• 한국환경과학회지
• /
• 제8권4호
• /
• pp.443-449
• /
• 1999

This paper describe the working of algal culture system under batch and continuous feeding effluents in biological treatment process. The main objective of this study was the determination of fundamental opeating parameters such as dilution rates, light intensity, biomass concentration, nutrients contents, which engender an effective nutrient and organic waste removal process. The results of this research indicate that the algae system will remove effectively nutrient and organic waste. In batch cultures, 91.8% dissolved orthophosphate and 83.3% ammonia nitrogen were removed from the sewage in ten days. In continuous flow systems, a detention time of 2.5 days was found adequate to remove 91% T-P, 87% T-N and 95% $NH_3-N$. At 22-28$^{\circ}C$, 60 rpm, with an intensity of 3500 Lux, the specific growth rate, k was 0.59/day in batch experiments. The optimal growth temperature and nutrients rate (N/P) were respectively $25^{\circ}C$ and 3~5. With an abundant supply of untrients, it was possible to sustain substantial population densities in the temperature range of 22~28$^{\circ}C$.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
• /
• pp.92-95
• /
• 2000

A mixed bacterial culture capable of mineralizing methyl tort-butyl ether (MTBE), other fuel oxygenates ethers, tertiary carbon alcohols, benzene and toluene was used to inoculate batch reactor and sequence batch reactor (SBR) to treat gasoline contaminated ground water containing about 60 mg/L MTBE, 5 mg/L benzene, 5 mg/L toluene, and low concentrations of several other aromatic and aliphatic hydrocarbons. Respirometery studies showed that MTBE degrading mixed culture could treat MTBE contaminated ground water with addition of nitrogen and phosphate. SBR was operated to demonstrate the feasibility of using suspended growth activated system for the treatment of ground water and to confirm that the respirometry derived kinetics and stoichiometric coefficients were useful for predicting reactor performance. Theoretical performance of the reactor was predicted using mathematical models calibrated with biokinetic parameters derived from respirometry studies.

• 한국미생물·생명공학회지
• /
• 제22권3호
• /
• pp.304-308
• /
• 1994

A suitable culture method and bioreactor type for itaconic acid production were chosen by comparing the maximal concentration of itaconic acid produced in various systems. In batch culture, the maximal concentration of itaconic acid produced in a bubble column reactor was about 5% greater than that produced in stirred-tank or external-loop airlift reactor. These results were thought to be due to lower shear force and higher mass transfer efficiency in a bubble column reactor in comparison with other reactors. Moreover, the fed-batch mode in a bubble column was found to be a suitable one, producing about 25% higher concentration of itaconic acid compared to batch mode.

• 한국미생물·생명공학회지
• /
• 제18권4호
• /
• pp.406-410
• /
• 1990

토양에서 분리한 알칼리내성 Bacillus sp.의 자체 chromosomal DNA에서 유래된 strong promoter를 지닌 plasmid p-12B1을 공여균주에 삽입시키고 이 promoter의 활성을 최적화할 수 있는 배양조건을 검토하였다. 글루코오스가 고갈된 시점부터 세포의 활성은 유지되나 포자는 형성되지 않을 정도로 낮은 글루코오스 소비속도를 유지해 제한된 글루코오스를 연속적으로 공급해줌으로써 promoter의 활성을 최대로 높일 수 있었다. 또한 배지조성의 변화로 균체를 생육시킨 후 유전자 발현을 유도하는 것이 가능하였으며, 이 점에 대해서는 보다 구체적인 연구가 진행되어야 할 것이다.

• KSBB Journal
• /
• 제14권3호
• /
• pp.365-370
• /
• 1999

To optimize the culture conditions for Beauveria bassiana 726, the effects of culture medium, pH, and temperature on mycelium and spore production were investigated. The optimum temperature and pH for the cultivation of B. bassiana 726 were 28 $^{\circ}C$ and 5.0, respectively. The optimized medium was composed of 1.0~2.0% total sugar from molasses, 0.5% corn steep liquor and 0.05% KH$_2$PO$_4$. In the cultivation of B. bassiana 726 with the optimum medium, the specific growth rate and substrate utilization were well-fitted with the proposed kinetic model in the shake flask and stirred tank reactor. When the fed-batch cultivation using carbon suorce, nitrogen source, and mineral salt as a feeding medium was compared with batch cultivation in stirred tank reactor, mycelium (12.7 g/L) and spore production (5.4$\times$$10^8/mL$) were enhanced up to 110% and 85%, respectively.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2001년도 추계학술발표대회
• /
• pp.351-354
• /
• 2001

