• 대한화학회지
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• 제35권5호
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• pp.586-588
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• 1991

• Journal of Microbiology and Biotechnology
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• 제28권10호
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• pp.1664-1670
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• 2018

Titanium dioxide ($TiO_2$) has wide applications in food, cosmetics, pharmaceuticals and manufacturing due to its many properties such as photocatalytic activity and stability. In this study, the biosynthesis of $TiO_2$ nanoparticles (NPs) was achieved by using Baker's yeast. $TiO_2$ NPs were characterized by X-ray Diffraction (XRD), UV-Visible spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray analysis (EDX) studies. The XRD pattern confirmed the formation of pure anatase $TiO_2$ NPs. According to EDX data Ti, O, P and N were the key elements present in the sample. SEM and TEM revealed that the nanoparticles produced were spherical in shape with an average size of $6.7{\pm}2.2nm$. The photocatalytic activity of $TiO_2$ NPs was studied by monitoring the degradation of methylene blue dye when treated with $TiO_2$ NPs. $TiO_2$ NPs were found to be highly photocatalytic comparable to commercially available 21 nm $TiO_2$ NPs. This study is the first report on antimicrobial study of yeast-mediated $TiO_2$ NPs synthesized using $TiCl_3$. Antimicrobial activity of $TiO_2$ NPs was greater against selected Gram-positive bacteria and Candida albicans when compared to Gram-negative bacteria both in the presence or absence of sunlight exposure. $TiO_2$ NPs expressed a significant effect on microbial growth. The results indicate the significant physical properties and the impact of yeast-mediated $TiO_2$ N Ps as a novel antimicrobial.

• 한국수산과학회지
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• 제37권1호
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• pp.7-12
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• 2004

This study investigated the possibility of salinity acclimation of freshwater rotifers (Brachionus calyciflorus) as live food for sweetfish (Plecoglossus altivelis) larvae, and also examined the optimal salinity for the growth of sweetfish. Freshwater rotifers cultured in 0 and 4 PSU and seawater rotifers (B. rotundiformis) cultured in 33 PSU were supplied to the larvae with four kinds of enrichment material (condensed freshwater Chlorella, $\omega-yeast,$ baker's yeast, Super Selco) and larval growth at 4 PSU was examined. Growth of the freshwater rotifers positively increased from 0 PSU to 6 PSU, but decreased when over 8 PSU was reached. Growth and survival of the sweet fish larvae reared in 0 PSU were significantly lower than those reared in either 4 PSU or 33 PSU. This indicated that the freshwater rotifers (B. calyciflorus) could be used as live food for sweetfish larvae reared in 4 PSU. The body weight of sweetfish larvae fed on freshwater rotifers enriched with Super Selco was the highest at 0.163 mg, but there was no significant difference in survival and body length of the fish fed with the other enrichment materials. The content of n-3 HUFA of the sweetfish larvae fed on the freshwater rotifers enriched with Super Selco and the condensed freshwater Chlorella was higher than that enriched with $\omega-yeast$ and baker's yeast. These results indicated that B. calyciflorus cultured with the condensed freshwater Chlorella could be used for the sweetfish larvae without enrichment, and the most efficient enrichment material for B. calyciflorus is Super Selco.

• KSBB Journal
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• 제6권3호
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• pp.299-307
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• 1991

In this paper the effect of light on non-aerated Baker's Yeast(Saccharomyces cereuisiae) production and the protein excretion to the extracellular fluid is studied. Previous results in our laboratory indicate that at pH=5 and T-32$^{\circ}C$ yeast may be affected by light, but those differences seem to be within statistical variation of the data. In this paper, cell and extracellular protein concentrations along with redox potential are monitored for batch fermentations in the presence and absence of light at pH levels of 3 and 5 and at 31$^{\circ}C$, in order to explore whether possible light effects can be more readily discerned at lower pH values. Yeast particle size distributions are also determined over the course of fermentation using a particle counter in order to add one more measuring tool to our usual cell and total protein measurements. An apparently noticeable difference in the redox potential is observed between the light and the dark runs for early times for the pH=3 runs. The particle size distributions show differences in the particle diameters between light and dark runs at pH=3, but those differences fall within one standard deviation of the mean particle diameters.

