• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.24-30
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• 2009

In this study, solubilization experiments of n-decane, n-undecane and n-dodecane oil were performed by micellar solutions of polymeric nonionic surfactant Pluronic L64($EO_{13}PO_{30}EO_{13}$) at room temperature. A single spherical drop of hydrocarbon oil was injected into aqueous surfactant solution using an oil drop contacting technique and solubilization rate of hydrocarbon oil was measured by observing the size of oil drop with time. It was shown that solubilization rate decreased with the alkane carbon number(ACN) of the hydrocarbon oil. The solubilization rate was also found to be independent of initial oil dorp size and almost linearly proportional to the initial surfactant concentration. These results revealed that solubilization of n-decane, n-undecane and n-dodecane oils by L64 micellar solution is controlled by interface-controlled mechanism but not by diffusion-controlled mechanism. The equilibrium solubilization capacity(ESC) was measured by a turbidimeter and the result showed that EAC decreased with an increase in ACN but increased with both increases in surfactant concentration and solubilization rate. Dynamic interfacial tension measurements showed that interfacial tension and equilibrium time increased with an increase in ACN of hydrocarbon oil but decreased with an increase in surfactant concentration.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1563-1570
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• 2010

To construct a highly sensitive detection system for endocrine disruptors (EDs), we have compared the activity of promoters with the n-alkane-inducible cytochrome P450 gene (ALK1), isocitrate lyase gene (ICL1), ribosomal protein S7 gene (RPS7), and the translation elongation factor-1${\alpha}$ gene (TEF1) for the heterologous gene in Yarrowia lipolytica. The promoters were introduced into the upstream of the lacZ or hERa reporter genes, respectively, and the activity was evaluated by ${\beta}$-galactosidase assay for lacZ and Western blot analysis for hER${\alpha}$. The expression analysis revealed that the ALK1 and ICL1 promoters were induced by n-decane and by EtOH, respectively. The constitutive promoter of RPS7 and TEF1 showed mostly a high level of expression in the presence of glucose and glycerol, respectively. In particular, the TEF1 promoter showed the highest ${\beta}$-galactosidase activity and a significant signal by Western blotting with the anti-estrogen receptor, compared with the other promoters. Moreover, the detection system was constructed with promoters linked to the upstream of the expression vector for the hER${\alpha}$ gene transformed into the Y. lipolytica with a chromosome-integrated lacZ reporter gene under the control of estrogen response elements (EREs). It was indicated that a combination of pTEF1p-hER${\alpha}$ and CXAU1-2XERE was the most effective system for the $E_2$-dependent induction of the ${\beta}$-galactosidase activity. This system showed the highest ${\beta}$-galactosidase activity at $10^{-6}\;M\;E_2$, and the activity could be detected at even the concentration of $10^{-10}\;M\;E_2$. As a result, we have constructed a strongly sensitive detection system with Y. lipolitica to evaluate recognized/suspected ED chemicals, such as natural/synthetic hormones, pesticides, and commercial chemicals. The results demonstrate the utility, sensitivity, and reproducibility of the system for identifying and characterizing environmental estrogens.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.207-213
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• 2003

Kochujang was prepared for this study with raw material inoculated by commercial enzyme of amylase and protease. Volati1e compounds of Kochujang were analyzed using a purge and trap method during fermentation and identified with GC-MSD. Total 54 kinds of volatile flavor components like 16 kinds of alcohol, 16 kinds of ester, 7 kinds of acid, 4 kinds of aldehyde, 2 kinds of alkane, 1 kind of benzene, 3 kinds of ketone, 1 kind of alkene, 2 kind of amine, 1 kind of phenol, other 1 were found. Total number of volatile flavor detected right after manufacturing were 23 kinds like 3 kinds of alcohol, 6 kinds of ester, 3 kinds of aldehyde. After 30 days storage, total number of volatile flavor went up to 31 kinds with addition of 4 kinds of alcohol, 1 kind of ester. The total number of volatile flavor after 120 days storage were increased to 49 kinds. Volatile flavor compounds detected during the storage period were total 20 kinds like 6 kinds of alcohol such as 2-methyl-1-propanol, ethanol, 3-methyl-1-butanol, 5 kinds of ester such as ethyl acetate, isoamyl acetate, ethyl butyrate, 3 kinds of aldehyde such as butanal, acetaldehyde and 6 kinds of others. Even though peak area % of flavor compound varied depends on fermentation period, ethanol, ethyl acetate, ethyl butyrate, ethenone, 2-methyl-1-propanol, 3-methyl-1-butanol were the main compounds that consisted of flavor from Kochujang which was made with enzyme treatment. Ethly acetate showed the highest result in the treatment of right after manufacturing, 3-methyl-1-butanol had up to 90th day and ether were the other days.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.23-28
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• 2017

