• 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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• 제24권5호
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• pp.661-666
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• 2014

Both lactic acid productivity and cell growth were linearly correlated with yeast extract supplementation in batch fermentation. During conventional continuous operation, although fresh feed was introduced into the bioreactor with a significantly low dilution rate (0.04 $h^{-1}$), the amount of yeast extract employed was not enough to maintain the growth of microorganism. However, when the fresh feed contained 100 g/l glucose and 2 g/l yeast extract during cell-recycle continuous operation at a dilution rate of 0.04 $h^{-1}$, more than 90 g/l lactic acid was continuously produced, with the average productivity of 3.72 $g/l{\cdot}h$. In this experiment, 82 g of yeast extract (77% of reduction yield) could be reduced for the production of 1 kg of lactic acid compared with batch fermentation of a similar volumetric productivity.

• KSBB Journal
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• 제9권2호
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• pp.180-185
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• 1994

본 연구에서는 캘리포니아 양귀비(Eschscholtzia californica) 세포를 airlift 배양기에 적용 배양할 때 shake flask 배양보다 benzophenanthridine alkaloid의 생산성이 감소하는 원인을 찾고 이를 극복하기 위한 실험을 수행하였다. Alkaloid 생산성 감소의 주된 원인은 air sparging에 의해 $CO_2$ 및 ethylene과 같은 유용 성분의 gas가 stripping 되는 것으로 나타났으며 이 stripping 되는 gas를 다시 공급하는 gas recycle 식 airlift 배양기를 개발하였다. 이 배양기에 캘리포니아 양귀비 세포를 배양한 결과 alkaloid 함량이 일반 airlift 배양기 운전 결과보다 약 2.7배 증가하였다. 또한 이 배양기의 gas reservoir의 용량 변화에 따라 alkaloid의 생산성 및 이산화탄소의 농도가 영향을 받음을 확인하였다.

• 한국미생물·생명공학회지
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• 제17권6호
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• pp.624-628
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• 1989

A study on the citric acid production using Saccharomycopsis lipolytica (NRRL Y7576) was carried out in shake-flasks, air-lift and membrane recycle bioreactors. The cells entrapped in Ca-alginate beads were used in shake-flasks and air-lift reactor. Repeated batch fermentation in shake-flasks was successfully performed for 34 days and resulted in a yield of 54%. Increased yield (63%) was obtained in the air-lift reactor operation using nitrogen deficient medium (NDM). In the membrane recycle bioreactor operation, the maximal dry cell mass concentration was 39 g/1 at a dilution rate of 0.02 h$^{-1}$ and the yield with NDM was higher than that with growth medium. In addition, the yield and volumetric productivity with pure oxygen supply were greatly improved compared with those with air supply.

• KSBB Journal
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• 제14권4호
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• pp.445-451
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• 1999

E. coli TGI/pDG7 $\alpha$ 와 빵효모의 혼합세포계에 의한 글루타치온 생산을 Aerated Slurry Bioreactor에서 수행하였다. 글루타치온 생산 효소는 34시간 동안 안정성을 보였으며, 글루타치온 수율은 4.6 mM을 유지함을 보였다. 고농도의 혼합세포를 이용한 Aerated Slurry Bioreactor에서 기질의 공급속도가 글루타치온 생산에 미치는 영향을 조사하였다. 세포가 회수되어 기질공급속도 5.2 mL/hr에서 글루타치온의 생산농도는 32시간에서 현탁반응보다 낮아짐을 보였고, 반면 세포가 회수되지 않은 기질공급속도 5.2 mL/hr에서는 22시간 동안 유지되었고 2.6 mL/hr에서는 42시간 동안 유지되었다. 글루타치온의 생산성은 기질공급속도가 10.4 mL/hr에서 25.7 mg/g wet $cell{\cdot}hr$이었으나, 2.6 mL/hr에서는 1.65 mg/g wet $cell{\cdot}hr$이었고 5.2mL/hr에서는 5.28 mg/g wet $cell{\cdot}hr$이었다. 계면활성제(Tween 80)을 사용한 경우, 글루타치온 생산시간을 25시간에서 45시간으로 연장되었다. 글루타치온 생산있어 산소가 세포계의 효소에 산소에 의해 영향을 미칠 것으로 판단되었고, 공기를 질소로 교체하여 글루타치온 생산시간을 40시간으로 연장시켰다.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1369-1373
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• 2009

