• KSBB Journal
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• v.14 no.5
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• pp.534-538
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• 1999

For the optimization of operating conditions for plant cell suspension culture in bioreactors, effects of bioreactor types, various kinds of impellers, and aeration rates were examined using Nicotiana tabacum cells as a model system. Stirred tank bioreactor and airlift bioreactor were used for the comparison of bioreactor type. Growth rates in both bioreactors were lower than in shake flasks. In terms of final cell concentration, stirred tank bioreactor supported a little bit better growth compared to airlift bioreactor. Impeller type did not affect cell growth significantly, but it was apparent that cell size index decreased in the case of using hollowed paddle impeller. When the aeration rate was maintained at 0.3 vvm, cell growth was the best. At above 1.0 vvm, growth inhibition as well a browning was noticed. In addition, it was found that cell size index reduced proportionally to the increased of aeration rate.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1342-1350
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• 2009

This paper investigates the production and optimization of $\beta$-galactosidase enzyme using synthetic medium by Kluyveromyces lactis NRRL Y-8279 in stirred tank bioreactor. Response surface methodology was used to investigate the effects of fermentation parameters on $\beta$-galactosidase enzyme production. Maximum specific enzyme activity of 4,622.7 U/g was obtained at the optimum levels of process variables (aeration rate 2.21 vvm, agitation speed 173.4 rpm, initial sugar concentration 33.8 g/L, incubation time 24.0 hr). The optimum temperature and pH of the $\beta$-galactosidase enzyme produced under optimized conditions were $37^{\circ}C$ and pH 7.0, respectively. The enzyme was stable over a pH range of 6.0-7.5 and a temperature range of $25-37^{\circ}C$. The $K_m$ and $V_{max}$ values for O-nitrophenol-$\beta$-D-galactopyranoside (ONPG) were 1.20 mM and $1,000\;{\mu}mol/min{\cdot}mg$ protein, respectively. The response surface methodology was found to be useful in optimizing and determining the interactions among process variables in $\beta$-galactosidase enzyme production. Hence, this study fulfills the lack of using mathematical and statistical techniques in optimizing the $\beta$-galactosidase enzyme production in stirred tank bioreactor.

• KSBB Journal
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• v.14 no.4
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• pp.440-444
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• 1999

For the effecient production of clavulanic acid., a mutant strain Streptomyces clavuligerus KK was selected from Streptomyces clavuligerus ATCC 27064 through mutation with NTG. S. clavuligerus ATCC 27064 produced about 200 mg/L of calvulanic acid when the medium was composed of 1%(W/V) glycerol, 1.5%(W/V) soybean flour, 0.1%(W/V) $KH_2PO_4$, 0.2%(V/V) soybean oil. A selected mutant, S. clavuligerus KK, produced about 1150 mg/L of clavulanic acid in the same medium. After the addition of $MgSO_4$ to the basal medium, S. clavuligerus KK produced about 1550 mg/L of clavulanic acid, with shows about 1.3 times higher than that produced in the basal medium. In order to select the proper bioreactor for the production of clavulanic acid, a batch culture was performed in an airlift, a bubble column and an stirred tank bioreactors. In an airlift bioreactor, about 1350 mg/L of clavulanic acid was produced, in a bubble column bioreactor, about 1550 mg/L, in a stirred tank bioreactor, about 2200 mg/L, respectively. The production of clavulanic acid in stirred tank bioreactor was about 50% higer than that by an airlift and a bubble column bioreactors. According to this result, the stirred tank bioreactor was selected as a proper bioreactor.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.1
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• pp.72-74
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• 2001

Transgenic Nicotiana tabacum cells were cultivated for the production of murine granulocyte macrophage-colony stimulating factor (mGM-CSF) in both a stirred tank bioreactor and an airlift bioreactor with draft tube. Cell growth and mGM-CSF production in the airlift bioreactor were found to be better than those achieved in the stirred tank bioreactor. In the airlift bioreactor, 9.0g/L of cells and 2.2ng/mL of mGM-CSF were obtained (11.0g/L and 2.4ng/mL, respectively in shake flasks). Although the lag period was prolonged and mGM-CSF production was lowered by 33% in the stirred thank bioreactor as compared to the control culture, the maximum cell density was increased up to 12.0g/L due to better mixing by agitation at the higher cell density.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.164-167
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• 2006

