• The Korean Journal of Mycology
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• v.45 no.4
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• pp.336-344
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• 2017

The anti-inflammatory effects of cell-free extracts from wild yeasts, Meyerozyma guilliermondii YJ34-2 and Rhodotorula graminis YJ36-1, caused by the inhibition of nitric oxide (NO) activity and cytotoxic effects were determined. Cell-free extracts from these two yeast strains had dose-dependent inhibitory effects on the production of lipopolysaccharide-induced NO and there were no cytotoxic effects on the treated cells or negative effects on their proliferation. Their cell-free extracts were also shown to have inhibitory effects on pro-inflammatory cytokines, such as tumor necrosis factor $(TNF)-{\alpha}$ and $prostaglandin-E_2$, in a dose-dependent manner. Maximal inhibitory activity on NO production occurred in cell-free extracts of Meyerozyma guilliermondii YJ34-2 cultivated at $30^{\circ}C$ for 24 hr and Rhodotorula graminis YJ36-1 cultivated at $25^{\circ}C$ for 24 hr in the yeast extract-peptone-dextrose (YPD) media.

• Molecules and Cells
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• v.26 no.3
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• pp.299-307
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• 2008

To characterize gene expression that is dependent on the strength of calorie restriction (CR), we obtained transcriptome at different levels of glucose, which is a major energy and carbon source for budding yeast. To faithfully mimic mammalian CR in yeast culture, we reconstituted and grew seeding yeast cells in fresh 2% YPD media before inoculating into 2%, 1%, 0.5% and 0.25% YPD media to reflect different CR strengths. We collected and characterized 160 genes that responded to CR strength based on the rigorous statistical analyses of multiple test corrected ANOVA (adjusted p value < 0.1 or raw p value < 0.0031) and Pearson correlation (|r| > 0.7). Based on the individual gene studies and the GO Term Finder analysis of 160 genes, we found that CR dose-dependently and gradually increased mitochondrial function at the transcriptional level. Therefore, we suggest these 160 genes are markers that respond to CR strength and that might be useful in elucidating CR mechanisms, especially how stronger CR extends life span more.

• KSBB Journal
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• v.14 no.2
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• pp.181-187
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• 1999

We have investigated industrial media for lactic acid fermentation to reduce the cost of nitrogen sources. Corn steep liquor (CSL) was successfully used at 5% (v/v) in batch fermentations. Use of soluble CSL improved the productivity about 20% with an advantage of clearer fermentation broth. Yeast extract-complemented CSL improved the productivity about 20% with an advantage of clearer fermentation broth. Yeast extract-complemented CSL media further increased the increased the productivity. It was found that 3.1 g/L yeast extract and 5% CSL could be an effective substitute for 15 g/L yeast extract in 10% glucose medium. Brewing yeast was also used as a sole nitrogen source equivalent to 5% CSL. A continuous culture coupled with cell-recycle by microfiltration at the dilution rate of 0.05-0.065 h-1 led to the highest lactic acid productivity. Lactic acid was recovered by electrodialysis from the cell free broth. Depleted cell free broth supplemented with 5-10 g/L of yeast extract performed reasonably in batch and continuous cultures. Reuse of the fermentation broth may reduce the cost of raw materials as well as minimize the fermentation wastes.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.151-166
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• 2023

Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1337-1340
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• 2008

The objective of this study was to evaluate the microbial safety of raw beef used to produce Korean beef jerky, The raw beef samples harbored large populations of microorganisms. In particular, psychrophilic bacteria were found to be most numerous ($9.2{\times}10^3-1.0{\times}10^5\;CFU/g$) in the samples. Mesophilic bacteria and anaerobic bacteria were present in average numbers ($10^3-10^5\;CFU/g$). Spore-forming bacteria and coliforms were not detected below detection limit. Yeast and molds were detected at $2.2{\times}10^1-7.8{\times}10^2\;CFU/g$ in the raw beef. Ten samples of raw beef were analyzed for the presence of pathogenic bacteria. Bacillus cereus was isolated from sample B, G, and H. The B. cereus isolates from raw beef samples were identified with 99.8% agreement according to the API CHB 50 kit.

• Applied Biological Chemistry
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• v.48 no.3
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• pp.246-251
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• 2005

The aim of this study was to evaluate an efficacy about activation on macrophage, using model that measured cell viability, nitric oxide (NO), iNOS (inducible nitric oxide synthase) expression and tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) on Raw 264.7 cells following treatment of Germanium-fortified Yeast in 0, 5, 10, 25, 50, 100, $200\;{\mu}g/ml$ and the same concentration of dried yeast without germanium. Cell viability (%) and NO produced in activated-macrophage were dose-dependant, a significant increase of the cell viability (132.5%) and NO in $10\;{\mu}g/ml$ (p < 0.05). Increase in iNOS level was in $10\;{\mu}g/ml$. $TNF-{\alpha}$ was produced dose-dependant, e.g. in activated-macrophage with a significant increase of the $TNF-{\alpha}$ in 5 and $10\;{\mu}g/ml$ (p < 0.05). Therefore, Germanium-fortified Yeast had an efficacy of NO mediated iNOS and $TNF-{\alpha}$ production by activated macrophage. This result showed that Germanium-fortified Yeast induced activation of cellular immunity, returned to normalcy on injured immune system and procured anticancer system by activation of macrophage, which was important in immune and anticancer function.

