• KSBB Journal
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• v.11 no.3
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• pp.329-339
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• 1996

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.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.75-80
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• 1998

Ammonium ion is notorious for the adverse effects upon many of the important uses of water such as toxcity to fish, corrosion of metals and concrete, and concern over man's consumption. A clinoptilolite, which is a naturally occurring zeolite selective for ammonium ion exchange, has been used. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir equation or by the Freundlich equation. As the particle size of the clinoptilolite decreased, exchange capacity was increased. The smaller particle size enhaced the exchange of ammonium ion due to the greater surface area and decreased diffusion to the exchange sites within the zeolite. Ammonium ion exchange capacity tended to decrease when the temperature increased from $20^{\circ}C$ to $35^{\circ}C$, and the temperature correction factor was found to be 0.98 in the Langmuir equation.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1465-1470
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• 2004

A short and efficient synthesis, solvent extraction and potentiometric measurements of new thiazole-containing naphtho-crown ethers are reported. The naphthalene moiety enhances the ammonium ion selectivity over potassium ion. The selectivity of ${NH_4}^+/K^+$ follows the trend $3\;{\approx}\;2\;>\;1$, indicating that the differences in conformational changes of 2 and 3 in forming ammonium complexes affect little on the resulting ammonium/potassium extraction selectivity ratio. The ammonium ion-selective electrodes were prepared with noctylphenyl ether plasticized poly(vinyl chloride) membranes containing 1-4 the effect of one naphthalene unit introduced on either right (2) or left (3) side of thiazolo-crown ether on their potentiometric properties (e.g., ammonium ion selectivity over other cations, response slopes, and detection limits) were not apparent. However, the ammonium ion selectivity of 1, 2 and 3 over other alkali metal and alkaline earth metal cations is 10-100 times higher than that of nonactin.

• KSBB Journal
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• v.10 no.2
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• pp.170-175
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• 1995

The effect of nitrogen source on production of a high viscosity exopolysaccharide, methylan, from methanol by Mentylobacterium organophilum was investigated in fed-batch culture. During the fermentation, cells continued to grow even after the nitrogen source added to the medium was depleted and methylan production was stimulated under the condition which ammonium ion was depleted. Cell growth increased proportionally to the initial concentration of ammonium ion in the medium, but methylan production was significantly inhibited at the high concentration of ammonium ion. As the initial concentration of ammonium ion increased, the specific growth rate, the specific product formation rate and the specific substrate consumption rate decreased due to the inhibitory effect of excess ammonium ions. In order to reduce the inhibitory effect by high concentration of ammonium ion. The control of ammonium ion concentration within the desired level(usually $0.45g/\ell$) was necessary. When ammonium ion concentration was maintained below $0.15g/\ell$ by exponential feeding, methylan production could be increased up to $12.5g/\ell$.

• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.995-997
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• 2002

The synthesis and characterization of a nitrobenzene modified hexahomotrioxacalix[3]arene 1 are described.When calixarene 1 bound with ammonium ions carrying fluorescence group, the fluorescence of ammonium ions were effectively quenched and chang e of emission intensity provided the information of ammonium ion binding events to the calixarene 1.

• KSBB Journal
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• v.13 no.4
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• pp.404-410
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• 1998

Three types of adsorbents were developed by immobilizing synthetic zeolite, Philipsite-Gismonine, in alginate, cellulose acetate and dialysis membrane for the in situ removal of ammonium ion which inhibits growth and productivity of animal cells such as CHO cells producing tPA. Ammonium ion removal efficiency and cell growth promoting effect with various immobilized adsorbents were evaluated and the membrane type was selected as an optimal immobilized adsorbent. The experiments were then simulated by adding 8mM ammonium chloride and immobilized adsorbent in order to validate the removal effect under high density cell cultures. The results showed increase in maximum cell density by three times, in cell viability, and in tPA productivity by 40%. And it was found that the promoting effects were more significant in case of high ammonium ion concentration system. It was also found that the optimum addition time for immobilized adsorbents was 48 hr in the absence of ammonium chloride addition and 72 hr in the presence of ammonium chloride addition.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.578-583
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• 2005

