• Journal of Life Science
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• v.9 no.1
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• pp.22-25
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• 1999

In order to study the mechanism for the adaptation to salt stress, we mutagenized budding yeast Saccharomyces cerevisiae with Ethylmethane sulfonate, and isolated salt-tolerant mutants. Among the salt-tolerant mutants, two strains exhibit additional temperature sensitive phenotype. Here, we report that these two salt-tolerant mutants are specific to {TEX}$Na^{+}${/TEX} rather than general osmotic stress. These mutant strains may contain mutations in the genes involved in {TEX}$Na^{+}${/TEX} home-ostasis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.1
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• pp.101-107
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• 1993

Zygosaccharomyces rouxii is a salt-tolerant yeast which plays an important role during the ripening stage of soy sauce fermentation. Z. rouxii used in the experiment could grow in YPD (1 % yeast extract, 2% peptone and 2% glucose, pH5.0) medium with 18% (w/v) NaCl, whereas Saccharomyces cerevisiae could only grow in YPD medium with less than 8% NaCl. In the presence of 15% NaCl, Z. rouxii accumulates a large amount of glycerol as a compatible solute within the cells in the exponential phase. It is a characteristic of salt-tolerant yeasts. From the chemical analyses on membrane lipid fluidity, the membrane structure of the cells grown in 15% NaCl was suggested to become more rigid and its fluidity was decreased to keep glycerol within the cells in response to surrounding medium with high concentrations of salt.

• Journal of Microbiology and Biotechnology
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• v.7 no.1
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• pp.75-80
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• 1997

An ethanolic fermentation process was developed for preparing Doenjang with high ethanol. Higher and efficient viable cell production of salt-tolerant ethanolic yeast is a prerequisite for the successful commercial-scale process of ethanol production during Doenjang fermentation. Culture conditions of salt-tolerant yeast, S. cerevisiae KFCC 10823, was studied in terms of the effect of several environmental and nutritional factors. Viable cell numbers were the highest in a medium containing the following components per liter of water: soysauce, 300ml; dextrose, 50 g; beef extract, 5 g; yeast extract, 5 g; $KH_2PO_4$, 5 g; NaCl, 50 g. The optimal culture conditions of S. cerevisiae KFCC 10823 were pH 5.5, $25^{\circ}C$, 200 rpm and 0.5 vvm. Yeast viability during batch fermentation was gradually decreased to a level less than $90{\%}$ after 35 hours. The maximum cell number was $2.2{\times}10_7$ cells/ml at the optimal condition. Doenjang prepared with ethanolic yeast was ripened after 45 days at $30^{\circ}C$. This Doenjang contains 470 mg% of amino nitrogen and 2.5% ethanol. The shelf-life at $30^{\circ}C$ was theoretically estimated as 444 days.

• KSBB Journal
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• v.17 no.6
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• pp.509-514
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• 2002

Experiments were carried out to optimize the fermentation conditions for the production of erythritol by salt-tolerant mutant, Candida magnoliae M26. The optimum conditions of erythritol production showed a 1.0 vvm aeration and 500 rpm agitation at 28$\^{C}$ with an initial medium pH of 7.0. The pH control during the fermentation did not improve the erythritol yield and productivity. The maximum erythritol concentration of 143.3 g/L was obtained with 57% yield and 0.70 g/L-h productivity from 250 g/L of glucose and 5 g/L of yeast extract under an optimum fermentation conditions. The medium containing 0.5 M KCl or 0.5 M NaCl enhanced the production of erythritol and glycerol. However, glycerol production increased and erythrtiol production decreased by increasing the concentration of NaCl or KCl.

