• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.378-381
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• 2000

The optimal conditions and properties for the immobilization of marine bacterium Pseudomonas aeruginosa BYK-2 have been determined. For the high productioon of biosurfactant, Na-alginate, PVA, modified PVA were used as a carrier. The optimal emulsifying activity on immobilized Pseudomonas aeruginosa BYK-2 showed 1036Unit (about 2.2g/L biosurfactant) in Basal salt medium(B.S.M.) at $25^{\circ}C$, 100rpm. Ca-alginate was selected the optimal bead among PVA, modified PVA and Ca-alginate. The optimal cell load in alginate bead was 10 gCWW/100g carrier. As the results of incubation of immobilized 5g Ca-alginate bead (conditions; 3% alginate, bead diameter: 2.3mm, 10% cell load) in 50m1 production medium, The emulsifying activity of 1407Unit, about 3.0g/L biosurfactant was obtained from immobilized cell after cultivation of 92hr at $25^{\circ}C$, 100rpm.

• Applied Biological Chemistry
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• v.46 no.1
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• pp.1-6
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• 2003

Abstract: In order to improve the system for biological nitrogen oxidizing process in sewage and wastewater, a bacterium having high abilities to oxidize of nitrogen was isolated from wastewater and polluted soils. The strain was identified to Bacillus sp. CH-N, based on the physiological and biochemical properties. Characteristics and oxidizing ability of both ammonia and nitrite were examined for the strain, Bacillus sp. CH-N. The strain showed the oxidizing rate about 80% to 90% on the sewage and wastewater after 48 h culture. The nitrogen oxidizing rate was increased in proportion to the initial concentration of glucose. The microorganism, Bacillus sp. CH-N cell immobilized on ceramic carrier were evaluated for the oxidation of ammonia in culture media.

• KSBB Journal
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• v.23 no.3
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• pp.213-218
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• 2008

The present study was to investigate the continuous production of alcohol using immobilized carrier manufactured by polymeric materials. Fermentation runs with a crushed rice, with constituents recovered from batch culture and with ones from continuous culture were thus compared. The performances of immobilized carrier were governed by sandwitched synthetic polymers, the evolution of the continuous culture was steadily governed by the production of alcohol in the lag time of batch culture. The main focus was set on the enhancement of the alcohol production by an newly-developed polymeric forms. This polymeric form led to a drastic increase of the microorganism and the production cost in the continuous reactor was thereby reduced. The sandwitched polymeric-formed carrier, which was resistant to external environments, serves as an interesting alternative to maintain the stability of biological process. These whole results were discussed with the aim to better understand the continuous process implied in the microorganism's build-up during cultivation of fermentation broth.

• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.373-380
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• 1993

When the cells of yeast K35 were immobilized in Ca-alginate gel, cell concentration and viability decreased as alginate concentration increased. Considering the results, 2% (w/v) Ca-alginate concentration would be suitable. Among various concentrations of additives and cross-lin-king agent, the addition of 1.67% (w/v) of bentonite together with 0.33% (v/v) of glutaraldehyde (ABG bead) resulted in the highest ethanol production of 1.8%(w/v), using YPD medium containing 2% glucose. ABG bead seemed to be more resistant to phosphate ion than Ca-alginate bead. 0.33%(w/v) of phosphate was a proper concentration for the ethanol production by ABG bead. Scanning electron microscopic observation depicted that the immobilized cells on the bead surface were coated by alginate gel and that the cells in the internal bead were cross-linked with alginate matrix. When repeated-batch culture was performed with ABG bead for 40 days in a packed-bed reactor, ethanol concentration of about 90~110 g/l-gel was maintained. Cell viability was maintained around 70%, and outgrowing cell concentration was below 6.3% of total cell concentration. Consequently, the results showed that ABG head was a potential carrier for continuous production of ethanol compared to conventional Ca-alginate bead.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1208-1212
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• 2007

Production of extracellular epothilone B, one of the potent anticancer agents, by free and immobilized Sorangium cellulosum was studied using the repeated batch culture process. The concentration of alginate used in immobilization was directly related to the mass transfer rate of nutrients, mechanical stability, and the epothilone B production yield. With the optimized 3% (w/v) calcium alginate carrier, a prolonged repeated batch culture was investigated for the 5 repeated batches for 24 days. The maximum productivity of epothilone B obtained from the alginate-immobilized cells was 5.03 mg/l/day, which is 3 times higher than that of free cells (1.68 mg/l/day).

