• Journal of Microbiology and Biotechnology
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• v.2 no.1
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• pp.14-20
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• 1992

Some microorganisms isolated from soil, including some bacteria and fungi, were found to secrete an extracellular soymilk-clotting enzyme. Among them, an isolated fungus showed the highest soymilk-clotting activity and the strain was assigned to genus Penicillium based on its cultural and morphological characteristics, and designated as Penicillium sp. L-151K. Soymilk-clotting enzymes A and B produced by Penicillium sp. L-151K were purified by ammonium sulfate precipitation and chromatographies on Sephadex G-25, CM-Sephadex, Sephadex G-100 and phenyl-Toyopearl gel. The two purified enzymes A and B were found to be homogeneous by polyacrylamide gel electrophoresis at pH 9.5. The molecular weights of enzyme A and B were 24, 000 and 40, 000, respectively, by gel filtration on Sephadex G-100. Enzymes A and B coagulated soymilk optimally at $60^\circ{C}$ and were stable up to $50^\circ{C}$. Both enzymes were most active at pH 5.8 for soymilk coagulation, and were stable with approximately 80% of original activity from pH 3.0 to 5.0. Each enzyme was an acidic protease with an optimum pH of 3.0 for casein digestion. The soymilk-clotting efficiency of these enzymes was improved with $CaCl_2\;or\;MgCl_2$ when making soymilk-curd.

• Journal of Microbiology and Biotechnology
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• v.6 no.1
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• pp.19-25
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• 1996

Chitosanase from Bacillus sp. HW-002 was purified with CM-cellulose column chromatography, and HPLC with DEAE- TSK gel and YMC-pack Diol 120. The purified enzyme appeared as a single band on SDS-polyacrylamide gel. The molecular weight of the enzyme was estimated to be about 46 kDa on SDS-polyacrylamide gel, and was estimated to be about 23 kDa by GFC. The optimal pH of chitosanolytic activity was about pH 5.5-6.0, and the purified enzyme was most stable at pH 5.0. The optimal temperature of chitosanolytic activity was $65^{\circ}C$ and the enzyme was stable at $45^{\circ}C$ for 1 h. Chitosan was the most favorable substrate among various $\beta$-glucan. UVmax of the purified enzyme was 195 nmand was not noted around 280 nm. The main product of enzyme reaction with chitosan was chitobiose.

• Environmental Engineering Research
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• v.11 no.4
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• pp.181-193
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• 2006

The hydrophilic or hydrophobic characteristics of dissolved organic matter (DOM) from different origins in lake and river waters were investigated using spectrometric and chromatographic analyses of water samples. DOM in a deep, mesotrophic lake (Lake Unmun) was fractionated using three types of ion exchange resins and classified into aquatic humic substances (AHS), hydrophobic neutrals (HoN), hydrophilic acids (HiA), hydrophilic neutrals (HiN), and bases (BaS). The DOM fractionation provided insight into the understanding of the nature of heterogeneous DOM molecules present in different water sources. The UV/DOC ratios were determined for samples from the influent river and lake waters during DOM fractionation and incubation. AHS prevailed over DOM in the lake and river waters. After biodegradation, the relative contribution of AHS in the total DOM became more significant. It indicates that the AHS fraction would increase while water stay long time in the lake.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.698-705
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• 2016

In this study, we have studied the polymerization of polyethylene wax using metallocene catalysts and its physical properties. Various polymerization conditions were tried for polymerization of polyethylene wax. We have evaluated hydrogen reactivity and studied on characteristics of polymerization effected by ligand structure of metallocene catalysts against Ziegler-Natta catalysts which are widely used for polymerization of polyethylene. We have also checked hydrogen used for chain transfer agent, molecular weight change and distribution by different ratios of ethylene gas. Finally, we suggest proper structure of metallocene catalysts for polymerization of polyethylene wax.

• Fisheries and Aquatic Sciences
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• v.20 no.10
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• pp.26.1-26.9
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• 2017

Fishes in genus Sardinella are small pelagic species, which plays an important role in marine ecosystem as the first consumer. Those species are also commercially important, whose total catch reaches 278,600 tons in 2011 in Indonesia, but their identification has been difficult for their morphological similarity. In this study, we reported Sardinella jussieu for the first time in Indonesian coastal area (Banten Bay, Indonesia, $6^{\circ}\;0^{\prime}\;50.00^{{\prime}{\prime}}\;S-106^{\circ}\;10^{\prime}\;21.00^{{\prime}{\prime}}\;E$). We were able to confirm the species by both its morphological characteristics including the black spot at dorsal fin origin, the dusky pigmentation at caudal fin, 31 total scute numbers, and DNA sequence identity in the GenBank database by the molecular analysis. Its total mitochondrial genome was determined by the combination of next-generation sequencing and typical PCR strategy. The total mitochondrial genome of Sardinella jussieu (16,695 bp) encoded 13 proteins, 2 ribosomal RNAs, 22 transfer RNAs, and the putative control region. All protein-coding genes started with ATG and typical stop codon and ended with TAA or TAG except for ND4 in which AGA is used. Phylogenetic analyses of both COI region and full mitochondrial genome showed that S. jussieu is most closely related to Sardinella albella and Sardinella gibbosa

