• Applied Biological Chemistry
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• v.39 no.1
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• pp.16-19
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• 1996

The yeast strains isolated for Choungju brewing in the previous report were examined for their microbiological characteristics, together with some comparative tests with Japanese sake yeasts. The isolates KP-16, 21 and 54 were identified as the strains belong to Saccharomyces cerevisae according to the morphological and physiological properties described in Lodder's 'The Yeasts - A texanomic study'. The isolates were grouped into the pink-colored strains by 2,3,5-tripheny tetrazolium chloride over-lay method. The strains KP-16 and 21 were found to be distinguished from the strain KP-54 in aspects of fermentation of sugars, assimilation of carbon sources, and pellicle formation on malt extract broth. ${\alpha}-methyl-D-glucoside$ was not assimilated or fermented by the isolated yeast strains and this is one of the different characters from the Japanese sake yeasts. The isolated strains appeared to have the requirements for biotin and pantothenate, and to have higher tolerance to ethanol than the Japanese sake yeasts. The biotin requirement was not found in the sake yeasts.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.87-94
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• 2015

High voltage pulsed electric fields (PEF) treatment is one of the more promising nonthermal technologies to fully or partially replace thermal processing. The objective of this research was to investigate the microbial inactivation mechanisms of PEF treatment in terms of intra- and extracellular changes in the cells. Saccharomyces cerevisae cells treated with PEF showed cellular membrane damage. This resulted in the leakage of UV-absorbing materials and intracelluar ions, which increased with increasing treatment time and electric fields strength. This indicates that PEF treatment causes cell death via membrane damage and physical rupture of cell walls. We further confirmed this by Phloxine B staining, a dye that accumulates in dead cells. Using scanning and transmission electron microscopy, we observed morphological changes as well as disrupted cytoplasmic membranes in PEF treated S. cerevisae cells. In addition, PEF treatment led to damaged chromosomal DNA in S. cerevisiae.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1835-1842
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• 2014

Various microorganisms are involved in the fermentation of Mageoli, Korean traditional liquor. Among them, the most predominant microorganism is yeast, including Saccharomyces cerevisae. This study investigated the effects of crude polysaccharides separated from Mageoli mash (CP-M) on activation of peritoneal macrophages in cell culture medium. Four types of yeasts, S. cerevisae 89-1-1, 98-2, 268-3, and 113-4, were used. When peritoneal macrophages were treated with $10{\mu}g/mL$ of CP-M fermented with S. cerevisae 113-4, the concentration of nitric oxide (NO) in the medium was highest ($33.3{\mu}M$). The concentrations of IL-6 and -12 were also highest at 116.3 pg/mL and 59.8 pg/mL, respectively. In the case of CP-M cultured at 15, 20, and $30^{\circ}C$ after inoculation with S. cerevisae 113-4 and fermented at different temperatures, production of NO and IL-6 by peritoneal macrophages did not change compared to the control. For CP-M obtained after fermentation at $25^{\circ}C$, however, NO concentration increased 2.7~3.3 fold and IL-6 concentration by 5.7 fold compared to the control. Furthermore, the effect of fermentation period on expression of CP-M functionality was examined. NO production by CP-M of the 5th day mash was highest, increasing 2.2 fold compared to 0-day CP-M. However, there were no significant differences in concentration of IL-6 or -12 according to different fermentation periods, although CP-M showed a large decrease after 10 days. The results show that fermentation conditions with the highest activity were observed in CP-M inoculated with S. cerevisae 113-4 and fermented at $25^{\circ}C$ for 5 days. CP-M consisted of 78.6% neutral sugar, 11.6% acidic polysaccharide, and 9.8% protein. In particular, the sugar composition of neutral sugar consisted of mannose (47.8%), glucose (29.6%), and galactose (12.7%). Based on the results, CP-M is assumed to be an extracellular polysaccharide originating in yeast with high mannose content.

• The Korean Journal of Food And Nutrition
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• v.9 no.2
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• pp.160-166
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• 1996

In order to develop a pumpkin wine, the brewing conditions and sensory evalution of the wine were studied. The pumpkin can be made into wine by ethanol fermentation with Saccharomyces cerevisae. When the mash was adjusted 15aA pumpkin and 25% sugar and fermented for 15 days, the product was highly evaluted in color, flavor and taste. Contents of the refined pumpkin wine were 80mg/ml of total sugar, 70mg/ml of reducing sugar, 2.1 of acidity and 12% of ethanol, and it's pH was 3.6.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.2
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• pp.91-97
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• 2005

