• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.617-621
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• 2002

In order to optimize the carrot hairy root culture for SOD production, a fed-batch culture of hairy roots was performed in a bioreactor. Maximum SOD activity was obtained when the hairy roots were transferred to the MS medium containing 110 g/1 concentration of sucrose. By controlling the sucrose concentration (70 g/1 sucrose for growth and 110 g/1 sucrose far production, respectively) In a two-stage fed-batch culture, 29 g/1 of the hairy roots was obtained based on the final dry mass. The volumetrically determined SOD activity and productivity in the fed-batch culture were about 6 times higher than those from the flask culture containing sucrose at 30 g/1 concentration.

• KSBB Journal
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• 제13권4호
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• pp.456-460
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• 1998

Fed-batch fermentations were carried out in order to improve the efficiency of hirudin production by recombinant Saccharomyces cerevisiae. A fed-batch fermentation done with the optimized semi-synthetic medium resulted in a maximum hirudin concentration of 342mg/$\ell$ by keeping a galactose concentrations between 10 and 30g/$\ell$ which corresponded to a 11.4-fold increase in hirudin concentration compared with the simple bach fermentation done with the same medium. Comparison of the chromatographic pattern of proteins in the growth medium clearly showed that the use of the semi-synthetic medium is more advantageous for separation of hirudin than the case o fusing the complex medium. Continuous cell recycle fermentation done at dilution rate of 0.1h-1 and an inlet galactose concentration of 100g/$\ell$ yielded a maximum hirudin productivity of 19.1mg hirudin/$\ell$$.$h.

• Journal of Microbiology and Biotechnology
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• 제11권1호
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• pp.13-16
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• 2001

Maltose and soluble starch were used as secondary sources of carbon for glucoamylase production by Aspergillus awamori in solid state fermentation. During batch cultivation, maltose above 2.5%(w/w) repressed glucoamylase production, but, by adding either 2.5% (w/w) maltose or 1.25% (w/w) soluble starch to fed-batch cultivations, glucoamylase activity was increased by 15% and 170% over standard medium, respectively. The data showed that maltose is a weak inducer of glucoamylase production in solid stat fermentation.

• Journal of Microbiology and Biotechnology
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• 제1권2호
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• pp.111-115
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• 1991

The green alga, Dunaliella salina under fed-batch cultivation produced 51.12 mg of hydrocarbon per liter with maintaining 0.313 (g dry wt/l). About 20% of hydrocarbon production yield based on dry biomass was obtained from both batch and fed-batch processes. Optimum culture conditions of light intensity, pH and salt concentration were obtained as 0.0080 (kJ/$cm^2$/h), 8.0 and 1.4 (g of NaCl/l), respectively by response surface analysis. The production of hydrocarbons in D. salina was closely correlated to cell growth. Fed-batch cultivation produced more hydrocarbons and maintained better cell growth than a batch process.

• KSBB Journal
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• 제15권3호
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• pp.219-225
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• 2000

Bacillus thuringiensis를 생물농약으로 이용하기 위해서는 고농도의 포자형성에 의한 높은 살충성의 8 -endotoxin를 생산하는 것이 중요하다. 따라서 본 연구에서는 B. thuringiensis의 고농도 배양에 의한 높은 포자형성 수율을 얻기 위하여 40%의 용존산 소량과 $28^{\circ}C$에서 여랴 가지 방법의 유가식 배양법을 검토하였다. 최종 배양액의 glucose 농도가 50 g/L가 되도록 하는 경우의 유가식 배양에서는 continuos fed-batch culture의 linear gradient f feeding 법에 의하여 $9.37{\times}109$ cell/mL의 최대 생존 세포 수와 8 8.33 X 109 spore/mL의 최대 포자 수를 얻었으며, 이때의 포자 형 성율은 88.9% 이었다 최종 배양액의 glucose 농도가 100 m/L가 되도록 하는 경우의 유가식 배양에서는 intermittent fed-batch culture의 pH-stat 법에 의하여 $1.35{\times}1010$cell/mL의 최대 생존 세포 수와 $1.35{\times}1010$ spore/mL의 최대 포자 수를얻었으며, 이 때의 포자 형성율은 97.8% 이엇다.

• 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.

• KSBB Journal
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• 제6권4호
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• pp.389-394
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• 1991

Emulsan is an extracellular emulsifying agent produced by the hydrocarbon-degrading Acinetobacter species RAG-1. In this study emulsan production of Acinetobacter calcpaceticus RAG-1 was investigated under various culture modes such as batch, fed-batch, membrane cell recycle, and continuous culture. The productions of emulsan under both ethanol-sufficient fed-batch and membrane cell recycle cultures were all 15.0U/ml, which was 53% increase in emulsan activity compared to that of pH controlled batch culture. Emulsan production was found to be strongly dependent on the residual ethanol concentration. In continuous culture the emulsan productivity increased with dilution rate.

• Journal of Microbiology and Biotechnology
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• 제6권4호
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• pp.295-298
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• 1996

Under glutamine-limited condition, $2\times10^6$ (viable cells/ml) of maximum cell density and 13.5 ($\mu g$/ml) of tissue-type Plasminogen Activators (tPA) production were maintained by spike feeding fresh medium in fed-batch cultivation of human recombinant melanoma cells. It showed that tPA production was much seriously affected than cell growth according to initial glutamine concentrations. Above 3.4 (mmol/I) of glutamine concentration both cell growth and tPA production were not much affected by increasing initial glutamine concentration. Glutamine depleted situation was occurred at latter periods of batch and fed-batch cultivations below 5.4 (mmole/I) of initial glutamine concentration. It also showed that maximum glutamine consumption and ammonia evolution rates were closely related to initial glutamine concentrations. Maximum specific tPA production rate was estimated as $8.1\times19^{-6}$ ($\mu g$/cells/h) at 3.4(mmol/I) of glutamine concentration, which is higher than that from other batch and fed-batch processes.

• Journal of Microbiology
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• 제40권1호
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• pp.82-85
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• 2002

The aerobic batch growth of Issatchenkia orientalis DY252 with glucose and fructose medium was investigated at 32$\^{C}$ and pH 5.0. Aerobic ethanol production was evident with yeast I, orientalis. A diauxic lag of about 1 h between growth on glucose and growth on ethanol during batch culture was observed. However, no diauxic growth occurred with fructose. As the incubation temperature was increased from 32 to 39$\^{C}$, viability at the end of each batch culture declined significantly, from 93 to 43%, Unlike the effect of temperature, viability was not greatly affected by incubation pH, and cell yield values in a range of 0.45-0.48 were obtained. In order to overcome overflow metabolism, a fedbatch culture under glucose limitation was carried out. Compared with aerobic batch culture, about 10% improvement in cell yield was achieved with a fed-batch culture in optimal conditions.

• KSBB Journal
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• 제19권5호
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• pp.410-414
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• 2004

Fed-batch cultures of Enterococcus faecalis RKY1 were performed to maximize the L(+)-Iactic acid concentration in the bioreactor. The highest lactic acid concentration was obtained at around 225 g/L by intermittent feeding the concentrated glucose media containing 500 g/L of glucose and 15 g/L (or 75 g/L) of yeast extract. However, in all fed-batch cultures, volumetric productivities of lactic acid gradually decreased due to the inhibitory effect of lactic acid produced during the fermentation. The highest value of lactic acid concentration obtained in this work corresponded to around 1.5-fold increase compared with conventional batch fermentation.