• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.687-691
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• 2003

Whole-cell immobilization of the hydrocarbon rich microalgae, Botryococcus braunii and B. protuberans, in alginate beads under air-lift batch cultures resulted in a significant increase in chlorophyll, carotenoid, dry weight, and 1ipid contents at stationary and resting growth phases, as compared to free cells. Photosynthetic activity in both the species, of Botryococcus was enhanced, relative to free cells, at any growth phase of cultures. Immobilization exerted a protective influence on ageing of the cultures as reflected by higher chlorophyll and dry weight contents. Entrapment also stabilized the chlorophyll and carotenoid contents even at stationary and resting phases as compared to free cells in both the species.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1317-1322
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• 2005

This work describes neo-fructooligosaccharides (neo-FOSs) production using the immobilized mycelia of Penicillium citrinum. Some critical factors were evaluated to optimize maximal production of neo-FOS. Optimal alginate and cell concentrations were determined to be $1.96\%$ alginate and $7.17\%$ cell, respectively, by statistical analysis. The optimal concentration of $CaCl_{2}$, which is related to bead stability, was determined to be 2 M. It was possible to increase the neo-FOS production by adding 15 units of glucose oxidase to the batch reaction. By co-immobilizing cells and glucose oxidase, neoFOS productivity increased $123\%$ compared with the whole-cell immobilization process. Based on the results above, a co-immobilization technique was developed and it can be utilized for large-scale production.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.299-304
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• 1980

By using whole cells of Leuconostoc oenos ML-34 immobilized in polyacrylamide gel, deacidification of grape juice and wine was attempted. The immobilization did not destroy the original malo-lactic fermentation ability of the cells. However, the speed of malic acid decomposition by the immobilized cells was slow due to the slow transportation of the substrate through the gel layer. By reducing malic acid content in grape juice to a desired degree one may control the level of acid taste in wine fermented with the treated grape juice.

• YAKHAK HOEJI
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• v.33 no.6
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• pp.365-371
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• 1989

Microbiological conversion of sterols to 17-ketosteroids has been recognized as a source for commercial preparation of steroidal drugs. In order to develop bacterial strains and process with Brevibacterium lipolyticum IAM 1398 capable of converting cholesterol to 1,4-Androstadiene-3,17-dione (ADD) at about 27% yield, we studied on strain improvement, fermentation condition and whole cell immobilization. By using UV and/or NTG as mutagens, a mutant to convert cholesterol to ADD with higher yield than 60% was selected. Better production of ADD was manifested in the case of maltose used as a supplemental carbon source, and yeast extract or soytone as a nitrogen source. Addition of tween 80 (0.05%) as a surfactant beneficial for increasing the productivity. The optimal initial pH of the medium was 6.5 and optimal culture temperature was $30^{\circ}C$. Whole cell immobilization by using carrageenan, agar, alginate and acrylamide was carried out and the activity of conversion was tested. In the case of carrageenan and agar, immobilized cells were active for at least two cycles of fermentation.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1803-1808
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• 2008

For practical application, the stability of permeabilized Ochrobactrum anthropi SY509 needs to be increased, as its half-life of enzymatic denitrification is only 90 days. As the cells become viable after permeabilization treatment, this can cause decreased activity in a long-term operation and induce breakage of the immobilization matrix. However, the organic solvent concentration causing zero cell viability was 50%, which is too high for industrial application. Thus, whole-cell immobilization using glutaraldehyde was performed, and 0.1% (v/v) glutaraldehyde was determined as the optimum concentration to maintain activity and increase the half-life. It was also found that 0.1% (v/v) glutaraldehyde reacted with 41.9% of the total amine residues on the surface of the cells during the treatment. As a result, the half-life of the permeabilized cells was increased from 90 to 210 days by glutaraldehyde treatment after permeabilization, and no cell viability was detected.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1234-1241
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• 2016

