• 한국미생물·생명공학회지
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• 제21권5호
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• pp.511-512
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• 1993

The production of vinegar containing high acetic acid concentration was carried in a single stage fed-batch culture. The initial and residual ethanol concentration were 50.0g/l and 5.0g/l, respectively, and the ethanol concentration was maintained from 5.0g/l to 10.0g/l during fedbatch culture. The fermentation temperature was decreased by 1C for every increase of 2.0% in acidity. The maximum productivity was 2.53g/l-hr and the acidity was 16.08% after 40 hours of acetic acid fermentation.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.319-323
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• 2005

This study is concerned with development of efficient culture methods for lactic acid fermentation of Lactobacillus sp. RKY2. The cell-recycle repeated batch fermentation using cheese whey and corn steep liquor as raw materials was tried in order to further enhance the productivity of lactic acid. In addition, fermentation efficiencies could be considerably enhanced by cell-recycle continuous culture. Through the cell-recycle repeated batch fermentation, lactic acid productivity was maximized to 6.34 $g/L{\cdot}h,$ which corresponded to 6.2 times higher value than that of the batch fermentation. During the cell-recycle continuous fermentation, the last dry cell weight at the end of fermentation could be increased to 25.3 g/L.

• KSBB Journal
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• 제25권2호
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• pp.187-192
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• 2010

S. cerevisiae ATCC 24858을 이용한 ethanol 생산에서, aeration 효과를 ethanol 수율, specific ethanol production rate, ethanol 생산성 측면에서 분석하여, 반복 유가식 공정전략을 설계하였다. Ethanol 수율과 ethanol 생산성은 공기를 0.33 vvm 넣었을 때, 공기를 넣지 않고 배양한 것에 비하여 더 큰 값을 보였고, 24시간 마다 배지를 교체한 배양이 36시간 마다 배지를 교체한 배양 보다 더 큰 값을 보였다. 총 ethanol 생산량 값이 가장 큰 경우는 0.33 vvm의 공기를 넣고, 배지를 24시간마다 완전히 갈아주었을 때이고, 이때 가장 많은 703.8 g의 ethanol이 생산되었다.

• Journal of Microbiology and Biotechnology
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• 제1권2호
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• pp.126-129
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• 1991

In order to produce ${\gamma}-linolenic$ acid by Mucor sp. KCTC 8405P. the fungus was cultivated in fed-batch culture with two phases. i.e., growth in yeast-like form and induction to hyphal growth by pH shift of the culture medium during cultivation. The synchronous growth of the fungus into the appropriate sizes was important for the high density cell culture of this dimorphic fungus. Dissolved oxygen concentration in the medium did not affect degree of unsaturation of fatty acids and ${\gamma}-linolenic$ acid content. Under the culture conditions applied in this experiment. the fungus was found to produce 100 g/l dry mycelia containing 40% of the lipids, where ${\gamma}-linolenic$ acid comprised about 9% of the total extractable fatty acids.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권6호
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• pp.459-464
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• 2004

The objective of this study is to improve cephalosporin C (CPC) production byoptimization of medium and culture conditions. A statistical method was introduced to optimize the main culture medium. The main medium for CPC production was optimized using a statistical method. Glucose and corn steep liquor (CSL) were found to be the most effective factors for CPC production. Glucose and CSL were optimized to 2.84 and $6.68\%$, respectively. CPC produc­tion was improved $50\%$ by feeding of $5\%$ rice oil at day 3rd and 5th day during the shake flask culture of C acremonium M25. The effect of agitation speeds on CPC production in a 2.5-L bio­reactor was also investigated with fed-batch mode. The maximum cell mass (54.5 g/L) was obtained at 600 rpm. However, the maximum CPC production (0.98 g/L) was obtained at 500 rpm. At this condition, the maximum CPC production was improved about $132\%$ compared to the re­sult with batch flask culture.

• Journal of Microbiology and Biotechnology
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• 제10권3호
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• pp.321-326
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• 2000

To examine the feasibility of the long-term production of the human granulocyte colony stimulating factor (hG-CSF) using the $_{L}-arabinose$ promoter system of Escherichia coli, flask relay culture and cyclic fed-batch culture were performed. In the flask relay culture, it was found that the pismid was maintained stably up to about 170 generations in an uninduced condition, whereby the cells could also maintain the capability of expressing hG-CSF expression were maintained stably up to at least 100 generations. In contrast, in the cyclid fed-batch culture, segregational plasmid instability was observed within about 4 generations after induction, even though the cell growth and hG-CSF production reached their maximum balues, 78.0 g/l of dry cell weight and 7.0 g/l of hG-CSF, respectively. It would appear that, when compared to the flask relay culture, the high-cell density and high-level expression of hG-CSF in the cyclic fed-batch cultrure led to the segregational plasmid instability; in other words, a severe metabolic burden existe on the cells due to the high-level expression of hG-CSF. Accordingly, based on these long-term cultures, the segregational and structural plasmid instability was observed and a strategy to overcome such problems could be designed.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1947-1953
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• 2006

