• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.5
• /
• pp.845-848
• /
• 1994

The fermenting conditions for acetic acid production with Acetobacter sp. FM-10 which could grow in the medium containing 10% ehtanol were investigated. Initial concentration of acetic acid in broth medium affected greatly to the fermentation speed. For example , the acetic acid production increased proportionally by the increasing of initial concentration was higher that 1.0%. When the cultivation was started with broth medium containing 5% ethanol, the additional adding ethanol during the fermentation was not significantly increased the acidity of the medium. The acidity of the medium containing 10% ethanol was reached to 8.3% after shaking than static cultivation by about 10 days with 150 rpm shaking speed. Acetic acid production with shaking cultivation was faster the static cultivation by abot 10 days under the same condition except shaking. In acetic acid fermentation with the batch style fermentor , the optimum fermentation condition was 700 rpm of agitation speed and 5L/min air flow rate in 3L culture medium .

• Journal of the Korean institute of surface engineering
• /
• v.22 no.2
• /
• pp.78-87
• /
• 1989

Mechanism of formation of electroless composite coatings is similar to that of electrodeposited composite coating, but the amount of particles entraped in electroless coating is higher that the one of electrodeposited coatings. The methol of entrapment by the metal for SiC and Al2O3 particles is different from that for WC particles. In the former case the particles are gracually engulfed by the depositing metal, wheran with WC a metal envelope is rapidly fomed around each particles. This difference can be attributed to the difference in electrical resistivity of the particles. Inclusion density of SiC and Al2O3 particles during copeposition depend on the particle size, agitation condition, vabration conditions and electrolyte temperatures.

• KSBB Journal
• /
• v.16 no.1
• /
• pp.76-81
• /
• 2001

Stigmastanol, a functional agent of cholesterol-lowering in humans, was synthesized from stigmasterol. To investigate the usability as a raw material, the contents of sterol in vegetable oils and extract of soybean chaff were analyzed. The total sterol contents showed high values of 213.7 and 209.8 mg/100g in corn and soybean oils respectively. The extract of soybean chaff has played a good role as a raw material with high sterol contents. The kinetics of hydrogenation of stigmasterol was studied using a 5% Pd/AC catalyst in the temperature range of 30~$60^{\circ}$C. Increasing temperature showed a prominent decrease in conversion. The optimum temperature was $40^{\circ}$C for high yield of stigmastanol. The effects of $H_2$ pressure, agitation speed, catalyst loading, and stigmasterol concentration on reaction rate profile were also examined. From the power law model analysis using the initial rates of reaction, the reaction order was calculated as 0.705 for stigmasterol concentration and 0.147 for hydrogen pressure.

• 한국생물공학회:학술대회논문집
• /
• 2003.04a
• /
• pp.236-239
• /
• 2003

Erinacine which is produced from Hericium erinaceus mycelia is known to have a stimulating activity of nerve growth factor(NGF) synthesis. Thus, this work was concentrated on the maximum production of Hericium erinaceus mycelia. In order to maximize cell growth, the cultivation was performed with varying the agitation rate and applying the additional medium. As the results, the mycelium concentration was 24.2g/L.

• Journal of Life Science
• /
• v.11 no.1
• /
• pp.11-13
• /
• 2001

Several culture conditions affecting cellulose production by a newly isolated Acetobacter sp. A9 were examined by cultivating cells under shaking cultures. The inoculum size in the range of 1-10% (v/v) did not influence cellulose production. Maximum cellulose production was obtained with 200 rpm of agitation speed. The cells grown in the 75 ml of medium in a 250-ml conical flask produced the highest level of cellulose. The strain was able to produce cellulose at 25-3$0^{\circ}C$ with a maximum at 3$0^{\circ}C$. Cellulose production occurred at pH 4.5-7.5 with a maximum at pH6.5.

