• Bulletin of Food Technology
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• v.23 no.2
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• pp.214-219
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• 2010

Saccharomyces cerevisiae는 전통적으로 알코올 음료와 bioethanol 생산에 이용되지만, 발효가 진행되는 동안 효모의 에탄올 생성은 에탄올의 축적에 의한 충격으로 세포활성에 손상을 초래한다. 본 연구는 S. cerevisiae의 에탄올 스트레스 반응과 에탄올 내성의 분자적 기초에 관해 수행되었으며, 에탄올 스트레스가 진행되는 동안 효모의 에탄올 생성 향상을 위한 유전 공학 전략의 수립에 활용될 수 있다. 이전의 연구들은 유전자 발현에 대한 에탄올 스트레스의 충격이 환경적 영향을 받기 때문에 다양한 균주와 조건들에 관해 이루어졌다. 그러나 에탄올 공격에 의해 영향을 받은 gene ontology 범주에서의 일부 공통점은 S. cerevisiae의 에탄올 스트레스 반응이 해당과정 및 미토콘드리아 기능과 관련된 유전자 발현의 증가와 에너지가 요구되는 성장과정과 관련된 유전자의 발현 감소에 따라 에너지 생산에 제약 받음을 의미한다. Genomewide screens를 이용한 연구는 vacuole function의 유지가 에탄올 내성에 대해 중요함을 암시한다. 아마도 단백질 turnover와 이온 항상성 유지에 이 세포기관의 역할이 중요하기 때문인 것으로 사료된다. 특히 에탄올 스트레스가 일어날 때 핵 내 Asr1과 Rat8의 축적은 비록 이 가설이 논란이 많은 주제로 남아있지만 S. cerevisiae가 에탄올 스트레스에 대한 특별한 반응을 가지고 있음을 의미한다.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.158-164
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• 2008

The fusants which contain starch utilizing ability and alcohol fermenting ability were developed by protoplast fusion of Saccharomyces cerevisiae KOY-1 and Saccharomyces diastaticus KCTC 1804. Sacharomyces cerevisiae KH-12 was obtained by haploid induction from Saccharomyces cerevisiae KOY-1. The auxotropic mutants of yeast were obtained by using an ethylmethane sulfonate (EMS). The frequency of protoplast formation in Saccharomyces cerevisiae KOY-1 $(Met^-)$ and Saccharomyces diastaticus KCTC 1804 $(Trp^-)$ were 90.5% and 97.7%, respectively. The frequency of fusant formation was $1.79{\times}10^{-4 }$ for the regenerated protoplast and the 1,000 fusants were obtained. Fusant FA 776 was selected as a potential yeast which contain an alcohol fermenting ability in the starch medium. The genetic stability was 4.64% for 10 passages of generation. Fusant FA 776 produced 13mg/ml of alcohol in 24% starch medium and showed 1.86-fold higher alcohol fermenting ability than Saccharomyces diastaticus KCTC 1804.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.63-68
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• 2003

Saccharomyces cerevisiae KNU5377 is a constitutively thermotolerant, fermentative strain at high temperatures over 4$0^{\circ}C$. The exposure to 0.5 M NaCl caused S. cerevisiae KNU5377 to be lost its constitutive thermotolerance. Furthermore, the NaCl adaptation beyond 0.3 M during the overnight culture forced the strain-specific fermentation ability of S. cerevisiae KNU5377 to be disappeared. However, these phenomena did not occur in the reference, Saccharomyces cerevisiae ATCC24858. As a result, this adaptation led both strains to show the closely similar thermotolerance level and alcohol fermentation ability, implying the NaCl adaptation eliminated its strain-specific characteristics of S. cerevisiae KNU5377 Therefore it indicated that the superior intrinsic characteristics of S. cerevisiae KNU5377 must be related to the NaCl adaptation. On the other hand, the heat adaptation elevated alcohol productivity for both strains, but surprisingly did it for KNU5377 at the rate of two times higher than the reference's one; this suggests that KNU5377 possesses more efficient system enough to cause the difference. Consequently, these characteristics of S. cerevisiae KNU5377 must be interesting targets for further study to understand on how KNU5377 could acquire the constitutive thermotolerance and the outstanding fermentative capacity at high temperatures.

• Journal of Microbiology
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• v.38 no.1
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• pp.48-51
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• 2000

In liquid cultures using sucrose media, the coculture of Monascus with recombinant Saccharomyces cerevisiae expressing the glucoamylase gene from Aspergillus niger enhanced red pigment production by approx. 19％, compared with the coculture of wild type S. cerevisiae. Coculture with recombinant S. cerevisiae was more effective than with wild type S. cerevisiae for Monascus red pigment production. Cocultures of Monascus with commercial amylases of Aspergillus also induced high production of pigment and morphological changes in a solid culture using sucrose media.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.305-308
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• 1990

In order to clone the gene coding for 3-isopropylmalate dehydrogenase of Muyveromyces fragilis, a shuttle plasmid vector pHNll4 was used. It can serve as a cloning vector in Saccharomyces cerevisiae DBY746 for other Sau3AI-cleaved DNA segment of Kluyveromyces fragilis. Two cloned fragments which complement the leu2 mutation of Saccharomyces cerevisiae and E, coli were obtained. Their length was 4.4 kb an 3.5 kb, and their orientation was opposite each other. From the fact that the two recombinant plasmids were expressed in Saccharomyces cerevisiae and E, coli, probably the two inserts had the promoter of Ktuyveromyces fi-agilis and that of Kluyveromyces fiagilis was efficiently assosiated with RNA polymerase of Saccharomyces cerevisiae and E. coli. According to the result of Southern hybridization, we thought that the cloned fragment has low homology with 3-isopropylmalate dehydrogenase coding region of E. coli and Saccharomyces cerevisiae.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.485-492
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• 1996

