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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Korean Society for Biotechnology and Bioengineering
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Volume & Issues
Volume 11, Issue 6 - Dec 1996
Volume 11, Issue 5 - Oct 1996
Volume 11, Issue 4 - Aug 1996
Volume 11, Issue 3 - Jun 1996
Volume 11, Issue 2 - Apr 1996
Volume 11, Issue 1 - Feb 1996
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Taxol Production in Taxus spp. Cell Culture : Semisynthesis of Taxol from Baccatin III in Cell Cultures of Taxus baccta Pendula
KSBB Journal, volume 11, issue 3, 1996, Pages 263~269
Anticancer agent taxol was synthesized from baccatin III which was extracted from cell cultures of European yew, Taxus baccata Pendula. Callus and suspension cultures of T. baccata Pendula showed the formation baccatin III. The content of baccatin III in cell cultures reached 0.015% (w/w) on dry weight basis. The semisynthetic approaches were made with baccatin III and taxol side chain. To prepare taxol side chain, (-)-N-((S)-2-hydroxy-1-phenylethyl) benzamide was synthesized first from (S)-(+)-phenylglycine. Then (-)-N-((IS,2S)-2-hydroxy-1-phenyl-3-butenyl) benzamide was synthesized with vinyl magnesium bromide. The synthesis of (2R, 3S)-(-)-2-(1-ethoxyethoxy)-3-phenyl-3-(phenylmethanamido) propanoic acid with RuCl3, catalyst was the final step to prepare taxol side chain. The semisynthetic reactions yielded 0.0002% taxol, 0.0005% 7-epi-10-deacetyltaxol, and unidentified taxanes on dry weight basis. It is suggested that the semisynthesis of taxol from baccatin III could be an alternative source of taxol and related taxanes.
Production of Glucose Oxidase Using Recombinant Yeast
KSBB Journal, volume 11, issue 3, 1996, Pages 270~275
Heterologous expression of glucose oxidase gene using recombinant yeast has been carried out. Polymerase chain reaction was conducted to obtain the gene encoding glucose oxidase from Aspergillus niger and sequence comparison indicated the cloned 1.9kb DNA fragment appeared to be the glucose oxidise structural gene containing a signal sequence for extracellular location. Transforming shuttle vector was constructed with YEp352 to express the cloned glucose oxidase gene under the control of either GAL1 or GAL10 promoter. Plate assay of recombinant yeasts has shown that GAL1 promoter was more effective in yielding glucose oxidise than GAL10 promoter. Among the five different concentrations of galactose tried, 1% galactose showed the highest induction of glucose oxidase. Cellular localization experiment of recombinant enzyme using spheroplast revealed that most of enzymes (80%) were secreted into culture media in contrast to A. niger. There is no difference in heat-stability of recombinant enzyme up to
compared to the glucose oxidase from A. niger However, a dramatic reduction of enzyme activity was observed in both enzymes at
A Kinetic Modeling for the Dynamics of Hybridoma Cells in Suspension Culture
KSBB Journal, volume 11, issue 3, 1996, Pages 276~287
Batch suspension cultures of hybridoma cell were performed with various initial glutamine concentrations to investigate the effects of glutamine on cell growth and death, monoclonal antibody production, glucose and glutamine consumption, and the production of lactate and ammonium ion. An mathematical kinetic model was formulated to describe the kinetics of cell growth, the consumption of nutrients (glucose and glutamine), and the production of monoclonal antibody and waste metabolites (lactate and ammonium ion) based on experimental data. An equation for the specific growth rate was developed such that superimposed Monod equation in glucose and glutamine, with non-competitive type inhibition relations in ammonium ion and lactate. The inhibition constant for lactate was inversely proportional to the lactate concentration. The specific death rate was considered to be a function of glucose, glutamine, ammonium ion and lactate concentration.
Characteristics of Recombinant CHO Cell Growth and Erythropoietin Production in Serum-Containing Media and Serum-Free Media
KSBB Journal, volume 11, issue 3, 1996, Pages 288~294
We have investigated the characteristics of recombinant CHO cell growth and erythropoletin(EPO) production at different concentrations of serum and inoculation density. Cell growth and EPO production were increased with the increase of serum concentration and inoculation density. Enhancement of CHO cell growth and EPO production by medium exchange using serum-free medium at the growth phase of cells was studied. It was found that the exchange of culture medium with serum-free medium was favorable for growth of cells and production of EPO. The maximum number of cell and concentration of EPO obtained by exchanging culture medium were
and 7,470units/m1, respectively, compared to
and 2,380units/m1 in serum-containing medium without medium exchange. It was observed that CHO cell growth was correlated with EPO production in serum-free media.
