• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.378-384
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• 2005

Vanillin is one of the world's principal flavoring compounds, and is used extensively in the food industry. The potential vanillin production of the bacteria was compared to select and clone genes which were appropriate for highly productive vanillin production by E. coli. The fcs (feruloyl-CoA synthetase) and ech (enoyl-CoA hydratase/aldolase) genes cloned from Amycolatopsis sp. strain HR104 and Delftia acidovorans were introduced to pBAD24 vector with $P_{BAD}$ promoter and were named pDAHEF and pDDAEF, respectively. We observed 160 mg/L vanillin production with E. coli harboring pDAHEF, whereas 10 mg/L of vanillin was observed with pDAHEF. Vanillin production was optimized with E. coli harboring pDAHEF. Induction of the fcs and ech genes from pDAHEF was optimized with the addition of 13.3 mM arabinose at 18 h of culture, from which 450 mg/L of vanillin was produced. The feeding time and concentration of ferulic acid were also optimized by the supplementation of $0.2\%$ ferulic acid at 18 h of culture, from which 500 mg/L of vanillin was obtained. Under the above optimized condition of arabinose induction and ferulic acid supplementation, vanillin production was carried out with four different types of media, M9, LB, 2YT, and TB. The highest vanillin production, 580 mg/L, was obtained with LB medium, a 3.6 fold increase in comparison to the 160 mg/L obtained before the optimization of vanillin production.

• KSBB Journal
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• v.14 no.1
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• pp.76-81
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• 1999

Characteristics and oxidizing ability of both $NH_4-N$ and$NO^2$-N were examined for the strains isolated from wastewater treatment facilities and from natural systems by using Winogradsky columns. In case of $NH_4$-N, the most efficient strain was Nitrosomonas KB1 isolated from wastewater treatment facility of K corporation and in case of $NO_2$-N, it was Nitrobacter KB2 from the same site as Nitrosomonas KB1. For Nitrosomonas KB1, 91% of $NH_4$-N was oxidized after 4 days of cultivation. Optimal growth temperature and initial pH of Nitrosomonas KB1 were $28^{\circ}C$ and 7, respectively. In comparison to oxidizing rates with changing initial concentration of $NH_4$-N, the ammonia oxidizing rate was increased up to 6.7 mg/day for the initial $NO_2$-N concentrations for the region lower than 100 mg $NH_4-N/L$, but it was gradually reduced for the region higher than 100 mg $NH_4-N/L$. For Nitrobacter KB2 90% of $NO_2$-N was removed after culturing for 4 days. Optimal growth temperature and initial pH of Nitrobacter KB2 was $28^{\circ}C$ and 7, respectively. And the nitrite oxidizing rate was increased in proportion to the initial concentrations of $NO_2$-N up to 200 mg/$\ell$, and it was maintained almost 4.2 mg/day irrespective of initial $NO_2$-N higher than 200 mg/L.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.174-178
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• 1999

An anthocyanin-deficient tomato (Lycopersicon esculentum Mill.) strain, H957, shows an unusual tolerance to low phosphorus (P). To investigate whether the tolerance originates from a tissue/cellular strength, plant tissue culture procedure was employed which facilitate to characterize the tolerance independent of morphological features. The tolerance was analyzed by comparing H957 against H883, its maternal wild type, while each explant was co-cultured on minimal P media. Comparisons were made in fresh weight, dry weight, callus and shoot formation, mineral contents, and P utilization ratios at $0-400{\cdot}\bar{I}MP$, . Growth of the two strains was severely impaired at 0 and $12.5{\cdot}\bar{I}MP.\;At\;25-200{\cdot}\bar{I}MP$, however, H957 consistently showed a greater fresh and dry weight than H883. Shoot onset of H957 was less delayed than H883 compared to optimal P conditions. H957 tissue contains an overall lower P concentration than H883. These observations indicate that H957 may tolerate to low P by its tissue or cellular strength in P utilization side from its morphology.

• Journal of Life Science
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• v.26 no.5
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• pp.571-583
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• 2016

Biogenic amines are produced primarily by microorganisms found in fermented foods and are often implicated in poisoning incidents in humans. In this study, 620 strains of microorganisms were isolated from traditional Korean fermented food in Sunchang in order to screen for non-biogenicamine-producing microorganisms present in these foods. One strain was identified and named Bacillus subtilis SCJ1, by using 16S rRNA sequencing and biochemical characterization. We investigated the cell growth of this organism in order to understand its potential for industrial application. To this end, we optimized the culture medium constituents by using the response surface methodology. The Plackett-Burman experimental design was used for screening of the medium constituents, such as molasses, yeast extract and peptone, for improving cell growth. In order to determine the optimal concentration of each constituent, we used a central composite design. Consequently, the optimized concentrations of molasses, yeast extract and peptone were predicted to be 27.5 g/l, 7.5 g/l and 17.5 g/l, respectively. By model verification, we confirmed that a 1.49-fold increase in dry cell weight compared to the basal medium-from 1.32 g/l, to 1.9722 g/l-was achieved.

