• The Journal of the Korean Society for Microbiology
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• v.20 no.1
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• pp.55-63
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• 1985

Phosphate, ammonia, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate were examined for their ability to control the heat-stable enterotoxin (ST) production in succinate salts medium or in M9 medium. The results obtained were summerized as follows. 1. When the initial phosphate concentration was adjusted to 1.0mM, ST production was decreased to 80u/ml or less. But when the initial phosphate concentration was adjusted to 64mM or 100mM, enterotoxin production was 320u/ml. 2. When the initial ammonia concentration in the medium was adjusted to 1.0mM, no ST production and cell growth were observed. But when ammonia concentration was adjusted to 10mM, 19mM, 38mM or 76mM, enterotoxin production was 320u/ml. 3. Among carbon sources, glucosamine, glucose, pyruvate, succinate, fumarate, malate and acetate, acetate supported the highest specific production (928 unit/O.D.) of heat-stable enterotoxin. From this results, we could assume that heat-stable enterotoxin production is controlled by stringent control mechanism. 4. When the pH of the succinate salts medium was kept between 6.2 to 6.5, no heat-stable enterotoxin production was observed, but when the pH of the medium was kept between pH 6.2 to 6.5, 267 unit/O.D. of heat-stable enterotoxin was produced. 5. Glucose inhibited the heat-stable enterotoxin production and the mechanism was assumed due to its capacity to lower the pH of the medium during catabolysis and its high metabolic energy.

• Microbiology and Biotechnology Letters
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• v.7 no.4
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• pp.205-209
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• 1979

Lactobacillus acidophilus exhibited more growth and produced greater amounts of acid in the soy milk than Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillu helveticus examined. The supplementation of the soy milk with glucose accelerated the growth of L. acidophilus, and enhanced acid production by L. acidophilus whereas sucrose addition was without effect. The supplementation of the soy milk containing five percent glucose with a methionine accelerated the growth of L. acidophilus, and enhannced acid production by L. acidophilus. L. acidophilus showed greater population in the soy milk containing five percent glucose which was treated with 0.0008％ protease (9.40$\times$10$^{8}$ /m/) than the soy milk containing five percent glucose (2.02$\times$10$^{9}$ /ml) moreover L. acidophilus produced greater amounts of acid in the soy milk containing five percent glucose which was treated with 0.0008％ protease (1.47 ％) than in the soy milk containing five percent glucose (0.56％)

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.259-262
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• 2000

The production of pullulan by Aureobasidium pullulans HP-2001 was investigated under various ratios of glucose as carbon source and yeast extract as the nitrogen source, Highest conversion rate (productivity) of glucose to pullulan was 40.0% when concentrations of glucose and yeast extract were 5% and 0.15%, respectively. Maximal production of pullulan was 29.3g/1 when the concentration of glucose was 8%(w/v) and that of yeast extract was 40:1. On basis of the result that production of pullulan was found in a medium which concentration of glucose as carbon source was up to 20%(w/v), Aureobasidium pullulans HP-2001 seemed to overcome the catabolite repression. Conversion rate of pullulan from 20%(w/v) of glucose was 11.1%.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.739-748
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• 2001

A self-organizing fuzzy logic controller using a genetic algorithm is described, which controlled the glucose concentration for the enhancement of flavonoid production in a fed-batch cultivation of Scutellaria baicalensis G. plant cells. The substrate feeding strategy in a fed-batch culture was to increase the flavonoid production by using the proposed kinetic model. For the two-stage culture, the substrate feeding strategy consisted of a first period with 28 g/I of glucose to promote cell growth, followed by a second period with 5 g/I of glucose to promote flavonoid production. A simple fuzzy logic controller and the self-organizing fuzzy logic controller using a genetic algorithm was constructed to control the glucose concentration in a fed-batch culture. The designed fuzzy logic controllers were applied to maintain the glucose concentration at given set-points of the two-stage culture in fed-batch cultivation. The experimental results showed that the self-organizing fuzzy logic controller improved the controller\`s performance, compared with that of the simple fuzzy logic controller. The specific production yield and productivity of flavonoids in the two-stage culture were higher than those in the batch culture.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.504-508
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• 1991

$1.85\times 10^{-10}$ (mmole/cell/h) of specific glucose consumption rate was obtained under fed-batch cultivation of recombinant mamalian ce11s with maintaining $4.7\times 10^{-7}(\mu g/ceil/h)$ of average specific erythropoeitin production rate. Higher maximum cell density was also achieved than for both cases of batch and perfusion cultivations. It proves that glutamolysis dominates metaboiic pathways at latter period of cultivation where quasi steady state was maintained. Substrate limitation of glucose concentration was estimated as 13 (mmole/l) under fed-batch conditions. while specific product production rate was decreased according to cultivation time, erythropoeitin production was increased as glucose concentration in the media increased up to 13.2 (mole/l).

