• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1017-1021
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• 2004

To isolate a mutant which overproduces threonine and tryptophan, mutants of Saccharomyces cerevisiae were screened after UV and EMS mutagenesis. Hydroxynorvaline, a Thr analogue was used for selection of a Thr-overproducing mutant after UV mutagenesis. Among 31 mutants, TC 5-1 was selected as the strain candidate, based on amino acid analysis. TC 5-1 was then treated by EMS mutagenesis for Trp overproduction. Eight mutants were selected using fluorotryptophan for Thr and Trp overproducing strains. Amino acid analysis results showed that TC 6-1 was the best strain since it had the highest amount of Thr and Trp among mutants.

• The Korean Journal of Mycology
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• v.49 no.2
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• pp.243-248
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• 2021

In this study, screening of potent non-pathogenic wild yeast with high anti-dementia butyrylcholinesterase (BChE) inhibitory activity and production condition of a BChE inhibitor were described. Among 36 non-pathogenic wild yeasts, Saccharomyces cerevisiae WJSL 0113 showed the highest BChE inhibitory activity of 85.2%. The specific BChE inhibitor was maximally produced when S. cerevisiae WJSL 0113 was cultured at 30℃ for 48 h in a yeast extract-peptone-dextrose medium.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.290-295
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• 2009

Red-algae agar, consisting of D-galactose and 3, 6-anhydro-L-galactose, is usable for bio-ethanol production if hydrolyzed to monomer unit. The objective of this study is to produce bio-ethanol from agar using the heat and acid-treatment. Bio-ethanol was produced by Saccharomyces cerevisiae KCCM1129 strains using agar-pretreatment. The optimal condition for reducing sugar conversion by agar was found to be 15 min reaction at a HCl concentration of 0.1 N and $120^{\circ}C$. The optimum concentration for maximum cell growth was 0.1 N NaCl (17.88 g/L). Over 0.1 N NaCl, the cell growth decreased to 6.78~10.76 g/L. At 16% agar concentration, the ethanol production obtained by optimum pretreatment was found to be 10.16 g/L.

• Applied Biological Chemistry
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• v.35 no.3
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• pp.157-164
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• 1992

In order to produce nicotinamide adenine dinucleotide (NAD) which is a pyridine nucleotide coenzyme, Saccharomyces sake KBA No. 6 having high NAD content was selected from 12 strains of yeast and various factors affecting the production of NAD were investigated. For NAD production, 4% of glucose was effective as a carbon source and 2% of bactopeptone was the best nitrogen source. The optimum pH and temperature was 5.0 and $30^{\circ}$, respectively. Also, when 4 mg/ml of nicotinamide and 3 mg/ml adenine were used as precursors simultaneously, NAD production was the best. To increase NAD production, 2 valence metal ions were used during cultivation and $Zn^{2+}$ was very efficient. Among the surface active agents, anionic sodium dodesyl sulfate (SDS) was effective. Under the optimum conditions, the maximum amount of produced NhD was 35 mg/100 ml medium after cultivation of 144 hrs and 89% of total NAD amount, 31 mg of NAD, was leaked into culture broth.

• KSBB Journal
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• v.15 no.4
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• pp.388-392
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• 2000

An on-line glucose flow injection analysis system was developed and used for the automatic analysis and addition of glucose in the cultivationof a Saccharomyces cerevisiae in a korean paper digestion wastewater in order to increase the cell concentration. The system was composed of a ceramic sampler a sampling valve an injection valve an immobilized glucose oxidase column a debbble a flow cell with platinum electrodes a potentiostat a computer and interface system and tubing pumps. The glucose concentration of the wastewater medium was mainitained at the low concentration of $176{\pm}31 mg/L$ with the on-line FIA system and by adding glucose and $>(NH_4)_2S0_4$ the cell concentration as total cell count can be increased by 3.1times.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.90-94
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• 1988

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunodiffusion method were used for the species differentiation of yeasts, Saccharomyces cerevisiae, Candida utils, Candida tropicalis, and Kleuyveromyces fragilis. Comparing the electrophoretic patterns of soluble and membrane proteins, Saccharomyces cereνisiae was similar to Candida utilis but was different from Candida tropicalis and Kleuyveromyces fragilis. In immunochemical properties of soluble proteins, Saccharomyces cerevisiae was almost identical with Candido utilis. However, Saccharomyces cerevisiae or Candida utilis was quite different from Candida tropicalis and Kleuyveromyces fragilis in their immunoreactivities. In immunochemical properties of membrane proteins, almost the same results were obtained irrespective of four yeast species. By using SDS-PAGE and immunodiffusion methods, Saccharomyces cerevisiae and Candida utilis were difficult to differentiate but both species were easily differentiated from Candida tropicalis and Kleuyveromyces fragilis.