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.38-45
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• 1998

To extract insoluble proteins and to improve funtional properties of abolished proteins, an phytase producing Aspergillus sp. SM-15 was isolated from soil. The enzyme was purified and its enzymological characteristics were investigated. Phytase production reached to maximum when the wheat bran medium containing 1% mannose, 1% yeast extract, 1% (NH4)2HPO4 and 0.2% calcium chloride was cultured for 4 days. Phytase was purified 17.1 fold and specific activity was 244.32unit/mg by a sequencial process of ammonium sulfate fraction, ion exchange chromatography and gel filtrations Pruified enzyme was confirmed as a single band by the polyacrylamide gel electro-phoresis. The molecular weight of phytase was estimated to be 46,000. The optimum pH and temperature for the phytase activity were 5.5 and 5$0^{\circ}C$. The enzyme is stable in pH 4.5~5.5, 6$0^{\circ}C$. The activity of purified enzyme was inhibited by Hg2+ whereas activited by Pb2+ and Fe2+. The activity of phytase was inhibited by the treatment with iodine. The result indicate the possible involvement of histidine at active site. Km and Vmax of the puridied phytase were 37.037mM/L and 159.87umol/min, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.6
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• pp.605-611
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• 1990

$\beta$-Galactosidase activity was not detected at green mature stage but were 21.79 and 380.23 units/100g-fr. wt. in mature and soft persimmon, respectively. The molecular weight of $\beta$-galactosidase was estimated to be 115, 000 daltons by the method of gel filtration. Vmax and Km value were 0.095m mo1e p-nitrophenyl-galactoside and 1.8$\times$10$^{-2}$ mM, respectively. The optimum temperature and pH of $\beta$-galactosidase were 45$^{\circ}C$ and 4.2, respectively. $\beta$-Galactosidase was inhibited by SDS.

• ETRI Journal
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• v.24 no.3
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• pp.221-225
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• 2002

We performed nonlinear transmission measurements and quantum-chemical calculations on dithienothiophene(DTT)-based molecules to gain insight into the effect of acceptor and donor groups on two-photon absorption(TPA) properties. The TPA intensity showed dispersion characteristics of the single-photon absorption spectrum. When the molecules included an asymmetric donor-acceptor pair, the single- and two-photon absorption maximum wavelengths were red-shifted more than when the molecules had a symmetric donor-donor structure. We interpreted this result as indicating that the $S_2$ state plays the dominating role in the absorption process of molecules with a symmetric structure. The experimental TPA ${\delta}$ values at the absorption peak wavelength showed a dependence on the structural variations. We found the self-consistent force-field theory and Hartree-Fock Hamiltonian with single configuration interaction formalism to be valid for evaluating TPA ${\delta}$. Although the quantum-chemical calculations slightly underestimated the experimental ${\delta}$ values obtained from nonlinear trans -mission measurements, they reasonably predicted the dependence of the ${\delta}$ value on the structural variations. We confirmed the role of molecular symmetry by observing that donor-donor substituted structure gave the highest experimental and theoretical TPA ${\delta}$ values and that the donor-acceptor substituted structure showed a greater red-shift in the TPA absorption maximum wavelength. Overall, the theoretical ${\delta}$ values of DTT-based molecules were in the order of $10^{-46}\;cm^4{\cdot}s{\cdot}photon^{-1}$ and are higher than that of AF-50 by nearly two orders of magnitude.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.350-354
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• 1991

Characteristics of a gas chromatographic detector using glow discharge as the ionization source was studied in helium flow. Discharge current greater than 10$_6$ A was observed from the electric field 400 V/mm for the electrode distance 1 mm. The discharge current of 0.1~0.3 mA could be used for the detection of organic compounds. Discharge current was almost constant for the helium flow rate greater than 10 ml/min, but the discharge was easily disappeared by an injection of a small amount of organic compound in the flow rate of 0~30 ml/min. From the decrement of the discharge current depend on several compounds, it was suggested that the sensitivity of the glow discharge ionization chromatographic detector is strongly influenced by the molecular weight of the compounds.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.62.2-62.2
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• 2014

We compiled near-infrared photometric and polarimetric catalog of sources in ~3 $9^{\prime}{\times}69^{\prime}$ size field in the eastern side of the Large Magellanic Cloud (LMC). This catalog lists all 1969 sources which are brighter than 14 mag and which signal to noise ratio of degree of polarization is greater than 3 in the J, H, and Ks bands. The photometric and polarimetric data were simultaneously obtained in J, H, and Ks bands using SIRPOL, an imaging polarimeter of the InfraRed Survey Facility (IRSF), in 2008 December and 2011 December. We classified the objects into several groups based on their locations on the color-magnitude diagram and compared their general properties of polarization. We measured wavelength dependence of this field to verify interstellar polarization of the LMC which occurred from the dichroic extinction. We also discuss the polarization structure in this field with the results from molecular cloud studies.