• The Korean Journal of Food And Nutrition
• /
• v.9 no.3
• /
• pp.236-241
• /
• 1996

Starter cultures were developed for the extension of the shelf life of bread. Lactobacillus plantarum and Bifidoacterium longum were selected as the mixed culture with Propionibacterium freudenreichii. P. fredenreichii with B. longum and L. plantarum produced 2.261% and 1.715% total acid, and pH value of cultured solutions was near 3.95. Propionic acid was produced 14 ~16 mg/ml by P. freudenreichii with L. plantarum and B. longum during 17 days, which was more than that of L. brevis. The pH values of the bread were 4.83 and 4.89 in respect to B. longum and L. plantarum when the fermented products were used to make the bread. Mold was not found for 10 days of storage of the bread at room temperature when the fermented products of B. longum were used for making bread. 37$^{\circ}C$, pH 6.0 and the lowest agitation were optimum conditions for the production of propionic acid in the scaled up fermentation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.354-357
• /
• 2004

The addition of oxygenates to diesel fuel can significantly reduce particulate emissions. Dibutyl maleate (DBM) and tripropylene glycol methyl ether (TGME) have been identified as possible additives based on their physicochemical characteristics and performance in engine test. However, their potential environmental impacts are unknown. therefore, practical considerations in the selection of an oxygenate additives should include cost, availability, compatibility with engines and fuel, and, particularly, its overall environmental impact. This study was investigated to determine optimal condition for the analysis of potential diesel oxygenates using SPME technique with GC-FID. Four fibers were compared and CAR/PDMS fiber was found to be the most sensitive when used direct-sampling. An absorption time of 30min and a desorption time of 5min provided to be the most sensitivity. The effects of experimental parameters such as the addition of salts, agitation, absorption time, compositon on the analysis were investigated. Analytical parameter such as linearity was also evaluated.

• Macromolecular Research
• /
• v.12 no.2
• /
• pp.240-245
• /
• 2004

Monodisperse PMMA micro spheres are prepared by means of a simple soap-free emulsion polymerization in methanol-enriched aqueous medium in a single step process. The size and uniformity of the microspheres are dependent on the polymerization temperature. In a stable system, the uniformity is improved with the polymerization time. The most uniform and stable micro spheres are obtained under mild agitation speed of 100 rpm at 70$^{\circ}C$. The monodisperse PMMA microspheres in the size range of 1.4-2.0 $\mu\textrm{m}$ having less than 5% size variation are successfully achieved with varying concentrations of monomer and initiator. As the monomer and initiator concentrations increase, the larger micro spheres with enhanced uniformity are obtained. However, the decreased amount of water induces the polydisperse PMMA particles due to the generation of secondary particles.

• Microbiology and Biotechnology Letters
• /
• v.9 no.1
• /
• pp.1-6
• /
• 1981

Crystallization conditions of disodium guanosine-5'-monophosphate (5'-GMP. 2Na) were studied. The solubility of 5'-GMP. 2Na was decreased by addition of methanol and the optimum condition was as follows. The crystallization was carried out at 45$^{\circ}C$ with agitation rate of 160-200 rpm., which is Reynold's No. of 25, 000-32, 000. When concentration of methanol was 7.5%~10.0%, the 5'-GMP. 2Na was easily crystallized by addition of crystal seed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.508-511
• /
• 2004

This study focused on the effect of autonomic microcapsules on the mechanical properties of structural material. Several types of microcapsules with healing agents were manufactured by varying agitation speed of high speed stirrer. The size distribution of microcapsules was measured by a particle size analzer. The epoxy specimens embedded with microcapsules were manufactured and the degree of cure of such epoxy specimen was measured by a differential scanning calorimetry. The tensile modulus and tensile strength in epoxy specimens embedded with microcapsules were evaluated in order to investigate the effects of microcapsules on mechanical properties of structural materials. The configuration of microcapsules and morphology of fracture surfaces for the epoxy specimen were examined by an optical microcope and a scanning electron microscope. According to the results, tensile strength of the epoxy specimen embedded with microcapsules was indicated a little reduction, but tensile modulus was not much affected on microcapsules.