• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1260-1268
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• 2014

Screening of a gene library from Paenibacillus sp. PBS-2 generated in Escherichia coli led to the identification of a clone with lipolytic activity. Sequence analysis showed an open reading frame encoding a polypeptide of 378 amino acid residues with a predicted molecular mass of 42 kDa. The esterase displayed 69% and 42% identity with the putative ${\beta}$-lactamases from Paenibacillus sp. JDR-2 and Clostridium sp. BNL1100, respectively. The esterase contained a Ser-x-x-Lys motif that is conserved among all ${\beta}$-lactamases found to date. The protein PBS-2 was produced in both soluble and insoluble forms when E. coli cells harboring the gene were cultured at $18^{\circ}C$. The enzyme is a serine protein and was active against p-nitrophenyl esters of $C_2$, $C_4$, $C_8$, and $C_{10}$. The optimum pH and temperature for enzyme activity were pH 9.0 and $30^{\circ}C$, respectively. Relative activity of 55% remained at up to $5^{\circ}C$ with an activation energy of 5.84 kcal/mol, which indicates that the enzyme is cold-adapted. Enzyme activity was inhibited by $Cd^{2+}$, $Cu^{2+}$, and $Hg^{2+}$ ions. As expected for a serine esterase, activity was inhibited by phenylmethylsulfonyl fluoride. The enzyme was remarkably active and stable in the presence of commercial detergents and organic solvents. This cold-adapted esterase has potential as a biocatalyst and detergent additive for use at low temperatures.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.102-111
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• 1998

Large amount of sludge have been generating in the process of water and wastewater treatment in urban area, and it has been making many environmental problems. Currently almost of sludge is landfilled, and since sludge is difficult to handle and dehydrate, the permeated water from the filled-in ground contaminate the surrounding soil and groundwater which may cause serious environmental and sociological problems. The organic component in sludge can be almost removed through the heat treatment process, and the final product is called artificial soil or artificial media according to the temperature control. To produce artificial media using sludge, chabazite and lime were used as an additive, and the mixture of sludge & additives was thermally treated in the firing kiln at about 800~1, 100。C for about fifteen minutes. The physical and chemical characteristics of the produced artificial media were analyzed, and it showed that it can be used as an artificial media for plant production or soil conditioner for farmland. The concentrations of the toxic heavy metals in the artificial media were lower than the soil quality standard for farmland. The characteristics of produced artificial media, using the mixture of sludge and additives through the heat treatment, is similar to the natural chabazite and soil. The analyzed result of the mineral composition of artificial media showed that it has a characteristics similar to natural stable soil, so the produced artificial media may be applied to farmland or water culture without causing adverse effect. Therefore this study showed that the above process can be a feasible alternative for sludge treatment.

• Journal of the Korean Electrochemical Society
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• v.4 no.2
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• pp.41-46
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• 2001

The effect of organic additives such as PEG ind MPS on throwing power have been studied in the fabrication of porous reticular metal by electrodeposition using the mixture of cupric sulfate and sulfuric acid as electrolyte. Both the polarization test and the electrodeposition on the stacked electrodes, mean pore diameter of which was $250{\mu}m$, were performed to illustrate the behavior of throwing power quantitatively. As far as PEG was concerned, it lowered throwing power of electrodeposition on the porous electrode used in this work while the addition of MPS up to 500 ppm in electrolyte enhanced throwing power monotonously. When both MPS and PEG were added in electrolyte, the effect of MPS on throwing power was superior to that of PEG. However, the excess addition of MPS was found to cause the defect in mechanical strength of deposit layer. From the result of SEM observation, it could be concluded that less than 50 ppm of MPS in electrolyte was appropriate to avoid the breakage of deposit layer.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.6
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• pp.812-815
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• 2005

This study was conducted to see the influence of additives and fermentation periods on Mott grass silage (MGS) characteristics, its chemical composition and to compare the digestion kinetics of Mott grass (MG) and MGS in Nili buffaloes. Mott grass chopped with a locally manufactured chopper was ensiled using two additives, cane molasses and crushed corn grains each at 2, 4 and 6% of forage DM for 30 and 40 days in laboratory silos. The pH, lactic acid concentration, dry matter (DM), crude protein and fiber fractions of MGS were not affected by the type or level of additive and fermentation periods. The non-significant pH lactic acid concentration, and chemical composition of MGS indicated that the both molasses and crushed corn were utilized at similar rate for the growth of lactic acid bacteria and production of organic acids. The MG ensiled with molasses at 2% of fodder DM for 30 days was screened out for in situ digestion kinetics in Nili buffaloes. Ruminal DM and neutral detergent fiber (NDF) degradabilities of MGS were significantly (p<0.05) higher than that of MG. The DM and NDF rate of degradation, lag time and extent of degradation was nonsignificant between MGS and MG. The higher ruminal degradation of DM and NDF of MGS than MG was probably a reflection of fermentation of MG during ensilation that improved its degradability by improving the availability of easily degradable structural polysaccharides to ruminal microbial population. The results in the present study have indicated that MG ensiled with either 2% molasses or 2% crushed corn for 30 days has better nutritive value for buffalo.

