• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.88-93
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• 1989

To improve a new yeast strain capable of converting xylan to ethanol directly, we tried protoplast fusion between xylose fermenting yeast (Candida sp. X-6-41) and xylan assimilating yeast (Crypto-coccus sp. XB-33), finally selected the most promising two fusants (XFU-1 and XFU-2). As the optimum conditions for protoplast formation, the yeast cells were cultured to exponential phase in YPD and YPX containing 0.6M KCI, respectively, and then treated with zymolyase (0.25mg/$m\ell$), cellulase(4mg/$m\ell$) and 100mM 2-mercaptoethanol at pH 8 and 3$0^{\circ}C$. The protoplasts of parental auxotrophs were fused in the presence of 20mM CaCl$_2$and 40% polyethylene glycol(M.W.4000). The physiological and morphological characteristics of the fusants, such as assimilation of carbon sources, cell size, growth rate, xylanase activity and xylan fermentation ability were investigated. Xylanase activity of fusants that cultured in chemically minimal medium was higher than that of fusants that cultured in completed medium, because xylanase producing activity of xylose fermenting yeast(X-6-41) was inhibited by isoleucine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.340-347
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• 2019

This study investigated the brewing properties of rice beer made with yeast isolated from traditional whole wheat nuruk. The experimental method was followed by alcohol fermentation and quality analysis for six months after separating the yeast from nuruk. The yeasts isolated from traditional nuruk showed normal fermentation characteristics, like those of commercial yeast, in terms of alcohol production capability, sugar content, and pH reducing power. Especially, the yeast (KCCM 301) isolated from whole wheat nuruk showed higher contents of glycogen and trehalose than that of commercial yeast, and so KCCM 301 yeast has excellent yeast vitality. Meanwhile, the yeast (KCCM 90301) isolated from traditional Nuruk produced significantly higher alcohol and ester contents than that of commercial yeast. This has a positive effect for supplementing the taste and aroma of rice beer. In conclusion, the yeasts isolated from whole wheat nuruk showed the general alcohol fermentation pattern and aroma content of rice beer. These yeasts seem to be effective in strengthening the flavor of rice beer.

• YAKHAK HOEJI
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• v.36 no.5
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• pp.469-473
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• 1992

Yeast alcohol dehydrogenase (YADH) has an acidic residue that interacts with the 2'- and 3'-hydroxyl groups of the adenosine ribose of the $NAD^+$ coenzyme. The acidic residue of Asp-223 (according to horse liver alcohol dehydrogenase amino acid sequence) is supposed to determine the coenzyme specificity for $NAD^+$ rather than $NADP^+$. We mutated Asp-223 to leucine and the mutant YADH was expressed in yeast and characterized for the coenzyme specificity. The turnover numbers of mutant enzyme for $NAD^+$ and ethanol were decreased 3.5- and 4.8-fold compared to wild-type enzyme, respectively. Contrastively, catalytic specificity for $NADP^+$ was increased 13-fold. As a result, the mutant YADH also employed $NADP^+$ as a coenzyme.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1160-1164
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• 2008

An novel amylolytic yeast, Saccharomyces cerevisiae HA 27, isolated from nuruk, displayed resistance against high sugar (50% glucose) and alcohol (15%). Maximal production of amylolytic enzyme by S. cerevisiae HA 27 was achieved on 9 days of cultivation at the optimal temperature $20^{\circ}C$ and pH 6.0. The activity of amylolytic enzyme produced by S. cerevisiae HA 27 was stable, even at $70^{\circ}C$, and over a broad pH range (4.0-11.0). Also, the amylolytic enzyme of S. cerevisiae HA 27 showed optimal activity in pH 5.0 at $50^{\circ}C$. S. cerevisiae HA 27 exhibited 6.2%(v/v) alcohol fermentation ability using starch as a carbon source.

• Microbiology and Biotechnology Letters
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• v.14 no.5
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• pp.365-369
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• 1986

The activity of glucoamylase and pullulanase, properties of glucoamylase and ethanol productivities of fusants were studied. Glucoamylase and pullulanase activity of fusants were higher than parents. The optimal pH and temperature of glucoamylase of fusants were very similar to the those produced by S. diastaticus. In alcohol fermentation. fermenting ability and fermentation rate of fusants were higher and faster than either of its parental strain. The maximum of alcohol yield in 15% of liquefied potato starch was 7.8% (v/v)

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1411-1416
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• 2009

The suppressive effects of glutathione-enriched Saccharomyces cerevisiae FF-8 strain (FF-8 GY) on alcoholinduced hepatotoxicity have been studied. FF-8 GY (256 mg/L) from the fermentation at a large scale bioreactor was used. Either of 5% FF-8 GY or 5% commercial glutathione-enriched yeast extract (GYE) with or without 30% alcohol was tested with rats for 4 weeks. FF-8 GY and GYE were found to reduce those alcohol-elevated serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) activities. Blood alcohol and acetaldehyde were also decreased by FF-8 GY and GYE. Interestingly, FF-8 GY drastically increased both hepatic alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) activities in comparison to GYE group, thus FF-8 GY would be more effective in blood alcohol and acetaldehyde reduction. Attenuated lipid droplet accumulation in hepatocytes was observed in both FF-8 GY and GYE when alcohol stimulated the accumulation. Therefore, FF-8 GY may be useful to protect liver from alcohol-induced hepatotoxicity.