The purpose of this research is malodor reduction of food waste leachate by some microorganism. In oder to observe the efficiency of malodor reduction by different microorganisms, 300ml of food waste leachate was fermented by the addition of 10% precultured seed microorganism such as marine algae of Spirulina plantensis, Chlorella vulgaris, the yeast Saccharomyces cerevisae and bacteria Bacillus cereus for 10 days. During the fermentation the change in pH, salinity and sensory evaluations were tested. As the results, the pH values of samples in the beginning were 3.5~4.0. After fermentation they are increased to the level 4.9~7.4. The salinity values of the samples fermented by Spirulina plantensis and Chlorella vulgaris were lowered rapidly. By the sensory evaluation, the efficiency of malodor reduction by Chlorella vulgaris of the marine microalgae showed almost inodorous degree of ordor 1.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.183-188
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• 2002

The ohmic heating of foods for sterilization provides a shorter come-up time compared to conventional thermal processes. The electric fields as well as the heat generated by ohmic heating facilitate germicidal effects. In the present study, the effect of ohmic heating on the structure and permeability of the cell membrane of yeast cells, Saccharomyces cerevisae, isolated from Takju (a traditional Korean rice-beer), was investigated. The ohmic heating was found to translocate intracellular protein materials out of the cell wall, and the amount of exuded protein increased significantly as the electric field increased from 10 to 20 V/cm. As higher frequencies were applied, more materials were exuded. Compared to conventional heating, more amounts of proteins and nucleic acids were exuded when these cells were treated with ohmic heating. The molecular weights of the major exuded proteins ranged from 14 kDa to 18 kDa, as analyzed by Tricine-SDS PAGE. A TEM study also confirmed the leakage of cellular materials, thus indicating irreversible damage to the cell wall by ohmic heating. It was, therefore, concluded that the electric fields generated by ohmic heating induced electroporation, causing irreversible damage to the yeast cell wall and promoting the translocation of intracellular materials.

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.42-48
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• 1998

In order to maximize the secretory expression of human serum albumin (HSA) in the yeast Saccharomyces cerevisiae, a series of HSA expression vectors were constructed with a combination of different promoters, 5' untranslated regions (5'UTR), and secretion signal sequences. The expression vector composed of the galactose-inducible promoter GALl0, the natural 5'UTR, and the natural signal sequence of HSA directed the most efficient expression and secretion of HSA among the constructed vectors when introduced into several S. cerevisiae strains. Although the major form of HSA expressed and secreted in the yeast transformants was the mature form of 66 kDa, the truncated form of 45 kDa was also detected both in the cell extract and in the culture supernatant. The level of the intact HSA protein in the culture supernatant reached up to 30 mg/l at 24 h of cultivation in a shake-flask culture but began to decrease afterwards, indicating that the secreted HSA protein was unstable in a prolonged culture of yeast.

• New & Renewable Energy
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• v.7 no.4
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• pp.3-9
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• 2011

Optimization of initial total sugar concentration of sweet sorghum juice, aeration time and aeration rate on ethanol production was performed by response surface methodology (RSM). The optimum conditions for ethanol production from concentrated sweet sorghum juice were determined as follows: initial total sugar concentration, 21.2 Brix; aeration time, 7.66h; aeration rate, 1.22 vvm. At the optimum conditions, the maximum ethanol yield was predicted to be 91.65% by model prediction. Similarly, 92.98% of ethanol yield was obtained by verification experiment using optimum conditions after 48 h of fermentation. This result was in agreement with the model prediction.

• The Korean Journal of Food And Nutrition
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• v.10 no.3
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• pp.360-364
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• 1997

Rice Sikhye was fermented by Saccharomyces cerevisiae for 10 day at 29$^{\circ}C$. Fermentable sugars such as glucose, maltose and maltotriose in rice Sikhye were converted into ethanol by the yeast, but limit dextrin was remained after the fermentation. Rice Sikhye wine was found to contain 5.3% of limit dextrin, 6.5% of ethanol, 2.9 $\mu$mol/ml of amino acid, 457$\mu\textrm{g}$/ml of protein, and the acidity of the Sikhye showed 3.1, respectively, and its pH was 3.67. Limit dextrin in rice Sikhye wine showed both signal of $\alpha$-1,4- and $\alpha$-1,6-glucosidic linkage wit its estimation ratio of 5.6:1 by 1H-NMR analysis. The taste of rice Sikhye wine was similar that of wine.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.275-277
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• 2009

Swimming enhancing effects of ssanghwatang fermented with Saccharomyces cerevisae in mice were investigated, and then the blood biochemical parameters related to fatigue were measured. Compared to the control group, the swimming time was significantly increased in fermented ssanghwatang (FST) group from day 4 ($29.27{\pm}4.73$ vs. $50.27{\pm}9.05\;min$, p<0.05). The lactate level, an important indicator of fatigue, was drastically lower in FST group than in control group ($2.13{\pm}0.13$ vs. $1.40{\pm}0.12\;mmole/L$, p<0.01). These results suggest that FST possesses stimulatory effects which can enhance exercise performance and reduce fatigue.