• Journal of Ginseng Research
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• v.18 no.1
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• pp.49-52
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• 1994

A yeast was isolated from the spoiled ginseng product. The isolate was ellipsoidal shaped yeast measured around 2.0 to 2.5 w in diameter. The strain formed pseudomycelium on potato-dextrose agar medium. The isolated yeast used glucose as fermentable sugar, and showed assimilation activity for glucose, sorbitol and mannitol. The strain was also able to grow in the presence of 1% acetic acid and 50% (w/v) glucose-yeast extract agar. The isolated osmophilic yeast was identified as a strain of Zygosauharomyce sp.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.143-148
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• 1996

Thousand actinomycetes and 50 soil samples were used for the isolation of microorganisms producing yeast cell wall lytic enzymes. Among 493 strains producing large clear zones on autolysed washed yeast (AWY), 117 strains were selected on living yeast cell agar plates. With the method of lytic activity, one strain (St-1702) was selected, which was temporarily identified as Streptomyces eurythermus. The optimal condition for enzyme production of this strain was partially determined as follows: incubation of the strain for 3 days at 30$\circ$C in the medium containing 2% freeze dried yeast cell, 1% glucose, 1% K$_{2}$HPO$_{4}$, 0.01% MgSO$_{4}$'7H$_{2}$O, 0.5% peptone, and 0.2% (NH$_{4}$)$_{2}$CO$_{3}$ with pH 7.0. The protoplast formation of yeast by using the enzyme produced by this strain was compared with commercial enzymes.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1597-1604
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• 2006

To screen for an anti-yeast substance (AYS), many bacteria were isolated from soil and a strain AY2000 was selected. The strain AY2000 was identified as Rahnella aquatilis by morphology, biochemical properties, and 16S r-RNA nucleotide sequence analyses. The strain AY2000 showed anti-yeast activity against Candida albicans and Saccharomyces cerevisiae, whereas R. aquatilis ATCC33071 as a type strain did not show the activity against the yeasts under the same condition. The growth of yeast cell was significantly inhibited by AYS produced by the strain AY2000, as shown by optical density and MTT assay. The minimum inhibitory concentration (MIC) of the AYS against S. cerevisiae and C. albicans at $28^{\circ}C\;was\;20{\mu}g/ml\;and\;60{\mu}g/ml$, respectively. The MIC of AYS against hyphae of C. albicans at $37^{\circ}C\;was\;600{\mu}g/ml$. Scanning electron microscopic analysis revealed that yeast cells treated with AYS had an irregular form with a wrinkled and rough surface.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.445-451
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• 1996

The strain YCH-37, which produces yeast cell wall lytlc enzyme, was isolated from soil. From the microscopic observation, morphological and cultural characteristics, this strain was identified to fungus, Dicyma sp. So, we named this strain as Dicyma sp. YCH-37. The lytic enzyme effectively lysed Salmonella typhimurium among intact living bacteria and Torulopsis, Hansenula, Zygosaccharomyces among intact living yeast, as well as autoclaved yeast strains. The yeast cell wall lytic enzyme was succesively purified to 204 folds with 13% yields through yeast glucan affinity adsorption and DEAE-cellulose column chromatography. The enzyme was identified to monomeric protein with molecular weight of 25,000 daltons from the results of SDS-PAGE and gel filtration. The optimum pH and temperature for the yeast lytic activity were 8.0 and 50$\circ$C, respectively. The enzyme was stable up to 40$\circ$C, and between pH 4.0-pH 10.0.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.3
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• pp.354-357
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• 2005

The in vitro degradability of yeast and the effect of yeast on the in vitro degradability of forage may differ in terms of the specific yeast strains or their incubation conditions. Thus in experiment 1, two strains of sake yeast (strainK7 and strainK9) and one strain of bakers' yeast (KY5649) were incubated in an aerobic condition. In experiment 2, aerobically or anaero bically incubated K7 was used for investigating the in vitro degradability of yeast, the effect of yeast on the in vitro degradability of forage, and the degradability of yeast by pepsin and pronase treatment. The in vitrodegradability of bakers' yeast was significantly (p<0.05) higher than those of sake yeasts. The in vitro degradability of anaerobically incubated yeast was significantly (p<0.01) higher than that of aerobically incubated yeast. The degradability of bakers' yeast by pepsin treatment was significantly (p<0.01) higher than that of the sake yeasts. The degradability of bakers' yeast by pronase treatment was slightly higher than that of the two sake yeasts, while the degradability of anaerobically incubated yeast by both enzymes, respectively, was significantly (p<0.01) higher than that of aerobically incubated yeast. The degradability of forages was increased significantly (p<0.05) by the addition of yeasts. The degradability of roughage by sake yeast tended to be higher than that by the bakers' yeast. The degradability of roughage was significantly (p<0.05) higher by anaerobically incubated yeast than by aerobically incubated yeast. Given the above results, it seems that in vitro degradability of yeast and the magnitude of the increment of roughage degradation differ among the yeast strains and their incubation conditions.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.7-12
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• 1994

