• Journal of Life Science
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• v.18 no.2
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• pp.287-290
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• 2008

In order to obtain yeast cells producing a bacteriocin, Subpeptin JM4-A or Subpeptin JM4-B, the 48 bp oligonucleotides corresponding to Subpeptin JM4-A and Subpeptin JM4-B genes including codon for start and stop were chemically synthesized and cloned into pAUR123, an yeast expression vector. Transformed yeast cells exhibited growth inhibition of Bacillus subtilis, Escherichia coli and Pseudonomas aeruginosa. This result indicates that yeast cells producing Subpeptin JM4-A or Subpeptin JM4-B possess bacteriocidal properties against both Gram positive B. subtilis and Gram negative E. coli and P. aeruginosa cells. The recombinant yeast strains constructed in this study can be applied in the food preservative or. animal foodfeed.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.101-105
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• 2008

In order to obtain yeast cells producing a bacteriocin OR-7, the 180 bp polynucleotide corresponding to the OR-7 gene including codons for start and stop was chemically synthesized and cloned into pAUR123, an yeast expression vector. Transformed yeast cells exhibited growth inhibition of Bacillus subtilis, Campylobacter jeuni, Escherichia coli and Pseudomonas aeruginosa. This result indicates that yeast cells producing OR-7 possess bacteriocidal properties against both Gram positive B. subtilis and Gram negative C. jejuni, E. coli and P. aeruginosa cells. The recombinant yeast strain constructed in this study can be applied in the food preservative or animal feed.

• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.659-667
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• 2006

In order to standardize the manufacturing processes of Hahyangju, a traditional Korean liquor, 29 yeast strains were isolated from traditional Nuruk. Strain N8 exhibited a particularly strong resistance to sugar. Strains HA2, HA3 and HA4 grew successfully in medium containing 10% ethanol. In comparison with the growth exhibited by these strains when grown in a yeast malt extract medium, the ethanol production rates for the three strains were 10.8%, 10.45%, and 10%, respectively in a yeast malt extract medium containing 25% glucose. Based on these results, HA3 was the strain selected for use in the manufacturing processes of Hahyangju and it was identified as a Saccharomyces cerevisiae strain with 97% ITS sequence similarity. The use of Saccharomyces cerevisiae HA3 causcd a decrease in the lactic acid content, acidity and growth of lactic acid bacteria in the fermentation mash. Following thc addition of Saccharomyces cerevisiae HA3 to the manufacturing process of Hahyangju, the second fermentation mash showed a 22% increase in the alcohol production rate associated with traditional fermentation; however, the amino acidity, pH and reducing sugar content showed little change. Sensory evaluation of Hahyangju fermented with S. cerevisiae HA3 also showed better scores than Hahyangju mashed by the traditional method.

• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.80-89
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• 1996

The expression and secretion of human lactoferrin (hLf) in Sacclnromyces diastaticus were performed. 1. For the secretion of hLf in yeast, recombinant plasmid pYEGLf was constructed using promoter, secretion signal sequence of glucoamylase I gene (STA1) and transcriptional terminator of GAL7 gene. 2. Each correct recombinant plasmid was selected by mini-preparation of plasmid DNA from E coli transformant and restriction enzyme digestion analysis. The selected plasmids, pYEGLf, were transformed into S. diastaticus YIY345 as a expression host, respectively. 3. Western blot analysis using rabbit anti-hLf was carried out to identify expressed hLf. Positive signals were shown in culture supernatant of pYEGLf transformant. 4. About $100{\mu}g-1mg$ of concentrated culture supernatant of positive clone were loaded on paper disc and tested for the antimicrobial activity against E coli. However, no activity was observed. We concluded that this fact results from low concentration of hLf secreted from yeast, compared with the fact that MIC of hLf is as high as $3mg/m{\ell}$. Therefore, the purification of secreted hLf may be require to investigate the antimicrobial activity. From this study, the feasibility of low-cost production of sufficient quantities of human lactofferin for nutritional and therapeutical applications were suggested.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.47-52
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• 2009

