• Applied Biological Chemistry
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• v.30 no.1
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• pp.31-39
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• 1987

This study has been investigated the effect of Ganordema lucidum extract on Saccharomyces cerevisiae growth and physiology. Sacch. cerevisiae was inoculated in Hayduck solution medium which were added 0, 0.1, 0.5, 1.0% extracts of G. lucidum and fermented at $30^{\circ}C$ for 5 days respectively. Some results about cell number, alcohol content and carbon dioxide products during fermentation are as follows: $CO_2$ evolution of yeasts by addition of extract of G. lucidum was more increased than control after the fermentation for 120 hours. It was the most abundant by addition of 1.0% extract of pot-culture G. lucidum. The cell number of yeasts during the fermentation w as more increased than control by addition of extract of G. lucidum. It was by addition of extract of pot-culture G. lucidum that the cell number of yeasts was more increased than by each addition of extract of wood-culture G. lucidum and G. lucidum. Dry weight of yeasts was systematically increased in addition of extract of pot 0.5%>pot 1.0%>wild 1.0%>wood 1.0%=wood 0.5%>wild 0.5%>wild 0.1%>pot 0.1%>wood 0.1%>control in order. It was by addition of extract of pot-culture G. lucidum that. the dry weight of yeasts was more increased than by addition of woodculture G. lucidum and wild G. lucidum. Alcohol quantity by addition of extract of G. lucidum was increased more than 3 times after the fermentation for 72 hours compared with control but there was no any difference among them after the fermentation for 120 hours. The rate of sugar-consumption and fermentation of yeast by addition of extract of G. lucidum was highly increased during the early fermentation. As times went, there was no difference among them during the subsequent fermentation.

• Journal of the Korean Society of Food Culture
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• v.15 no.4
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• pp.233-239
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• 2000

In order to optimize the quality of pine sprout tea, its chemical properties were analyzed and the yeasts associated with the quality of pine sprout tea during the storage were isolated and identified. In proximate composition moisture content was 20.13%, but other components except sugar were relatively low. Sugars such as glucose(30.15%), fructose(19.57%), and sucrose(9.27%) were major sugars which contained up to 76.73%. Total vitamin C and soluble tannin contents were 11.31 mg% and 68.31 mg%, respectively. Thirteen kinds of free amino acids were detected, but they were contained only in trace. In fatty acid composition 64.69% of fatty aids composed mainly of saturated fatty acids and major fatty acids were oleic acid, palmitic acid, and tricosaenoic acid. Among 8 mineral elements detected, calcium content was highest with 79.00 mg% and followed by potassium(45.16 mg%) and magnesium(8.93 mg%). The sweetness of pine sprout tea was gradually decreased from $70^{\circ}\;Brix\;to\;63^{\circ}\;Brix$ and 3.2% of ethanol at the initial concentration was increased to 6.0% during the storage of 40 days. The yeasts associated with the quality and alcohol formation of pine sprout tea during the storage were identified by Biolog MicrostationlTM system, as Zygosaccharomyces rouxii, Kluyveromyces lodderae, Kluyveromyces wickerhamii, and Pichia fluxuum.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1539-1545
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• 2010

In beer, glutathione works as the main antioxidant compound, which also correlates with the stability of the beer flavor. In addition, high residual sugars in beer contribute to major nonvolatile components, which are reflected in a high caloric content. Therefore, in this study, the Saccharomyces cerevisiae GSH1 gene encoding glutamylcysteine synthetase and the Saccharomycopsis fibuligera ALP1 gene encoding ${\alpha}$-amylase were coexpressed in industrial brewing yeast strain Y31 targeting the ${\alpha}$-acetolactate synthase (AHAS) gene (ILV2) and alcohol dehydrogenase gene (ADH2), resulting in the new recombinant strain TY3. The glutathione content in the fermentation broth of TY3 increased to 43.83 mg/l as compared with 33.34 mg/l in the fermentation broth of Y31. The recombinant strain showed a high ${\alpha}$-amylase activity and utilized more than 46% of the starch as the sole carbon source after 5 days. European Brewery Convention tube fermentation tests comparing the fermentation broths of TY3 and Y31 showed that the flavor stability index for TY3 was 1.3-fold higher, whereas its residual sugar concentration was 76.8% lower. Owing to the interruption of the ILV2 gene and ADH2 gene, the contents of diacetyl and acetaldehyde as off-flavor compounds were reduced by 56.93% and 31.25%, respectively, when compared with the contents in the Y31 fermentation broth. In addition, since no drug-resistant genes were introduced to the new recombinant strain, it should be more suitable for use in the beer industry, owing to its better flavor stability and other beneficial characteristics.