A yeast strain secreting glucoamylase was transformed with an expression vector (pMS12) containing the promoter of yeast alcohol dehydrogenase I gene ADC1, mouse salivary $\alpha$-amylase cDNA, and a segment of yeast $21\mu m$ plasmid. The transformed strain could produce ethanol from starch (4%, w/v) through a direct one-step process with the conversion efficiency of 93.2%, during 5 days of fermentation, while the original, untransformed strain exhibited a conversion efficiency of 38.1% under the same condition. When the regulatory site of the ADC1 promoter region was removed, the production of ethanol increased to 29~37% in the presence of exogenous 3%(v/v) ethanol in the fermentation medium.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.187-193
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• 2008

Biological removal capacities for volatile organic compounds (VOCs) were determined using a yeast strain, Candida tropicalis. In this study, VOCs including toluene, benzene, p-xylene, and styrene as single substrates or mixtures were tested in the batch culture of the yeast strain. In addition, a kinetic model was applied to evaluate substrate interactions between the VOCs. The yeast strain was able to biodegrade each VOC effectively as a growth substrate, implying it could applied to wide range of VOCs. When the yeast strain was subjected to VOCs in mixtures, the biodegradation rate of one substrate were either increased (stimulated) or decreased (inhibited) by the presence of the others. Both benzene and toluene were inhibited by the other VOCs, and substrate interaction parameters estimated in the model indicated that styrene was the strongest inhibitor for the benzene and toluene biodegradation. Meanwhile, the biodegradation of p-xylene and styrene was stimulated by the presence of either benzene or toluene. The biodegradation rate of p-xylene was significantly increased especially by the presence of toluene, and the styrene biodegradation was enhanced greatly by the benzene addition. The results of the substrate interaction by the yeast strain suggest that the biodegradation rates for the VOCs in mixtures should be carefully evaluated. Furthermore, the competitive inhibition coefficient could be applied as a useful index to determine the substrate interaction

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.355-359
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• 1992

Yeast cells of a fusant strain constructed by protoplast fusion of Saccharomyces cerevisiae and Kluyveromyces frugilis were immobilized on calcium alginate beads. The increment of the ethanol tolerance of this strain to 8.0%, when compared with the parent K, fragilis, was confirmed. Based on the results from jar fermentation, a packed-bed reactor of theh immobilized yeast cells was operated. The optimal performance of the immobilized yeast reactor for ethanol production was achieved when supplying 10% lactose (suplemented 1.0% yeast extract) at a temperature of 30.deg.C. The maximal ethanol productivity was obtained as 13.3 g/I/hr at a dilution rate of $0.76 hr^{-1}$.

• YAKHAK HOEJI
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• v.3 no.1
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• pp.15-20
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• 1957

Resume 1. The toxic effect of $CuSO_4$ on the growth of yeast began in the 0.2mM and colony formation was completely inhibited in the 3mM $CuSO_4$ media. 2. The yeast strain which was trained sucessively from lower concentration media to higher one, could grow even in 10mM $CuSO_4$ media. 3. Rlb strain produced brown pigment in copper media. 4. Resistance of Rlb strain to $CuSO_4$ did not revert in non copper media. 5. The appearance of resistant strain was regarded as the result of "Mutation and Selection". 6. The alcohol fermentation ability of Rlb strain was lower than that of parent strain. 7. Rlb strain yielded some effective substance which induced the parent strain to resist against $CuSO_4$. 8. The dehydrogenase activity of yeast was inhibited by $CuSO_4$.

• Journal of Species Research
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• v.10 no.4
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• pp.336-343
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• 2021

In 2020, as a subset study to discover indigenous yeast species in Korea, a total of 22 yeast species were isolated from soil samples collected in Gwangju-si, Gyeonggi-do. Among them, 10 strains were unreported species. From the high 26S rRNA gene sequence similarity and formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged independent and predefined yeast species. The 22 strains were assigned to the genera Dothiora (1 strain), Sarocladium (1 strain), Tetrapisispora (1 strain) and Torulaspora (2 strains) of the phylum Ascomycota; the genera Erythrobasidium (1 strain), Leucosporidium (4 strains), Ustilentyloma (2 strains), Fellozyma (1 strain), Sampaiozyma (2 strains), Filobasidium (1 strain), Solicoccozyma (2 strains) and Vishniacozyma (4 strains) of the phylum Basidiomycota. This is the first official report of the following species in Korea: Dothiora cannabinae (1 strain), Sarocladium strictum (1 strain), Fellozyma inositophila (1 strain), Filobasidium magnum (1 strain), Solicoccozyma phenolicus (1 strain), Solicoccozyma terreus(1 strain), Vishniacozyma tephrensis(1 strain) and Vishniacozyma victoriae (3 strains). Cell morphology, phenotypic features and biochemical features are described in the Species Description section.