• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.293-297
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• 2002

The cyclodextrin glucanotransferase (CGTase) gene from Bacillus stearothermophilus NO2 was expressed in Saccharomyces cerevisiae 2805 under the adhl promoter. The CGTase was purified from S. cerevisiae 2805/pVT-CGTS. The purified enzyme exhibited a optima of activity around pH 7.0 and $65^{\circ}C$. Thermal stability of the enzyme was increased fairly as compared with the CGTase of B. stearothermophilus NO2. The conversion yield of cyclodextrin (CD) and the production ratio of $\alpha$-, $\beta$,-, ${\gamma}$-CD from starch were showed similarly aspect to the CGTase of B. stearothermophilus NO2.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.331-335
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• 1996

Characteristics of ethanol fermentation were investigated during the stationary culture of a killer yeast, Saccharomyces cerevisiae B15-1. Specific ethanol production rate reached the maximum level, 1.203 g-EtOH/g-cell-hr, at 150 g/l of the initial glucose concentration. No big differences were obtained in ethanol fermentability based on the initial sugar concentration below 150 g/l. When 200 g/l of sugar was used, fermentability dropped significantly. Although the final cell mass and the amount of ethanol produced were increased, their increase rates were declined according to the increase of initial sugar concentration. It was found that most of the sugar used below 150 g/l of concentration could be changed to ethanol. However, when 200 g/l of sugar was used, some of them remained in the media even after increase of cell mass and fermentation stopped. The ethanol yield was decreased when initial sugar concentration was high, and were increased when the amount of ethanol produced was increased and finally reached the plateau over 60 g/l of ethanol concentration.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.1017-1024
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• 2014

This study was carried out to develop mulberry wines fermented with traditional microorganisms (Saccharomyces cerevisiae B-8). S. cerevisiae B-8 is a traditional fermentation microorganism isolated from domestically grown Rubus occidentalis. Each S. cerevisiae B-8 and Fermivin was inoculated into mulberry up to $1{\times}10^9$ CFU/kg, followed by incubation at $25^{\circ}C$ for 10 days. Mulberry fermented with S. cerevisiae B-8 (MBB) had a high alcohol content (16.47%), and the fermentation rate of MBB was faster than that of mulberry fermented with Fermivin (MBF). The total polyphenol and flavonoid contents of MBB were higher than those of MBF. DPPH radical scavenging activity of MBB was as high as that of MBF. ABTS radical scavenging activity of MBF was higher than those of MBB and mulberry juice (MBJ). In addition, reducing power of MBB was much higher than other samples. Flavor constituents of the two fermented wines were analyzed by gas chromatography and mass spectrometry. Twenty-three compounds from the sample were separated and identified as fifteen esters, six alcohols, an aldehyde, and an acetate. Particularly, tetradecanoic acid, ethyl ester of orris and violet flavor were ten times more abundant in MBB than in MBF. Several ester components were two times more abundant in MBB than in MBF. In conclusion, current findings indicate that MBB might have better antioxidant activities with flavor, which contributes to improved wine production with high quality and function.

• Food Science and Preservation
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• v.30 no.6
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• pp.1043-1055
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• 2023

This study was conducted to suggest an extraction method for preparing the extract from green tea leaves that possess enhanced antioxidant and antibacterial activities. Different ethanol concentrations were tested to recover phenolics and flavonoids, and 50% ethanol was the best under heat treatment (121℃, 15 min). The ethanol extract exhibited excellent DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and growth inhibition against B. cereus, B. licheniformis, S. aureus subsp. aureus, and A. hydrophila subsp. hydrophila. To enhance the antioxidant and antibacterial activities, cell-wall degrading enzymes (2.5% cellulose+2.5% pectinase, v/w dry sample) treatment and Saccharomyces cerevisiae fermentation were applied singly or in combination. The enzymatic treatment of green tea leaves notably increased extraction yield. However, the antioxidant and antibacterial activities of the extract were lower than those of the control (heat-treated 50% ethanol extract). In contrast, the yeast fermentation alone did not affect the yield, but enhanced antioxidant and antibacterial activities, contributing to the increase in the extract's total phenolic and flavonoid contents.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.118-123
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• 2005

For the expression in Saccharomyces cerevisiae, Bacillus stearothermophilus cyclodextrin glucano­transferase gene (cgtS) in pCGTS (4.8 kb) was subcloned into the surface expression vector, pYD1 (GALl promoter). The constructed plasmid, pYDCGT (7.2 kb) was introduced into S. cerevisiae EBY100 cells, and then yeast transformants were selected on the synthetic defined media lacking tryptophan. The formation of cyclodextrin (CD) was confirmed with active staining of culture broth of transformant grown on starch medium. Enzymatic reaction products with respect to the culture time and the reaction time were examined by TLC analysis. The results indicated that the enzyme activity was exhibited after 12 h cultivation and CD was produced after 10min of enzymatic reaction. When the surface-engineered yeast cells were cultured on galactose medium, maximum activities of CGTase were about 21.3 unit/l and 16.5 unit/l at $25^{\circ}C\;and\;30^{\circ}C$, respectively. The plasmids stability showed about $80\%\;even\;at\;25^{\circ}C\;and\;30^{\circ}C$.

• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.49-54
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• 2005

An experiment was conducted to investigate whether dietary yeast (Saccharomyces cerevisiae, SC) and its' structural components, i.e., yeast cell-extract (YE) and yeast cell-wall (CW) could influence growth performance, ileal morphology and serum lipids of male broiler chickens. There were four dietary treatments, each consisting of 6 replicates (10 birds per replicate). Chickens were fed a corn-soybean meal base control diet and diets containing SC ($0.5\%$), YE ($0.25\%$) and CW ($0.25\%$), respectively for 5-wk-experimental period. Dietary SC, YE and CW versus the control diet did not affect growth performance of male broiler chickens. Ileal morphology as to villus height, crypt depth and villus:crypt ratio of birds fed on the control diet was not significant from those fed on diets rich in SC, YE and CW, respectively. Dietary SC significantly lowered (P<0.05) serum total cholesterol by on average $19.7\%$ as compared to the control group. In addition, chickens fed on diets with either YE or CW lowered serum cholesterol by on average 15.3 and $12.5\%$, respectively as compared to the control albeit that the former only reached statistical significance. In conclusion, our study observed the hypocholesterolemic effect of SC in male broiler chickens. Moreover, YE, i.e., an extract of intracellular components of SC contains active molecules that are responsible far lowering serum cholesterol concentrations, but their identification at the molecular level needs to be assessed.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.5
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• pp.699-703
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• 2005

An experiment was conducted to investigate the effects of various dietary levels of Saccharomyces cerevisiae (SC) on the growth performance and meat quality (i.e., tenderness and oxidative stability) of Ross broiler chickens. Two hundred and forty dayold broiler chicks were fed four experimental diets with graded levels of SC at 0.0, 0.3, 1.0 and 3.0%. Each treatment consisted of six cages with 10 chicks per cage. Feed and water were provided ad libitum throughout the experiment that lasted for 5 wk. Birds were switched from starter to finisher diets at 3 wk of age. The average BW gains of broiler chickens increased (linear p<0.05) during either 0-3 or 0-5 wk of age as dietary SC levels increased. A linear effect (p<0.05) of SC on feed intake during either 4-5 wk or 0-5 wk of ages was also monitored. The addition of SC to the control diet significantly lowered shear forces in raw breast, raw thigh, and boiled drumstick meats (linear p<0.05). Upon incubation, 2-thio-barbituric acid-reactive substances (TBARS) values increased gradually in breast and thigh meats while more dramatic increase was noted in skin samples. The TBARS values of either breast or thigh meats were not significantly affected (p>0.05) by dietary treatments up to 10 d of incubation. At 15 d of incubation, TBARS values of breast and thigh meats from all SC-treated groups were significantly lower (p<0.05) than those of the control. It appears that dietary SC could enhance growth performance of broiler chickens, and improve tenderness and oxidative stability of broiler meats.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.32-36
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• 1988

The yeast gene HOM3 encodes aspartokinase, which catalyses the first step (aspartate to and from beta-aspartyl phosphate) of common pathway to threonine and methionine. The yeast HOM3 gene expression is known to be regulated by threonine and methionine specific control, and also by general control of amino acid biosynthesis. Isolation and characterization of the HOM3 gene are essential for the molecular genetic study on its regulation of expression. A recombinant plasmid pSC3 (15.5kb, vector YCp50) has been cloned into E. coli HB101 from yeast genomic library through their complementing activity of HOM3 mutation in a yeast recipient strain M34-24B. Organization of the plasmid was characterized by delineation of restriction cleavage sites in the insert fragment.

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.40-45
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• 2010

The gene encoding $\beta$-agarase (agaB) which hydrolyzes $\beta$-1,4 linkages of agarose from Zobellia galactanivorans was cloned and fused to Saccharomyces cerevisiae mating factor alpha-1 secretion signal ($MF{\alpha}1$), in which the transcription of $MF{\alpha}1$-AgaB was under the control of AOX1 (alcohol oxidase 1, methanol inducible) promoter. The constructed plasmid pPIC-AgaB (9 kb) was integrated into HIS4 gene locus of Pichia pastoris genome. Successful integration was confirmed by performing colony PCR. The transformed cells showed red halos around its colonies in methanol agar plate by adding iodine solution, indicating the active expression of agaB in P.pastoris. By SDS-PAGE and zymographic analysis, the molecular weight of $\beta$-agarase was estimated to be a 53 kDa and about 15% N-linked glycosylation was occurred. The activity of extracellular $\beta$-agarase reached 1.34, 1.42 and 1.53 units/mL by inducing 0.1, 0.5, and 1% methanol, respectively, at baffled flask culture of P.pastoris GS115/pPIC-AgaB for 48 hr. Most of the enzyme activity was found in the extacellular fraction and the secretion efficiency showed 98%. Thermostability of recombinant $\beta$-agarase was also increased by glycosylation.