• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.243-251
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• 2001

The effects of various operating parameters(agitation speed, impeller type, antiform agents, impeller spacing etc.) on air-liquid mass transfer was characterized by volumetric mass transfer coefficient($k_La$). Also, the dual-impeller agitated systems are compared with single-impeller agitated systems with a special focus on its applications for bioreactors, $k_La$ was take over a range of 200~450 rpm of agitation speed, and 0.5~2.5 vvm of air flow rates, for four single impeller and impeller combinations consisting of four impeller types, namely rushton, pitched blade, scaba, intermig were tested. The rushton impeller showed the best $k_La$ as compared with other single impellers. The dual impeller system are found to be superior as compared to single impeller in all aspects, The best combination of the dual impeller was a intermig of axial flow type as an upper impeller and a rushton of radial flow type as a lower part. Also, the control of the DO level with the variation of agitation speed was more efficient than that with an increase in air flow rate. The addition of antiform dropped the $k_La$ very large up to 1g/L regardless the type. PPG was less effect on $k_La$ than other antiforms. The impeller spacing and presence of solute are found very effective on $k_La$. When the $NaNO_3$is presented as solute, the $k_La$ increased approximately 50% then control.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.660-666
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• 1997

The production of doxorubicin by a mutant of Streptomyces peucetius subsp. caesius was studied. The optimal culture conditions, such as inoculum size and medium composition were established to improve the productivity of doxorubicin. The optimal medium composition was found to be 4% maltose, 0.5% HEPES, 0.02% $K_2HPO_4$, 0.01% $MgSO_4$. As an antiform agent, 0.001% KG(10% Adekanol+10% Silicone) was suitable one among various agents. Culture was carried out in 2.5 L jar-fermenter with different aeration rates of 1.5, 1.0, and 1.5 v/v min. The maximum production of doxorubicin(29 mg/l) was obtained at 1.5 v/v min of aeration rate, and even at 1.0 v/v min, the production of doxorubicin was increased up to 15% compared with that of shake-flask culture.

• Korean Journal of Food Science and Technology
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• v.22 no.7
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• pp.846-851
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• 1990

An attempt was made in this study to investigate the possibility of processing garlic into an garlic oleoresin and investigate on the storage stability of it. To obtain a garlic oleoresin, water, phosphoric acid, garlic extract, poly sorbate and KM-72 as antiform agent were mixed with lecithin, and then these mixtures were homogenized at $50{\sim}55^{\circ}C$ for $5{\sim}7\;min$, cooled down to $25^{\circ}C$, and finally mixed with TBHQ (tert-butylhydroquinone) as antioxidant and garlic essential oil. Optimum components for garlic oleoresin consisted of 1.0% garlic essential oil, 10.5% garlic extract, 10.0% poly sorbate, 0.01% KM-72, 18.0% lecithin, 0.05% TBHQ, 0.15% of phosphoric acid solution and 60.0% water. Judging from thiosulfinate and pyruvate content, and sensory evaluation, quality damage of garlic oleoresin hardly occurred at $5^{\circ}C$ but occurred considerable level at $25^{\circ}C$ during storage for 60 days.