• Journal of Microbiology and Biotechnology
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• 제8권5호
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• pp.441-448
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• 1998

A cellobiose-utilizing recombinant yeast having $\beta$-glucosidase activity was developed for ethanol production from a mixture of glucose and cellobiose. Using $\delta$-sequences of Tyl transposon of yeast as target sites for homologous recombination, a heterologous gene of $\beta$-glucosidase was integrated into the chromosome of Saccharomyces cerevisiae. The $\delta$-integrated recombinant yeast, Saccharomyces cerevisiae L2612 (Pb-BGL), showed perfect mitotic stability even in nonselective media and showed ca. 1.5 fold higher $\beta$-glucosidase activity than the recombinant yeast harboring the $2\mu$-based plasmid vector system. A mathematical model was developed to describe the $\beta$-glucosidase formation and ethanol production from the Saccharomyces cerevisiae L2612 ($p\delta-BGL$). The model newly described that the heterologous $\beta$-glucosidase production mediated by ADH1 promoter is regulated by glucose and repressed by ethanol.

• 대한본초학회지
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• 제22권4호
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• pp.219-225
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• 2007

Objectives : We investigated the anti-aging effects on skin with Saccharomyces fermented modified Kyungohkgo extract (SFKE). Methods : Fermented modified Kyungohkgo extracts by 14 different kinds of microorganism were prepared and most effective Saccharomyces fermented modified Kyungohkgo extract among these was selected for anti-aging agent. We measured various effects related to skin such as scavenging activity against free radical, cell proliferation, collagen synthesis and toxicity of SFKE were evaluated and compared with modified Kyungohkgo extract (KE). Results : Free-radical scavenging activity and cell proliferating ratio of SFKE were 2 and 8 times higher than those of KE. The SFKE could significantly increase the collagen synthetic ratio compared with KE treated group. SFKE showed no toxicity at all tested concentrations. Conclusions : The results of our study propose that SFKE have good anti-aging effects on skin.

• 생명과학회지
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• 제12권4호
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• pp.483-489
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• 2002

S. cerevisiae에서 glucoamylase 유전자의 promoter와 signal sequence 그리고 MF$\alpha$1의 prosequence를 이용하여 합성 곤충 defensin를 발현하고 항균활성을 보유한 형태로 분비하는데 성공하였다. Defensin의 여러 생화학적인 특성을 조사한 결과 열 안정성이 높아 10$0^{\circ}C$에서 30분간 가열하여도 항균활성을 온전히 유지하였으며 조사한 pH 영역, 2.0-12.0에서 항균활성의 변화가 없었다. 또한 여러 단백질 분해효소를 처리하면 항균활성이 완전히 사라졌으나 전분질 분해효소, 섬유소분해효소 및 지질분해효소의 처리는 항균 활성에 전혀 영향이 없었다. 황산암모늄침전, SP-Sepharose column cormatography, RP-HPLC 등의 조작을 통해 defensin을 순수한 형태로 정제하였으며 Tricine-SDS-PAGE를 통해 분자량이 약 4.0 kDa임을 확인하였고 정제한 defensin은 항균활성을 보유하였다.

• KSBB Journal
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• 제15권3호
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• pp.274-279
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• 2000

한지자숙폐액을 사료첨가효모의 생산기질로 재이용할 수 있는 가를 검토하기 위하여 사료첨가효모제품으로부터 분리한 Sacch­a aromyces CereVlSlae종을 한지자숙폐액에 배양하였다. 자숙폐액원액에서는 균이 증식하지 못하였으나, 희석액에서는 증식하였으 며, 증류수로 7.5배 희석시 최대증식을 보였다. Jar fennenter배양 에서의 최대총균수는 $1.34{\times}107/mL$이었으며, 최대생균수는 $1.1{\times}107/mL$이었다. 배양액의 균체농도를 증가시키기 위하여 배양중 에 자숙폐액원액을 침가하여 총균수를 최대 $8.2{\times}107/mL$까지 증 가시킬 수 있었다. 지숙폐액원액과 함께 $(NH_4)_2S0_4 및 KH_2P0_4$ 까지 첨가함으로써 최대균체농도에 도달하는 시간을 단축시킬 수 있었다.