• Food Science and Preservation
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• v.17 no.6
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• pp.807-813
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• 2010

Muscat Bailey A grapes, one of the major grape varieties in Korea, contain 18-20% (w/w) sugars, which is less than the amount required to make red wine. In the present study, fermentation of freeze-concentrated Muscat Bailey A grape juice to $24^{\circ}Brix$ was performed using several industrial wine yeasts, including Saccharomyces cerevisiae $OC_2$, S. cerevisiae Fermivin and S. cerevisiae W-3. During fermentation, changes in the levels of soluble solids, alcohols, and yeast viable counts were monitored. Wine quality parameters including organic acid, minor alcohol, sensory score, etc. were also analyzed. Alcohol contents reached maximal levels after 9 days of fermentation, and were 12.6% (v/v) when Fermivin was used and 13% (v/v) when strains $OC_2$ and W-3 were used. No major difference between strains was apparent, except that Fermivin fermentation was somewhat slower in terms of both alcohol production and sugar consumption. Similar levels of soluble solids and total phenols were measured in wines fermented by each of the three strains. The total acid level of W-3 wine was high, whereas the alcohol content of Fermivin wine was low. Although the wines were variable in terms of acetaldehyde and minor alcohol contents, the levels of these materials were much lower than the limits set by the Korean National Tax Service. Upon sensory evaluation, $OC_2$ wine obtained the highest scores in terms of color, flavor, and overall acceptance. However, the best taste score was awarded to the Fermivin wine, which had the same flavor score as $OC_2$ wine but a slightly lower overall acceptance score.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.794-800
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• 1999

This study was carried out to obtain the basic information for improving the flavor quality of yakju. Three kinds of yakju were prepared with different yeast strains to investigate the effects of those strains on flavor components. A total of 23 strains were isolated from fruits such as apple, pear, persimmon and citron and two strains were excellent in producing ethanol and flavors. They were identified as Saccharomyces cerevisiae S 2 and Saccharomyces cerevisiae S 6 from morphological cultural test and physiological quality. Yakju A, B and C were prepared with S 2, S 6 and Saccharomyces cerevisiae IFO 1950, respectively. Flavor components of yakju were analyzed by gas chromatography and mass spectr ometry. A total of 57 peaks were detected and 13 compound were identified. They were 4 alcohol, 2 esters, 7 acids and miscellaneous compounds.

• Journal of Microbiology
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• v.38 no.4
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• pp.209-217
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• 2000

Mycobacterium sp. strain JCl DSM 3803 grown in methanol showed no methanol dehydrogenase or oxidase activities found in mast methylotrophic bacteria and yeasts, respectively. Even though the methanol-grown cells exhibited a little methanol-dependent oxidation by cytochrome c-dependent methanol dehydrogenase and alcohol dehydrogenase, they were not the key enzymes responsible for the methanol oxidation of the cells, in that the cells contained no c-type cytochrome and the methanol oxidizing activity from the partially purified alcohol dehydrogenase was too low, respectively. In substrate switching experiments, we found that only a catalase-peroxidase among the three types of catalase found in glucose-grown cells was highly expressed, in the methanol-grown cells and that its activity was relatively high during the exponential growth phase in Mycobacterium sp. JCl. Therefore, we propose that catalase-peroxidase is an essential enzyme responsible for the methanol metabolism directly Of indirectly in Mycobacterium sp. JCl.

• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.222-229
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• 1994

In order to develop a method of economical production and to reduce energy-consumption in fuel alcohol production, we investigated the fermentation characters of two newly selected thermotolerant yeasts. The RA-74-2 showed stable and superior fermentability between 30 and $40^{\circ}C$ in 20% glucose media in comparison to the industrial strains. The optimum concentration of glucose for economical fermentation at $40^{\circ}C$ was 15-18%, and organic nitrogen was necessary for a satisfactory fermentation. The optimum pH was 4.0 and aeration was adversed for high temperature fermentation. Agitation was an important factor at $40^{\circ}C$ and the addition of magnesium ion 0.2% was required in this experiment. When the inoculum was increased, ethanol productivity as well as the speed of fermentation increased. On the other hand RA-912, which can grow at $48^{\circ}C$, showed similar fermentability between 30-$45^{\circ}C$ in 20% glucose media As the concentration of substrate decreased, fermentation ratio increased at $45^{\circ}C$ (45%, 65%, 95% fermentation ratio in 20%, 15%, 10% glucose media, respectively). Also, requirement of organic nitrogen and magnesium ion in RA-912 was similar in RA-74-2. The optimum pH for fermentation was 5.0, and the effects of agitation were enhanced at $37^{\circ}C$ than at $45^{\circ}C$. As the inoculum was increased, fermentation speed became more enhanced but the ethanol productivity was less affected. RA-912 showed fermentability with various substrates. Among the substrates used, inulin was the most promising substrate for the high-temperature fermentation. When 14.5% inulin was used as the substrate, 93% and 55% fermentation ratios were shown at $37^{\circ}C$ and $45^{\circ}C$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.435-443
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• 1989

