• KSBB Journal
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• v.8 no.5
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• pp.457-464
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• 1993

In this study, an attempt was made to investigate optimum cell growth and products by Bacillus amyloliquefaciens 23350 in batch culture by varing carbon soures. Maximum dry cell density increased with the increase of initial glucose concentration. Maximum dry cell density was obtained with the highest value of 5.2g/l at 30g/l of initial glucose concentration. By adding acetic acid at 20g/l of initial glucose concentration, the cell growth rate decreased with the increase of initial acetic acid concentration. Among the various carbon sources, maximum $\alpha$-amylase production was obtained with 225unit/ml at 10g/1 of initial glucose concentration. Optimum production of $\alpha$-amylase was obtained with 376unit/ml at 2g/l of initial acetic acid concentration and 20g/l of initial glucose concentration. By 10g/1 of initial glucose concentration, both good maximum specific cell growth rate and maximum $\alpha$-amylase production rate were obtained. In view of the results studied optimum production and specific production rate of $\alpha$-amylase, acetic acid was initially added 2~4g/l with 20g/1 of initial glucose concentration in batch culture.

• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.89-95
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• 1998

Rhodopseudomonas sphaeroides K7 and E15-1 produced hydrogen from glucose rapidly for the first 24 hrs of culture under the anaerobic and photosynthetic conditions and then ceased the hydrogen production because of the accumulation of organic acids such as acetic acid and formic acid in the culture broth, decreasing the pH to 4.2-4.5. Only 43% and 73% of glucose in the culture were consumed even after 6 days of incubation by R. sphaeroides K7 and E15-1, respectively. The hydrogen production and glucose consumption, however, were substantially increased when the pH of the culture was adjusted to 6.8-7.0: Hydrogen production continues even after 10 days of culture and glucose was consumed completely after 2.5 and 4.5 days by R. sphaeroides K7 and E15-1, respectively, Furthermore, the bacteriochlorophyll contents in R. sphaeroides K7 and E15-1 were increased by 44 and 9 folds and the cell concentrations by 10 and 2.5 folds, respectively, after 7 days of culture. R. sphaeroides K7 and E15-1 also produced hydrogen from acetic, lactic, butyric and malic acids under the anaerobic and photosynthetic conditions even though the amounts of hydrogen produced were lower than that from glucose. The results of this experiment indicate that under the anaerobic and synthetic conditions R. sphaeroides K7 and E15-1 might use the NADH oxidation mediated by ferredoxin and hydrogenase to evolve hydrogen from glucose for the first 24 hrs and then the organic acids produced were used as electron donners for the production of hydrogen in the nitrogen-limited condition.

• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.543-546
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• 1998

The effect of glucose concentration on the production of erythritol by Trichosporon sp. was mainly studied. The specific growth rate and production rate of erythritol gave the highest values of $0.23 h^{-1}\; and\; 4.2 g/\ell/h,\; respectively,\; on\; 100 g \; glucose/\ell$ of medium. The conversion yield of erythritol during the exponential phase and the stationary phase was constantly maintained at 19% and 51 %, respectively, while the glucose concentration in the medium varied from 100 g/$\ell$ to 400 g/$\ell$. The maximum overall erythritol conversion yield of 47% was obtained when the glucose concentration in the medium was 400 g/$\ell$. It corresponded to a 74% increase compared with the 100 g/$\ell$ glucose medium. The diauxy growth of this microbe was also observed. It grew exponentially consuming glucose, then after the second lag phase, biomass slowly increased using glycerol and erythritol.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.982-985
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• 2002