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.56-60
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• 1990

A bacterial strain of Brevibacterium sp. CHI was isolated from soil and used to produce an enzyme (nitrile hydratase) necessary for carrying out the bioconversion of acrylonitrile to acrylamide. Various immobilization methods and enzyme stability were investigated. The nitrile hydratase showed the maximum stability at pH 7 for the free cells. EDTA and phenyl methyl sulfonyl fluoride were selected as the protease inhibitor and the enzyme stability was evaluated by changing inhibitor concentration. Acrylamide beads were the best carriers among four carriers we tested in terms of stability and physicoehemical strength. The storage stability of the immobilized cells decreased with increasing acrylamide concentration of the gel phase at 4$^{\circ}C$, and was very low at acrylarnide concentration above 25%.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.366-374
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• 2015

Herein, we established a repeated-batch process for ethanol production from glycerol by immobilized Pachysolen tannophilus. The aim of this study was to develop a more practical and applicable ethanol production process for biofuel. In particular, using industrial-grade medium ingredients, the microaeration rate was optimized for maximization of the ethanol production, and the relevant metabolic parameters were then analyzed. The microaeration rate of 0.11 vvm, which is far lower than those occurring in a shaking flask culture, was found to be the optimal value for ethanol production from glycerol. In addition, it was found that, among those tested, Celite was a more appropriate carrier for the immobilization of P. tannophilus to induce production of ethanol from glycerol. Finally, through a repeated-batch culture, the ethanol yield (Y_e/g) of 0.126 ± 0.017 g-ethanol/g-glycerol (n = 4) was obtained, and this value was remarkably comparable with a previous report. In the future, it is expected that the results of this study will be applied for the development of a more practical and profitable long-term ethanol production process, thanks to the industrial-grade medium preparation, simple immobilization method, and easy repeated-batch operation.

• Clean Technology
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• v.21 no.4
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• pp.224-228
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• 2015

Phospholipase D (PLD) was immobilized on a submicro-porous membrane through covalent immobilization. The immobilization was conducted on the porous membrane surface with the treatment of polyethyleneimine, glutaraldehyde, and the anhydrase, in sequence. The immobilization was confirmed using X-ray photon spectrometer. The pH values of phosphatidylcholine (PC) dispersion solution with buffer were monitored with respect to time to calculate the catalytic activities of PC for free and immobilized PLD. The catalytic rate constant values for free PLD, immobilized PLD on polystyrene nanoparticles, and immobilized PLD on a porous cellulose acetate membrane were 0.75, 0.64, and 0.52 s^-1, respectively. Reusability was studied up to 10 cycles of PC hydrolysis. The activity for the PLD immobilized on the membrane was kept to 95% after 10 cycles, and comparable to the PLD on the nanoparticles. The stabilities for heat and storage were also investigated for the three cases. The results suggested that the PLD immobilized on the membrane had the least loss rate of the activity compared to the others. From these studies, the porous membrane was feasible as a carrier for the PLD immobilization in the production of phosphatidic acid.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.333-337
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• 1996

For continuous production of galactooligosaccharides(GOS), $\beta-galactosidase$ with h1gh transgalactosylation activity from Bacillus sp. A 4442 was Immobilized onto $Diaion^{TM}$ HPA 75(styrene-divinylbenzene resin). The parameters influencing enzyme immobilization were scrutinized in order to maximize immobilization yield while minimizing enzyme inactivation. The optimum conditions turned out to be: Tris buffer concentration 30 mM, pH 8.0, contact time at room temperature 3 hr, and enzyme loading 25 mg protein/g resin. Both the thermal stability and the operational stability of immobilized enzyme were markedly enchanced by the treatment with 0.5% glutaraldehyde as a cross-linker. Under the experimental conditions established, the yield of ${\beta}-galactosidase$ immobilization was 40% or more and the activity of the immobilized enzyme ca. 200 U/g resin. When a packed-bed reactor was employed to continuously convert lactose to GOS, the specific production, which refers to as the amount of commercially valuable GOS produced by a unit amount of immobilized ${\beta}-galactosidase$, was found to be ca. 300 g GOS/g carrier.

• Korean Journal of Environmental Biology
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• v.27 no.3
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• pp.244-251
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• 2009

To assess the algicidal effect of a bacterium, Pseudomonas fluorescens HYK0210-SK09 (SK09), attached to activated carbon polyvinyl alcohol (ACPA) and cellulose sponge (CS) carriers against Stephanodiscus hantzschii, the present study was carried out in an indoor-microcosm. As comparing immobilization effects of two carriers, the ACPA carrier allowed for higher packing cell density of SK09 compared to the CS carrier. In the microcosm, immobilized SK09 cells were applied to control S. hantzschii blooms. Immobilized SK09 cells exhibited a species-specific activity towards the diatom, showing an algicidal effect up to 72% attached by ACPA carriers and to 51% attached by CS carriers. In particular, a level of conductivity treated with ACPA carriers was decreased than that of CS carriers. The present study clearly demonstrates that ACPA-immobilized SK09 cells could effectively control S. hantzschii blooms and improve water quality in the microcosm ecosystem.