Decrease of the Activation and Carbamylation of Rubisco by High CO2 in Kidney Bean
KSBB Journal, volume 11, issue 3, 1996, Pages 295~302
The measurements of rubisco parameters are important in photosynthetic studies. In this experiment, we used photometric assay method to detect these major parameters, such as activity, carbamylation and amount of rubisco. The main advantages of this method are very simple and as sensitive as conventional methods which usually produce radioactive waste. In this study, with kidney bean (Phaseolus vulgatis L.) leaves grown at normal
(350ppm) and high
(650 ppm), we investigated the effect of
concentration on activation and carbamylation of rubisco by measuring the rubisco activity, carbamylation rate and amount of rubisco using a dual beam (334nm and 405nm) spectrophotometer, and analyzed the polypeptide profiles of rubisco by SDS-PAGE. When
concentration was raised from 350ppm to 650ppm, all parameters of rubisco were decreased :
for initial and total rubisco activity, respectively ; from 79% to 58.9% for carbamylation rate ; from
for amount of rubisco. These results suggests that the decrease in rubisco activity at high
was caused by carbamylation. The analysis of the preparation by SDS-PAGE showed two major polypeptides at 50 and 14.5 kD which were identified as the large and the small subunits of rubisco. There were no differences in the intensity compared high
in both 50 kD and 14.5 kD bands. We also found that these inhibitory effects of
were reversible. When high
was switched to normal
, the parameters of rubisco changed were almost the same as normal rubisco parameters. These data provide an evidence that activity of rubisco was recovered by
concentration of 350 ppm.
Effect of the Environmental and Nutritional Conditions on the Growth of Marine Microalga Isochrysis Galbana Parke
KSBB Journal, volume 11, issue 3, 1996, Pages 303~310
The marine microalga Isochrysis galbana Parke was studied to optimize its growth conditions in flask culture. Important medium components studied include nitrogen source, buffer, trace elements and vitamins. Environmental conditions include pH, temperature, light intensity, mixing extent and working volume. The medium prepared from natural sea-waters gave a higher final cell density than the medium prepared from synthetic sea-water Nitrate was a better source than ammonium. In the range of 0.4∼2mM, the final cell density was proportional to the initial nitrate concentration and the cell yield was estimated to be 8.5g dry cell wt/g N. For phosphate, optimal growth was observed in 0.1∼1.0mM but a considerable variation in pH was resulted. The addition of Tris at 5mM or 7mM could stabilize the medium pH, but this significantly reduced both growth rate and final cell density, The effect of trace elements and vitamins was negligible. Optimal temperature and initial pH were
and 8. When the intensity of incident light was varied in the range of 400∼2100 lux, the growth rate increased from 10mL to 70mL, the final cell density decreased although the initial growth rate did not change. Optimal agitation speed was 100rpm when working volume was 30mL. With optimal conditions, the maximum specific growth rate obtained was 0.021hr-1 and the final cell density was 1.1g/L.
Effects of Polyethylene Glycol on Glucoamylase Production in Recombinant Yeast Culture
KSBB Journal, volume 11, issue 3, 1996, Pages 311~316
The effects of polyethylene glycol (PEG) on glucoamylase production in recombinant Saccharomyces cerevisiae were studied. By PEG addition, the cell growth was not affected. However, the glucoamylase production was increased in all range of PEG molecular weights and concentrations. The optimal molecular weight of PEG was 6000 and the optimal concentration was 1g/L. Using these optimals, the extracellular glucoamylase activity was 23% higher in PEG-containing medium than that in medium without PEG.
Characteristics of Galactooligosaccharide Production Using Cellulases
KSBB Journal, volume 11, issue 3, 1996, Pages 317~322
Galactooligosaccharlde (GOS) is a kind of functional oligosaccharides that can be used as a food ingredient and a cosmetic additive. In this paper, characteristics of GOS synthesis by cellulase, using lactose as a substrate, were investigated. Penicillium funiculosum cellulose was found to be the most efficient for GOS production among six cellulose tested. The optimum pH and temperature for GOS production were 5.0 and
, respectively. There was an optimum ratio of lactose concentration to enzyme loading; the value was 10 (w/w). The reaction pattern of P. funiculosum cellulase is consistent with that of microbial
-galactosidase which shows transgalactosylation activity. Amounts of GOS produced from 20% (w/v) lactose after 6 h incubation at
, were 23% (w/w) based on total saccharide in the reaction medium. The GOS % increased with initial lactose concentration in the range of 5 to 20%. The products mainly consisted of a trisaccharide and tetrasaccharide from HPLC and TLC analysis. Among enzymes involved in transgalactosylation reaction, high molecular weight fractions over 50,000 Da, presumably
-glucosldase, were considered to be responsible for GOS production. Using this cellulose, a direct synthesis of galactosyl g1ucoside including GOS could be readily achieved with lactose as a galactosyl donor.
