• KSBB Journal
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• v.7 no.1
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• pp.79-83
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• 1992

The characteristics of Erwinia rhapontici cells with $\alpha$-glucosyltransferase activity immobilized in Ca-alginate beads and the performance of two different types of reactor-stirred tank reactor(STR) and packed bed reactor(PBR)-charged with these immobilized cells to produce palatinose from sucrose were investigated. The optimal pH(5.5-6.0) and temperature($30-35^{\circ}C$) showed no appreciable difference between free and immobilized cells. The apparent Km value of the immobilized cells(0.28M) was approximately two times higher than that of free cells(0.13M) at $30^{\circ}C$. The half life of the immobilized cells was found to be 380 h with STR while much greater operational stability was achieved with PBR. Continuous operation of PBR at a space velocity of $0.2h^{-1}$ for 30 days showed only 5% loss of initial activity.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.709-712
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• 2005

Structured lipid (SL) was synthesized by enzymatic interesterification of algae oil and corn oil in stirred tank batch reactor, The reaction, performed for 15hr at $65^{\circ}C$, was catalyzed by sn-1,3-specific lipase RM IM from Rhizonucor miehei without organic solvent. DHA, oleic acid, and linoleic acid contents of SL were 14.9, 17.3, and 31.8 mol%, respectively. ${\alpha}-,\;{\gamma}-,\;and\;{\delta}-tocopherol$ contents and physiochemical property of SL were evaluated. During 15 hr reaction, most reaction occurred within 6 hr, and highest relative production rate was observed between 3 to 6 hr.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.2
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• pp.115-121
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• 2005

Using a general Saccharomyces cerevisiae as a model strain, continuous ethanol fermentation was carried out in a stirred tank bioreactor with a working volume of 1,500 mL. Three different gravity media containing glucose of 120, 200 and 280 g/L, respectively, supplemented with 5 g/L yeast extract and 3 g/L peptone, were fed into the fermentor at different dilution rates. Although complete steady states developed for low gravity medium containing 120 g/L glucose, quasi-steady states and oscillations of the fermented parameters, including residual glucose, ethanol and biomass were observed when high gravity medium containing 200 g/L glucose and very high gravity medium containing 280 g/L glucose were fed at the designated dilution rate of $0.027\;h^{-1}$. The observed quasi-steady states that incorporated these steady states, quasi-steady states and oscillations were proposed as these oscillations were of relatively short periods of time and their averages fluctuated up and down almost symmetrically. The continuous kinetic models that combined both the substrate and product inhibitions were developed and correlated for these observed quasi-steady states.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.6
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• pp.544-549
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• 2006

The performance of immobilized fungal cells on celite beads for the production of gibberrelic acid was investigated in flasks and 7-L stirred-tank reactor. Repeated incubations of immobilized fungal cells increased cell concentrations and volumetric productivity. The maximum volumetric productivity obtained in the immobilized-cell culture was 3-fold greater than that in suspended-cell culture. The concentration of cotton seed flour (CSF), among the various nutrients supplied, most significantly influenced productivity and operational stability. Notably, insoluble components in CSF were found to be essential for production. CSF at 6 g/L with 60 g/L glucose was found to be optimal for gibberellic acid production and stable operation by preventing excessive cell growth.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.1-6
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• 2005

Optimal criterion for the scale-up production of schizophyllan, a fungal polysaccharide secreted by Schizophyllum commune, was investigated. For the production of the polysaccharide in a 150-l bioreactor, the culture conditions optimized in a 15-l bioreactor were applied to a 150-l bioreactor with scale-up process, by changing impeller speed and airflow rate. The optimized impeller speed in the 15-l bioreactor was 50 rpm in a technical medium based on barley. For establishment of the scale-up process, 3 kinds of criteria were used while the gas throughput number was kept constant, as follows; constant volume-related power input, constant tip speed of stirrer, and constant Reynolds number. In the 150-l bioreactor, the highest values for the maximum specific growth rate (1.17/day) and productivity (0.63 g/L${\cdot}$day) were achieved in the culture condition from constant volumerelated power input criterion.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.84-90
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• 2005

Thermal decomposition of the copolymer of ${\alpha}$-Methylstyrene(AMS) with Acrylonitrile(AN) was investigated. The copolymer was synthesized in a continuous stirred tank reactor(CSTR) at $80^{\circ}C$ using toluene and benzoyl peroxide(BPO) as solvent and initiator, respectively. The reactor volume was 0.3 liters and residence time was 3 hours. The activation energy of thermal decomposition was in the ranges of $34{\sim}54$ kcal/mol for AMS with AN copolymer. The thermogravimetric trace curves were well agreed with the theoretical calculation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.3
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• pp.163-170
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• 2002