A study was carried out to determine glucose kinetics, nutrient balance and milk production of lactating Etawah crossbred goats. The animals (27.2 to 29.1 kg BW) were randomly divided into four levels of dietary treatment groups: the first group R1 received 100% (3 kg) fresh king grass (Penisetum purpuroides), the second group R2 received 75% king grass and 25% king grass silage prepared with chicken manure, the third group R3 received 50% king grass and 50% silage, and the fourth group R4 received 100% silage. In addition to the roughage, each group received 800 g of concentrate (CP 14.77% of DM; 17.26 MJ/kg). Animals fed king grass silage made with chicken manure were found to be superior to the group fed king grass alone. Glucose kinetics and retained energy were significantly affected. Calculations showed that glucose requirements for maintenance and milk production can be met for the groups with high levels of silage (R3 and R4). The values of glucose flux were in the range of 2.52 to 4.50 mg/min.kg $BW^{0.807}$ which are lower, but close to, the values for the temperate lactating dairy cow. The present glucose flux value for the lactating Etawah crossbred goat is higher than the previous value published from this laboratory.

• Journal of Microbiology and Biotechnology
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• v.29 no.6
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• pp.905-912
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• 2019

Bioethanol has attracted much attention in recent decades as a sustainable and environmentally friendly alternative energy source. In this study, we compared the production of bioethanol by Candida molischiana and Saccharomyces cerevisiae at different initial concentrations of cellobiose and glucose. The results showed that C. molischiana can utilize both glucose and cellobiose, whereas S. cerevisiae can only utilize glucose. The ethanol yields were 43-51% from different initial concentrations of carbon source. In addition, different concentrations of microcrystalline cellulose (Avicel) were directly converted to ethanol by a combination of Trichoderma reesei and two yeasts. Cellulose was first hydrolyzed by a fully enzymatic saccharification process using T. reesei cellulases, and the reducing sugars and glucose produced during the process were further used as carbon source for bioethanol production by C. molischiana or S. cerevisiae. Sequential culture of T. reesei and two yeasts revealed that C. molischiana was more efficient for bioconversion of sugars to ethanol than S. cerevisiae. When 20 g/l Avicel was used as a carbon source, the maximum reducing sugar, glucose, and ethanol yields were 42%, 26%, and 20%, respectively. The maximum concentrations of reducing sugar, glucose, and ethanol were 10.9, 8.57, and 5.95 g/l, respectively, at 120 h by the combination of T. reesei and C. molischiana from 50 g/l Avicel.

• Journal of Plant Biology
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• v.12 no.2
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• pp.7-14
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• 1969

Dunaliella tertiolecta did not show any increase in respiration rate when supplied with glucose, glycerol, sucrose, L-alanine, acetate, pyruvate and succinate. This was in contrast to Chlorella pyrenoidosa, which, under identical conditions, showed significant increase when supplied with glucose or acetate but not with the other compounds. Production of 14CO2 from added 14C-glucose in D. tertiolecta was lower than the other 14C-labelled substrates: L-alinine, glycerol, succinate, but higher than 14C-sucrose addition. And it was also lower than C. pyrenoidosa experiments which was added 14C-glucose as a substrate. Light reduced amounts of labelled carbon dioxide from 14C-glucose or 14C-acetate and increased incorporation of 14C from the substrates to cell materials in either D. tertiolecta or C. pyrenoidosa. The contribution of 14C from 14C-glucose to 14CO2 in cell-free system of D. tertiolecta were much higher than in whole cell suspension. It was contrast to C. pyrenoidosa which were showed reduction of 14CO2 production in cell-free systems than whole cell suspensions. When cell-free systems of D. tertiolecta and C. pyrenoidosa were supplied with ATP, NAD, NADP or/and hexokinase, it was remarkably increased production of 14CO2 from the substrates than the control. It was concluded that the low ability of D. tertiolecta to metabolize glucose were caused by the impermeability of the cell membrane to glucose and were not due to deficiencies of enzyme systems concerning glucose metabolism. In the cell-free systems, it seemed to be more active pentose phosphate pathway than glycolytic pathway in D. tertiolecta.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.352-355
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• 2000

Production of pullulan by Aureobasidium pullulans HP-2001 with agro-industrial byproducts was investigated. Agro-industrial byproducts from the rice processing industry for the traditional Korean food (AIB-A), apple juice production (AIB-B), and soybean sauce production (AIB-C) were used for carbon and nitrogen source for production of pullulan. Major components of AIB-A were glucose, maltose, maltotriose, and dextran. AIB-A and B were found to be good substitute to glucose as carbon source. Productivity of pullulan with AIB-A and B as carbon source was similar to that glucose. Molecular weight of pullulan produced with AIB-A and B was higher than that with glucose. Major components of AIB-B and C were carbohydrate, protein, fat and ash. AIB-C was also a good substitute to yeast extract as nitrogen source. Some of physiological conditions were examined for the large scale production of pullulan.