The regulation of the synthesis of alcohol-oxidase(E. C. 1. 1. 3. 13) was investigated in the methanol-utilizing yeasts during growth on different carbon sources. For this experiment, Pichia pastoris CBS 2612 and Pichia pastoris CBM 10 were cultured in mineral salt medium by changing its carbon sources. The production of alcohol-oxidase was varied by the carbon sources. For example, alcohol-oxidase was undetectable in all strains submitted to the test in the medium with glucose, but its production was rapidely increased when the carbon source was changed from glucose to methanol after 48hrs of incubation. Moreover, this enzyme was not synthesized during growth on the primary aliphatic alcohols alone(ethanol, propanol, butanol or pentanol) or on the mixed substrates(0.5% methanol+0.5% primary aliphatic alcohols). When cells were grown on the various carbon sources(glucose, xylose, lactose, glycerol, galactose, saccharose, sorbose, lactic acid or acetic acid), The alcohol-oxidase activity was detected a very little amounts. These carbon sources together with methnol yieled far better synthesis of alcohol-oxidase than in case of carbon sources alone. Especially, the alcohol-oxidase activity of the cells grown on sorbose, lactose or lactic acid together with methanol was far better or similar than that of cells grown on methanol alone. The apparent Km values for the methanol of Pichia pastoris CBS 2612 and Pichia pastoris CBM 10 enzymes were 1.92 and 210 mM, respectively. It is also active towards alcohols of shorter alkyl-chain length than $C_7$, insaturated alcohols(allylalcohol, crotyl-alcohol) and secondary alcohols (iso-amylacohol, iso-butylalcohol). The affinity of alcohol-oxidase for this alcohols decreased with the increasing length of the alkyl-chain.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.2
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• pp.254-260
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• 2012

This study was conduced to ferment high quality wine by using Omija fruit. Dry Omija farmed and dried in the Moonkyung area was used in this study. The Omija was soaked in 10~40 folds of distilled water to extract water-soluble components and the fluid was filtered after soaking for 6 hours at $50^{\circ}C$. Strains of alcoholic yeast were isolated respectively from spoiled Omija extract. Isolated alcoholic yeasts, OM-1 and OM-2, showed a round to ellipsoidal shape and formed white or milky white colonies on a solid YM medium. Two yeasts produced 10.33~11.23% alcohol from Omija extract adjusted to $10^{\circ}Brix$ with sugar. Their abilities to ferment alcohol were higher than those of other yeast strains belonging to Saccharomyces cerevisiae such as KCTC 7296 (standard strain of Korean Biological Resources Center), Makgeolli yeast, or beer yeast. The isolates OM-1 and OM-2 showed similar abilities in alcohol fermentation. However, the wine fermented by OM-2 got a better sensory score especially with color. Growth of OM-2 was significantly accelerated by addition of a 0.1% urea and 0.02% mineral mixture. A vitamin mixture was effective for the growth only when urea was added as well.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.161-167
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• 1998

Whey is by-product from natural cheese manufacturing process. For alcoholic fermentation, the initial lactose content and pH were adjusted to 4.5% and 4.2, respectively. Two strains of yeasts (Kluyveromyces marxianus, Saccharomyces cerevisiae) and seven strains of lactic acid bacteria (Lactobacillus brevis, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus lactis, Leuconostoc cremoris, Lactococcus lactis and Streptococcus thermophilus) were examined for their alcohol production and sensory acceptability. Ethanol content in the whey fermented by lactose-fermenting K. marxianus was 2.8% at 4th day of incubation and that fermented by nonlactose fermenting S. cerevisiae was 0.2%. In case of mixed fermentation with yeasts and tactic acid bacteria (LAB being inoculated at 0 hr), the maximum ethanol production was obtained in the sample inoculated at 16 hr by s. cerevisiae, and in the sample inoculated at 24 hr by K. marxianus. The optimum temperature was $37^{\circ}C$ for alcohol production under static condition. The production of $CO_2$ gas was higher in the whey fermented by K. marxianus (1.88%) than by S. cerevisiae (0.04%). The titratable acidity of the whey gradually increased with fermentation time and its content was 0.39% at 4th day of fermentation by K. marxianus and 0.52% by S. cerevisiae. Among seven strain of latic acid bacteria tested, Lactococcus lactis exerted synergistic effect for acid production with K. marxianus. Therefore, overall results suggestd that the combination of Lactococcus lactis and K. marxianus was best choice in fermenting cheese whey for edible purpose.