• The Korean Journal of Mycology
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• v.26 no.3 s.86
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• pp.361-364
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• 1998

Among the organic sources of nitrogen tested, yeast extract and soytone were excellent for the mycelial growth of Tricholoma matsutake DGUM 26001. The mycelial growth was enhanced, when yeast extract at the concentration up to 1.0% was added to the starchpyridoxine medium. After 30-day cultivation of the mycelia at $24^{\circ}C$ in the medium supplemented with yeast extract, 518 mg/50 ml of dry mycelia could be harvested.

• Microbiology and Biotechnology Letters
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• v.25 no.5
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• pp.512-519
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• 1997

RNA accumulating strain of Torulopsis versatilis MT-1 was cultured in molasses medium for higher contents of RNA in cell. Yeast cells were harvested at logarithmic phase on synchronous culture. Yield of cells on dry base to input sugar was 59.5%. Crude protein content was 55.1% in cell. RNA content was 13.9%. Some problems found in the process for the preparation of yeast extracts were improved by the addition of culture broth of Streptomyces faecalis MSF which secrete RNase (5' nuclease and 5' adenylic acid deaminase). When the culture broth of S. faecalis MSF was added in autolysis process 46% of RNA in cell was converted to I and G(5' inosinic acid and 5' guanylic acid) in extract. By addition of 3-7% culture broth of S.faecalis MSF in autolysis or enzymolysis process at the start or early stage, RNA in extract was converted easily to I and G and protein in cells was easily extracted and hydrolyzed to amino acid. Taste of those yeast extracts was delicious. The yeasty smell in yeast extracts was removed. And cell debris was easily removed from extract.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.85-90
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• 2005

A downstream process was developed for the production of yeast extract from brewer's yeast cells. Various downstream processing conditions including clarification, debittering, and the Maillard reaction were considered in the development of the process. This simple and economic clarification process used flocculating agents, specifically calcium chloride ($1\%$). After the clarification step, a Maillard reaction is initiated as a flavor-enhancing step. By investigating the effects of several operation parameters, including the type of sugar added, sugar dosage, glycine addition, and temperature, on the degree of browning (DB), giucose addition and reaction temperature were found to have significant effects on DB. A synthetic adsorption resin (HP20) was used for the debittering process, which induced a compositional change of the hydrophobic amino acids in the yeast hydrolysate, thereby reducing the bitter taste. The overall dry matter yield and protein yield for the entire process, including the downstream process proposed for the production of brewer's yeast extract were 50 and $50\%$, respectively.

• KSBB Journal
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• v.19 no.4
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• pp.245-249
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• 2004

A combined method of autolysis and enzymatic hydrolysis of baker's yeast was developed for the production of yeast extract, which is widely used as a natural food ingredient. From statistical analysis, NaCl and ethanol addition were found to be significantly effective factors in autolysis of yeast. The optimum dosages of salt and ethanol were 3% and 1%, respectively. Heat treatment and the use of cell lytic enzyme were not significantly effecting on the autolysis. Yeast hydrolysate was prepared by autolysis, followed by enzymatic hydrolysis using proteases, nuclease and deaminase. Additionally, the hydrolysate was processed by downstream process including Maillard reaction and debittering. The total dry matter yield and total nitrogen yield for the process were 76% and 59%, respectively. Compared to a process using brewer's yeast, when baker's yeast was used as a raw material, a higher recovery yield was obtained.

• Journal of Microbiology
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• v.45 no.2
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• pp.128-132
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• 2007

The red yeast Xanthophyllomyces dendrorhous (previously named Phaffia rhodozyma) produces astaxanthin pigment among many carotenoids. The mutant X. dendrorhous G276 was isolated by chemical mutagenesis. The mutant produced about 2.0 mg of carotenoid per g of yeast cell dry weight and 8.0 mg/L of carotenoid after 5 days batch culture with YM media; in comparison, the parent strain produced 0.66 mg/g of yeast cell dry weight and a carotenoid concentration of 4.5 mg/L. We characterized the utilization of carbon sources by the mutant strain and screened various edible plant extracts to enhance the carotenoid production. The addition of Perilla frutescens (final concentration, 5%) or Allium fistulosum extracts (final concentration, 1%) enhanced the pigment production to about 32 mg/L. In a batch fermentor, addition of Perilla frutescens extract reduced the cultivation time by two days compared to control (no extract), which usually required five-day incubation to fully produce astaxanthin. The results suggest that plant extracts such as Perilla frutescens can effectively enhance astaxanthin production.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.221-225
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• 1992