The aim of this study was to evaluate the effect of yeast(Saccharomyces exiguus SJPAF1, referred to as SA) addition on odor emission and contaminants reduction in piggery sluny. Four different rates of yeast addition were compared: no addition(SA0), 0.7L(SA0.7), 1.0L(SA1.0), and 1.5L(SA1.5) to one tone of piggery slurry. Odor emission tended to decrease with increasing the yeast application with concurrent effects of changes in temperature on outside of reactors. Particularly, reduction in ammonia emission was proportional to the yeast application rate; it reduced from 161.1 ppm in SA0 to 47.1 ppm in SA1.5 after 6 days of treatment Decomposition of piggery shiny by yeast increased to 13.8% more in SA1.5, and total amounts of piggery slurry decreased to 12.5% in SA1.5. Total coliforms were detected below 30MPN $ml^{-1}$ in SA1.5, while $8.3{\times}10^3$ MPN $ml^{-1}$ of Total coliforms were found in SA0. However, the effect of yeast addition in piggery slurry seemed to have no influence on the removal efficiency of contaminants such as BOD, COD, $NO_3^{-}-N$, $NH_4^{+}-N$, $PO_4^{-}P$. Consequently, the yeast(Saccharomyces exiguus SJPAF1) addition of 1.5% in the piggery sluny seems to have potential applicability for improving agent of pig-farm environment.

• Journal of Life Science
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• v.19 no.12
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• pp.1685-1689
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• 2009

Phytochelatins (PCs) are small polypeptides synthesized by PC synthase (PCS). They are present in various living organisms including plants, fission yeast, and some animals. The presumed function of PCs is the sequestration of cytosolic toxic heavy metals like cadmium (Cd) into the vacuoles via vacuolar membrane localized heavy metal tolerance factor 1 (HMT-1). HMT-1 was first identified in fission yeast (SpHMT-1), and later in Caenorhabdtis (CeHMT-1). Recently, its homolog has also been found in PC-deficient Drosophila (DmHMT-1), and this homolog has been shown to be involved in Cd detoxification, as confirmed by the heterologous expression of DmHMT-1 in fission yeast. Therefore, the dependence of HMT-1 on PC in Cd detoxification should be re-evaluated. I heterologously expressed SpHMT-1 in cytosolic PC-deficient yeast, Saccharomycea cerevisiae, to understand the dependence of HMT-1 on PC. Yeast cells expressing SpHMT-1 showed increased tolerance to Cd compared with control cells. This result indicates that SpHMT-1 is not strictly correlated with PC production on its function. Moreover, yeast cells expressing SpHMT-1 showed increased tolerance to exogenously applied glutathione (GSH) compared with control cells, and the tolerance to Cd was further increased by exogenously applied GSH, while tolerance in control cells was not. These results indicate that the function of SpHMT-1 in Cd detoxification does not depend on PCs only, and suggest that SpHMT-1 may sequester cytosolic GSH-Cd complexes into the vacuole.

• Korean Journal of Food Science and Technology
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• v.13 no.2
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• pp.91-100
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• 1981

As a primary study for SCP production from soybean curd waste water, selection of yeast and optimum cultivation condition of selected yeast on soybean curd waste water were investigated. Eighteen strains of the genus Candida and Saccharamyces were tested to compare their abilities to grow on soybean curd waste water. Candida utilis YUFE 1508 and Candida guilliermondii KFCC 35120 grew most successfully. Optimum pH and optimum temperature of the basal medium for growth of the two strains were $6.0{\sim}6.5$ and $25^{\circ}C$, respectively. The optimum culture medium of the two yeasts was soybean curd waste water supplemented with molasses 2.5% (as total sugar), ammonium acetate 0.1-0.3% (as nitrogen), $KH_2PO_4$ 0.1-0.2% (as phosphorus), and $K_2HPO_4$ 0.05% (as phosphorus). But yeast growth was not affected by metal salts. Under the optimum cultivation condition, the maximum cell weights of Candida utilis YUFE 1508 and Candida guillfermondii KFCC 35120 were 1.313g and 1.322g/100ml of culture broth respectively after 48 hr of cultivation. The cell yields of Candida utilis YUFE 1508 and Candida guilliermondii KFCC 35120 were 68.4% and 74.2%, respectively, based on utilized sugar. On the other hand, crude protein of dry yeast produced by Candida utilis YUFE 1508 and Candida guilliermondii KFCC 35120 under optimum condition was 54.0% and 56.8%, respectively.