• KSBB Journal
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• v.15 no.5
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• pp.482-488
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• 2000

The Fab fraction of PDC-E2 specific human monoclonal antibody was produced using recombinant E. coli, and the effects of glucose and acetate were investigated to develop an optimal strategy for recombinant human antibody production. Higher glucose concentration in the culture media resulted inn higher cell growth and glucose consumption rate, which in turn resulted in an increased acetate production rate. When glucose was depleted, cells began to consume acetate as an energy source, and this consumption rate depended on the glucose concentration. When the residual glucose concentration was high, the accumulation of acetate was accelerated due to an increase in the acetate production rate and a decrease in the acetate consumption rate. Futhermore, it was found that a high accumulation of acetate, accompanied by a high glucose concentration, inhibited human antibody formation; the critical acetate concentration was $0.6g/\ell$. During production, a high glucose concentration enhanced cell growth, but inhibited antibody formation due to catabolic repression. Therefore, it is important to keep the concentration of both glucose and acetate as low as possible to increase antibody production after induction. Accordingly, it is important to accurately control the concentration of glucose and acetate in the culture media to obtain high cell densities and high productivity levels of recombinant human antibody.

• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.560-564
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• 2013

${\small{D}}$-Ribose is a value-added five-carbon sugar used for riboflavin production. To investigate the effects of oxygen supply and mixed sugar concentration on microbial production of ${\small{D}}$-ribose, a transketolase-deficient Bacillus subtilis SPK1 was cultured batch-wise using xylose and glucose. A change of agitation speed from 300 rpm to 600 rpm at 1 vvm of air supply increased both the xylose consumption rate and ${\small{D}}$-ribose production rate. Because the sum of the specific consumption rates for xylose and glucose was similar at all agitation speeds, metabolic preferences between xylose and glucose might depend on oxygen supply. Although B. subtilis SPK1 can take up xylose and glucose by the active transport mechanism, a high initial concentration of xylose and glucose was not beneficial for high ${\small{D}}$-ribose production.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.909-922
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• 1997

The purpose of this study was to evaluate the effect of high glucose on prostaglandin E2 production in human gingival fibroblasts and periodontal ligament cells in vitro. In control group, the cells($5{\times}10^4\;cells/ml$) were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum, 45mg/dl glucose. In experimental groups, glucose was added to the above culture condition at the final glucose concentrations of 100mg/dl(Test group 1), 200mg/dl (Test group 2) and 400mg/dl (Test group 3). Then each group was tested for the cell proliferation rate, protein levels, and prostaglandin E2 production at $\frac{1}{2}$, 1, 2, 5 days. The results were as follows : 1. As glucose concentration increased, cell proliferation rate decreased significantly at 1, 2, 5 days in human gingival fibroblasts and periodontal ligament cells(P<0.01). 2. In human gingival fibroblasts, test group 2 and 3 showed significantly decreased protein levels as compared to control group at 5 days (P<0.01). 3. In human periodontal ligament cells, as glucose concentration increased, protein levels decreased significantly at 2 days and 5 days(P<0.01). 4. Prostaglandin $E_2$ production in human gingival fibroblasts and human periodontal ligament cells significantly increased as glucose concentration increased(P<0.01). results at 5 days showed obvious difference as compared to those at 2 days. From the above results, high glucose appeared to affect cellular activities including cell proliferation rate, protein levels and enhance prostaglandin $E_2$ production. It was assumed that prostaglandin E2 production by high glucose enhances inflammatory reaction and has a toxic effect on human gingival fibroblasts and human periodontal ligament cells. This study suggests that periodontal disease in diabetic patient is related to prostaglandin $E_2$ production.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.45-50
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• 2000

For the maximum production of pullulan from glucose as a carbon source, the effects of glucose concentration, pH and dissolved oxygen concentration on the cell growth and mass production of high-molecular weight pullulan by A. pullulans ATCC 42023 were evaluated. A. pullulans showed optimum pullulan productivity when glucose concentration was 0.3M (54g/L). And inhibitory effects on the cell growth and the pullulan production were observed at the glucose concentration higher than 0.3M (54g/L). The influence of pH control and dissolved oxygen on the pullulan production and growth of A. pullulans was studied. In shake-flasks, maximum pullulan production was obtained with $11.98g/{\ell}$ when initial pH was 6.5. In the batch fermentation, the maximum pullulan production of $13.31g/{\ell}$ was obtained with constant pH 4.5. And it was found that pullulan yield and synthesis rate increased with oxygen availability. For the production of commercially useful pullulan with high-molecular weight, a mixed carbon source, which was a mixture of glucose and glucosamine, was used for the pullulan fermentation with A. pullulans. On the basis of 5% mixed carbon source, culture with 3% glucosamine with 2% glucose was optimum condition for the production of high (M.W.> 1,000,000) and medium (M.W.> 200,000) molecular weight pullulan with considerable yields of cell mass and product. And the influence of pH control on the molecular weight of pullulan was studied in batch fermentation. It was found that the productivity of high-molecular weight pullulan with pH control at 6.5 was higher than that with no pH control.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.522-530
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• 1994

Bacteriocin-producing lactic acid bacteria, Lactococcus sp. HY 449, was isolated from dairy products. Using response surface methodology, the various concentrations of medium compo- nents (tryptone, glucose, yeast extract, tween 80, and initial pH) were tested to find the optimum conditions for maximum bacteriocin production and growth of Lactococcus sp. HY 449. Central composite design was used to control the concentrations of medium components in the experiment. Bacteriocin production and cell growth of Lactococcus sp. HY 449 were most affected by glucose and yeast extract. Estimated optimum growth conditions of Lactococcus sp. HY 449 were as follows; tryptone 1.08%, glucose 1.129%, yeast extract 0.674%, tween 80 0.11%, and initial pH 7.19. Also estimated optimum conditions for bacteriocin production were tryptone 0.937%, glucose 1.108%, yeast extract 0.163%, tween 80 0.09%, and initial pH 6.98.