• KSBB Journal
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• v.15 no.6
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• pp.573-577
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• 2000

The optimum fermentation conditions for the production of cellulose by a newly isolated Acetobacter sp. A9 were determined in static cultures. The strain was able to produce cellulose at $25-30^{\circ}C$ with a maximum at $30^{\circ}C$. Cellulose production occurred at pH 6.5-8.0 with a maximum at pH 6.5. The optimal culture medium was found to consists of 1.0% glucose, 1.0% yeast extract, 0.7% polypeptone, 0.15% acetic acid and 0.02% succinic acid. Cellulose production by Acetobacter sp. A9 followed the growth curve. Highest cellulose production, under optimum conditions, was $24.1m^2$, although this strain typically produced only $12.1 g/m^2$ in the basic medium. Cellulose production also depended on the depth and volume of the medium.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.895-902
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• 2014

Bacterial cellulose (BC) has played important role as new functional material for food industry and industrial products based on its unique properties. The interest in BC from static cultures has increased steadily in recent years because of its potential for use in medicine and cosmetics. In this study, we investigated culture condition for BC production by Acetobacter sp. F15 in static culture. The strain F15, which was isolated from decayed fruit, was selected on the basis of BC thickness. The optimal medium compositions for BC production were glucose 7%, soytone 12%, $K_2HPO_4$ 0.2%, $NaH_2PO_4{\cdot}_2H_2O$ 0.2%, lactic acid 0.05% and ethanol 0.3%, respectively. The strain F15 was able to produce BC at $26^{\circ}C-36^{\circ}C$ with a maximum at $32^{\circ}C$. BC production occurred at pH 4.5-8 with a maximum at pH 6.5. Under these conditions, a maximum BC thickness of 12.15 mm was achieved after 9 days of cultivation; this value was about 2.3-fold higher than the thickness in basic medium. Scanning electron micrographs showed that BC from the optimal medium was more compact than plant cellulose and was reticulated structure consisting of ultrafine cellulose fibrils. BC from the optimal medium was found to be of cellulose type I, the same as typical native cellulose.

• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.41-45
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• 1999

Microbial cellulose has many potential applications due to its excellent physical properties. The production of cellulose from Acetobacter xylinum in submerged culture is, however, beset with numerous problems. The most difficult one has been the appearance of negative mutants under shaking culture conditions, which is deficient of cellulose producing ability. Thus genetic instability of Acetobacter xylinum under shaking culture condition made developing a stable mutant major research interest in recent years. To find a proper type of bioreactor for the production of microbial cellulose, several production systems were developed. Using a reactor system with planar type impeller with bottoms sparging system, it was possible to produce 5 g/L microbial cellulose without generating cellulose minus mutants, which is comparable to that of static culture system.

• Iberoamérica
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• v.12 no.1
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• pp.407-439
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• 2010

Growth of researches addressing cross-culture in international business is exponential. This article reviews the extant researches around the national culture and describes the various conceptualization of culture through discussion of some of popular models of national culture. This article presented some of the most important issues in international business surrounding globalization, especially convergence and divergence of cultures and cultural changes. Global rapid changes in international business environment request the reconsideration of the assumption of cultural stability and the simple view of culture, which tends to examine the static influence of a few cultural factors in isolation form other cultural factors and contextual elements. This paper identifies a valid cultural grouping and proposes the following typology of the possible methodologies in international business; Ethnological description, Use of proxies, Direct values inference, and Indirect values inference. Rather than selecting a single methodology, it appears to be more appropriate to use multi-method in the cross-cultural international business research. It has been shown that cultural change is intertwined with socioeconomic-institutional variables, and that these variables may also add to determine culture contemporarily. This paper also explained the dynamics of culture as multi-level, multi-layer constructs. According to this model, we may understand how the dynamic nature of culture conveys the top-down-bottom-up processes where one cultural level affects changes in other level of culture.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.175-180
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• 2005

In this study, we investigated the optimal medium composition for bacterial cellulose (BC) production by Gluconacetobacter sp. RKY5. Among the various kinds of carbon sources, glycerol was the most efficient as a sole carbon source and its optimal concentration for BC production was 15 g/L. The optimal concentration of yeast extract as a nitrogen source for BC production was found to be 8 g/L. $K_{2}HPO_{4}$ and acetic acid were selected respectively as a phosphate source and a secondary substrate, and both optimal concentrations were 3 g/L. The amount of produced BC was 4.59 g/L in a static culture and 6.5 g/L in a shaking culture condition with 150 rpm. These values were 2.1 and 2.7 times higher than those in a static (2.16 g/L) and a shaking (2.41 g/L) cultures using HS medium generally used for BC production.

