• KSBB Journal
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• 제13권3호
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• pp.259-267
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• 1998

Optimal feeding strategies in bioreactor operation of Scutellaria baicalensis G. plant cell culture were investigated to maximize the production of flavone glycosides by using a structured kinetic model which can predict culture growth and flavone glycosides synthesis in a rigorous, quantitative manner. For the production of baicalin and wogonin-7-0-GA, the strategies for glucose feeding into Scutellaria baicalensis G. plant cell culture were proposed based on the model, which are a periodic fed-batch operation with maintenance of cell viability and of specific production rate respectively, and a perfusion operation with maintenance of specific production rate for baicalin and wogonin-7-0-GA. Simulation results showed that the highest volumetric concentration of flavone glycosides was obtained in a periodic fed-batch operation with maintenance of cell viability among all the suggested strategies. In the periodic fed-batch operations, the higher volumetric production of flavone glycosides was achieved compared with that in the perfusion operation. It can be concluded that a periodic fed-batch operation with maintenance of cell viability would be the optimal and practical operating strategy of Scutellaris baicalensis G. plant cell culture for the production of flavone glycosides.

• KSBB Journal
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• 제13권4호
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• pp.411-417
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• 1998

The possibility of application of membrane type immobilized adsorbent to the fed-batch or perfusion culture system with anchorage-independent cells as well as batch system was investigated. The improvement in cell density and cell viability due to the combination of immobilized adsorbent with each culture system was evaluated for the investigation, and the optimum culture system employing immobilized adsorbent system was suggested based on the results. It was observed that the system with immobilized adsorbent showed better cell growth and cell viability than that without immobilized adsorbent in every operation system of batch, fed-batch, and perfusion. In case of batch system, 200% improvement of maximum cell density was observed in the system where ammonium chloride was added on purpose. And 50% improvement of maximum cell density was observed in the fed-batch system where ammonium ion accumulates significantly, while small increase in maximum cell density was observed in the perfusion system where dilution of waste byproducts exists. Especially, the fed-batch system showed the most significant improvement on cell growth because both compensation of nutrient and removal of ammonium ion occurred simultaneously in the system. Therefore a combined system of immobilized adsorbent and fed-batch operation could be suggested as an optimum system with in situ removal of ammonium ion.

• Journal of Microbiology and Biotechnology
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• 제8권3호
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• pp.203-207
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• 1998

Fed-batch fermentations with different feeding media were carried out in order to increase the productivity of invertase expression using a recombinant Saccharomyces cerevisiae containing plasmid pRB58. Two batch cultures showed the expression of the SUC2 gene at a low concentration of glucose, suggesting that glucose concentration could be used as a control variable in a fed-batch operation mode. In the fed-batch culture by feeding the basal medium, cell mass and specific invertase activity did not increase much as compared with the simple batch culture. A series of fed-batch cultures revealed that the sucrose-supplemented medium increased cell mass whereas the enriched medium did specific invertase activity. To capitalize on the synergism of the sucrose-supplemented medium and the enriched medium, the sucrose-supplemented enriched medium was used as a feeding medium. The fed-batch culture using this medium resulted in a 2.4-fold increase in cell mass and a 1.9-fold enhancement in specific invertase activity compared with those of the batch culture. The increase in cell mass and specific invertase activity led to a marked increase in total invertase activity, 250U/ml, which was 6.3 times higher than that of the batch culture.

• Environmental Engineering Research
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• 제20권1호
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• pp.65-72
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• 2015

A comparative study on response of a toxic compound thiocyanate ($SCN^-$) was carried out in continuous and fed batch moving bed reactor systems. Both systems had three sequential anaerobic, anoxic and aerobic reactors and operated at same hydraulic retention time. Feed $SCN^-$ was first increased from 600 mg/L to 1,000 mg/L for 3 days (shock 1) and then from 600 to 1,200 mg/L for 3 days (shock 2). In anaerobic continuous reactor, increase of effluent COD (chemical oxygen demand) due to shock load was only 2%, whereas in fed batch reactor it was 14%. In anoxic fed batch reactor recovery was partial in terms of $SCN^-$, phenol, COD and $NO{_3}{^-}$-N and $NO{_2}{^-}$-N removals and in continuous reactor complete recovery was possible. In both systems, inhibition was more significant on aerobic reactors than anaerobic and anoxic reactors. In aerobic reactors ammonia removal efficiency deteriorated and damage was irreversible. Present study showed that fed batch reactors showed higher substrate removal efficiency than continuous reactors during regular operation, but are more susceptible to toxic feed shock load and in nitrifying reactor damage was irreversible.