This report describes the use of a transtubular bioreactor to study the relative effects of diffusion versus perfusion of medium on antibody production by a hybridoma cell line. The study was performed with a high-density cell culture maintained in a serum-free, low-protein medium for 77 days. It was determined that the reactor possessed a macro-mixing pattern residence time distribution similar to a continuous stirred tank reactor (CSTR), However, due to the arrangement of the medium lines in the reactor, the flow patterns for nutrient distribution consist of largely independent medium path lengths ranging from short to long. When operated with cyclic, reversing, transtubular medium flow, some regions of the reactor (with short residence times) are more accessible to medium than others (with long residence times). From this standpoint, the reactor can be divided into three regions: a captive volume, which consists of medium primarily delivered via diffusion; a lapped volume, which provides nutrients through unilateral convection; and a swept volume, which operates through bilateral convection. The relative sizes of these three volumes were modified experimentally by changing the period over which the direction of medium flow was reversed from 15 min (larger captive volume) to 9 h (larger swept volume). The results suggest that antibody concentration increases as the size of the diffusion-limited (captive) volume is increased to a maximum at around 30 min with a sharp decrease thereafter. As reflected by changes in measured consumption of glucose and production of lactate, no significant difference in cellular metabolism occurred as the reactor was moved between these different states. These results indicate that the mode of operation of the transtubular bioreactor may influence antibody productivity under serum-free, low-protein conditions with minimal effects on cellular metabolism.

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.238-241
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• 2010

The purification of indole from 54.3wt% indole fraction (temperature range of distillate: $250{\sim}255^{\circ}C$) recovered by extraction-distillation combination of coal tar fraction (temperature range of distillate: $240{\sim}265^{\circ}C$) was examined by solute crystallization. The feed consists of eight components such as quinoline, iso-quinoline, indole, quinaldine, 1-methylnaphthalene, 2-methylnaphthalene, biphenyl and phenyl ether. Hexane and an aqueous solution of methanol (50 : 50 vol%) were used as the crystallization solvent and the coolant, respectively. A batch stirred tank of glass material was used as a crystallization apparatus. By increasing the operation temperature and the volume ratio of solvent to feed at initial, the purity of indole increas ed, but yields of indole showed a decreasing tendency. Solute crystallization method using hexane as a solvent was excellent because the purity of 99.3 wt% indole was recovered at the yield of 50% without washing operation.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.479-484
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• 2013

This study was performed to examine the effect of copper on the biodegradability, nitrification, denitrification and oxygen uptake rate (OUR) using batch reactor and continuous flow stirred tank reactor (CSTR) of anaerobic/anoxic/oxic ($A_2/O$). The results of this study can be summarized as follows. In the case of the effect of copper on organic treatment, the bad effect initiated when it was above 4.5 mg/L copper with batch reactor and above 2.0 mg/L copper with CSTR. Concerning the case on nitrification and removal of nitrogen, it showed bad effect when copper was above 4.5 mg/L with batch reactor for nitrification and 1.0 mg/L with CSTR for the removal of nitrogen. The bad effect on the removal of phosphorus began when it was 4.5 mg/L copper with batch reactor and 2 mg/L copper with CSTR. In the case of OUR, it decreased as microbial activity was affected when copper concentration was above 1.5 mg/L in both case of batch reactor and CSTR.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.357-361
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• 2005

The bioconversion of linoleic acid (LA) to conjugated linoleic acid (CLA) was investigated to examine LA-adaptation of Bifidobacterium breve KCTC 3461 to additions of 1 to 5 mg/mL of LA overtime. To induce LA-adaptation, B. breve KCTC 3461 was treated with LA, according to three schemes. For LA-adapted B. breve the maximum concentration of CLA, $300\~350{\mu}g/mL$, was obtained in cys-MRS medium containing 1 mg/mL of LA. The CLA production significantly increased with increasing LA concentration, from 1 to 4 mg/mL, but the conversion of LA to CLA gradually decreased. The CLA production capability of B. breve, and its tolerance, improved significantly with LA-adaptation. The addition of LA (1 mg/mL) into the culture broth after 24 h of cultivation in a 100-mL media bottle was most effective at promoting CLA production. In a 2.5-L stirred-tank bioreactor, the observed conversion and productivity of $56.6\%\;and\;35.4{\mu}gmL^{-1}h^{-1}$, respectively, by LA-adapted B. breve were approximately 6.6 and 9.8 times higher than those of LA-unadapted B. breve.