• The Research Journal of the Costume Culture
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• v.8 no.6
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• pp.791-805
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• 2000

The purpose of this study is to analyze the jeans advertising campaigns of the 1990's in South Korean magazine advertisements and their relation to the beauty trends of the 1990's in South Korea. There are three significant and varying periods in the 1990's. Each period will be dissected into four categories. The four categories are 1. Catchphrases 2. Pose selection of the models 3. Selection of models 4. Overall images and themes of the ads. The results are as follows : 1. 1990∼1993 ; Youth & Freedom From 1990 to 1993, jean ads emphasized the catchphrsase and the dynamic pose more and used the Korean model. The ads displayed youthful energy and the freedom of the younger generation. 2. 1994∼1997 ; Sex Appeal From 1994 to 1997, the second transition in jeans advertisements focus shifted from the youthful images of the early 90's to more sexually oriented ads. In terms of model selections and pose, Caucasian models instead of Korean models, and static pose were used more. The ads emphasized the image more than the catchphrase. 3. 1998∼1999 ; Diversity of Individuality & Naturalism During 1998 to the present day, the jeans ads no longer focused on groups but the diversity of individuality. The other focus of ads was the naturalism and the harmony with the nature. Both the static and dynamic pose, Korean model, and the image ads were used.

• Preventive Nutrition and Food Science
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• v.5 no.3
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• pp.165-169
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• 2000

Kombucha beverages were made from sweetened tea by Oriental, European and Tibetan tea fungus starters. The hot water extracts o green tea, black tea, Gugija and Omija were mixed with white and/or brown sugar, and were fermented under a static culture at 3$0^{\circ}C$. Titrable acidity, pH, color and cellulose production in kombucha beverages were evaluated. All tea fungus starters showed a higher acid production in green/black tea extracts rather than Gugija and Omija extracts. In green/black tea extracts Oriental tea fungus produced a kombucha beverage with a higher titrable acidity and lower pH than those of European and Tibetan tea fungus starters. By the static fermentation of green/black tea extract for 18 days, Oriental, Tibetan and European tea fungus starters produced cellulose pellicles of 0.43g, 0.16g, and 0.19 g (dry weight) on the top in the culture, respectively. As a mother starter, the cellulose pellicle was more efficient in acid production compared with tea fungus broth. Oriental/Tibetan mixed tea fungus showed the best acid production in the green/black tea extract supplemented with brown sugar.

• KSBB Journal
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• v.11 no.5
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• pp.550-556
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• 1996

A complex medium was developed for the production of microbial cellulose by Acetobacter xylinum ATCC 23769. The optimum concentration of each nutrient for the production of microbial cellulose was determined to be 10g peptone, 20g yeast extract, 5g glucose, 1.56g Na2HPO4, 1.8g KH2PO4, 0.05g MgSO4, 0.002g FeCl3, 5g citric acid and 10 mL ethanol per liter. With synergistic effects of citric acid and ethanol, cellulose productivity achieved in developed medium was 0.446 gram of cellulose per gram glucose for static culture, which is much higher than reported values. Cell growth and the cellulose production in the developed medium under static culture was also investigated.

• Journal of Microbiology and Biotechnology
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• v.28 no.6
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• pp.902-908
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• 2018

Optimization of the culture medium to maximize menaquinone-7 (MK-7) production by Bacillus subtilis strain KCTC 12392BP in static culture was carried out using statistical experimental methods, including one factor at a time, fractional factorial design, and response surface methodology (RSM). Maltose (carbon source), tryptone (nitrogen source), and glycerol (activator) were identified as the key medium components for MK-7 synthesis by the fractional factorial design, and were selected for statistical optimization by RSM. The statistical analysis indicated that, in the range that was studied, maltose, tryptone, and glycerol were all critical factors having profound effects on the production of MK-7, with their coefficients for linear and quadratic all significant at the p < 0.05 level. The established model was efficient and feasible, with a determination coefficient ($R^2$) of 0.9419. The predicted concentrations of maltose, tryptone, and glycerol in the optimal medium were determined as 36.78, 62.76, and 58.90 g/l, respectively. In this optimized medium, the maximum yield of MK-7 reached a remarkably high level of $71.95{\pm}1.00{\mu}g/ml$ after 9 days of static fermentation, which further verified the practicability of this optimized strategy.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1412-1423
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• 2019

The filamentous fungus Aspergillus tubingensis that belongs to the black Aspergillus section has the capacity to produce high-value metabolites, for instance, naphtho-gamma-pyrones (NGPs). For these fungal secondary metabolites, numerous biological properties of industrial interest have been demonstrated, such as antimicrobial, antioxidant and anti-cancer capacities. It has been observed that production of these secondary metabolites is linked with fungal sporulation. The aim of this research was to apply osmotic and oxidative environmental stresses to trigger the production of NGPs in liquid cultures with CYB (Czapek Dox Broth). In addition, numerous parameters were tested during the experiments, such as pH value, incubation time, container geometry, and static and agitation conditions. Results demonstrate that the produced amount of NGPs can be enhanced by decreasing the water activity ($a_w$) or by adding an oxidative stress factor. In conclusion, this study can contribute to our knowledge regarding A. tubingensis to present an effective method to increase NGP production, which may support the development of current industrial processes.