Effects of Precursors and Exogenous Taxanes on Taxane Production by Cell Suspension Cultures
KSBB Journal, volume 11, issue 3, 1996, Pages 323~328
Effects of three kinds of precursors as well as exogenous taxanes on the production of taxol and its derivatives were investigated in Taxus cuspidata and Taxus brevifolia cell suspension cultures. When geraniol was added as a precursor of geranylgeranyl pyrophosphate to enhance diterpenoid metabolism, production of some taxanes including taxol was enhanced. The time of addition and amount of feeding were found to be important factors. Feeding of camphor and menthol resulted in negative effects on taxol production. Influences of exogenous taxanes on taxane production by cell cultures were found to be very complicated. When taxol, baccatin III, cephalomannine were exogenously added into the culture, production of baccatin III, 7-epi-10-deacetyltaxol, 10-deacetyltaxol was increased respectively.
Ammonium Ion Effects and Its In Situ Removal by Using Immobilized Adsorbent in Hybridoma Cell Culture
KSBB Journal, volume 11, issue 3, 1996, Pages 329~339
The effects of ammonium ion on cell growth kinetics, monoclonal antibody productivity, and cell metabolism of hybridoma cells were investigated. The mouse-mouse hybridoma cell line VlIIH-8 producing mouse IgG2a was used as a model system. Ammonium ion showed an inhibitory effect on cell growth and monoclonal antibody production. New immobilized adsorbents were developed for the reduction of the inhibitory effect of ammonium ion. The ammonium ion selective zeolite, Phillipsite-Gismondine was entrapped in calcium alginate bead or in dialysis membrane and applied to the hybridoma cell culture system for the in situ removal of ammonium ion from culture media. The effects of ammonium the both serum supplemented and serum free media on the cell growth were studied by applying immobilized adsorbents of calcium alginate bead type. The results demonstrated a substantial enhancement in cell growth. Applying immobilized adsorbents of dialysis membrane type to serum supplemented media also resulted in the stimulation of cell growth, cell viability and monoclonal antibody production.
Changes in Rheological Properties of Culture Broth During the Biopolymer Production by Bacillus sp
KSBB Journal, volume 11, issue 3, 1996, Pages 340~346
Variations of rheological properties of culture broth during the production of biopolymer by an alkali tolerant Bacillus sp. were investigated. Correlations among the rheological characteristics of culture broth, cell growth and biopolymer production were examined. Rheology of the culture broth changed in the course of fermentation. The culture broth showed a non-Newtonian flow behavior, as the viscosity and pseudoplasticsity increased during the cultivation. The rheological parameters such as flow index, consistency index, yield stress and apparent viscosity during the cultivation were not influenced by the cell growth, but significantly related to the biopolymer synthesis. Changes in the rheological parameters of the broth were affected not only by the biopolymer concentration, but also by the progress of fermentation. Some rheological parameters showed maximum values just before the completion of biopolymer production and substrate consumption. Hence, it was shown that the rheological characteristics of the culture broth could be used as a good indicator for the detection of the progress or completion of fermentation.
Enzyme Deactivation During Enzyme Recycling with Ultrafiltration Hollow Fibers
KSBB Journal, volume 11, issue 3, 1996, Pages 347~352
The enzyme deactivation in a membrane recycling system for the simultaneous saccharification and fermentation(SSF) was studied under various temperature and pressure. The optimum molecular weight cut off(MWCO) of the ultrafiltration membrane for recycling cellulase and
-glucosidase was 50,000. When the cellulase was recycled continuously through the membrane system, it was not deactivated. But the activity of
-glucosidase was decreased with an increase in operating temperature and transmembrane pressure. After 720 minutes at
and 24.8 psig , the activity of
-glucosidase was reduced by 35% of the initial activity. Such tendencies could be well explained by the results of highly induced shear at the fiber surface of membrane when temperature and transmembrane pressure became higher.
Uranium Leaching from Low-Grade Uranium Ore by Thiobacillus ferrooxidans
KSBB Journal, volume 11, issue 3, 1996, Pages 353~359
The experiments were conducted in the leaching of aqueous uranium from low-grade uranium ore by Thiobacillus ferrooxidans. The optimal concentration of ferrous iron in 9K medium was 16.2g/L when the uranium ore concentration in slurry was 40g/L. The leaching rates were increased by decreasing the particle size of uranium ore and by increasing uranium ore concentration. In the leaching experiments in an agitated vessel reactor, only 39.3% of uranium was leached out within 12 days, which was comparable as that in the shaking incubator, without any notable improvement. Hence, it was observed that an agitated vessel reactor was not effective in the leaching of uranium from uranium ore by T. ferrooxidans. In the leaching experiments in a draught-tube reactor, the maximum concentration of uranium leached and cell number were a 12.8mg/L and
respectively. The uranium yield reached up to 91.4% within 11 days culture due to enhanced aeration and mixing characteristics of draught-tube reactor as compared to agitated vessel reactor.