• 미생물학회지
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• 제23권2호
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• pp.90-100
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• 1985

The present study was designed to investigate cellular regulation of phosphate metabolism between catabolically repressed and derepressed states in yeast (Saccharomyces uvarum). The activities of various phospatases and the contents of phosphate compounds were detected according to the culture phase and various phosphate concentrations. As the results, Saccharomyces uvarum derepressed many phosphate metabolizing enzymes such as alkaline phosphatase, acid phosphatase and ATPase more than ten fold simultaneously during catabolic repression (phospgate and sugar starvation). At the same state, the amounts of orthophosphate, nucleotidic labile phosphate and acid soluble polypgosphate were increased, compared to basal levels of normally cultivated cells. $Mg^{++}-stimulated$ type among all phospatases was appeared to have most of the enzyme activity. It could be postulated that $K^+ -stimulated$ alkaline phosphatase was directly or indirectly correlated with the synthesis of acid insoluble polyphosphate $Mg^{++}-stimulated$ phosphatase with the degradation of polyphosphates. In case of cultivation in the medium supplemented with sugar and phosphate (catabolic derepression), phospgatase activities except for alkaline phosphatase were decreased rapidly through the progressive batch culture, After 12 hrs culture, at early exponential phase, the cellular accumulation of acid insoluble polyphosphate increased about 5 fold, compared to those of the starved cells. Under catabolic repression, it could be postulated that intracellular phosphate metabolism was regulated by derepressions of phosphatases. The function of polyphosphate system was shown to compensate the ATP/ADP system as phosphate donor and energy source especially during catabolic repression.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1318-1323
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• 2004

This study describes the purification and characterization of a novel antihypertensive angiotensin 1­converting enzyme (ACE) inhibitory peptide from Saccharomyces cerevisiae. Maximal production of the ACE inhibitor from Saccharomyces cerevisiae was obtained from 24 h of cultivation at $30^{\circ}C$ and its ACE inhibitory activity was increased by about 1.5 times after treatment of the cell-free extract with pepsin. After the purification of ACE inhibitory peptides with ultrafiltration, Sephadex G-25 column chromatography, and reverse-phase HPLC, an active fraction with an $IC_{50}$ of 0.07 mg and $3.5\%$ yield was obtained. The purified peptide was a novel decapeptide, showing very low similarity to other ACE inhibitory peptide sequences, and its amino acid sequence was Tyr-Asp-Gly-Gly-Val-Phe-Arg-Val-Tyr-Thr. The purified inhibitor competitively inhibited ACE and also showed a clear antihypertensive effect in spontaneously hypertensive rats (SHR) at a dosage of 1 mg/kg body weight.

• 한국미생물·생명공학회지
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• 제30권4호
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• pp.293-297
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• 2002

효모 S. cerevisiae에서 B. stearothermophilus 유래의 CGTase를 발현 생산하였으며, 분비, 생산된 단백질을 정제하여 그 특성을 조사하였다. 재조합 효모 S. cerevisiae 2805/pVT- CGTS가 생산하는 CGTase의 분자량은 효모에서 발현될 때 고당쇄가 부가되어 야생형의 68kDa에 비해 15-160% 증가된 약 78-178 kDa으로 나타났다. 효모 S. cerevisiae에서 발현된 CGTase의 효소반응 최적활성조건은 pH7.0, $65^{\circ}C$였고, 열안정성에 있어서 $75^{\circ}C$에서 약 90%의 잔존활성을 가질 정도로 내열성이 개선되었다. 효모 S. cerevisiae에서 발현된 CGTase는 5% soluble starch를 기질로 약 40.2%의 CD 전환율 및 3 : 6 : 1의 $\alpha$-, $\beta$-, ${\gamma}$-CD의 생산 비율을 나타내어 야생형과 별다른 변화가 없었다.