• Biomolecules & Therapeutics
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• v.26 no.1
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• pp.39-44
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• 2018

In 1923, Dr. Warburg had observed that tumors acidified the Ringer solution when 13 mM glucose was added, which was identified as being due to lactate. When glucose is the only source of nutrient, it can serve for both biosynthesis and energy production. However, a series of studies revealed that the cancer cell consumes glucose for biosynthesis through fermentation, not for energy supply, under physiological conditions. Recently, a new observation was made that there is a metabolic symbiosis in which glycolytic and oxidative tumor cells mutually regulate their energy metabolism. Hypoxic cancer cells use glucose for glycolytic metabolism and release lactate which is used by oxygenated cancer cells. This study challenged the Warburg effect, because Warburg claimed that fermentation by irreversible damaging of mitochondria is a fundamental cause of cancer. However, recent studies revealed that mitochondria in cancer cell show active function of oxidative phosphorylation although TCA cycle is stalled. It was also shown that blocking cytosolic NADH production by aldehyde dehydrogenase inhibition, combined with oxidative phosphorylation inhibition, resulted in up to 80% decrease of ATP production, which resulted in a significant regression of tumor growth in the NSCLC model. This suggests a new theory that NADH production in the cytosol plays a key role of ATP production through the mitochondrial electron transport chain in cancer cells, while NADH production is mostly occupied inside mitochondria in normal cells.

• KSBB Journal
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• v.6 no.1
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• pp.69-77
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• 1991

When S. fradiae was cultured in S medium, it stavted to produce neomycin in the middle of stationary phase of growth. Antibitoic production is regulated not only by glucose but also by metabolites formed from glucose. A chemically defined minimal salt broth was developen for the study of metabolites activating produition of antibiotic in a neomycin producer. When growth and production or antibiotic in minimal salt broth was examined with a full grown or a vefctativc mycelium, the medium was found not to be good for the growth, but to be good enough for the production of antibiotic with a full grown mycelium. When many carbotlydrates, organic acids, or alcohol were supplmented with instead of glucose in the medium suspcndcn with a full grown mycelium, the amount of antibiotic produced in the medium containing fumaratc was 5 times more than that in the medium with glucose. Further study indicated that the medium is not good also for the growth but good for the production of antibiotic. The antibiotic produced in this medium was identified to be neomycin. The activation of the production of neomycin by fumarate was further confirmed in a complex medium. Fuinarate is suspected to initiate and to activate the biosynthesis of neomycin at the gene level.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.268-272
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• 2003

Experiments were carried out to investigate the selection of industrial medium and optimization of fermentation process for the production of erythritol by Candida magnoliae SR101. In the batch fermentation, light steep water(LSW) was the best nitrogen source for the industrial production of erythritol. 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, 44% of erythritol yield with 110 g/L of erythritol concentration and 0.66 g/L-hr of productivity, respectively were obtained. Two-stage fed-batch culture was performed to improve the volumetric productivity of erythritol. High density cell culture in the growth stage was performed by batch type with 100 g/L glucose and 500 mL/L LSW concentration, respectively. The cell yield was 0.72 g-cell/g-glucose. Productivity of erythritol was increased and concentration of organic acids such as gluconic acid and acetic acid were decreased when initial pH of 6.5 controlled by 28% ammonia water For increasing yield of erythritol, glucose concentration in the production stage was tested. 37% of total erythritol yield with 186 g/L of erythritol concentration and 1.66 g/L-hr of erythritol productivity were obtained when 820 g of glucose powder was directly added for making up 450 g/L of glucose at production stage.