In this experiment, we tested various nitrogen sources and then culture condition was optimized for industrial applications. The batch culture of Candida magnoliae SR101 grown in a defined medium supplemented with light steep water (LSW) as a sole nitrogen source showed a relatively high yield of erythritol production (53%), which was slightly higher than that using yeast extract as a nitrogen source, while the productivity and cell mass were maintained at similar levels. For the optimization of culture condition, the batch culture was performed. When the concentration of LSW was 65 mL/L in the defined medium containing 250 g/L of glucose, the concentration, yield and productivity of erythritol were 110 g/L, 44%, and 0.66 g/L-hr, respectively. The high yield and comparable productivity obtained with a cheap nitrogen source could be expected as a basis for the mass production of erythritol in the industrial scale.

• KSBB Journal
• /
• 제8권1호
• /
• pp.28-35
• /
• 1993

The serum free medium was developed and used for the suspension culture of mammalian cells. Although there were the problems of the longer lag time and the smaller maximum cell concentration achievable, the higher specific productivity as well as other advantages of the serum free medium can make it a more realistic alternative. The existence of a staggering period in glucose concentration vs. time profile in the batch culture can be a practical indicating signal for performing fed batch culture. The concentration dependence of the effects of the additives in the serum free medium as well as its economic feasibility was also tested.

• 한국미생물·생명공학회지
• /
• 제17권5호
• /
• pp.504-509
• /
• 1989

Streptococcus lactis IFO 12007의 nisin 생산을 위한 발효조건을 검토하였다. Nisin 생성을 위한 포도당의 농도는 60g/ι이며 pH와 온도는 각각 6.5와 3$0^{\circ}C$이었다. 이 조건에서 최대 2,000IU/$m\ell$의 생산량을 보이며 이 때 specific glucose uptake rate: 0.59g/g/h, specific nisin productivity는 34924iu/g/h, growth yield는 0.24, 7시간 후 균체 생산량은 4.81g/ι이었다. 비성장속도는 온도와 pH에 의하여 영향을 많이 받으며 증식활성화 에너지는 1.35kca1/ mole이었다. 유가배양에 의하여 1420IU/$m\ell$의 nisin을 생산하며 연속배양은 0.38h$^{-1}$까지 가능하고 이때 nisin 농도는 740IU/m1, specific nisin productivity는 45000IU/g/h, true growth yield 는 0.144, maintenance energy는 207mg glucose/g-cell/h 이었다.

• 한국미생물·생명공학회지
• /
• 제27권4호
• /
• pp.327-332
• /
• 1999

A highly productive fed-batch fermentation process was developed for the production of L-ornithine by using a new stabilized strain, Breviabcterium ketoglutamicum BK52. Fed-batch cultures with a continuous feeding of the complex medium were conducted on various operating conditions. The optimal concentration of phosphate in the complex medium was 2.1g/L. The optimal feeding rate of L-arginine was 0.028g/L/hr. The optimal feeding point of the complex medium was determined to be at 40 OD of the cell mass. The final L-ornithine concentrations within 64hrs of cultivation in 5 and 50 liter fermenters were 73g/L and 71g/L, respectively. The maximum overall L-ornithine productivity was 1.14g/L/hr which was about 2 times higher than that of the conventional fed-batch culture with intermittent feeding. The overall productivity of the fermentation system is remarkably improved by employing the optimized conditions, and it offers a significant potential for industrial application.

• Journal of Microbiology and Biotechnology
• /
• 제12권4호
• /
• pp.687-691
• /
• 2002

To enhance the production of flavonoids [baicalin, wogonin-7-Ο-glucuronic acid (GA)], which are secondary metabolites of Scutellaria baicalensis Georgi(G.) plant cells, a multilayer perceptron control system was applied to regulate the substrate feeding in a fed-batch cultivation. The optimal profile for the substrate feeding rate in a fed-batch culture of S. baicalensis G. was determined by simulating a kinetic model using a genetic algorithm. Process variable profiles were then prepared for the construction of a multilayer perceptron controller that included massive parallelism, trainability, and fault tolerance. An error back-propagation algorithm was applied to train the multiplayer perceptron. The experimental results showed that neurocontrol incorporated with a genetic algorithm improved the flavonoid production compared with a simple fuzzy logic control system. Furthermore, the specific production yield and flavonoid productivity also increased.