myo-Inositol, a growth factor for Saccharomyces cerevisiae (S. cerevisiae), has been known to be incorporated into phosphatidylinositol (PI), which is a kind of phospholipid in the cell membrane, by a membrane-associated PI-synthesizing enzyme. The deficiency of myo-inositol in S. cerevisiae adversely affected the membrane structure and function. On the basis of biochemical functions of myo-inositol, the effect of deficiency of myo-inositol on the aerobic glucose metabolism was investigated by measuring specific oxygen uptake rate (Q$_{O2}$) used as an indicator representing the respiratory capacity of S. cerevisiae in batch and continuous cultures. The respiratory capacity of aerobic glucose metabolism in S. cerevisiae was also monitored after glucose pulse-addition in a continuous culture (D=0.2, 1/hr), in which glucose was utilized through respiratory metabolism. The deficiency of myo-inositol was found to lead to both the decrease of the maximum specific oxygen uptake rate (Q$_{O2max}$) observed from the batch as well as in the continuous culture experiment and the decrease of the respiratory capacity of aerobic glucose metabolism of S. cerevisiae determined from the glucose pulse-addition experiment, in which the glucose flux into respiratory and fermen- tative metabolism was quantitatively analyzed.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.977-982
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• 2008

The production of ethanol by microbial fermentation as an alternative energy source has been of interest because of increasing oil price. Saccharomyces cerevisiae and Zymomonas mobilis are two of the most widely used ethanol producers. In this study, characteristics of ethanol fermentation by Saccharomyces cerevisiae CHY1077 and Zymomonas mobilis CHZ2501 was compared. Brown rice, naked barley, and cassava were selected as representatives of the starch-based raw materials commercially available for ethanol production. The volumetric ethanol productivities by Saccharomyces cerevisiae from brown rice, naked barley and cassava were $0.68g/l{\cdot}h$, $1.03g/l{\cdot}h$ and $1.28g/l{\cdot}h$ respectively. But for the Zymomonas mobilis, $2.19g/l{\cdot}h$(brown rice), $2.60g/l{\cdot}h$(naked barley) and $3.12g/l{\cdot}h$(cassava) were obtained. Zymomonas mobilis was more efficient strain for ethanol production than S. cerevisiae.

• Journal of Life Science
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• v.11 no.2
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• pp.190-195
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• 2001

The cuclodextrin glucanotransferase (CGTase) gene of Bacillus macerans was subcloned at the downstream of yeast ADH1 promoter, and then the resulting plasmid pVT-CGTM(9.15 kb) was introduced into the yeast host strain, Saccharomyces cerevisias 2805. The transformed yeast, S. cerevisiae 2805/pVT-CGTM, showed the starch-hydrolyzing activity on the starch-azure plate. The optimal conditions for the CGTase expression were found to be 2% dextrose, initial pH5.5, 3$0^{\circ}C$, and 48hr cultivation. Under this condition, the extracellular CGTase activity reached at 0.53 U/mL, whereas the intracellular activity was about 0.03U/mL. This result indicates that the signal peptide of Bacillus CGTase functioned well in S. cerevisiae.

• KSBB Journal
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• v.11 no.2
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• pp.173-180
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• 1996

The contamination of the environment by heavy metals results in a serious public health problem due to the toxicity of those pollutants even at low concentrations. Microorganisms may be used to remediate wastewaters contamlialtd with heavy metals. The waste S. cerevisiae is an inexpensive readily available source of biomass for bioremediation of wastewater. S. cerevisiae was investigated for their ability to absorb Pb. The crushed biomass of S. cerevisiae exhibited higher Pb uptake capacity than the living S. cerevisiae and the sterilized S. cerevisiae. At the same metal concentration, metal uptake per unit concentration or adsorbent decreased when the biomass concentration rises. The order of the biosorption capacity of the living S. cerevisiae was Pb>Cu>Cd=Co>Cr. When S. cerevisiae was pretreated with 0.1 M NaOH, Pb uptake was increased by 150 percent and 0.1 M HC1, 0.1 M $H_2S_O4$ solutions were efficient in the desorption of Pb. The sorption equilibrium of Pb ions can be described by the Freundlich and Langmuir models.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1240-1249
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• 2005

Saccharomyces cerevisiae KNU5377 has potential as an industrial strain that can ferment wasted paper for fuel ethanol at $40^{\circ}C$ [15, 16]. To understand the characteristics of the strain, genome-wide expression was performed using DNA microarray technology. We compared the homology of the DNA microarray between genomic DNAs of S. cerevisiae KNU5377 and a control strain, S. cerevisiae S288C. Approximately $97\%$ of the genes in S. cerevisiae KNU5377 were identified with those of the reference strain. YHR053c (CUP1), YLR155c (ASP3), and YDR038c (ENA5) showed lower homology than those of S. cerevisiae S288C. In particular, the differences in the regions of YHR053c and YLR155c were confirmed by Southern hybridization, but did not with that of the region of YDR038c. The expression level of mRNA in S. cerevisiae KNU5377 and S288C was also compared: the 550 ORFs of S. cerevisiae KNU5377 showed more than two-fold higher intensity than those of S. cerevisiae S288C. Among the 550 ORFs, 59 ORFs belonged to the groups of ribosomal proteins and mitochondrial ribosomal proteins, and 200 ORFs belonged to the group of cellular organization. DIP5 and GAP1 were the most highly expressed genes. These results suggest that upregulated DIP5 and GAP 1 might take the place of ASP3 and, additionally, the sensitivity against copper might be contributable to the lowest expression level of copper-binding metallothioneins encoded by CUP 1a (YHR053c) and CUP1b (YHR055c) in S. cerevisiae KNU5377.