• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.471-474
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• 2001

To optimize the culture conditions for fungal pathogen YK101, the effects of culture medium, temperature and agitation on mycelium production were investigated. The optimum temperature and agitation for the cultivation of YK101 were $28^{\circ}C$ and 150rpm, respectively. The optimized medium was composed of 1.0- 2.0% total sugar from sucrose, 1.0% yeast extract and 0.05% $MgSO_4$ ${\cdot}$ $7H_2O$.

• KSBB Journal
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• v.17 no.3
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• pp.307-310
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• 2002

In order to obtain high density seed cells for biofiltration, we studied batch and fed-batch culture of P. putida. Studies were carried out to find optimum fermentation conditions such as pH, concentration of glucose and agitation speed. Specific growth rate of P. putida was dependent on agitation speed and a high rpm of 300 was necessary to carry out the efficient aerobic growth of P. putida. Specific growth rate was highest at pH 7. Feeding glucose and yeast extract continuously at the initial growth phase was the most effective way to get high cell density of P. putida.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.419.2-420
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• 2002

Caco-2 is a cell line derived from the human colon adenocarcinoma and often used as a model for studying intestinal drug absorption. It has been well-known that a strong correlation holds between in vitro permeability across Caco-2 cell monolayers and in vivo bioavailability for various drugs. but the correlation curves varied depending on laboratories. The permeabilities of drugs across Caco-2 cell monolayers have been measured under different agitation conditions. (omitted)

• The Korean Journal of Food And Nutrition
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• v.11 no.6
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• pp.640-646
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• 1998

For the production of nonprotein $\alpha$-glucosidase inhibitor from the Streptomyces sp. NS15 strain, effects of initial optimum pH, nitrogen sources, carbon sources, cationic metal ions, agitation speed and aeration rate were investigated. Initial optimum pH of medium was 7.0. The most effective nitrogen and carbon sources were soybean meal 2.0%(w/v) and glucose 1.6%(w/v), respectively. The cationic metal ins had no stimulating effect on inhibitory activity of $\alpha$-glucosidase except Fe2+. Agitation speed and aeration rate were effective at 400rpm and 1vvm, respectively. In the jar-fermenter cultivation for 4 days under optimal culture conditions, the culture broth showed the inhibitory acitivity of 3,200units/ml, which is 25 times higher than that of basic medium (CYM) for porcine intestinal $\alpha$-glucosidase. The inhibitory activity of $\alpha$-glucosidase reached about 3,200units/ml after 4 days of cultivation and decreased gradually for a further two days.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.141-146
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• 2011

Loess, a natural clay, was evaluated as an adsorbent for the decolorization of Acid Orange II, an azo and reactive dye, from aqueous solution. Adsorption studies were performed at $30^{\circ}C$ and the effect of reaction time, loess dosage, initial concentration, loess particle size, pH, agitation rate were investigated to determine the optimum operation conditions. The removal efficiencies of color were measured to evaluate the effectiveness of loess. From this study, it was found that optimal reaction time was 10 min. Color removal efficiencies of Acid Orange II were increased as higher loess dosage, initial concentration and agitation rate. However, color removal efficiencies decreased when pH is high and loess particle becomes large. Adsorption of Acid Orange II fitted to the pseudo-second-order rate kinetics more than first-order rate kinetics. Langmuir and Freundlich adsorption isotherm constants and correlation coefficients were calculated and compared. It was concluded that the adsorption data of Acid Orange II onto loess fitted to the Freundlich model more than Langmuir model.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.91-96
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• 2022

The photocatalytic degradation of salicylic acid takes place in several stages involving coupled phenomena, such as the transport of molecules and the chemical reaction. The systems of transport equations and the photocatalytic reaction are numerically solved using COMSOL Mutiphysics (CM) simulation software. CM will make it possible to couple the phenomena of flow, the transport of pollutants (salicylic acid) by convection and diffusion, and the chemical reaction to the catalytic area (bauxite or TiO2 doped by nanoparticles). The simulation of the conversion rate allows to correctly fit the experimental results. The temporal simulation shows that the reaction reaches equilibrium after a transitional stage lasting over one minute. The outcomes of the study highlight the importance of diffusion in the boundary layer and the usefulness of injecting micro-agitation into the microchannel flow. Under such conditions, salicylic acid degrades completely.