• Korean journal of food and cookery science
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• v.22 no.1 s.91
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• pp.22-29
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• 2006

Yogurt base was prepared from milk powder $(14\sim18%)$ to which was added 0.4% Saururus chinensis (Lour.) Bail water extract (SCE) and fermented with lactic acid bacteria (a mixed strain of Streptococcus thermophilus and Lactobacillus bulgaricus) at $37^{\circ}C$ for 24 hr. The viscosity of the yogurt added SCE (SCE yogurt) made from 18% milk was higher than that of SCE yogurt containing $14\sim16%$ milk, whereas the pH and titratable acidity of the SCE yogurt were not significantly different on the range of milk contents. The optimal milk concentration for SCE yogurt manufacture was 18%. In order to optimize the preparation of dressing from SCE yogurt, the central composite design was conducted in terms of the yogurt (30, 40, 50, 60, 70 g), the mayonnaise (6, 12, 18, 24, 30 g) and the salt (0.1, 0.3, 0.5, 0.7, 0.9 g) contents. Sensory evaluation was performed and evaluated using a response surface methodology. The optimum ingredient ratio for SCE yogurt dressing was determined to be 61.2% of yogurt, 23.5% of mayonnaise, 0.58% of salt, 0.58% of honey, 1.75% of mustard, 0.23% of Tabasco pepper sauce, 0.94% of wine and 0.04% of white pepper.

• Fire Science and Engineering
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• v.27 no.6
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• pp.50-56
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• 2013

The radiation effects on the auto-ignition and extinction characteristics of a non-premixed fuel-air counterflow field were numerically investigated. A detailed reaction mechanism of GRI-v3.0 was used for the calculation of chemical reactions and the optically-thin radiation model was adopted in the simulations. The flame-controlling continuation method was also used in the simulation to predict the auto-ignition point and extinction limits precisely. As a result, it was found that the maximum H radical concentration, $(Y_H)_{max}$, rather than the maximum temperature was suitable to understand the ignition and extinction behaviors. S-, C- and O-curves, which were well known from the previous theory, were identified by investigating the $(Y_H)_{max}$. The radiative heat loss fraction ($f_r$) and spatially-integrated heat release rate (IHRR) were introduced to grasp each extinction mechanism. It was also found that the $f_r$ was the highest at the radiative extinction limit. At the flame stretch extinction limit, the flame was extinguished due to the conductive heat loss which attributed to the high strain rate although the heat release rate was the highest. The radiation affected on the radiative extinction limit and auto-ignition point considerably, however the effect on the flame stretch extinction limit was negligible. A stable flame regime defined by the region between each extinction limit became wide with increasing the fuel temperature.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.471-478
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• 2000

The pharmacokinetic properties of KR-V compounds, recently developed as new anti-HIV agents, were studied after i.v. and p.o. administration in rats. The concentrations of the KR-V series were determined in rat plasma using an high-performance liquid chromatography (HPLC)-UV detection system. Of the 19 KR-V compounds investigated in the present study, only KR-V 3, 10, 14, 16 and 18-1 showed oral bioavailability. The plasma concentration-time data could be adequately described by an one-compartment open model. In the i.v. kinetic study (10mg/kg), the CLt of KR-V 3, 10, 14 and 16 (>4L/hr/kg) were significantly higher than that of KR-V 18-1 (1.1 L/hr/kg). The AUC of KR-V 18-1 was greater ($8.97{\mu}g{\cdot}hr/ml$) than that of the other compounds, but the Vd (0.58 L/kg) was lower. In the p.o. kinetic study (50mg/kg), although the t-1/2 of KR-V 18-1 was shorter than that of the other compounds, the AUC ($3.659{\mu}g{\cdot}hr/ml)$ and $C_{max}(1.891{\mu}g/ml$) were markedly higher. In a seperated in vitro experiment, only KR-V 18-1, of the 5 compounds with bioavailibility, exhibits potent activity against HIV-1 mutant strains. Therefore, KR-V 18-1 is expected to become a new potent anti-AIDS drug candidate/lead compound.