There have been a number of studies of methods for recycling animal wastewater to provide new bioresources. In the present work, a marine algal culture medium, designated KEP II, was prepared by adding swine waste (3% v/v) fermented by soil bacteria to a dilution of f/2 culture medium (CT). When Phaeodactylum tricornutum was grown in batch culture in KEP II, the cells lasted long at the exponential phase producing the specific growth rate and biomass; the production of total amino acids and secondary metabolites rose up to 5-fold. It also substantially enhanced the maximum quantum yield of photo system (PS) II of P. tricornutum, greatly increased the level of thylakoid membranes containing PS, and stimulated the production of pyrenoids, including enzymes for $CO_2$ fixation in chloroplasts. KEP II should improve the cost efficiency of industrial mass batch cultures and the value of microalgae for long-term preservation of fresh aquaculture feed as well as production of anticancer and antioxidant agents. Specifically, a low-cost medium for growing the diatoms of aquaculture feed will be economically advantageous.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.287-290
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• 2000

회분배양에서 교반속도와 통기량에 대한 영향을 살펴본 결과 400 rpm과 1.0 vvm의 조건에서 균체량은 25.1 g/L, 다당체는 2.5 g/L로 가장 높게 생성되었다. 회분배양을 기초로 균체량과 다당체 생성을 높이기 위해 glucose를 대수기에 공급한 결과 배양 6일째 균체량은 29,2 g/L, 다당체 생성은 3.3 g/L로 회분배양보다 우수한 결과를 보였다.

• KSBB Journal
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• 제5권3호
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• pp.269-277
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• 1990

메탄올이용균인 Methylobacillus sp. SKI의 균체생산효율을 증대시킬 목적으로 마이크로컴퓨터 제어 배양기를 이용해 고농도 유가배양을 수행하였다. 배양액의 초기 메탄올농도를 1.0%(v/v)로 하여 회분배양할 경우 배양 13시간만에 2.07g/l의 균체농도에 도달하였다. 공기 공급에 의한 유가배양에서 최대교반속도 1200rpm, 최대 공기유량 5.0$\ell$/min의 조건으로 배양시 약 15시간만에 13.7$\ell$/ldml 균체농도에 도달하였다. 산소공급에 의한 유가배양에서 최대교반속도 1200rpm, 공기유량 1.0$\ell$min, 최대산소유량 5.0$\ell$/min의 조건으로 배양시 17시간만에 45.3g/l의 균체농도에 도달하였다. 균의 대수 증식기를 공기공급에 의한 유가 배양으로 회분배양에 비해 약 3시간, 산소공급에 의한 유가배양으로 회분배야에비해 약 3시간, 산소공급에 의한 유가배양으로 회분배양에 비해 약 4시간 더 연장할 수 있었다. 즉, 유가배양로 단시간에 높은 농도의 균체를 얻은 것은 feedback제어에 의해 메탄올을 저해농도 이하로 유지시키면서 용존산소를 한계농도 이상으로 제어함으로써 균의 대수적 증식으로 연장시킨 결과이다. 산소공급에 의한 유가배양중 균체농도 27.6g/l에서 미량원소성분이 결핍되었고, 42.8g/l에서 $Mg^2^+$성분이 결핍되었으므로 배양중에 추가공급되었다.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.225-230
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• 2004

A plasminogen kringle domain 1 to 3, rKl-3, was expressed in Escherichia coli under the control of T7 promoter. For the cost-effective production of rKl-3, the induction process was analyzed and optimized. Induction characteristics with lactose were analyzed in terms of induction time and inducer concentration in various culture conditions including batch and high-cell-density fed-batch cultures. In the fed-batch culture, the induction around 6 h after initiation of the DO-stat fed-batch culture resulted in the highest expression level of rKI-3 among the induction points examined. The highest demand of oxygen at this point was crucial for the maximum expression level of rKI-3. As the lactose concentration increased, the expression level also increased, though the expression level showed a plateau above a concentration of 14 mM of lactose. Lactose acted less specifically than IPTG since most of it was hydrolyzed to glucose and galactose. However, using lactose, the cell growth and the maximum expression level of rKl-3 increased by 20% and 24%, respectively, compared with those using IPTG in the fed-batch culture. The lactose seemed to be hydrolyzed by intracellular and extracellular $\beta$-galactosidase liberated by cell lysis at the same time. Residual concentration of glucose was maintained to a a limit of detection by high performance liquid chromatography, and galactose was not consumed by the host strain Escherichia coli BL2l(DE3).