• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.845-848
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• 2001

For understanding physiology and metabolism under various culture conditions, combined analysis of transcriptome and proteome is attractable way. We have manufactured DNA microarray containing 2,850 genes including all functionally known and putative ones. In this study, we report analysis of transcriptome and proteome during the high cell density culture of E. coli by using DNA microarray and 2-DE. Fed-batch fermentation of E. coli was carried out by exponential feeding of nutrients until the maximum cell density reached 74 g dry cell weight/L (g DCW/L). Changes in transcriptome and proteome during the HCDC are analyzed qualitatively and quantitatively to provide their physiological and metabolic meanings.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.105-108
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• 2003

To enhance the performance of a serum-free medium (SFM) for human thrombopoietin (hTPO) production in suspension cultures of recombinant Chinese hamster ovary (rCHO) cells, several low-cost hydrolysates such as yeast hydrolysate (YH), soy hydrolysate, wheat gluten hydrolysate and rice hydrolysate were tested as medium additives. Among various hydrolysates tested, the positive effect of YH on hTPO production was most significant. When 5 g/L YH was added to SFM, the maximum hTPO concentration in batch culture was 40.41 ${\mu}g/mL$, which is 11.5 times higher than that in SFM without YH supplementation. This enhanced hTPO production in YH-supplemented SFM was obtained by the combined effect of enhanced $q_{hTPO}$ and increased culture longevity. In addition YH supplementation did not affect in vivo biological activity of hTPO. Taken together, the results obtained demonstrate the potential of YH as a medium additive for hTPO production in serum-free suspension cultures of rCHO cells.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.249-252
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• 2003

Maximal production of heteropolysaccharide-7(PS-7) with a batch culture for 48 hr was $10.0\;g/{\ell}$ and its conversion rate from 2% (w/v) glucose to PS-7 was 50%. After substitution of media, production of PS-7 continued and reached its maximal production. The highest productivity occurred when the fresh medium, which contained all ingredients, for the production of PS-7 was substituted. Higher production of PS-7 was maintained at a dilution rate of 0.0125, which was established as the optimal dilution rate for the production of PS-7 by B. indica HS-2001.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.932-937
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• 2004

In situ extraction by organic solvent was studied in order to improve the recovery yield of hydrocarbon from the culture of Botryococcus braunii, a green colonial microalga. When the solvent mixture of octanol as an extractive solvent and n-octane as a biocompatible solvent was added to a two-phase column, the algal growth was seriously inhibited, even at a low concentration of polar octanol. Therefore, a two-stage cell-recycle extraction process was proposed to improve the contact area between the organic phase and the aqueous phase. The hydrocarbon recovery with in situ cell-recycle extraction showed a three-fold increase (57% of cell) in yield over that with two-phase extraction. In addition, over 60% of the hydrocarbon could be recovered without serious cell damage by downstream separation when this process was applied to the culture broth after batch fermentation.

• 한국미생물·생명공학회지
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• 제23권2호
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• pp.220-228
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• 1995

For polyhydroxyalkanoic acid (PHA) production, several microorganisms were isolated from sewage sludge. One of them, GB-77 strain, was chosen from its PHB/HV copolymer production on only fructose without cosubstrate. The isolated strain GB-77 was identified as the genus Alcaligenes. Optimal temperature and pH for cell growth were 36C and 6.8. Optimal medium composition was 10 g/l of fructose and 5 g/l of polypeptone, 1 $\times$ 10$^{-2}$M Na$^{2}$HP0$^{4}$, 1.3 $\times$ 10$^{-2}$M KH$^{2}$PO$^{4}$. To investigate the optimal condition for polyhydroxyalkanoic acid production two-stage culture technique was used; first stage for cell growth and second stage for PHA production on unbalanced growth conditions. Optimal conditions for high PHA production were C/N ratio 50, temperature 36$\circ$C and pH 6.8. To overcome fructose inhibition on cell growth, intermittent feeding fed-batch culture technique was used. Total cell concentration was 17.4 g/l with 9.1 g/l of PHA. The purified PHA was identified PHB/HV copolymer by NMR analysis.

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.401-406
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• 1994

The medium compositions of Alcaligenes eutrophus were optimized for increasing PHB productivity. It is very important to optimize the concentrations of inorganic salts and trace eleme- nts as well as carbon and nitrogen sources to maximize cell growth rate and productivity. The fed-batch culture of Alcaligenes eutrophus by dual feeding of ammonia water and glucose under optimized initial medium concentrations was carried out. Glucose was fed manually according to glucose consumption rate and ammonia water by pH-stat. The final cell concentrations and PHB content in 30 hours were 122 g/l and 65% of dry cell weight(yielding 79 g of PHB/l), respectively and 2.64 g/l/hr of PHB production rate was obtained.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권6호
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• pp.331-334
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• 2002

Culture conductivity and on-line NADH fluorescence were used to measure cellular growth in plant cell suspension cultures of Podophyllum hexandrum. An inverse correlation between dry cell weight and medium conductivity was observed during shake flask cultivation. A linear relationship between dry cell weight and culture NADH fluorescence was obtained during the exponential phase of batch cultivation In a bioreactor under the pH stat (pH 6) conditions. It was observed that conductivity measurement were suitable for biomass characterisation under highly dynamic uncontrolled shake flask cultivation conditions. However, if the acid/alkali feeding is done for pH control the conductivity measurement could not be applied. On the other hand the NADH fluorescence measurement allowed online-in situ biomass monitoring of rather heterogenous plant cell suspension cultures in bioreactor even under the most desirable pH stat conditions.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권5호
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• pp.359-362
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• 2001

The production of an extracellular polysaccharide, EPS-R, from the marine bacterium Hahella chejuensis was investigated at various aeration rates in a batch culture. Higher aeration rate resulted in enhanced EPS production and increased the viscosity of the culture broth. At an aeration rate of 1.5 vvm, EPS-R (12.2 g/L) was obtained with a yield (Y$\_$p/s) of 0.6 from the STN medium after 72 h of cultivation. The H. chejuensis cells changed rod morphology to a short-rod form in the stationary growth phase.

• Journal of Microbiology and Biotechnology
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• 제11권5호
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• pp.880-883
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• 2001

To optimize co-production of dextran and mannitol from sucrose by Leuconostoc mesenterides ATCC 13146, a batch culture fermentation was conducted by using various concentrations of sucrose and initial culture pHs. The production of dextran and mannitol showed a growth-associated pattern. The highest yields of both dextran and mannitol were obtained at pH 6.0 and $10\%$ (w/v) sucrose. They could be easily separated by using alcohol fractionation. Maximum yields of dexran and mannitol were 0.45 and 0.35 of the consumed sucrose, respectively. Overall productivities of dextran and mannitol were 1.47 and 0.37 g/l/h, respectively.

• Journal of Microbiology and Biotechnology
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• 제8권3호
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• pp.208-213
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• 1998

The effect of the addition of wheat bran to the growth medium on the production of cellulolytic enzymes of Trichoderma reesei Rut C30 was studied in batch culture using shake flasks. The activity of cellulase was enhanced by the addition of wheat bran to the cellulase production medium. $KH_2PO_4$-$K_2HPO_4$ buffer was used for pH control during cellulase production. As a result, high cellulase activities were obtained in shake flask culture; a CMC (carboxymethyl cellulose) activity of 125.78 U/ml was obtained from 2% Avicel- and 3% wheat bran-containing medium and an FP (filter paper) activity of 12.85U/ml was obtained from 1% Avicel- and 5% wheat bran-containing medium after 6 days of cultivation.