• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.101.2-102
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• 2003

The ability of P. chlororaphis O6 to induce resistance to Erwinia carotovora subsp. carotovara SCCI and to promote growth in tobacco was demonstrated in microtiter assays on plants pre-inoculated at the root level with the bacteria before challenge with the leaf pathogen. To identify th bacterial determinants involved in induced systemic resistance and plant growth promotion, cell culture of O6 grown in King's medium B was fractionated with organic solvents and purified using various columns. in vivo and in vitro assays with samples from successive fractionation steps of the O6 supernatant led to the conclusion that antibacterial compounds were observed in aqueous layer, and to the isolation of fractions containing metabolites that retained most of the resistance-inducing activity (70：30, methanol：water) and the plant growth promotion (80：20 and 90：10, methanol：water) after ODS column chromatography. Although these molecules remain to be purified further and structurally characterized, its isolation is an addition to the range of determinants from plant growth-promoting rhizobacteria known to stimulate plant defence.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.387-389
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• 1997

Effect of concentrations of wheat flour and glucose on the sponge fermentation of soda cracker by the mixed lactic acid bacteria of L. brevis, L. fermentum and L. plantarum was investigated. When glucose was added to the wheat flour solution, pH was higher and TTA (total titrable acid) was lower as compared with the medium without glucose. This results suggested that glucose in the solution stimulate cell growth but inhibit the production of organic acids. With increasing of wheat flour concentration, pH decreased and TTA increased during the sponge fermentation of soda cracker.

• Korea-Australia Rheology Journal
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• v.18 no.2
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• pp.103-107
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• 2006

Organic-inorganic composite of polyaniline and barium titanate (PANI-$BaTiO_3$) was synthesized via an in-situ oxidation polymerization of aniline in the presence of barium titanate ($BaTiO_3$) nanoparticles dispersed in an acidic medium. Barium titanate has large electric resistance and relatively high dielectric constant which is one of the essential properties for its electrorheological (ER) applications. The microstructure and composition of the obtained PANI/$BaTiO_3$ composite were characterized by SEM, FT-IR and XRD. In addition, we also employed a rotational rheometer to investigate the rheological performance of the ER fluids based on both pure PANI particle and PANI/$BaTiO_3$ composite. It was found that the composite materials possess much higher yield stresses than the pristine PANI due to unique dielectric properties of the inorganic $BaTiO_3$ particles. Finally, we also examined dynamic yield stress by analyzing its extrapolated yield stress data as a function of electric field strengths. Using the critical electric field strengths deduced, we further found that the universal yield stress equation collapses their data onto a single curve.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.80-85
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• 1999

To develop bioflocculant for wastewater treatment, about 60 type culture strains and 450 strains isolated from natural sources were examined for screening their ability to flocculate the swine wastewater. Among them, YWO-5 showed the highest activity for NTU removal efficiency and was identified as Bacillus megaterium according to the cultural, morphological and physiological properties. The maximum production of the flocculant was achieved in culture medium containing 2% glucose, 0.05% soytone, 0.01% $CaCl_2$, 0.05% $KH_2PO_4$, and 0.05% yeast extract with initial pH 6.5 when cultured with rotary shaker controlled at 20$^{\circ}C$ and 150 rpm. With jar fermentor, the maximum production was reached to NTU removal efficiency of 93% after 3 days under the optimal conditions. The bioflocculant produced by Bacillus megaterium YWO-5 was effective on various suspended solids and organic wastewaters.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.732-736
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• 2010

Five strains of tannic acid degrading bacteria were isolated and identified by phenotypic characterization. All the five isolates showed cell-associated activity, whereas only three showed extracellular activity. Serratia ficaria DTC, showing the highest cell-associated activity (0.29 U/l), was selected for further shake-flask studies. Tannase synthesis was growth associated and reached the peak in the late stationary phase of growth. Organic nitrogen sources enhanced the tannase production. Peak tannase production of 0.56 U/l was recorded in the medium having the initial pH of 6. The pH and temperature optima of the enzyme were found to be 8.9 and $35^{\circ}C$, respectively. This is the first report of cell-associated activity in the case of bacterial tannase. Cell-associated tannase of Serratia ficaria DTC could be industrially important from the perspective of its activity at broad temperature and pH ranges, and its unusually high activity at pH 8.9.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.135-139
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• 1991

