• 한국균학회지
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• 제26권3호통권86호
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• pp.361-364
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• 1998

시험한 유기 질소원 중 yeast extract와 soytone이 Tricholoma matsutake DGUM 26001의 균사생장에 가장 우수한 질소원이었다. Yeast extract를 starch-pyridoxine 배지에 1.0% 농도까지 첨가하였을 때, 균사생장이 증가하였다. $24^{\circ}C$에서 30일간 yeast extract가 첨가된 배지에서 배양하였을 때, 50 ml 배양액에서 518 mg의 건조 균사체를 얻을 수 있었다.

• 한국미생물·생명공학회지
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• 제25권5호
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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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• 제10권1호
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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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• 제19권4호
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• pp.245-249
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• 2004

천연 식품 소재로 널리 사용되는 효모 추출물을 제조하는 공정의 개선을 위하여 제빵용 효모를 이용하여 자기소화법과 효소처리법을 병용하여 효모 추출물을 제조하였다. NaCl과 에탄올이 효모의 자기소화에 영향을 미치는 인자이었으며 최적 첨가량은 각각 3%와 1%이었다. 효모의 열처리와 효모 세포벽 분해효소의 사용은 유의하지 않았다. 효모를 자기소화 시킨 후 단백질 분해효소와 핵산 분해효소를 처리하고 Maillard 반응과 debittering 공정을 거쳐 효모 추출물을 제조하였다. 최종적으로 얻어진 효모 추출물의 수율은 고형분 기준으로 76%, 총 질소 기준으로 59%이었다. 맥주 효모를 이용한 결과와 비교하면 제빵용 효모를 이용하는 것이 맥주 효모를 이용하는 것보다 수율면에서도 유리하였다.

• Journal of Microbiology
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• 제45권2호
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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.

• 한국식품과학회지
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• 제24권3호
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• pp.221-225
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• 1992

국내에서 대량생산될 수 있는 자생가능한 자원인 배추의 비전통적 이용을 위해 배추즙액에 효모 Candida utilis를 배양하여 단세포단백을 생산하는 연구를 하였다. 배추의 당함량은 $2.1{\sim}4.0%$의 범위에 있었고 배추원액을 그대로 사용하여 C. utilis를 배양했을 때보다는 배추즙액을 적절히 희석하여 배양하였을 때 증식속도가 빨라졌고 소비된 당에 대한 건조균체생산율도 17%에서 약 50% 정도로 향상되었다. 배추즙액에 C. utilis를 배양하여 단세포단백을 생산하고자 할 때는 당의 함량이 1.0% 정도로 희석하는 것이 적절하였고 당함량을 1.0%되게 조정한 배추희석액에 영양원을 첨가하여 그 영향을 평가해 보았을 때 glucose, $KH_2PO_4$나 $(NH_4)_2SO_4$는 첨가효과가 없거나 오히려 균체생산량을 감소시킨데 비하여 yeast extract나 peptone은 건조균체 생산 및 균체의 단백질 함량을 $10{\sim}20%$씩 증가시키는 효과가 있었으나 yeast extract나 peptone의 첨가량에 비해 건조균체생산량의 증가가 적어서 배추즙희석액 자체로만도 효모배양을 위한 좋은 기질임이 확인되었다.

• 한국미생물·생명공학회지
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• 제23권1호
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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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• 제11권6호
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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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• 한국생물공학회 2001년도 추계학술발표대회
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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).

• 미생물학회지
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• 제14권1호
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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.