• Membrane Journal
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• v.24 no.2
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• pp.113-122
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• 2014

Porous poly(L-lactic acid)(PLLA) scaffold membranes were prepared via. phase separation process. Chloroform, dichloromethane and 1,4-dioxane were used as solvent and, ethyl alcohol was used as non-solvent. Morphologies, mechanical properties and mass transfer characteristics of the scaffold membranes were investigated through SEM, stress-strain test and glucose diffusion test. The scaffold membranes obtained from the casting solutions with chloroform and with dichloromethane showed similar morphologies. They showed sponge-like porous structure with the pore size in the range of $3-10{\mu}m$ and, their porosities were in 50-80% range. Using 1,4-dioxane as solvent, nano-fibrous scaffold membranes with porosities over 80% were fabricated. When the polymer content in the solution with 1,4-dioxane was lowered to 4%, highly porous, macroporous and nano-fibrous scaffold membranes were obtained. The size of the macropore was tens of the microns and the porosity was around 90%. These results indicate that the solvent has significant effect on the scaffold membrane structure and, that scaffold membranes with various structures can be fabricated through phase separation method by choosing solvent and by controlling polymer concentration in the casting solution.

• Korean Journal of Microbiology
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• v.1 no.1
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• pp.38-44
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• 1963

According to the experiment on pure-isolation and the related contaminants of Chlorella, the phenomena of the ecological distributions of Chlorella in Korea have been manifested in several areas and also the aim that in going to do culture, biological and physiological study of Chlorella is carried out. Contaminants very oftenly occupied on the colony of the strains taken in order to fulfil pure-isolation of Chlorella, but in accordance with being piled up the minute research on this subject, I can obtain the desirable results as follows: 1. For the pure-isolation, the duration chose the time from May to September 1957 so that may easily isolate from contaminant water with utilizing the antibiotic substances. 2. To take long time, 36-48 hours until growth of nascent through the non-sporulated, it originates from the difference of the cultured media. In addition to the above mention, the mechanism of growth until nascent through the sporulated must not always require the ligh. However the supply of metabolic energy depend upon its nutritional conditions per phase. 3. The culture of Chlorella should be based on the lower culturing except adding especial conditions such as reagent concentration of media, artifical shake of media and other facts due to the natural conditions. And also these strains grew not only in distilled water but 2% NaCl solution without any abnormality in cell it self. I, therefore, guess it is possible to culture in sea-water under phasic environment. 4. In the experiment of ammonia detection, it is caused by the sampling surroundings to contain the minute quantity of ammonia in strain No. M 918; that is the place to be plenty of Carbohydrate on behalf of protein. 5. To compare the absorption curve of chlorophyll of higher plant with that of Chlorella, the absorption zone made mostly the Same ones each other but a little absorption grade dose not clearly appear. The colony which formed giant type grows with intensive colour and green band on surrounding of the colony and after that it was changed into all the green colour and developed up to end. 6. At first phase for a week, the development of Chlorella suspends the normal condition as in vivo but after a few days, the colour of chlorophyll gradually changed into blue-yellow which secrete the mucous substances on the agar media. The cell was flew out the contained substances itself on leaving the cell wall only, or the various micro-organism diffused on the outer-region of the cell.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.1
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• pp.125-129
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• 2008

The purpose of this study was to investigate the characteristics of Mamestra brassicae nucleopolyhedrovirus (MabrNPV)-K1 isolated in Korea. Polyhedra of MabrNPV-K1 showed irregular appearance in shape with the average diameter $1.8{\mu}m$. MabrNPV-K1 contained a number of nucleocapsids within a viral envelope embedded in polyhedron. The polyhedrin of MabrNPV-K1 was composed of single polypeptide with a M.W. of approximate 31 kDa which is identical to the commercialized MabrNPV, Mamestrin, as a biological control agent. The nucleotide and amino acid sequences within the coding region of MabrNPV-K1 polyhedrin shared 99.0% similarity with the polyhedrin gene from previous reported MabrNPVs. The median lethal concentrations ($LC_{50}$) of MabrNPV-K1 and Mamestrin to M. brassicae larvae were $3.9{\times}10^3$ PIBs/larva and $6.0{\times}10^4$ PIBs/larva, respectively. Mortality of the MabrNPV-K1 against to the third instars larvae was 15 times higher than that of the Mamestrin. The median lethal times ($LT_{50})$ of MabrNPV-K1 by the concentration of polyhedra were lower ($4.4{\sim}6.1$ days) than those of Mamestrin ($4.1{\sim}8.6$ days). These results suggest that a local strain MabrNPV-K1 has high pathogenicity to M. brassicae and may be useful for the development of biological control agent to control this.