Succinic acid was produced by continuous fermentation of Actinobacillus succinogenes sp. 130Z in an external membrane cell recycle reactor to improve viable cell concentration and productivity. Using this system, cell concentration increased to 16.4 g/l at the dilution rate $0.2\;h^{-1}$, up to 3 times higher than that of batch culture, and the volumetric productivity of succinic acid increased up to 6.63 g/l/h at the dilution rate $0.5\;h^{-1}$, 5 times higher than that of batch fermentation. However, in the continuous culture using a high dilution rate, operational problems including severe membrane fouling and contamination by lactic acid producer were observed. Another succinic acid producer, Mannheimia succiniciproducens MBEL55E, was also utilized in this system, and the cell concentration and productivity of succinic acid at the dilution rate of $0.3\;h^{-1}$ were found to be above 3 and 2.3 times higher, respectively, compared with those obtained at the dilution rate of $0.1\;h^{-1}$. These observations give a deep insight into the process design for a continuous succinic acid production by microorganisms.

• KSBB Journal
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• 제7권2호
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• pp.139-143
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• 1992

본 연구에서는 균주 S. cerevisiae ATCC 24858을 막분리를 이용한 미생물 재순환 연속에탄올 발효시스템에 적용하여 희석비 (0.3, 0.5, $0.7hr^{-1}$)와 주입기질의 당농도 (50, 100, 150, 200g/l)에 따른 균체농도 및 알콜생산성의 변화관계를 규명하여 보았다. 주입기질 당농도50g/l, 희석비$0.3hr^{-1}$ 내지 당농도200g/l, 희석비 $0.7hr^{-1}$ 사이의 실험범위에서 균체농도는 12g/l내지 107g/l 사이에, 알콜생산성은 7.0g/l 내지 55.6g/l 사이에 분포되었다. 더욱이 알콜생산성은 회분식 발효의 생산성에 비하여 최소 307배 내지 최대 29.3배 까지 증가하였다. 또한 본 연구의 실험범위에 대한 에탄올 평균수율은 0.42로써 이론수율의 82%였으며 회분식 수율보다 약간 상회하였다.

• KSBB Journal
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• 제5권2호
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• pp.159-165
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• 1990

Ethanol fermentation by Scccharomyces cervisiae was carried out in the cell recycle filter system with a cheap fabric filter having a pore size of 10${\mu}$m. Maximum biomass concentrations up to 85g/1 were obtained, but in practice operational concentrations were between 50 and 80g/1. Ethanol productivity was 42g/1-hr, with an ethanol concentration of 66g/1 and an ethanol yield of over 86%. Continuous operation was possible by applying periodic backflushing. The ethanol fermentation could be carried out without difficulty at a dilution rate up to 0.8h-1 In order to obtain a high cell concentration and ethanol productivity, development of filter module with the larger filtration area is required.

• 한국미생물·생명공학회지
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• 제14권2호
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• pp.193-198
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• 1986

Sacch. cerevisiae var. ellipsoideus 균주를 이용산업용 천연맥즙배지를 사용한 알콜연속 발효시 Hollow Fiber Recycle Reactor를 of용 Cell Recycle을 시켜 발효조내의 알콜 생산성을 높이기 위해 본 실험을 실시하였으며, 특히 Batch식과 연속발효시 HFR유무에 따른 특성을 비교 검토한 결과를 요약하면 다음과 같다. 1 Dilution rate가 0.1h$^{-1}$일때 11$^{\circ}$P 및 15$^{\circ}$P media를 이용한 알콜 연속발효에서 알콜농도는4.71% 및 5.82%(v/v) 이었으며 이때의 발효율은 각각 86.2%와 78.6 % 이었다. 2. HFR연속발효에서 D=0.1h$^{-1}$일때 알콜농도는 7.64% (v/v)로 높았으며, 이때의 생산성은 6.1g/l/h이었다. 또한 D=0.2h$^{-1}$일때 알콜농도와 생산성은 각각 7.62%(v/v) 및 12.2g/l/h/이었다. 3. HFR연속발효에서 D=0.3h$^{-1}$일때 알콜농도가 7.54% (v/v) 이었으며 알콜생산성은 18.1g/l/h 이었다. 4 알콜 생산성 비교에서 HFR 연속발효는 연속발효에 비해 4배의 증가효과가 있었으며 Batch발효에 비해서는 16.3배나 크게 증가하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.637-642
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• 1987

In immobilized cell reactors, effective cell mass is a very important parameter which must be estimated during operation for control and regeneration of biocatalyst. In this report, the effective cell mass in immobilized cell reactor was studied using a sequential estimation method. An immobilized yeast reactor was operated in batch recycle mode. The states of the immobilized cell reactor could be estimated from the process data using an extended Kalman filter.