• Korean Journal of Microbiology
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• v.35 no.4
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• pp.302-306
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• 1999

Production of biomass by fed-batch culture of Saccharomyces cerevisiae Hansen CBS5926, which is used to treat intestinal disorders, was investigated using ethanol as the sole carbon source. Ethanol was a better carbon source than glucose for high cell density culture of the st-rain since it could decrease the frequency of contamination while increasing the efficiency and final productivity of the fermentation process. Under optimal conditions, 38 g/ℓ of dry cell weight with $2.2{\times}10^{9}$ cfu/㎖ of maximum viable cell count was achieved after 72h cultivation. Freeze-drying of the cultured yeast cells resulted in severe reduction of viability. Of the freeze-drying protectants tested, 20% sucrose and 30% lactose were most effective for the preservation of yeast cells with a viability level of 16.3%. A combination of skim milk and lactose with 20% sucrose(w/v) exerted no synergistic influence upo the viability of the cells during cryopreservation by freeze-drying.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.167-169
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• 2011

The Saccharomyces cerevisiae S288c strain does not show haploid and diploid filamentous growth, and biofilm formation, because it has a flo8 nonsense mutation unlike ${\Sigma}1278b$ strain which has a FLO8 gene. During the heat stress experiments to investigate the role of ScKns1, LAMMER kinase in S. cerevisiae, we found that ${\Sigma}1278b$ strain revealed heat sensitivity at $37^{\circ}C$, a mild heat stress in contrast to S288c strain. We also found that the disruption of ScKns1 and the addition of sorbitol suppress heat sensitivity of ${\Sigma}1278b$ strain. These results suggest the possibility that Flo8 and ScKns1 may interact to transducer a signal for regulating heat stress through a novel signaling pathway.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1904-1911
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• 2006

The cell-free extracts of 250 yeasts were screened for their in vitro anti-angiogenic activity, to develop a new cancer metastasis inhibitor. Saccharomyces cerevisiae K-7 was selected as the producer of the anti-angiogenic agent, because it had the highest anti-angiogenic activity. The anti-angiogenic agent was produced maximally from hydrolysates of Saccharomyces cerevisiae K-7, when the yeast was cultured in yeast extract-peptone-dextrose medium at 30$^{\circ}C$ for 24 h, and cell-free extracts were than digested with pepsin for 4 h at 37$^{\circ}C$. The anti-angiogenic agent was further purified by ultrafiltration, Sephadex G-25 gel permeation chromatography and reverse-phase HPLC, and the anti-angiogenic activity of the final purified preparation was 72.7% at 10 $\mu$M/egg. The purified anti-angiogenic agent was found to originate from the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) molecule of Saccharomyces cerevisiae K-7, and its peptide sequence was Val-Ser-Trp-Tyr-Asp-Asn-Glu-Tyr-Gly-Tyr-Ser-Thr-Arg-Val-Val-Asp. In the MTT assay, the shape of the HT-l 080 cell was clearly changed to a circular type at 0.2 mM purified anti-angiogenic agent. This result indicated that the growth of the HT-I080 cell was significantly inhibited at 0.2 mM of the purified anti-angiogenic agent. The MMP activity of the treated HT-l080 cells was not affected, evidenced by the gelatin zymography, indicating that the anti-angiogenic mechanism of the purified anti-angiogenic agent is not mediated through MMP activity.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.296-305
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• 2020

Tricholoma matsutake is an ectomycorrhizal fungus, related with the host of Pinus densiflora. Most of studies on T. matsutake have focused on mycelial growth, genes and genomics, phylogenetics, symbiosis, and immune activity of this strain. T. matsutake is known for its unique fragrance in Eastern Asia. The most major component of its scent is (R)-(-)-1-octen-3-ol and is biosynthesized from the substrate linoleic acid by the sequential reaction of lipoxygenase and peroxide lyase. Here, we report for the first time the biosynthesis of (R)-(-)-1-octen-3-ol of T. matsutake using the yeast Saccharomyces cerevisiae as a host. In this study, cDNA genes correlated with these reactions were cloned from T. matsutake, and expression studies of theses genes were carried out in the yeast Saccharomyces cerevisiae. The product of these genes expression study was carried out with Western blotting. The biosynthesis of (R)-(-)-1-octen-3-ol of T. matsutake in recombinant Saccharomyces cerevisiae was subsequently identified with GC-MS chromatography analysis. The biosynthesis of (R)-(-)-1-octen-3-ol with S. cerevisiae represents a significant step forward.