Pyrolysis characteristics of waste plastic films were investigated by using a thermogravimetric analysis and pyrolyzer-gas chromatography/mass spectrometry. Thermogravimetric analysis results revealed that the pyrolysis of waste plastic films can be divided into two distinct reactions; (1) the decomposition reaction of starch at between 200 and $370^{\circ}C$ and (2) that of other plastic polymers such as PS, PP, PE at between 370 and $510^{\circ}C$. The kinetic analysis results obtained by using the revised Ozawa method indicated that the apparent activation energy of the pyrolysis reaction of waste plastic films was also changed dramatically according to the different decomposition reactions of two major waste plastic film components. Py-GC/MS results also revealed that the typical pyrolyzates of each polymer in waste plastic films were levoglucosan (starch), terephthalic acid (PET), styrene monomer, dimer, and trimer (PS), methylated alkenes (PP), and triplet peaks (PE) composed of alkadiene/alkene/alkane. The phthalate, used as a polymer additive, was also detected on the pyrogram of waste plastic films mixture.

• Korean journal of applied entomology
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• v.50 no.3
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• pp.185-194
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• 2011

Aliphatic cuticular hydrocarbons (CHCs) of different developmental stages of the spot clothing wax cicada, Lycorma delicatula (Hemiptera: Fulgoridae) were analyzed using GC and GC-MS. The numbers of carbons in the major CHCs of each developmental stage 32, 33, 28, 38, 37 in the egg, 1st, 2nd, 3rd, and 4th instar nymphal stages, and adults, respectively. The cuticle of Lycorma delicatula contains mainly methyl-branched 9-methylheptacosane (15.11%) in the egg stage, and a high proportion of n-heptacosane in nymphal stages (15.75, 22.42, 25.04, and 23.11 % in the 1st, 2nd, 3rd and 4th instars, respectively). In contrast, male and female adults had high proportions of n-nonacosane (13.42 and 16.55%). The chemical constituents of CHCs were classified into five groups (n-alkanes, monomethylalkanes, dimethylalkanes, trimethylalkanes, olefins) and group profiles of each developmental stage were compared. Egg surface was composed mainly monomethylalkanes (45.39%), a saturated hydrocarbon. Nymph CHCs consisted primarily of n-alkanes (37.63 to 46.12%). There was a difference between adult male and female CHCs. However, both contained n-alkanes and monomethylalkanes. CHCs with trimethyl or double bonded structure were rare in all stages.

• KSBB Journal
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• v.10 no.4
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• pp.349-356
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• 1995

To produce PHA(polyhydroxyalkanoic acid) from microbr, dozens of microorganism have been screened from sewage sludge. Selected a strain HJ out of 50 strains of PHA producing bacteria has a capability of accumulating large amounts of PHB/HV copolymer when grown in batch culture with a single carbon source (glucose) that was not generally considered as precursor of hydroxyvalerate monomer unit. The strain HJ was identified as the genus Pseudomonas with respect to morphological, cultural, and biochemical characteristics. The optimal temperature and pH for cell growth were $37^{\circ}C$ and 7.0. The optimal medium compositions for cell growth were glucose 1% as a carbon source, (NH4) 2SO4 0.2% as a nitrogen source, K2HPO4 0.3%, and KH2PO4 0.45%. TO investigate she optimal condition for PHA production two-step cultivation method was employed. PHA production was inducted by deficiency of NH4+, SO4-2, Mg+2. Besides carbon source, deficiency of all nutrients stimulated PHA productivity but deficiency of NH4+ stimulated the most HV monomer content. The highest PHA production was C/N molar ratio 95.2. Pseudomonas sp. HJ was also able to pyoduc PHB/HV copolymer when cultivated on alkane, alkanoate, alcohol as carbon sources. The contents of PHA and she proportions of hydroxyvalerate monomer units varied depending on the carbon sources. Especially Pseudomonas sp. HJ was able to incorporate hydroxyvalerate into PHB/HV to level as high as from 49 to 74 mol% when grown in a medium containing hexadecane and propionate. The purified PHA was identified PHB/HV copolymer by HNMR analysis.