• Mycobiology
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• v.42 no.2
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• pp.198-202
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• 2014

Two new yeast records, Cryptococcus adeliensis YJ19-2 and Cryptococcus uzbekistanensis YJ10-4 were screened from 60 yeasts strains that were isolated and identified from wild flowers in Yokjido, Gyeongsangnam-do, Korea. The morphological and cultural characteristics of the newly recorded yeasts and the physiological functionalities of the supernatants and cell-free extracts obtained from their cultures were investigated. The two newly recorded yeasts did not form ascospores and pseudomycelia. They also grew well in yeast extract-peptone-dextrose broth. C. uzbekistanensis YJ10-4 grew in a vitamin-free medium and was also tolerant to sugar and salt. Antihypertensive angiotensin I-converting enzyme inhibitory activity of the supernatant from C. adeliensis YJ19-2 was high (71.8%) and its cell-free extract also showed very high (81.2%) antidiabetic $\acute{a}$-glucosidase inhibitory activity.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.856-862
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• 2015

The objective of this study was to optimize the slurry contents and salt concentrations for ethanol production from hydrolysates of the seaweed Eucheuma spinosum. A monosaccharide concentration of 44.2 g/l as 49.6% conversion of total carbohydrate of 89.1 g/l was obtained from 120 g dw/l seaweed slurry. Monosaccharides from E. spinosum slurry were obtained by thermal acid hydrolysis and enzymatic hydrolysis. Addition of activated carbon at 2.5% (w/v) and the adsorption time of 2 min were used in subsequent adsorption treatments to prevent the inhibitory effect of HMF. The adsorption surface area of the activated carbon powder was 1,400-1,600 m²/g and showed selectivity to 5-hydroxymethyl furfural (HMF) from monosaccharides. Candida tropicalis KCTC 7212 was cultured in yeast extract, peptone, glucose, and high-salt medium, and exposed to 80, 90, 100, and 110 practical salinity unit (psu) salt concentrations in the lysates. The 100 psu salt concentration showed maximum cell growth and ethanol production. The ethanol fermentations with activated carbon treatment and use of C. tropicalis acclimated to a high salt concentration of 100 psu produced 17.9 g/l of ethanol with a yield (Y_EtOH) of 0.40 from E. spinosum seaweed.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.82-85
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• 2007

내염성 조건에서 phytase를 생성하는 효모 균주를 개발하기 위하여 phytase를 생산하는 효모인 S. cerevisiae CY 균주와 내염성 효모인 Z. rouxii Y-80 균주 사이의 전기적 세포융합을 실시하였다. S. cerevisiae CY 균주의 Z. rouxii Y-80 균주의 배양된 세포를 1.0%의 ${\beta}$-mercaptoethanol로 전처리하고 Tunicase로 세포벽을 분해시킨 후 원형질체를 얻었다. 각 균주의 원형질체는 electrofusion 완충액에 1:1의 비율로 현탁한 후 AC 13V에서 30초간 처리하고 고전압(DC 500 V/100 ${\mu}sec$)을 가하여 전기적 세포융합을 실시하였다. 선별된 융합균주는 NaCl이 10% 첨가된 배지에서 친주들과 비교한 결과 Z. rouxii Y-80 균주보다는 생육면에서 25% 이상 증가하였으며, phytase 활성도는 친주인 S. cerevisiae CY 균주 대비 53%의 생성도를 확인하였다.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.766-771
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• 2008

The proteolytic enzyme from Saccharomyces sp. B101 was purified to homogeneity by ammonium sulfate fractionation, ultrafiltration, diethyl aminoethyl (DEAE)-Sephadex A-50 ion-exchange chromatography, and Sephadex G-100 gel filtration chromatography from the culture supernatant of Saccharomyces sp. B101. The specific activity and the purification fold of the purified enzyme were 4,688.9 unit/mg and 18, respectively. The molecular weight of the purified enzyme was estimated to be 33 kDa by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH and temperature for the enzyme activity were pH 8.5 and $30^{\circ}C$, respectively. The enzyme activity was relatively stable in the pH range of 6.5-8.5 at below $35^{\circ}C$. The salt-tolerance and stability for the enzyme activity were relatively stable even at NaCl concentrations of 10 and 15%. The activity of enzyme was inhibited by $Ag^{2+}$ and $Fe^{2+}$, and activated by $Mn^{2+}$. In addition, the enzyme activity was potently inhibited by ethylenediaminetetraacetic acid (EDTA) and phenylmethyl sulfonylfluoride (PMSF). Based on these findings we concluded that the purified enzyme was a serine protease. Km and Vmax values for hammastein milk casein were 1.02 mg/mL and 278.38 unit/mL, respectively.