• Journal of Life Science
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• v.19 no.12
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• pp.1724-1730
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• 2009

The mannanase-producing bacteria, designated CS47, was isolated from the fresh feces of three horses (from a farm in Jinju National University). The isolate CS47 was facultatively anaerobic and grew at temperatures ranging from $20^{\circ}C$ to $50^{\circ}C$ with an optimal temperature of $38^{\circ}C$. The DNA G+C content of the isolate CS47 was 44 mlo%. The major fatty acids were anteiso-15:0 (39.6%), 17:0 (7.6%), and iso-15:0 (37.8%). The 16S rRNA gene sequence similarity between the isolate CS47 and other Bacillus strains varied from 93% to 98%. In the phylogenetic analysis based on these sequences, the isolate CS47 and Bacillus amyloliquefaciens clustered within a group and separated from other species of Bacillus. Based on the physiological and molecular properties, the isolate CS47 was classified within the genus Bacillus as Bacillus amyloliquefaciens CS47. The optimal pH and temperature for mannanase activity of B. amyloliquefaciens CS47 were pH 6.0 and $50^{\circ}C$, respectively. The thermal stability of mannanase from B. amyloliquefaciens CS47 is valuable when using this enzyme in industrial application.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.594-602
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• 2011

The effect of ${\alpha}$-, ${\beta}$- and ${\gamma}$-picolines on the stereochemistry of the coordination compounds of lanthanide(III) nitrates derived from 4[N-(furfural)amino]antipyrine semicarbazone (FFAAPS) has been studied. The general composition of the present coordination compounds is [Ln(FFAAPS)$(NO_3)_3$Pic] (Ln=La, Pr, Nd, Sm, Gd, Tb, Dy or Ho and Pic=${\alpha}$-, ${\beta}$- or ${\gamma}$-picolines). All these coordination compounds have been characterized by elemental analyses, molecular weight, molar conductance, magnetic susceptibility, infrared and electronic spectra. The infrared studies suggest that the FFAAPS behaves as a neutral tridentate ligand with N, N, O donor while ${\alpha}$-, ${\beta}$- or ${\gamma}$-picoline is coordinated to the lanthanide(III) ions via heterocyclic N-atom. Nitrates are bicovalently bonded in these compounds. From the electronic spectral data, nephelauxetic effect (${\beta}$), covalence factor ($b^{1/2}$), Sinha parameter (${\delta}%$) and the covalence angular overlap parameter (${\eta}$) have been calculated. Thermal stabilities of these complexes have been studied by thermogravimetric analysis. The coordination number of lanthanide(III) ions in the present compound is found to be ten. The antibacterial studies screening of the primary ligand FFAAPS and the complexes showed that the present complexes have moderate antibacterial activities.

• Analytical Science and Technology
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• v.19 no.3
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• pp.255-262
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• 2006

In this study, we attempted to evaluate the sorptive loss of VOC upon their contact with different material surfaces including clothing pieces. For the purpose of this study, we developed a method to evaluate such loss by employing a filter holder pack in the thermal desorption line of the GC/FID system. The calibration curves of different aromatic VOCs including benzene, toluene, and xylene were made by loading them at different quantities through the analytical line. A series of experiments were conducted repetitively to draw calibration data sets for all three materials covering glass fiber, cotton, and nylon. The results were then compared in terms of both material types and of VOC types. The extent of sorptive loss increased in a highly systematic manner across different materials such as glass fiber, cotton, and nylon. The patterns of sorptive loss also increased gradually across VOC type such toward in the direction of increasing molecular weights: benzene, toluene, and xylene. According to this experimental study, it is concluded that sorptive behavior of pollutint compounds like VOC can be controlled by the combined effects of both chemical properties and material characteristics.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.1
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• pp.1-10
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• 2015

Bio diesel has advantages to reduce GHG(Greenhouse Gas) compare with the fossil fuel by using oil comes from plant/animal sources and even waste such as used cook oil. The diversity of energy feeds brings the positive effects to secure the national energy mix. In this circumstance, micro-algae is one of the prospective source, though some technical barriers. We analyzed the bio diesel which was derived from Dunaliella tertiolecta LB999 through the BD100 quality specifications designated by the law. From that result, it is revealed that the oxidation stability is one of the properties to be improved. In order to find the reason for low oxidation stability, we analyzed the oxidation tendency of each FAME components through some methods(EN 14111, EN14112, EN16091). In this study, we could find the higher double bond FAME portion, the more oxidative property(C18:1${\ll}C18:3$) in bio diesel and main unsaturated FAME group is acted as the key component deciding the bio diesel's oxidation stability. It is proved experimentally that C18:3 FAME are oxidized easily under the modified accelerated oxidation test. We also figure out low molecular weight hydrocarbon and FAME were founded as a result of thermal degradation. Some alcohol and aldehydes were also made by FAME oxidation. In conclusion, it is necessary to find the way to improve the micro-algal bio diesel's oxidation stability.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.395-400
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• 2017