• The Korean Journal of Food And Nutrition
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• v.11 no.6
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• pp.606-611
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• 1998

For waste recyle, we were investigated on Gardenia blue color production using Gardenia by-product by Bacillus subtilits. Optimum conditions for producing blue pigment were found to be 30$^{\circ}C$, initial pH 6.5, glucose as a carbon source 3% and yeast extract as a nitrogen source 0.5%, respectively. Optimum conditions for fermentor culture were agitation speed 400rpm, aeration 2 vvm and inoculum 5%. The optimum perculture time for inoculum was 20 hrs for blue pigment production.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1445-1453
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• 2013

The scale-up criterion of constant oxygen mass transfer coefficient ($k_La$) was applied for the production of itaconic acid (IA) in a 50 L pilot-scale fermentor by the fungal cells of Aspergillus terreus. Various operating conditions were examined to collect as many $k_La$ data as possible by adjusting the stirring speed and aeration rate in both 5 L and 50 L fermentor systems. In the fermentations performed with the 5 L fermentor, the highest IA production was obtained under the operating conditions of 200 rpm and 1.5 vvm. Accordingly, we intended to find out parallel agitation and aeration rates in the 50 L fermentor system, under which the $k_La$ value measured was almost identical to that ($0.02sec^{-1}$) of the 5 L system. The conditions of 180 rpm and 0.5 vvm in the 50 L system turned out to be optimal for providing almost the same volumetric amount of dissolved oxygen (DO) into the fermentor, without causing shear damage to the producing cells due to excessive agitation. Practically identical fermentation physiologies were observed in both fermentations performed under those respective operating conditions, as demonstrated by nearly the same values of volumetric ($Q_p$) and specific ($q_p$) IA production rates, IA production yield ($Y_{p/s}$), and specific growth rate (${\mu}$). Specifically, the negligible difference of the specific growth rate (${\mu}$) between the two cultures (i.e., $0.029h^{-1}$ vs. $0.031h^{-1}$) was notable, considering the fact that ${\mu}$ normally has a significant influence on $q_p$ in the biosynthesis of secondary metabolites such as itaconic acid.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.70-75
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• 2010

This study was conducted to determine the influence of culture conditions such as temperature, time, water content, koji-thickness and agitation on the production of organic acid by Rhizopus sp. ZB9 isolated from Korean Nuruk during the preparation of rice koji, which is used in brewing the Korean rice wines, Takju and Yakju. Rice koji was made under different culture conditions, and the acidity of each koji was tested. The temperature range suitable for the production of organic acid was $28{\sim}32^{\circ}C$, and 36~48 hours of cultivation at that temperature range seemed to produce the optimum results. The production of organic acid increased in proportion to the increase in water content of steamed rice from 25% to 60%. An increase in koji-thickness induced no adverse effects on the production of organic acid, and agitation-work during cultivation showed very beneficial effects.

• KSBB Journal
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• v.19 no.1
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• pp.78-82
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• 2004

Experiments were carried out to select an organic nitrogen source and optimize the culture conditions for the production of arachidonic acid by Mortierella alpina DSA-12. Corn steep powder(CSP) was selected as an organic nitrogen source based on arachidonic acid production and raw material price. The optimum C/N ratio was in the range of 15 to 17 with the medium containing glucose as carbon source and CSP as nitrogen source. The optimum culture conditions for arachidonic acid production showed 500 rpm agitation and 25$^{\circ}C$ culture temperature at 0.5 vvm aeration. Under the optimum conditions, the concentration of cell, total lipid and arachidonic acid were 21.8 g/L, 10.2 g/L and 3.70 g/L, respectively, from 50 g/L glucose and 18 g/L CSP. In the 500 L fermenter with 0.5 vvm aeration and 200 rpm agitation, the concentration of cell, total lipid and arachidonic acid were 19.8 g/L, 9.1 g/L and 3.67 g/L, respectively, from 50 g/L glucose and 18 g/L CSP. This result showed that an arachidonic acid production could be possible with a bench-scale fermenter using corn steep powder as a nitrogen source.