• Preventive Nutrition and Food Science
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• v.14 no.2
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• pp.102-108
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• 2009

The comparative immunomodulatory effects of ${\beta}$-glucans isolated from mushroom fungi (Coriolus versicol), yeast (Saccharomyces cerevisiae) and bacteria (Agrobacterium) on the major functions of macrophages were evaluated. As parameters of macrophage functions, we examined tumoricidal activity, phagocytosis, nitric oxide (NO) production, and the induction of inducible NO synthetase (iNOS) in RAW264.7 cells, following treatments with ${\beta}$-glucans from the three different sources. The results indicated that all ${\beta}$-glucan treatments significantly induced tumoricidal activity in the RAW264.7 cells, with a remarkable effect shown by the beta-glucan from Agrobacterium at a concentration of $10{\mu}g/mL$. There was also a significant increase in iNOS-NO system activity in macrophages treated with ${\beta}$-glucans extracted from yeast; however, iNOS-NO system activity was not markedly changed by the treatment of ${\beta}$-glucans from C. versicolor mushroom fungi or Agrobacterium. Furthermore, the ${\beta}$-glucans from C. versicolor had a significant phagocytotic effect at concentrations of 1, 10, and $100{\mu}g/mL$. Taken together, the present data suggest that these ${\beta}$-glucans, isolated from three different sources, have different effects on macrophage function, and therefore, may have different clinical uses in different for various types of diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.789-799
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• 1998

Literatures on microorganisms of traditional Korean nuruk published since 1945 were reviewed in this paper. Traditional Korean nuruk consists of raw barley and various grains. Traditional Korean nuruk consists of unbolied raw barely and various grains. They are ground to paste and moistened, and then naturally inoculated by airborne microorganisms. Therefore, many kinds of microorganisms such as fungi, yeast, and bacteria grwo in nuruk. Since 1945, new 14 species of Aspergillus and 9 species of Penicillium have been identified from traditional Korean nuruk. Total number of fungal species identified so far is now up to 38 species among 12 different genus. Among newly isolated fungal species, Aspergillus penicilloides and Penicillium, expansum showed not only high production rate of acid and amylase but also extreme stability of the enzyme at room temperature for 3 months. As examples of newly isolated yeast species, there are 5 species of Candida, 4 species of Hansenula, 1 species of Pichia and 1 species of Schizosaccharomyces. Total number of yeast species isolated so far is up to 18 species from different 8 genus. Newly isolated bacteria, were Bacillus pumilus, Lactobacillus casei and Leuconostoc mesenteroides.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.158-164
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• 2024

With the steady growth in the scale of the domestic traditional liquor industry, the interest in makgeolli has also been increasing. As the demand for makgeolli increases, interest in manufacturing differentiated makgeolli by adding additional raw materials such as fruits is increasing. In this study, makgeolli with low storage persimmon juice was manufactured, and the sweet taste of persimmon was imparted without adding sweeteners. Unsweetened, high-quality persimmon makgeolli with an alcohol content of 15% or more was manufactured and its quality characteristics were analyzed. Yeast was selected after producing fermented yeast by treating domestic isolated yeast and commercial yeast. Upon producing fermented yeast, persimmon makgeolli was manufactured by varying the amount of persimmon juice added to the fermented yeast. As a result of analyzing the quality characteristics of persimmon makgeolli, the pH was 4.02-4.25, the total acid (citric acid, %) was 0.30-0.43, the amino acidity (glycine, %) range was 0.05-0.15, and the alcohol content (%) was 15.64-18.48.(p<0.05). Reducing sugar (%) was 1.82-12.68 and total sugar (%) was 1.41-10.42, exhibiting a tendency to increase as the amount of reducing sugar and total sugar and the amount of juice added increased (p<0.05). Considering the sensory characteristics, a sample with 50% persimmon juice added showed a significantly higher residual sugar content, and the residual sugar content had a positive effect on the sensory characteristics. Therefore, 50% persimmon juice was added when making persimmon makgeolli. It is suitable for high-quality, non-sweetened persimmon makgeolli that preserves the taste of persimmon, which suits the consumers'taste.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.166-172
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• 1997

Aspergillus niger was selected as a strain producing the potent raw starch hydorlyzing enzyme. These experiments were conducted to investigate the conditions of the glucoa- mylase production, the purification of the enzyme, some characteristics of the purified enzyme and hydrolysis rate on various raw starches such as com, rice, potato, glutinous rice, sweet potato, wheat and barley. The optimum cultural temperature and time for the enzyme production on wheat bran medium were $30^{\circ}C$ and 96hrs, respectively. The respective addition of yeast extract and nutrient broth on wheat bran medium increased slightly the enzyme production. The enzyme was purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. The specific activity of the purified enzyme was 30.7u/mg-protein and the yield of enzyme activity was 25.8%. The purified enzyme showed a single band on polyacrylamide disc gel electrophoresis and its molecular weight was estimated to be 56,000 by SDS-polyacrylamide disc gel electrophoresis. The isoelectric point for the purified enzyme was pH3.7. The optimum temperature and pH were $65^{\circ}C$ and pH 4.0, respectively. The purified enzyme was stable in the pH range of pH 3.0-9.5 and below $45^{\circ}C$, and its thermal stability was slightly increased by the addition of $Ca^{2+}$. The purified enzyme was activated by $Co^{2+},\;Sr^{2+},\;Mn^{2+},\;Fe^{2+},\;Cu^{2+}$. Raw rice starch, raw corn starch, raw glutinous rice starch, raw sweet potato starch, raw wheat starch and raw barley starch showed more than 90% hydrolysis rate in 48hrs incubation. Even raw potato starch, most difficult to be hydrolyzed, showed 80% hydrolysis rate. The purified enzyme was identified as glucoamylase.