Methanol is a versatile compound that can be biologically synthesized from methane (CH₄) by methanotrophs using a low energy-consuming and environment-friendly process. Methylocella tundrae is a type II methanotroph that can utilize CH₄ as a carbon and energy source. Methanol is produced in the first step of the metabolic pathway of methanotrophs and is further oxidized into formaldehyde. Several parameters must be optimized to achieve high methanol production. In this study, we optimized the production conditions and process parameters for methanol production. The optimum incubation time, substrate, pH, agitation rate, temperature, phosphate buffer and sodium formate concentration, and cell concentration were determined to be 24 h, 50% CH₄, pH 7, 150 rpm, 30℃, 100 mM and 50 mM, and 18 mg/ml, respectively. The optimization of these parameters significantly improved methanol production from 0.66 to 5.18 mM. The use of alginate-encapsulated cells resulted in enhanced methanol production stability and reusability of cells after five cycles of reuse under batch culture conditions.

• The Korean Journal of Mycology
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• v.11 no.3
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• pp.109-114
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• 1983

${\beta}-Galactosidase$ activity of Aspergillus phoenicis was studied using ONPG and lactose as substrate. It increased monotonically during the exponential growth phase and dropped rapidly at the beginning of the stationary one. It exhibited high tolerable temperature and acidic optimal pH which provides certain advantages from the industrial view point. Enzyme of ${\beta}-galactosidase$ had more subsrate affinity for ONPG than for lactose and its apparent maximum activity was also higher with the former as substrate. Activity of this enzyme depended upon the conditions of immobilization. Optimum crosslinking reaction was occurred at pH 7.2 and 0. 35 vol. % of glutaraldehyde concentration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.2
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• pp.322-327
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• 1994

For the improvement of L-lysine productivity, development of the continuous fermentation system by a bioreactor assembly was attempted. Primarily, optimal conditions on the whole cell immobilization of Corynebacterium glutamicum ATCC21514 were studied and 76.2% of immobilization ratio was obtained when the cells were entrapped with 4% k-carrageenan showing 4.0kg gel strength. A bioreactor system was set up using the immobilized cells was applied for the continuous production of L-lysine. The results obtained under the optimum conditions were compared with those of the batchwise fermentation. Experimental results obtained from 14 day continuous fermentation showed 36.7% of sugar conversion to L-lysine while the productivity of L-lysine was disclosed as 4.96mg/ml mg-dry cell weight /hr which is 2.5times and 4.1 times higher than those of the batchwise fermentation by the intact cells and by the immobilized cells, respectively.

• The Korean Journal of Food And Nutrition
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• v.11 no.3
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• pp.319-322
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• 1998

The whole cell of alkalophilic Streptomyces sp. B-2 which produce glucose isomerase was immobilized by entrapment method for the effective production of high fructose syrup. The highest immobilized activity was achieved when the enzyme was bound to 2% $textsc{k}$-carrageenan. Immobilized glucose isomerase the pH optimum was about pH 7.5~8.5. Immobilization of alkalophilic Streptomyces sp. B-2 on 2% $textsc{k}$-carrageenan at 7$0^{\circ}C$ showed an increase in glucose isomerase activity. GI activity of immobilized cells was maximum Co2+ concentration 10-3M, Mg2+ concentration 10-3M.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1278-1284
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• 2016

Rhizopus chinensis cells immobilized on loofah (Luffa cylindrica) sponges were used to produce biodiesel via the transesterification of soybean oil. In whole-cell immobilization, loofah sponge is considered to be a superior alternative to conventional biomass carriers because of its biodegradable and renewable properties. During cell cultivation, Rhizopus chinensis mycelia can spontaneously and firmly adhere to the surface of loofah sponge particles. The optimal conditions for processing 9.65 g soybean oil at 40℃ and 180 rpm using a 3:1 methanol-to-oil molar ratio were found to be 8% cell addition and 3-10% water content (depending on the oil's weight). Under optimal conditions, an over 90% methyl ester yield was achieved after the first reaction batch. The operational stability of immobilized Rhizopus chinensis cells was assayed utilizing a 1:1 methanol-to-oil molar ratio, thus resulting in a 16.5-fold increase in half-life when compared with immobilized cells of the widely studied Rhizopus oryzae. These results suggest that transesterification of vegetable oil using Rhizopus chinensis whole cells immobilized onto loofah sponge is an effective approach for biodiesel production.