• Journal of Animal Science and Technology
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• v.48 no.5
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• pp.691-698
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• 2006

Three species of the yeast Saccharomyces cerevisiae, Humicola grisea and Candida glabrata were assumed as microbial inoculants for fermentation of rice straw silage. Four types of silage innoculated with three yeasts including control (non-treatment) were opened on day 1, 3, 6, 9, 15 and 20 after ensiling, and analyzed for fermentation status (pH, crude protein, microbial counts) and the microbial population attached with silage texture using SEM (Scanning Electron Microscopy). The results obtained were summarized as fallow; The pH of silage juice was decreased to 4.3 after 6th day of fermentation in the treatments innoculated with yeast, but was not changed at the ranges of 5.47 to 5.67 in control. Crude protein concentration of silage was increased by 38～41% with yeast inoculation compared to control. From SEM observation, it could be confirmed that crude protein concentration of silage was increased by microbial growth and SCP synthesis. The yeast Saccharomyces cerevisiae and Candida glabrata could be used as useful fermenters of rice straw silage.

• The Korean Journal of Mycology
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• v.44 no.4
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• pp.307-313
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• 2016

To develop a functional strawberry Makgeolli, we produced Makgeolli using strawberry as an additive and then investigated its physicochemical properties. Among 7 different alcohol-fermenting yeasts, Saccharomyces cerevisiae JSK104 produced 17.4% ethanol on the 7th day of fermentation and was selected for use in the brewing of strawberry Makgeolli. Changes in physicochemical properties, numbers of yeast and lactic acid bacteria, and antihypertensive angiotensin-converting enzyme inhibitory activity were investigated during the fermentation of strawberry Makgeolli. The pH tended to decrease and the total acidity increased as the fermentation period elapsed. The ethanol content reached about 17% on the 7th day after fermentation, and the numbers of yeast and lactic acid bacteria reached a maximum on the 1st day of fermentation and then maintained a constant number. The antihypertensive angiotensin-converting enzyme activity reached a maximum after 5 days of fermentation and then was not significantly changed afterwards.

• Journal of Life Science
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• v.23 no.10
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• pp.1192-1198
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• 2013

To improve yeast strains for bioethanol production, yeasts with ethanol tolerance, thermotolerance, and ${\beta}$-1,3-glucanase activity were bred using yeast genome shuffling. Saccharomyces cerevisiae $BY4742{\Delta}exg1$/pAInu-exgA, which has extracellular ${\beta}$-1,3-glucanase activity, and the Aspergillus oryzae and S. cerevisiae YKY020 strains, which exhibit ethanol tolerance and thermotolerance, were fused by yeast protoplast fusion. Following cell fusion, four candidate cells (No. 3, 9, 11, and 12 strains) showing thermotolerance at $40^{\circ}C$ were selected, and their ethanol tolerance (7% ethanol concentration) and ${\beta}$-1,3-glucanase activity were subsequently analyzed. All the phenotypes of the two parent cells were simultaneously expressed in one (No. 11) of the four candidate cells, and this strain was called BYK-F11. The BYK-F11 fused cell showed enhanced cell growth, ethanol tolerance, ${\beta}$-1,3-glucanase activity, and ethanol productivity compared with the $BY4742{\Delta}exg1$/pAInu-exgA and YKY020 strains. The results prove that a new yeast strain with different characters and the same mating type can be easily bred by protoplast fusion of yeasts.