• KSBB Journal
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• v.17 no.2
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• pp.176-181
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• 2002

Astaxanthin (3,3＇-dihydroxy-${\beta}$, ${\beta}$-carotene-4-4＇-dione), a natural pigment of pink to red color, is widely distributed in nature particularly in the skin layer of salmonoids and the crust of shrimp, lobster, etc. Recently, it was produced from the yeast culture of Phaffia rhodozyma. Because of its high thermal stability and antioxidant functionality, its applications can be extended into food, cosmetics, and pharmaceutical ingredient beyond the traditional feed additive. Because of its very high lipophilicity, astaxanthin has been extracted traditionally by strong organic solvents such as chloroform, petroleum ether, acetone, etc. In this study, we developed a surfactant-based solubillization system for astaxanthin, and used it to extract astaxanthin from disrupted yeast cells. Among Tween 20, Triton X-100 and SDS, Tween 20 was identified as the most suitable surfactant in terms of extraction capacity and safety. The ethylene oxide group of Tween 20 was identified as the most significant factor to increase the HLB value that determined the extraction capacity. The effects of micelle formation condition, such as the molar ratio of astaxanthin and Tween 20, pH, and ionic strength were also investigated. pH and ionic strength showed no significant effects. The optimal molar ratio between astaxanthin and Tween 20 was 1 : 12. Antioxidant activity of astaxanthin was higher than ${\beta}$-carotene and ${\alpha}$-tocopherol. Astaxanthin in the crude extract from the yeast cell was more resistant to air and/or light degradation than pure astaxanthin, probably because of the presence of other carotenoids and lipids.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.436-444
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• 2016

Clamshells, which comprise more than 50% of a clam’s weight, are a major byproduct of the clam industry and are mainly composed of insoluble calcium carbonate. This study investigates the use of clamshells as a natural calcium resource. Highly soluble powdered calcium lactate (LCCL) was prepared from the calcined powdered shells of littleneck clams (LCCP) using response surface methodology (RSM) to predict optimum conditions. These conditions, as derived from pH, solubility, and yield of 11 LCCLs manufactured according to the RSM model, were 1.80 M lactic acid and 1.13 M LCCP. The actual values of pH (6.98), solubility (93.99%), and yield (351.23%) under the optimized conditions were as predicted. The derived LCCL exhibited a strong buffering capacity in the range of pH 2.78-3.90 when combined with less than 2 mL of 1 N HCl. The ranges of calcium content and solubility of LCCL were 7.7-17.5 g/100 g and 96.6-98.9%, respectively. Fourier transform infrared spectroscopy (FT-IR) of the LCCL identified it as calcium lactate pentahydrate, and field emission scanning electron microscopy (FESEM) revealed an irregular and rod-like microstructure. These results confirm the potential use of clamshells, converted to highly soluble organic acid calcium, as an additive to enhance calcium content in food ingredients.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.19.2-19.2
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• 2010

Printed electronics using printing process has broadened in all respects such as electrics (lighting, batteries, solar cells etc) as well as electronics (OLED, LCD, E-paper, transistor etc). Copper is considered to be a promising alternative to silver for printed electronics, due to very high conductivity at a low price. However, Copper is easily oxidized, and its oxide is non-conductive. This is the highest hurdle for making copper inks, since the heat and humidity that occurs during ink making and printing simply accelerates the oxidation process. A variety of chemical treatments including organic capping agents and metallic coating have been used to slow this oxidation. We have established synthetic conditions of copper nanoparticles (CuNPs) which are resistant to oxidation and average diameter of 20 to 50nm. Specific resistivity should be less than $4\;{\mu}{\Omega}{\cdot}cm$ when sintered at lower temperature than $250^{\circ}C$ to be able to apply to conductive patterns of FPCBs using ink-jet printing. Through this study, the parameters to control average diameter of CuNPs were found to be the introduction of additive agent, the feeding rate of reducing agent, and reaction temperature. The CuNPs with various average diameters (58, 40, 26, 20nm) could be synthesized by controlling these parameters. The dispersed solution of CuNPs with an average size of 20 nm was made with nonpolar solvent containing 3 wt% of binder, and then coated onto glass substrate. After sintering the coated substrates at $250^{\circ}C$ for 30 minutes in nitrogen atmosphere, metallic copper film resulted in a specific resistivity of $4.2\;{\mu}{\Omega}{\cdot}cm$.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.277-287
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• 2000