The possibility of using Chinese cabbage juice as a substrate for the production of Candida utilis cell mass was explored. Dry cell weight production and cell yield coefficient were 1.35-1.45 g/100 ml undiluted juice and 47-50%, respectively, when C. utilis was grown by shake flask culture at $30^{\circ}C$ for 24 hr on more than three-fold diluted Chinese cabbage juice to make the final sugar content be equal to or less than 1.0%. Supplementation of glucose(2%), $KH_2PO_4(0.2%)$ and $(NH_4)_2SO_4(0.2%)$ to three-fold diluted Chinese cabbage juice did not enhance the dry cell weight yield or the protein content of the yeast cell, while supplementation of yeast extract(0.2%) and peptone(0.2%) increased dry cell weight production and protein content but not as much as the amount of each nutrient added. It was found that Chinese cabbage juice was an excellent substrate for the cultivation of C. utilis.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.12-16
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• 1995

Medium components for lactic acid production were optimized with a strain of Lactobacillus sp., isolated by our Lab. Nitrogen source was the key component and manganese ion was also important for lactic acid production in this strain. Optimal concentration of manganese ion was 0.03 g/l as MnSO$_{4}$ 4 - 5 H$_{2}$O base. Other mineral elements, however, had little effect on it. Among the nitrogen sources we examined, yeast extract showed the highest productivity. Yeast extract, the exellent but very expensive medium component, could be partially replaced by soytone until 60% dry base with higher productivity, or by tryptone enforced with vitamines and nucleic acids. In order to replace yeast extract completely, we examined several inexpensive nitrogen sources and their enzymatic hydrolyzates. The hydrolyzate of vital wheat gluten was the best of them.

• Nutrition Research and Practice
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• v.11 no.6
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• pp.461-469
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• 2017

BACKGROUND/OBSECTIVE: Airway inflammation by eosinophils, neutrophils and alveolar macrophages is a characteristic feature of asthma that leads to pathological subepithelial thickening and remodeling. Our previous study showed that oxidative stress in airways resulted in eosinophilia and epithelial apoptosis. The current study investigated whether glutathione-containing dry yeast extract (dry-YE) ameliorated eosinophilia, goblet cell hyperplasia and mucus overproduction. MATERIALS/METHOD: This study employed $2{\mu}g$/mL lipopolysaccharide (LPS)- or 20 ng/mL eotaxin-1-exposed human bronchial epithelial cells and ovalbumin (OVA)-challenged mice. Dry-YE employed in this study contained a significant amount of glutathione (140 mg in 100 g dry yeast). RESULTS: Human bronchial epithelial cell eotaxin-1 and mucin 5AC (MUC5AC) were markedly induced by the endotoxin LPS, which was dose-dependently attenuated by nontoxic dry-YE at 10-50 ${\mu}g$/mL. Moreover, dry-YE inhibited the MUC5AC induction enhanced by eotaxin-1, indicating that eotaxin-1-mediated eosinophilia may prompt the MUC5AC induction. Oral supplementation with 10-100 mg/kg dry-YE inhibited inflammatory cell accumulation in airway subepithelial regions with a reduction of lung tissue level of intracellular adhesion molecule-1. In addition, ${\geq}50$ mg/kg dry-YE diminished the lung tissue levels of eotaxin-1, eosinophil major basic protein and MUC5AC in OVA-exposed mice. Alcian blue/periodic acid schiff staining revealed that the dry-YE supplementation inhibited goblet cell hyperplasia and mucus overproduction in the trachea and bronchiolar airways of OVA-challenged mice. CONCLUSIONS: Oxidative stress may be involved in the induction of eotaxin-1 and MUC5AC by endotoxin episode and OVA challenge. Dry-YE effectively ameliorated oxidative stress-responsive epithelial eosinophilia and mucus-secreting goblet cell hyperplasia in cellular and murine models of asthma.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.347-350
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• 2001

The dextran prodution by Leuconostoc mensenteroids NRRL-B512F was studied in a synthetic medium from sucrose as a sole carbon source. Especially, effect of nitrogen source was treated and compared in this study. In oder to maximize the cell growth and dextran produtivity through fermentation two nitrogen sources, yeast extract and tryptone, were used with various concentrations. At the end of fermentation, when the concentration of yeast extract was 9g/L we can obtain the maximum dry cell weight(14.1g/L), dextran dry weight(25.4g/L) and productivity(1.4g/L ${\cdot}$ hr).

• Korean Journal of Microbiology
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• v.14 no.1
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• pp.1-7
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• 1976

Effect of some nutrients on the growth of 3 yeast strains in the pulp mill waste liquor was determined during an attempt to lower the BOD content of the waste liquor and to produce the fodder yeast. The strains applied were Debaryomyces castelli Capriotti, D.phoffi Capriotti, and Cryptococcus luteolus (Saito)Skinner. The necessity of the addition of 0.2% ${NH_4}2SO_4$ 0.5% yeast extract, 0.2% $NH_2SO_4$, and 0.1% $MgSO_4$.$7H_2$O for the best growth of all three strains in the waste liquor was ascertained as a result. After 3-day treatment of the yeast cells on the waste liquor, the BOD content was lowered by about 60-70%. Harvested yeast cells contained ca. 75% water with 1.5-3% lipid, 40-46% protein, 50% carbohydrate and 3-5% ash on the dry weight basis, indicating the possibility of being utilized as the fodder yeast.