• KSBB Journal
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• 제16권4호
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• pp.415-419
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• 2001

Bacillus subtilis WB700에서 P43 프로모터를 사용하여 staphylokinase를 생산하기 위하여 배지 최적화 및 회분식 배양과 유가식 배양 두가지 시스템을 비교하였다. 여러 가지 질소윈 중에서는 tryptone이 가장 좋은 질소원 이었으며, MSR 배지를 사용한 경우 tryptone 15 g/L일 경우에 최적조건임을 알아내었다. MSR 배지에시 포도당을 제한 기질로 사용할 경우는 5 g/L일 때가 SAK의 발현에 최적 조건이었다. MSR 배지를 기본으로 이용하여 포도당 공급을 조절함으로서 발효조 내의 DO를 30%로 유지한 결과 오히려 MSR 배지를 이용하여 회분식 발효를 한 경우보다 좋지 못한 결과를 얻었으며, 이는 B. subtilis 숙주의 영양요구적 특이성과 P43 promoter의 stress 발생시 주 발현되는 특성 등에 기인한 것이라고 사료된다. MSR 배지를 이용하여 회분식 발효를 하였을 때 SAK 활성은 2880 unit이었고, 이때 배지 내로 분비된 SAK 농도는 455 mg/L이었다.

• KSBB Journal
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• 제18권5호
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• pp.418-423
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• 2003

발효조의 냉각수 공급 제어 신호와 냉각수의 유출입 지점의 온도를 온라인으로 측정하여 이 값들로부터 냉각량을 추정할 수 있는 실험식을 얻었다. 회분식 배양을 통하여 냉각량이 온라인으로 측정될 수 있음을 확인하였고 기질의 재투입시 냉각량의 변화를 통하여 유가배양의 제어변수로 활용할 수 있음을 점검하였다. 미리 프로그램된 목표 냉각량의 증가곡선에 따라 냉각량이 증가되면서 세포가 자라도록 유가배양을 실시하였다. 본 연구를 통하여 냉각량의 온라인 측정방법을 제시하였고 이를 유가배양 제어변수로 활용하여 세포의 성장속도를 조절할 수 있음을 보였다.

• Journal of Microbiology and Biotechnology
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• 제11권5호
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• pp.887-889
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• 2001

The gene encoding yeast pro-carboxypeptidase Y (pro-CPY) has been cloned and expressed in Escherichia coli. Most of the expressed pro-CPY was accumulated as cytoplasmic insoluble aggregates. In our previous study, active CPY was obtained by renaturation of entirely denatured pro-CPY followed by in vitro proteolytic processing with proteinase K along with the activation process. The same refolding process was performed to produce an active CPY from pro-CPY inclusion bodies with renaturation buffers containing proteinase K at different concentrations. The refolding efficiency decreased from $25\%\;to\;2\%$ in the renaturation buffers containing proteinase K at concentrations of $60{\mu}g/ml\;and\;0.6{\mu}g/mi$, respectively. In an attempt to increase the refolding efficiency with a lesser amount of proteinase K, a novel fed-batch refolding process was developed. In a fed-batch refolding, 99 ml of the renaturation buffer containing pro-CPY was gradually added into 1 ml of the renaturation buffer containing $60{\mu}g/ml$ of proteinase K to give a final proteinase K concentration of $0.6{\mu}g/ml$. The fed-batch refolding process resulted in a refolding efficiency of $18\%$, which corresponded to a 9-fold increase over that ($2\%$) in the batch process.

• Journal of Microbiology and Biotechnology
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• 제4권2호
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• pp.146-150
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• 1994

Production of poly-$\beta$-hydroxybutyrate (PHB) in fed-batch fermentation was studied. Utilization of carbon for PHB biosynthesis was investigated by using feeding solutions with different ratios of carbon to nitrogen (C/N). It was observed that at a high C/N ratio carbon source was more preferably utilized for PHB accumulation while its consumption for cellular metabolism appeared to be more favored at a low C/N value. A high cell concentration (184 g/l) was achieved when ammonium hydroxide solution was fed to control the pH, which was also utilized as the sole nitrogen source. For the mass production of PHB, two-stage fed-batch operations were carried out where PHB accumulation was observed to be stimulated by switching the ammonium feeding mode to the nitrogen limiting condition. A large amount of PHB (108 g/l) was obtained with cellular content of 80% within 50 hrs of operation.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.450-456
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• 1988

대장균 변이주를 이용한 L-트립토판의 최적생산을 위해 목적산물의 생산과 유기산의 생성과의 상호관계를 조사한 결과 비 산생성속도(specific acid production rate)가 증가할수록 L-트립토판의 생산이 감소하는 것으로 나타났다. 따라서 L-트립토판 발효시 산의 생성량을 줄이기 위해 조절식 유가배양법을 도입하였는데 이 배양공정에서는 배양액내의 용존산소농도에 따라 영양배지의 유가속도를 조절하는 방식을 사용하여 세포증식속도를 제한, 세포의 산소요구량이 공급량을 초과하지 않도록 하였다. 이러한 조절식 유가배양법으로 대장균 세포를 배양한 결과 기존의 유가배양식에 비해 비 산생성속도가 현저하게 감소하였으며 L-트립토판의 생산은 5배 정도나 증가되었다.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1979년도 추계학술대회 심포지움
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• pp.242-242
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• 1979

The general efforts of applied research and development can be divided into product development, process development, process design, process equipment design, and operation The fed batch culture as one effort of theprocess development in fermentation industry has been practiced since the early times of human history. One particular industrial application with long history is in the cultivation of the baker's yeast where the glucose effect at relatively high glucose concentration is the general rule.