Studies on the Transport of Acetic Acid by Electrodialysis
KSBB Journal, volume 11, issue 3, 1996, Pages 360~366
Electrodialysis of acetic acid was studied to find out the trend of the transport of organic acids through ultrafiltration and ion exchange membranes. The net transport rate of acetic acid was determined from the electro-migration velocity relative to the electro-osmotic flow rate through the membrane. Electro-osmosis flows through ultrafiltration membranes were from the anodic side to the cathodic side in the presence of electric field. The surface of ultrafiltration membrane was measured by the electro-osmotic flow to be charged negatively. Different transport behaviors of acetic acid were found with the ultrafiltration membranes of different materials. In general, regenerated cellulose membranes (YM series) were more effective than polysulfone membranes (PM series) for the transport of acetic acid. The transport of acetic acid was affected by electric strength, distance between the electrodes, surface area of electrode, temperature, and pore size of membrane. The transport rate through the ion exchange membrane was 1.5 to 3 times of those through the ultrafiltration membranes at the constant current of 150 mA in the experimental ranges. The transport rate of acetic acid through the ion exchange membrane increased by 10% with a pulse electric field of 10 sec/hr.
Growth Characteristics of Rhoodotorula sp. Y-55 on Ethanol, Acetic acid, and Acetaldehyde Substrates
Yeehn Yeeh ; Sang Hae Kim ; Woo Hong Joo ; Hong Ki Jun ; Oh Change Kwon ;
KSBB Journal, volume 11, issue 3, 1996, Pages 367~373
The growth characteristics of Rhodotorula sp. Y-55 were examined on minimal medium containing ethanol, acetic acid or acetadehyde as a sole carbon source by batch culture. The increased concentration of substrate reduced overall growth yield and prolonged lag time. The specific growth rate of the yeast was changed, depending upon the initial concentrations of ethanol and acetaldehyde during the exponential period, but was constant on acetic acid without regard to the initial substrate concentrations, giving a value of 0.l07h-1. The highest
value was obtained on ethanol and acetadehyde substrates and the respective values were 0.270 at 20g/L and 0.041h-1 at 0.2g/L. The maximum overall growth yields were appeared to be 32.6% for ethanol of 10g/L, 25.6% for acetic acid of 20g/L, and 45% for acetaldehyde of 0.2g/L. The respective cellular contents of crude protein and nucleic acids were determined to be 41.5 and 4.9wt% on ethanol and 40.2 and 4.7wt% at the concentration revealing maximal growth yield.
Production of Mannitol by Lactobacillus sp. KY-107
KSBB Journal, volume 11, issue 3, 1996, Pages 374~379
The production of extracellular mannitot by an efficient mannitol-producing bacterium, Lactobacillus sp. KY-107 was studied in shake flask culture using the modified MRS medium. Maximum mannitol production was obtained with fructose as the sole carbon source. Within 95 hours of incubation, a final concentration of 70g/L of mannitol from 100g/L fructose was obtained with an indicated yield of 86% based on fructose consumed. However, higher concentrations of fructose could not effectively be transformed to mannitol due to a lack of osmotolerance. The strain produced no other polyols such as glycerol and sorbitol as by-products. Yeast extract was best nitrogen source and high levels of inorganic phosphate up to 10g/L did not show any detrimental effect for mannitol formation. Manganese ion played important role in both cell growth and mannitol production. The optimum culture temperature and initial pH were
and 6-8, respectively.
Effects of Concentrations of Glucose and Maltose on the Growth of Recombinant E. coli
KSBB Journal, volume 11, issue 3, 1996, Pages 380~387
The growth of recombinant E. coli and formation of the by-products were investigated. Glucose was consumed in approximately 8hours of cultivation when initial glucose concentration was 5g/1. When higher initial glucose concentrations were employed, it took approximately 16 to 20hours for the glucose to be consumed. When maltose or glucose was used as a carbon source, lactic acid and acetic acid were main by-products, while propionic acid and methanol production was not significant. Much by- products were formed at the higher initial carbon source concentrations. Higher concentration of lactic acid was observed when glucose was used, while higher concentration of acetic acid was observed when maltose was used. Lactic acid production affected the cell yield while acetic acid production affected the growth rate.