Coke strength was increased by adding ash-free coal (AFC) binder. In this study, the effect of the AFC binder on the physical and chemical properties of coke was experimentally investigated to understand the molecular mechanism for the improved coke strength. For reduced $CO_2$ emission in steelmaking industry, torrefied biomass fuel mixed with coal binder is also considered. The interface between the base coal and AFC was thus examined using Scanning Electron Microscope (SEM). The coke strength was commonly measured by performing the indirect tensile test and Nuclear Magnetic Resonance (NMR) spectroscopy in $^1H$ and $^{13}C$ modes. For comprehensive mechanism study of the enhanced coke strength thus obtained, ordinary coal for thermal power plant use was carbonized with AFC for subsequent SEM examination. The NMR spectroscopy results of coke samples positively revealed that the tensile strength was proportional to the average number of aromatic rings.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.221-226
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• 2016

Production of eco-friendly and biologically harmless materials is strongly required in all industries. In particular, reducing volatile organic compounds in coating processes is extremely important to secure worker's safety. During recent two decades, extensive research works on water-borne polyurethane dispersion (PUD) have been continuously developed as an alternative to solvent-borne polyurethane. However, PUD was shown inferior mechanical properties to the organic solvent-borne polyurethane due to a limit to the molecular weight increase, which resulted in the limit of applications. To overcome this drawback, several approaches have been examined such as polymer blends and thermal/radiation induced crosslinking. Among these methods, the radiation curing system was suitable for industrialization because of the high crosslinking density and fast curing speed. In this study, we overcame the drawback for PUD via introducing benzophenone radiation curable units to PUD. We synthesized PUD films which possessed good dispersion in water for 30 days, increased Tg and Td more than $5^{\circ}C$ after UV curing film as well as improved young's modulus more than double.

• Membrane Journal
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• v.20 no.4
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• pp.312-319
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• 2010

Carbon membrane materials have received considerable attention for the gas separation including hydrocarbon mixture of ingredients of the volatile organic compounds(VOCs) because they possess their higher selectivity, permeability, and thermal stability than the polymeric membranes. The use of activated carbon membranes makes it possible to separate continuously the VOCs mixture by the selective adsorption-diffusion mechanism which the condensable components are preferentially adsorbed in to the micropores of the membrane. The activated carbon hollow fiber membranes with uniform adsorptive micropores on the wall of open pores and the surface of the membranes have been fabricated by the carbonization of a thin film of phenolic resin deposited on porous alumina hollow fiber membrane. Oxidation, carbonization, and activation processing variables were controlled under different conditions in order to improve the separation characteristics of the activated carbon membrane. Properties of activated carbon hollow fiber membranes and the characterization of a gas permeation by pyrolysis conditions were studied. As the result, the activated carbon hollow fiber membranes with good separation capabilities by the molecular size mechanism as well as selective adsorption on the pores surface followed by surface diffusion effective in the recovery hydrocarbons have been obtained. Therefore, these activated carbon membranes prepared in this study are shown as promising candidate membrane for separation of VOCs.

• Journal of Life Science
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• v.32 no.7
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• pp.510-522
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• 2022

In this study, to biosynthesize PHA with properties more similar to polypropylene, a Bacillus sp. EMK-5020 strain that biosynthesized poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was isolated from soil. Bacillus sp. EMK-5020 strain biosynthesized PHBV containing 1.3% 3-hydroxyvalerate (3HV) using reducing sugar contained in Makgeolli lees enzymatic hydrolysate (MLEH) as a single carbon source. As the amount of propionic acid, which was added as a second carbon source, increased, the content of 3HV also increased. PHBV containing up to 48.6% of 3HV was synthesized when 1.0 g/l of propionic acid was added. Based on these results, the strain was cultured for 72 hr in a 3 l fermenter using reducing sugar in MLEH (20 g/l) and propionic acid (1 g/l) as the main and secondary carbon sources, respectively. As a result, 6.4 g/l DCW and 50 wt% of PHBV (MLEH-PHBV) containing 8.9% 3HV were biosynthesized. Through gel permeation chromatography and thermogravimetric analysis, it was confirmed that the average molecular weight and the decomposition temperature of MLEH-PHBV were 152 kDa and 273℃, respectively. In conclusion, the Bacillus sp. EMK-5020 strain could biosynthesize PHBV containing various 3HV fractions when MLEH and propionic acid were used as carbon sources, and PHBV-MLEH containing 8.9% 3HV was confirmed to have higher thermal stability than standard PHBV (8% 3HV).