• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.309-314
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• 2004

in this study, hybrid bioreactor was used to apply physical stimuli in cell culture. Effect of the applied physical stimuli on the growth and differentiation of MC3T3-El cell in a three-dimensional Chitosan scaffold were studied by using the hybrid bioreactor. The hybrid bioreactor for physical stimulus was specially designed to apply uniaxial cyclic compressive and shear strain. Physical stimulus was applied over a period of 14 days with 150 cycles per day at a frequency of 0.5Hz. Strain magnitude was 2.5% of the scaffold size. Control group and physically stimulated group of the MC3T3-El tell were incubated and harvested at the indicated times (Day 6, 8, 10, 12, 14). The total amount of protein, which obtained information of cell growth, was determined by Lowey method. Alkaline phosphatase activity was examined by ELISA. Physically stimulated group using the hybrid bioreactor was increased in alkaline phosphatase activity comparing with control group. The nodule formation and calcium deposit of the physical stimuli group which resulted in cell differentiation was faster than that of control group.

• 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.

• Journal of Environmental Science International
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• v.25 no.3
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• pp.439-446
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• 2016

Domestic sewerage treatment plant is operated by activated sludge method and its modified method by using microorganism. In most cases, a method of using microorganism is directly controlled by the operator based on individual judgment through factors of DO, pH and ORP. In addition, under aerobic condition in bioreactor, energy consumption including excessive air injection is learned to be somewhat plenty. In order to solve this problem, in most of the process, improvement of internal recycling and activated environmental factor of microorganism were researched extensively. However, as factors are changed depending on various conditions, it is not sufficient as an indicator of judgment. As such, a research on operation of bioreactor that measures metabolic change in short time by directly measuring activated condition of microorganism using NADH fluorometer is required in reality.It is considered that the method like this could supplement problem of energy consumption being occurred in the existing treatment method and operational optimization of bioreactor would be enabled by controlling optimal air volume. Therefore, in this study, in order to obtain optimal operational indicator of bioreactor, proper air volume control test was performed and through batch test and site evaluation, possibility of NADH sensor being utilized as operational control indicator of bioreactor is intended to be analyzed. In order to compare with measured value, DO, ORP that are operational control indicator of existing bioreactor were used. As MLSS concentration was increased through batch test, NADH value was increased and site evaluation also showed similar tendency to batch test. Resultantly, it could be confirmed that changing level of NADH fluorometer was a sensor that could measure bioreactor condition effectively and optimized scale of bioreactor is considered to be utilized.

• The Korean Journal of Mycology
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• v.35 no.1
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• pp.37-42
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• 2007

The mushroom Lentinus lepideus was used to produce mycelial as well as soluble polysaccharides in bioreactor cultures. To determine optimal submerged culture conditions, both growth characteristics and water soluble polysaccharides production were compared among four different types of bioreactor and culture conditions. For the production of mycelial biomass, the following bioreactors were proven to be effective in decreasing order: an external-loop type air-lift bioreactor (ETAB; 7g/l), a balloon type air bubble bioreactor (BTBB; 6.2g/l), a stirrer type bioreactor (STB; 6g/l), and a column type air bubble bioreactor (CTBB; 5g/l). Maxiaml production of water soluble exopolysaccharides (EPS; 0.62g/l) and endopolysaccharides (PPS; 7.7%) could also be obtained from BTBB. The mycelial biomass increased with increase in glucose concentration from 15g/l to 75g/l in the media. In contrast, PPS contents in the cells decreased with increase in glucose concentration in the media, showing the highest PPS content (7%) at 15g/l. Among different medium feeding types, fed-batch culture based on concentration control in media (10g/l) produced higher mycelia than fed-batch culture based on volume control of media (5.8g/l) or batch culture (3.4g/l). EPS production was also higher in fed-batch culture based on medium concentration control than that in other feeding types.

• Journal of Plant Biotechnology
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• v.31 no.4
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• pp.307-312
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• 2004

The bioreactor system for the large-scale plant tissue culture was developed to control the pH concentration and DO (dissolved oxygen), and air flowrate. The system controlling the proper air flow rate for each bulblet growth stage and monitoring the contamination of bioreactor using the pH change was controled by computer program. For the uniform bulblet distribution in bioreactor, the proper air flow rate was 300 cc/min at the beginning of bulblet culture, 400 cc/min after 20 days, 500 cc/min after 40 days, 600 cc/min after 60days, and 700 cc/min after 80 days. It was possible to maintain the pH concentration within 5.5$\pm$0.5 during the culture by control system of bioreactor.

• 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 ...

• Environmental Engineering Research
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• v.22 no.2
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• pp.210-215
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• 2017

Produced water is the largest wastestream of oil and gas exploration. It consists of various organic and inorganic compounds that hinder its beneficial use. This study compared the treatment of produced water in a batch suspended and biofilm activated sludge process. The biofilm carrier material was made from Gardenia Carinata shell. COD, $NH_4{^+}-N$ and $NO_3-N$ removal was monitored in both the suspended (control) and floating carrier bioreactors. The results show a rapid reduction of produced water constituents in the floating carrier bioreactor. COD, $NH_4{^+}-N$ and $NO_3-N$ removal was in the range of 99%, 98% and 97% for the floating carrier bioreactor whereas it was 88%, 84% and 83% for the control bioreactor. The rapid reduction of COD, $NH_4{^+}-N$ and $NO_3-N$ clearly indicate that the floating carrier materials served as an attached growth medium for microorganisms, improved the breakdown of produced water constituents and reduced inhibition of microbial metabolic activities.

• Journal of Microbiology and Biotechnology
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• v.23 no.3
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• pp.335-342
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• 2013

In this study, we compared the performance of two control systems, fuzzy logic control (FLC) and conventional control (CC). The control systems were applied for controlling temperature and substrate moisture content in a solidstate fermentation for the biosynthesis of amylase and protease enzymes by Aspergillus oryzae. The fermentation process was achieved in a 200 L rotating drum bioreactor. Three factors affecting temperature and moisture content in the solid-state fermentation were considered. They were inlet air velocity, speed of the rotating drum bioreactor, and spray water addition. The fuzzy logic control system was designed using four input variables: air velocity, substrate temperature, fermentation time, and rotation speed. The temperature was controlled by two variables, inlet air velocity and rotational speed of bioreactor, while the moisture content was controlled by spray water. Experimental results confirmed that the FLC system could effectively control the temperature and moisture content of substrate better than the CC system, resulting in an increased enzyme production by A. oryzae. Thus, the fuzzy logic control is a promising control system that can be applied for enhanced production of enzymes in solidstate fermentation.

• 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.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.127-135
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• 2020

Small RNAs (sRNAs) are widespread and play major roles in regulation circuits in bacteria. Previously, we have demonstrated that transcription of esrE is under the control of its own promoter. However, the regulatory elements involved in EsrE sRNA expression are still unknown. In this study, we found that different cis-regulatory elements exist in the promoter region of esrE. We then screened and analyzed seven potential corresponding trans-regulatory elements by using pull-down assays based on DNA affinity chromatography. Among these candidate regulators, we investigated the relationship between the ferric uptake regulator (Fur) and the EsrE sRNA. Electrophoresis mobility shift assays (EMSAs) and β-galactosidase activity assays demonstrated that Fur can bind to the promoter region of esrE, and positively regulate EsrE sRNA expression in the presence of Fe²⁺.