• The Korean Journal of Mycology
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• v.10 no.2
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• pp.75-83
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• 1982

As a primary study for cell growth and alcohol production of a cider yeast, Saccharomyces sp. R-11, cultural and nutritional characteristics of the strain were investigated. The results obtained were as follows: The optimum culture medium for this strain was a synthetic medium, Henneberg B, and sucrose was the best carbon source for yeast growth and alcohol production. Optimum sugar concentrations for yeast growth and alcohol production were 15% and 25%, respectively. Optimum pH and temperature of the basal medium for growth of this strain were 4.5 and $30^{\circ}C$ respectively. The yeast growth was enhanced by the addition of 100 ppm of $Mg^{2+}$, but significantly inhibited by the addition of 100 ppm of $Co^{2+}$. Lower temperature and maintenance of optimum pH for yeast growth increased the final alcohol concentration. Under optimum condition for cell growth at stationary culture, generation time and specific growth rate of the strain were 7.5 hr and 0.092 $hr^{-1}$, respectively. At 8% initial alcohol concentration, yeast growth was inhibited about 50% and this strain could not be grown at more than 12% initial alcohol. The strain could be grown at less than 125ppm $SO_2$without alcohol addition, and at less than 75 ppm $SO_2$ with 8% initial alcohol. The higher sulfur dioxide concentration of a medium, the longer lag phase in yeast growth was observed. This strain could induced alcoholic fermentation at less than 10% initial alcohol concentration with 0 and 25 ppm $SO_2$, at less than 8% initial alcohol with 50 and 75 ppm $SO_2$, and at less than 6% initial alcohol with 100 and 125 ppm $SO_2$.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.4
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• pp.538-544
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• 1997

To utilize abundant poor persimmon fruits effectively, It was studied on alcohol fermentation strains which were isolated and indentified from poor persimmon fruits. The strains which had exellent alcohol production ability were analysized morphogical, cultural characteristics and identified Saccharomyces cerevisiae YJK 20, Sacachromyces kluveri DJ 97. Alcohol production ability between the isolated strains and industrial alcohol yeasts was compared in the YPD medium, persimmon extract medium. Isolated strains had high alcohol production ability in both of two medium, respectively. So it was expected that the strains. YKJ 20 and DJ 97 had good alcohol fermentation ability of persimmon fruits.

• Journal of Ginseng Research
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• v.3 no.2
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• pp.95-104
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• 1979

The effects of ginseng extracts on carbon dioxide generation, alcohol fermentation, and yeast cell production by Saccharomyces cerevisiae were investigated. The results are as follows. 1) In the process of fermentation, CO2 generation by yeast is faster in ginseng extracts media of 0.3%, 0. l% than in control. As the concentration of the extracts increases by 0.7% and 1.5%, CO2 generation is decreased. Among all these concentrations, CO2 generation is fastest in 0.3% of the extracts. 2) In the process of fermentation, the production of alcohol is larger in the order of 0.3%, 0.7% and 0.1% than in the control and least in 1.5%. 3) The number of yeast cell rapidly increased from 12 hours to 18 hours after cultivation and conspicuously increased in the order of 0.3%, 0.7%, 0.1%, control and 1.5%. 4) Dried yeast cell weight increased more in all the above concentration than control and among these it increased visibly in 0.3% of the extracts.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.469-473
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• 2006

Film-forming yeasts generate an undesirable yeasty flavor in fermented vegetables such as kimchi in the presence of oxygen. Antimicrobial materials including garlic oil (GO), heated garlic (HG), and allyl alcohol (AA) were investigated for use as alternative natural food preservatives to inhibit the growth of film-forming yeasts in fermented vegetables. Using the fermentation of cucumber pickles as a model system, GO, HG, and AA were effective in preventing film formation at concentrations of 0.006, 3.0, and 0.02%, respectively. The effectiveness of HG in preventing the growth of a film yeast, Hansenula anomala, was not influenced by pH, while that of potassium sorbate, a typical anti-yeast food preservative, was highly dependent on pH. All tested materials were effective when added at the beginning of fermentation due to their negligible inhibitory activity toward lactic acid bacteria.