For the regeneration of osseous defect on the furcation area, autogeneous bone graft has been primarily used. But it has the limitation of donor site, additive surgical operation etc. Recently anorganic xenogenic bone graft materials of removing all organic components are commonly used for the regeneration of periodontal defects. This study was the comparison of the effect on the regeneration with two types xenografts($Bio-oss^{(R)}$ and Ca-P thin coated Bovine bone powder) on the furcation involvement in Beagle dogs. After surgically induced chronic periodontitis in bifurcation area of premolar, $Bio-oss^{(R)}$ and Ca-P BBP were grafted on the osseous defects. Tissue blocks including defects with soft tissues were harvested following a four-& eight-week healing interval and prepared for histologic analysis. The results of this study were as follows: 1. $Bio-oss^{(R)}$ group: there were significant differences among the $Bio-oss^{?}$ group at 4weeks and 8weeks, but the control group had various appearances : new bone formation, resorption of graft materials by multinuclear giant cells, connective tissue cells intervention in the bone graft sites etc. 2. Ca-P BBP group: lots of new bone formation were observed but the arrangement of periodontal ligament was not completed at 4weeks. New bone were replaced mature bone and the periodontal ligaments showed the functional arrangement at 8weeks. 3. By reason of undergrowing the epithelium within the osseous defects, new bone formation was not happened in the upper area of bifurcation in $Bio-oss^{(R)}$ group. 4. In Ca-P BBP group, epithelial undergrowth was not seen and generally showed much more new bone formation. 5. Ca-P BBP group showed the osteocyte-like cells at the inner portion of the graft materials 6. Both groups were similar to resorptive appearances of graft materials, but Ca-P BBP group had the better effects of osteoconduction.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.285-285
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• 2010

Zinc oxide (ZnO) is a direct band gap semiconductor with 3.37 eV, which has in a hexagonal wurtzite structure. ZnO is a good candidate for a photocatalyst because it has physical and chemical stability, high oxidative properties, and absorbs of ultraviolet light. During ZnO is irradiated by UV light, redox (reduction and oxidation) reactions will occur on the ZnO surface, generating the radicals O2- and OH. These two powerful oxidizing agents have been proven to be effective in decomposition of harmful organic materials, converting them into CO2 and H2O. Therefore, we assume that oxygen on the surface of ZnO is a very important factor in the photocatalytic activities of ZnO nanoparticles. Recently, ZnO nanoparticles are studied in various application fields by many researchers. Photocatalyst research is progressing much in various application fields. But the ZnO nanoparticles have disadvantage that is unstable in water in comparison titanium dioxide (TiO2). The Zn(OH)2 was formed at the ZnO surface and ZnO become inactive as a photocatalyst when ZnO is present in the solution. Therefore, we prepared synthesized ZnO nanoaprticles that were immersed in the water and dried in the oven. After that, we measured photocatalytic activities of prepared samples and find the cause of their phtocatalytic activity changes. The characterization of ZnO nanoparticles were analyzed by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and BET test. Also we defined the photocatalytic activity of ZnO nanoparticles using UV-VIS Spectroscopy. And we explained changing of photocatalytic activity after the water treatment using X-ray Photoelectron Spectroscopy (XPS).

• Korean journal of food and cookery science
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• v.31 no.1
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• pp.9-17
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• 2015

Shindari is a traditional fermented drink of Jeju in Korea, which is made with boiled barley and nuruk for short fermentation periods. This study determined chemical, microbiological, and sensory characteristics of the modified Shindari with 15% carrots as an additive (carrot Shindari), and this study compared it with a traditional Shindari as a control. After fermentation at $30^{\circ}C$ for a day, the pHs of the carrot Shindari and traditional Shindari largely decreased, and the total acidities increased in both of the Shindari. The significantly higher scores of Hunter's color values were observed more in carrot Shindari than in traditional Shindari. Also, carrot Shindari (0.4954 g/100 g) had a significantly higher content of vitamin C than traditional Shindari (0.0030 g/100 g). The most abundant free sugar and organic acid were glucose and lactic acid, respectively, in both of the Shindari. The total numbers of bacteria, fungi and lactic-acid bacteria in both samples increased by log 3 CFU/mL after fermentation. Based on 16S ribosomal RNA gene analysis, the dominant lactic-acid bacteria was Pediococcus acidilactici in both samples. The DPPH (1.1-diphenyl-2-picrylhydrazyl) radical scavenging activity of carrot Shindari (60.13%) was higher than that of traditional Shindari (23.70%). In sensory evaluations (taste, flavor, color, and overall acceptance), the carrot Shindari had higher scores in all these values. In this study, the modified Shindari with carrot presenting high sensory characteristic as well as chemical and microbiologic characteristics provide an opportunity to improve the application of a traditional fermented drink of Jeju, Shindari.