• 한국미생물·생명공학회지
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• 제23권5호
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• pp.624-631
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• 1995

The fermentation characteristics of Saccharomyces cerevisiae F38-1, a newly isolated thermotolerant yeast strain from a high temperature environment have been studied using a fermentation medium containing 20% glucose, 0.2% yeast extract, 0.2% polypeptone, 0.3% (NH$_{4}$)$_{2}$SO$_{4}$, 0.1% KH$_{2}$PO$_{4}$, and 0.2% MgSO$_{4}$ without shaking at 30$\circ$C to 43$\circ$C for 5 days. The fermentability was over 90% at 30$\circ$C, 88% at 37$\circ$C, 77% at 40$\circ$C and 30% at 43$\circ$C. A similar fermentation result was obtained at pH between 4 and 6 at 30$\circ$C and 40$\circ$C. Aeration stimulated the growth of the strain at the beginning of the fermentation, but it reduced alcohol production at the end of alcohol fermentation. Optimal glucose concentration was determined to be between 18 and 22% at 40$\circ$C as well as 30$\circ$C, but the growth was inhibited at the glucose concentration of over 30%. A fermentability of over 90% was observed at 40$\circ$C in 2 days when the medium was supplemented by 2% yeast extract. A higher inoculum size increased the initial fermentation rate, but not the fermentation. A fermentability of over 90% was achieved in 2 days at 40$\circ$C in a fermentor experiment using an optimized medium containing 20% glucose and 1% yeast extract.

• Journal of Microbiology
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• 제40권3호
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• pp.245-247
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• 2002

A genomic DNA library of the fungus Trametes versicolor was constructed in a yeast integration vector which contains the URA3 gene of the budding yeast Saccharomyces cerevisiae and the gene responsible for hygromycin B resistance, and fragments acting as autonomously replicating sequences (ARSes) in the budding yeast were identified from the genomic DNA library. Sixteen recombinant plasmids from the library transformed the budding yeast Saccharomyces cerevisiae to Ura+ at high frequencies. They were maintained stably under selective conditions, but were gradually lost from yeast cells at different rates under nonselective conditions, indicating that they contain eukaryotic origins of DNA replication and exist as extrachromosomal plasmids. Base sequences of four ARS DNAs among the 16 cloned fragments revealed that all or the four contain at least one 11 bp ［(A/T)TTTA(T/C)(A/G)TTT(A/T)］consensus sequence of the budding yeast ARS.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.219-224
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• 1992

식염농도 3로$15^{\circ}C$에서 발효시킨 물김치에서 젖산균과 효모의 균수변화를 측정한 결과 숙성기까지 효모의 수가 증가한 후 후기에 감소하는 것으로 나타났으며 숙성적기에 효모를 분리동정한 결과 Saccharomyuces sp.가 24주로 대부분을 차지하였으나 Kluyveromyces fragilis 3주, Torulopsis candida 2주도 발견되었다. 이 중에서 S.saitoanus Y17, S.capensis Y29, S.chevalieri Y13, K.fragilis Y2, T.candida Y9를 같은 김치에서 분리한 젖산균 Lactobaccillus plan tarum Lp2, Pediococcus pentosaceus P1, Leuconostoc mesentroides Lu5와 각각 혼합배양하여 효모와 생육에 미치는 영향을 조사한 결과 모두 생육이 억제되었으며, 이는 lacti acid나 H2O2에 의한 억제가 아닌 다른 물질에 의한 것으로 밝혀졌다. 이 세 종류의 젖산균에 의해 영향을 받는 정도는 효모의 종류에 따라 매우 큰 차이를 나타내었다.