• Journal of Microbiology and Biotechnology
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• v.5 no.4
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• pp.229-233
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• 1995

Acremonium chrysogenum was immobilized in ionotropic gel beads to develop semi-continuous production of cephalosporin C (CPC). Barium alginate beads were more stable than calcium alginate or strontium alginate beads in chemically defined media. The gel stability of Ba-alginate was further increased by cross-linking with polyethyleneimine (PEI). The presence of carboxymethyl cellulose inside Ba-alginate beads did not reduce mass transfer resistance. Ba-alginate microbeads that had little diffusion limitation increased CPC production rate 1.6 fold higher than that of normal beads. CPC fermentation with immobilized cells in Ba-alginate microbeads was performed continuously for 40 days by way of repeated fed-batch operations. Mathematical modeling was developed to describe the repeated fed-batch fermentation system. Results of the computer simulation agreed well with the experimental data, which made it possible to predict an optimal feeding rate that could maximize total CPC productions.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.7-13
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• 2005

Chitosan-alginate capsules were formed by electrostatic interactions and exhibited an appropriate mechanical strength, permeability, and stability for the culture of hepatocytes. Pig hepatocytes were isolated and hepatocyte spheroids formed and immobilized in chitosan-alginate capsules. An encapsulation procedure of 3 min and spheroid formation period of 24 h were the optimum conditions for the best liver functions. Pig hepatocytes with a cell density of $6.0{\tomes}10^6$ cells/ml in the capsules were found to be most suitable for application in a bioartificial liver support system. The encapsulated pig hepatocyte spheroids exhibited stable ammonia removal and urea secretion rates in a bioreactor for 2 weeks. Accordingly, chitosan-alginate encapsulated hepatocyte spheroids in a packed-bed bioreactor would appear to have potential as a bioartificial liver.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.1
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• pp.23-31
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• 2003

A mathematical model was formulated to simulate the long-term performance of an anaerobic bioreactor designed to digest Korean food wastes. The system variables of various decomposition steps were built into the model, which predicts the temporal characters of Solid waste, and volatile fatty acid (VFA) in the reactor, and gas production in response to various input loadings and temperatures. The predicted values of VFA and gas production were found to be in good agreement with experimental observations in batch and repeated-input systems. Finally, long-term reactor performance was simulated with respect to the seasonal temperature changes from 5C in winter to 25C in Summer at different food waste input loadings. The simulation results provided us with information concerning the success or failure of a process during long-term operation .

• KSBB Journal
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• v.5 no.4
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• pp.391-396
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• 1990

4.0$\times$10-3 (IU/cells/day) of maximum specific scu-PA production, which was higher than those by a 75$\textrm{cm}^2$ T-flask and conventional perfusion systems, was maintained by tube-type bioreactor at 0.35 (1/h) of perfusion rate corresponding to 0.15 (dynes/$\textrm{cm}^2$) of shear stress. The production of scu-PA is also increased as shear stress was slowly increased, which is similar to natural human blood circulation. The tube reactor proves that there may be no limitation of oxygen supply by showing 1.0 (1/h) of oxygen transfer coefficient at steady state and this system yields much lower shear stress of 0.3(dynes/$\textrm{cm}^2$) than that of 5-8(dynes/$\textrm{cm}^2$) by conventional agitation systems.

• Environmental Engineering Research
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• v.21 no.1
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• pp.45-51
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• 2016

Membrane bioreactor (MBR) and reverse osmosis (RO) membrane system was applied to the treatment and reclamation of textile wastewater in Thailand. An experiment was carried out to determine the fouling behavior and effect of anti-scalant and biocide addition to flux decline and its recovery through chemical cleaning. The RO unit was operated for one month after which the fouled membranes were cleaned by sequential chemical cleaning method. RO flux was found rapidly declined during initial period and only slightly decreased further in long-term operation. The main foulants were organic compounds and thus sequential cleaning using alkaline solution followed by acid solution was found to be the most effective method. The provision of anti-scalant and biocide in feed-water could not prevent deposition of foulant on the membrane surface but helped improving the membrane cleaning efficiencies.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.279-279
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• 2005

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.113-113
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• 2003

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.314-314
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• 2005

• BMB Reports
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• v.38 no.6
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• pp.717-724
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• 2005

The nontoxic B subunit of cholera toxin (CTB) can significantly increase the ability of proteins to induce immunological tolerance after oral administration, when it was conjugated to various proteins. Recombinant CTB offers great potential for treatment of autoimmune disease. Here we firstly investigated the feasibility of silkworm baculovirus expression vector system for the cost-effective production of CTB under the control of a strong polyhedrin promoter. Higher expression was achieved via introducing the partial non-coding and coding sequences (ATAAAT and ATGCCGAAT) of polyhedrin to the 5' end of the native CTB gene, with the maximal accumulation being approximately 54.4 mg/L of hemolymph. The silkworm bioreactor produced this protein vaccine as the glycoslated pentameric form, which retained the GM1-ganglioside binding affinity and the native antigenicity of CTB. Further studies revealed that mixing with silkworm-derived CTB increases the tolerogenic potential of insulin. In the nonconjugated form, an insulin : CTB ratio of 100 : 1 was optimal for the prominent reduction in pancreatic islet inflammation. The data presented here demonstrate that the silkworm bioreactor is an ideal production and delivery system for an oral protein vaccine designed to develop immunological tolerance against autoimmune diabetes and CTB functions as an effective mucosal adjuvant for oral tolerance induction.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.2
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• pp.105-111
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• 2002

The biological removal of 2,4,6-trinitrotoluene (TNT) was studied in a bench-scale bioreactor using a bacterial culture of strain OK-5 originally Isolated from soil samples contaminated with TNT. The TNT was completely removed within 4 days of incubation in a 2.5 L bench-scale bioreactor containing a newly developed medium. The TNT was catabolized in the presence of different supplemented carbons. Only minimal growth was observed in the killed controls and cultures that only received TNT during the incubation period. This catabolism was affected by the concentration ratio of the substrate to the biomass. The addition of various nitrogen sources produced a delayed effect for the TNT degradation. Tween 80 enhanced the degradation of TNT under these conditions. Two metabolic intermediates were detected and identified as 2-amino-4, 6-dinitrotoluene and 4-amino-2, 6-dinitrotoluene based on HPLC and GC-MS analyses, respectively. Strain OK-5 was characterized using the BIOLOG system and fatty acid profile produced by a microbial identification system equipped with a Hewlett Packard HP 5890 II gas chromatograph. As such, the bacterium was identified as a Stenotrophomonas species and designated as Stenotrophomonas sp. OK-5.