Tridecanedioic acid (DC-13), starting material of the valuable musk ethylene brassylate, was obtained from n-tridecane by the Candida tropicalis mutant. The mutants were first obtained from primary screening step using the selective medium and then solid phase extraction sampling method was used for the selective isolation of organic acids from the cultured media of mutants. The resulting acids were directly converted to volatile tert-butyldimethyl silyl delivatives, which were then analyzed by gas chromatography. The efficient GC profiling method was used for the rapid identification of the mutant producing DC-13 in large quantity, and for the optimization of the culture conditions of mutant. The optimal culture conditions were found as follows: pH 8.0, 30$^{\circ}C$, 250rpm, 48hour of culture and $(NH_4)_2HPO_4$ as nitrogen source.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.05a
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• pp.202-205
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• 2006

Space design is a process of solving spatial problems to create and construct all kinds of human lives. It also bestows new values to a medium to induce human perception based on the relationships between 'human and space' surrounding people. Research on user behavior has several ultimate goals including understanding both individual behavior and the relations between the user and space from a more scientific and systematic perspective, predicting various phenomena that can happen between space and humans, and reflecting the results in space design. As user behavior that's once limited within given space is going through some changes due to the introduction of digital technologies, research on user behavior in today's space design should be newly illuminated in the aspects of organic relations. Space now works as a receptor communicating with the user and responding to user behavior, and user behavior once under one-sided influences from space becomes more diverse and active. The influences of user behavior, in turn, cause changes to space itself. Thus this study set out to suggest new directions in research on user behavior based on interactions between space and the user in space design.

• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.134-140
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• 1998

Eubacterium limosum KIST612 was cultured on phosphate-buffered basal medium (PBBM) with carbon monoxide (CO) as the sole energy and carbon source. The initial growth rate of this strain was approximately 0.17~0.25 $h^-1$/ and the $K_s$ value for dissolved substrate was 0.14 mM. CO was limiting during the growth of the bacterium when the CO partial pressure was less than 0.6 atm (0.5 mM dissolved CO). The bacterial growth rate was reduced in the presence of acetate. When sufficient CO was supplied using a gas-lift reactor, the acetate concentration went up to 90 mM in 116 h. Based on these findings, it is suggested that a pressurized reactor be used to develop a process to convert CO-rich gases into multi-carbon compounds.

• Journal of the Korean Society of Food Culture
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• v.35 no.5
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• pp.450-458
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• 2020

This study examined the optimal temperature and time conditions to maintain high quality Dongchimi during the fermentation and storage period. Dongchimi was fermented at low (5℃), medium (10 and 15℃), and high (20℃) temperatures until the acidity reached 0.2, 0.3, and 0.4%. respectively. From the consumer's preference test enrolling five consumers, Dongchimi fermented at 15℃ until an acidity of 0.3% (for approximately six days) was evaluated to be the optimal status because of its high score of overall acceptance, taste, and odor of consumers. To determine the optimal storage temperature of fermentation, Dongchimi was stored at three different temperatures (-1, 2, 5℃) for four weeks after fermenting at 15℃ for six days. During the storage period, most of the physicochemical properties (pH, acidity, reducing sugar content, and organic acid) and microbiological properties changed significantly in the 2 and 5℃ groups, resulting in a significant change in descriptive sensory analysis of Dongchimi. These results indicate that fermentation at 15℃ and storage at -1℃ for Dongchimi enables it to maintain the best quality for a long time.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.1-8
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• 2003

Strain FJI, a filamentous fungus isolated from rotten wood, showed high ability to hydrolyze cellulosic materials. To identify the strain FJI, ITS sequencing analysis and morphological observation were performed. The strain FJI was identified as Trichoderma harzianum. The strain produced a large amount of CMCase, xylanase, ${\beta}-glucosidase$, and avicelase. Optimal culture conditions for the production of the enzymes, such as pH, temperature, and inoculation concentration, were initial pH 6.0-7.0,$25-30^{\circ}C$, and $10^4$ ea-spores/ml in Mandel's medium, respectively. T.hanzianum FJI utilized various cellulosic materials and organic nitrogen sources to produce cellulases and xylanase, and also considerably a crystalline and/or insoluble material like Avicel and rice straw. The highest levels of CMCase and xylanase were 41.2 and 65.6 U/ml in 7 days of cultivation using 2.5% of carbon source (Avicel+CMC) and 0.5% of nitrogen source (peptone), respectively.