The influence of temperature and agitation on the growth of Escherichia coli expressing hepatitis B core antigen (HBcAg) in stirred tank bioreactor were investigated. The highest specific growth rate for E. coli$(0.844 h^{-1})$ was achieved at a temperature of $37^{\circ}C$ and an agitation speed of 250 rpm. The activation energy for the growth of the E. coli strain W3110lQ in the stirred tank bioreactor was estimated to be 11 kcal/mol. The highest protein yield was achieved at a temperature of $44^{\circ}C$ and an agitation speed of 250 rpm. The relative protein concentration at $44^{\circ}C$ is 30 and 6% higher compared to that at 30 and $37^{\circ}C$, respectively.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.4
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• pp.277-282
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• 2002

This paper proposes a nonlinear adaptive controller based on back-stepping method for tracking reference substrate concentration by manipulating dilution rate in a continuous baker's yeast cultivating process in stirred tank bioreactor. Control law is obtained from Lyapunov control function to ensure asymptotical stability of the system. The Haldane model for the specific growth rate depending on only substrate concentration is used in this paper. Due to the uncertainty of specific growth rate, it has been modified as a function including the unknown parameter with known bounded values. The substrate concentration in the bioreactor and feed line are measured. The deviation from the reference is observed when the external disturbance such as the change of the feed is introduced to the system. The effectiveness of the proposed controller is shown through simulation results in continuous system.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.3
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• pp.244-250
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• 2002

This paper proposed a modified observer based on Busawon's high gain observer using an appropriate time depended function, which can be chosen to make each estimated state converge faster to its real value. The stability of the modified observer is proved by using Lyapunov function. The modified nonlinear observer is applied to estimate the states in stirred tank bioreactor: out-put substrate concentration, output biomass concentration and the specific growth rate of the process. The convergences of the modified observer and Busawon's observer are compared trough simulation results. As the results, the modified observer converges faster to its real value than the well-known Busawon's observer.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.74.3-74
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• 2001

This paper proposes a nonlinear adaptive controller based on back-stepping method for tracking reference substrate concentration by manipulating dilution rate in a continuous baker´s yeast cultivating process in stirred tank bioreactor. Control law is obtained from Lyapunov control function to ensure asymptotical stability of the system. The Haldane model for the specific growth rate depending on only substrate concentration is used in this paper. Due to the uncertainty of specific growth rate, it has been modified as a function including the unknown parameter with known bounded values. The substrate concentration in the bioreactor and feed line are measured. The deviation from the reference is observed when the external disturbance such as the change of the feed is introduced to the system ...

• KSBB Journal
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• v.13 no.6
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• pp.700-705
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• 1998

Studies were made to investigate effects of the scale-up of stirred tank bioreactors on cell growth and alkaloids production for suspension cultures of Eschscholtzia californica. In the 1.5 L STR, cell lysis was observed at 110 rpm or higher agitation speed. The agitation speed of 30 L STR was 43.7 rpm to maintain the same shear stress developed in 1.5 L STR of 100 rpm. As a result of scale-up from 1.5 L to 30 L STR, the specific growth rate was decreased from 0.12 to 0.07 day-1. The alkaloids productivity was also decreased from 0.24 to 0.14 mg/L-day. Changes of mixing performance and oxygen transfer were studied to explain the decrease of cell growth and alkaloids production. Decreased oxygen transfer rate coefficient(KLa) and increased mixing time by the scale-up was observed at various aeration rates.

• KSBB Journal
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• v.27 no.1
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• pp.28-32
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• 2012

In this study, the treatment ability of the wastewater containing perchlorate by non-salt tolerant perchlorate reducing bacterial consortium (N-PRBC) was evaluated in a continuous stirred tank bioreactor (CSTR). To obtain the optimal operating condition the bioreactor was operated with the different wastewater empty bed retention time (EBRT). The treatment performance in the bioreactor could be maintained at 100 $mg-ClO_4{^-}L^{-1}$ up to a EBRT of 3 h, and the removal capacity in the CSTR was about 3.3 times higher than that in a batch operation. With a decrease from 9 h to 2 h in a EBRT, the volumetric perchlorate reduction rate was increased from 11.1 $mg-ClO_4{^-}L^{-1}h^{-1}$ to 50.0 $mg-ClO_4{^-}L^{-1}h^{-1}$, and the specific perchlorate reduction rates were increased from 3.01 $mg-ClO_4{^-}g-DCW^{-1}h^{-1}$. In conclusion, the treatment capacities in a CSTR were much better than those obtained in a batch operation.