Cell-free culture broth of marine halophilic bacterium, Kordia algicida was shown to possess specific algicidal ability against red tide organism, Cochlodinium polykrikides. Physiochemical characteristics of algicidal material originated in the bacterial culture broth were analyzed that its molecular weight was estimated to a 3,000 dalton and it was stable in heat and pH treatment. The algicidal fraction against C. polykrikoides obtained from gel permeable chromatography contained high concentration of ammonium ion as analyzed by ICP/Mass spectrum. C. polykrikoides by the fraction was quickly lysed within 1 min. It was shown that the effective concentration for algicide against C. polykrikoides was over 1mM of ammonium chloride. On the other hand, other metal ions presented in the algicidal fraction showed no algicidal effect against C. polykrikoides. In additon, ammonium ion exhibited species-specific killing spectrum for two species of red tide organisms, C. polykrikoides and Gymnodinium sanguieum. Therefore, further researches on the killing mechanism against C. polykrikoides exerted by ammonium ion, and subsequent development of replaceable algicidal materials will perform to provide useful tools for the control of red tide.

• KSBB Journal
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• v.13 no.4
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• pp.411-417
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• 1998

The possibility of application of membrane type immobilized adsorbent to the fed-batch or perfusion culture system with anchorage-independent cells as well as batch system was investigated. The improvement in cell density and cell viability due to the combination of immobilized adsorbent with each culture system was evaluated for the investigation, and the optimum culture system employing immobilized adsorbent system was suggested based on the results. It was observed that the system with immobilized adsorbent showed better cell growth and cell viability than that without immobilized adsorbent in every operation system of batch, fed-batch, and perfusion. In case of batch system, 200% improvement of maximum cell density was observed in the system where ammonium chloride was added on purpose. And 50% improvement of maximum cell density was observed in the fed-batch system where ammonium ion accumulates significantly, while small increase in maximum cell density was observed in the perfusion system where dilution of waste byproducts exists. Especially, the fed-batch system showed the most significant improvement on cell growth because both compensation of nutrient and removal of ammonium ion occurred simultaneously in the system. Therefore a combined system of immobilized adsorbent and fed-batch operation could be suggested as an optimum system with in situ removal of ammonium ion.

• KSBB Journal
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• v.20 no.6
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• pp.418-424
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• 2005

Photoheterotrophic evolution of molecular hydrogen by Rhodobacter sphaeroides is mediated by nitrogenase that is regulated transcriptionally and post-translationally by ammonium ion. Two PII-like proteins, GlnB and GlnK, play key roles in mediating inhibition and repression of nitrogenase in the presence of ammonium ion. glnB and glnK of R. sphaeroides were interrupted to abolish the ammonium ion effect controlling nitrogenase. Ammonium ion effect was still observed in mutant having an interruption in either glnB or glnK. However, the nitrogenase activity of glnB-glnK double mutant is not affected by ammonium ion. $H_2$ evolution was improved by increasing gene dosages of nitrogenase-coding genes, nifHDK in trans in glnB-glnK double mutant.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.750-757
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• 2009

The ammonium ion exchange characteristics of natural zeolite were investigated to remove ${NH_4}^+-N$. The effect of water temperature, particle size and competitive cation on the exchange capacity was examined. Ammonium ion exchange capacity tended to decrease when the temperature increased from $25^{\circ}C$ to $40^{\circ}C$. Exchange capacity was increased according to the particle size of natural zeolite comes to be small. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir isotherm model or by the Freundlich isotherm model. The ammonium ion exchange capacity ($q_m$) of zeolite carrier can be calculated $11.744mg-{NH_4}^+/g$-carrier. The ion exchange capacity of manufactured zeolite carrier was showed a similar tendency as ion exchange capacity of powder-sized natural zeolite. Therefore, zeolite carrier can be used for increasing of nitrogen removal efficiency in the wastewater treatment plants.