• Elastomers and Composites
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• v.40 no.4
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• pp.277-283
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• 2005

LV transition curves for poly(ethylene-co-15.3 mol% octene) ($PEO_{15}$) and poly(ethylene- co-17.0 mol% octene) ($PEO_{17}$) were measured in cyclo-pentane and cyclo-hexane. Between $40{\sim}150^{\circ}C$, the LV curve for ($PEO_{15}$ + cyclo pentane) located $1.1{\sim}2.7$ bar higher than that for ($PEO_{17}$+ cyclo-pentane). In cyclo-hexane, similar behavior was observed for $PEO_{15}$ and $PEO_{17}$ solution except the pressure difference reduced to $0.9{\sim}l.6$ bar. If the backbone structure of $PEO_{15}$ were identical to that of $PEO_{17}$, the LV line for $PEO_{17}$ would locate at high pressures than that for $PEO_{15}$, since the number average molecular weight of $PEO_{17}$ (Ave. Mn=153,040) is 1.9 times higher 4han that of $PEO_{15}$ (Ave. Mn=82,200). The difference in the octene comonomer content between $PEO_{15}$ and $PEO_{17}$ is only 1.7 mole%, nevertheless this small difference in the backbone structure of the PEO greatly affected the location of the L-V curves in the mixtures comprised of PEO and cyclo-alkane.

• Journal of Microbiology and Biotechnology
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• v.18 no.9
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• pp.1522-1528
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• 2008

The morphogenetic behavior of a tropical marine Yarrowia lipolytica strain on hydrophobic substrates was studied. Media containing coconut oil or palm kernel oil (rich in lauric and myristic acids) prepared in distilled water or seawater at a neutral pH supported 95% of the cells to undergo a transition from the yeast form to the mycelium form. With potassium laurate, 51 % of the cells were in the mycelium form, whereas with myristate, 32% were in the mycelium form. However, combinations of these two fatty acids in proportions that are present in coconut oil or palm kernel oil enhanced the mycelium formation to 65%. The culture also produced extracellular lipases during the morphogenetic change. The yeast cells were found to attach to the large droplets of the hydrophobic substrates during the transition, while the mycelia were associated with the aqueous phase. The alkane-grown yeast partitioned more efficiently in the hydrophobic phases when compared with the coconut oil-grown mycelia. A fatty acid analysis of the mycelial form revealed the presence of lauric acid in addition to the long-chain saturated and unsaturated fatty acids observed in the yeast form. The mycelia underwent a rapid transition to the yeast form with n-dodecane, a medium-chain aliphatic hydrocarbon. Thus, the fungus displayed a differential behavior towards the two types of saturated hydrophobic substrates.

• Journal of Environmental Science International
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• v.6 no.5
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• pp.473-480
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• 1997

Microorganisms producing bioemulslfiler were isolated from the sea water In Pusan coastal area. The isolated strain which had the highest emulsification activity and stability was identified as the genus Achetobacter from the results of morphological. cultural and biochemical tests and named Achetobacter sp. EL-C6 for convenience. The compositions of optimum medium for emulsification of crude oil by Acinetobacter sp. EL-C6 were crude oil 2.0%, NH4NO3 0.2%, $K_2HPO_4$ 0.01%, $MgSO_4$.$7H_2O$ 1.o%, $CaCl_2$.$2H_2O$ 0.1% and NaCl 3.0% at initial pH 7.5 and 3$0^{\circ}C$, respectively. The cultivation for emulsification of crude ell was carried out in 500m1 shaking flask containing 100m1 of the optimum medium at 3$0^{\circ}C$. The highest emulsification was observed after 5 days. The utilization on the various hydrocarbon of the Achetobacter sp. EL-C6 showed that utilization of n-alkane compounds were better than that of aromatic compounds. Among the petroleum compounds, crude ell was best utilized by the Achetobacter sp. EL-C6.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.47-54
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• 1996

Deuterium NMR studies have been carried out for two kinds of main- chain dimer liquid crystals $\alpha$.$\omega$-bis[(4,4`-cyanobipheny0oxy] alkane (CBA-n, n=9,100.The H-NMR spectra were recorded on a JEOP JNM-GSX-500 spectrometer by using deuterium labelled CBA-n at various temperatures. The RIS analysis of the NMR spectra was performed so as to elucidate the conformational characteristics of the spacer in the nematic phase. Following the previous treatment, the single-ordering-matrix model was adopted, in which the molecular axis was defined parallel to the line connecting the centers of the terminal mesogenic cores. Conformer fractions of the spacer were estimated by simulation so as to reproduce the observed NMR profile. The conformational entropy changes at both CN and NI interphases were estimated on the basis of the nematic conformations taken from the conformation map as well as those derived from the simulation. In these calculations the spacer was assumed th by in the all-trans conformation and in the random coil stats in the crystal and isotropic phases respectively. The esimated conformational entropy change values were then compared with the corresponding constant-volume entropies obtained from PVT measurements. The correspondence between both entropy values was found to be quite good in consideration of the uncertainties involved in both experiment and calculations.