of alkane-contaminated soil. Overall, we evaluated the abundance and metabolic activity of the bioremediation strain H17-1 using real-time PCR, independent of cultivation.

• 공업화학
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• 제19권1호
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• pp.59-65
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• 2008

비이온 계면활성제 $C_{12}E_8$ 마이셀에 의한 이성분 탄화수소 오일 혼합물 시스템의 가용화도(equilibrium solubilization capacity)를 $23^{\circ}C$에서 기체 크로마토그래피(GC)를 이용하여 측정하였다. 단일 성분의 탄화수소 오일 가용화도는 탄화수소 오일의 탄소수(ACN)가 증가함에 따라 거의 선형적으로 감소하였다. 한편 탄화수소 오일의 이성분 시스템은 사용한 두 탄화수소 오일의 탄소수(alkane carbon number, ACN) 차이에 따라 선택적 가용화 혹은 비선택적 가용화 경향을 나타내었다. 본 연구에서 가용화도 실험을 수행한 n-octane/n-nonane, n-nonane/n-decane과 n-decane/n-undecane 혼합물 시스템과 같이 이성분 탄화수소 혼합물의 탄소수 차이가 1인 경우에는 비선택적(non-selective) 가용화 경향을 나타내었다. 반면에 n-octane/n-decane과 n-octane/n-undecane 혼합물 시스템과 같이 탄소수 차이가 1보다 큰 경우에는 선택적(selective) 가용화 경향을 나타내었다.

• 한국미생물·생명공학회지
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• 제21권1호
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• pp.74-81
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• 1993

저온성 세균 Acinetobacter calcoaceticus A1-1의 유류분해 특성을 연구하기 위해 환경적 요인에 대한 영향을 살펴보았다. 이 세균의 성장율과 유화활성도에 대한 적정 환경조건은 온도 $15^{\circ}C$, pH 7.5, 염분도 0-3, 원유농도 0.1로 나타났고 질소원과 인원의 적정농도는$(NH_4)_2S0_4$과 $K_2HP0_4$, 형태로 각각 0.76 mM, 0.057mM이다. 온도에 따른 A.calcoaceticus A1-1의 유류분해 양상을 개스크로마토그라피로 분석한 결과 $10^{\circ}C$, $15^{\circ}C$에서 대부분의 탄화수소 피크가 감소되어 상당 정도의 유류분해를 관찰 할 수 있었다. 반면 $25^{\circ}C$의 경우에는 120시간 배양한 후에도 원유에 포함된 포화탄화수소 화합물들이 부분적으로만 분해되었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제11권1호
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• pp.1-6
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• 2006

환경 내에서 생물학적 복원을 이해하기 위해서는 미생물 기능성 군집 및 활성을 분석하는 것은 필수적이다. 본 연구에서는 유류오염 토양의 미생물 군집을 모니터링하기 위하여 난분해성 물질의 생물학적 분해에 관여하는 100개의 알려진 대사경로 및 유전자를 기반으로 한 oligonucleotide microarray를 개발하였다. 본 연구에 사용된 microarray는 유류오염 분해 대사에 관련된 유전자를 진단하기 위한 15개의 고유한 probe를 포함하고 있다. 디자인된 probe의 hybridization specificity는 표준 균주, Pseudomonas aeruginosa KCTC1636을 이용하여 확인 하였으며, 유류오염토양 시료의 분석결과 alkane, naphthalene, biphenyl, pyrene(PAH ring-hydroxylating) 분해에 관련된 8개의 유전자 발현을 확인 하였다. 이러한 결과는 DNA microarray가 유류오염토양환경에서 생물학적 분해유전자 진단에 효과적으로 이용될 수 있을 뿐만 아니라 생물학적 복원의 가능성을 진단하기에도 적합한 기법이라는 것을 나타내고 있다.