• KSBB Journal
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• 제6권2호
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• pp.189-194
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• 1991

The effect of wtlitc light on unaeraten growth of Baker's yeast and the accompanying ethanol production has been studied in a batch process at 27$^{\circ}C$. Over the 80-hour period of the Champagne yeast process without pH control, the cull growth was inhibited by the fluorescent light. Another observed difference between the runs is that the drop and subsequent rise in redox potential occurred much sooner in the fermentation with light than in the fermentation without light. This preliminary study indicated that ethanol production could be enhanced by light as the cell concentration is repressed. The possible pathway, shift of the sugar substrate toward ethanol and away from cells was manifested by another difference as well. As observed under the microscope, many of the yeast cells grown under light budded without dividing by the normal fission process as they did in the dark. Furthermore, the undivided and branched (light grown) cell did not agglutinate at the end of the fermentation process as did the distinct spherical (dark grown) cells.

• 한국식품조리과학회지
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• 제11권1호
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• pp.9-12
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• 1995

냉동내성빵효모의 냉동내성기구를 규명하기위한 일환으로 세포의 막 유동성에 관계되는 지질분석을 행하였다. 그 결과, 냉동내성효모 $D_{2-4}$나 CFY보다 비냉동내성 효모 Saccharomyces cerevisiae 2001이 스테롤 : 인지질의 비율이 비교적 높았다. 또 인지질조성이 조사되었는 데, 세효모 모두에 있어 phosphatidylcholine 함량이 가장 높았다. Phosphatidylcholine : phosphatidylethanolamine의 비율은 냉동내성효모가 비내성효모 보다 높게 나타났다. 인지질에 연결된 지방산 함량을 보면, linoleic acid 함량은 $D_{2-4}$에서 높게 나타났으며 지방산의 불포화도는 $D_{2-4}$가 CFY나 S. cerevisiae보다 높았다. 이 결과에서 yeast 세포막의 유동성은 각 효모마다 다르며, 이것들이 저온에서의 효모의 동결장해에 영향을 주는 것으로 생각된다. 생각된다.

• 한국식품과학회지
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• 제11권4호
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• pp.242-248
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• 1979

Arthrobacter luteus로부터 분리(分離)한 zymolyase 조효소(粗酵素) 표품(標品)의 효모(酵母) 세포벽(細胞壁)에 대한 용해(溶解) 활성(活性)을 측정(測定)함에 있어서, 보다 적합(適合)한 조건(條件)을 찾기 위하여, 맥아즙(麥芽汁) 배지(培地)에서, 진탕 배양(培養)한 S. sake의 용해(溶解)에 관여(關與)하는 제(諸) 인자(因子)의 영향(影響)을 검사(檢射)하였다. 1. 본(本) 용해(溶解) 효소(酵素)에 대한 S. sake 생세포(生細胞)의 용해(溶解) 감수성(感受性)은 대수(對數) 증식기(增殖期)의 세포(細胞)는 높았고, 지체기 및 정상기(定常期)의 세포(細胞)는 낮았다. 그 중에서 특(特)히 18시간(時間) 배양(培養)된 세포(細胞)는 가장 높은 용해(溶解) 감수성(感受性)을 보였다. 2. 본(本) 용해(溶解) 효소(酵素)는 S. sake의 생세포(生細胞)에 대해서 아주 낮은 용해(溶解) 활성(活性)을 나타냈으나, 효모(酵母) 세포(細胞)를 아유산(亞硫酸) 소-다(0.05 M)로 전처리(前處理)하므로서 그 용해(溶解) 활성(活性)은 4배(倍) 이상(以上)으로 증가(增加)되었다. 3. 시중(市中)의 빵 효모(酵母)에 대해 본(本 ) 용해(溶解) 효소(酵素)의 활성(活性)은 지급히 미약(微弱)하였고 아유산(亞硫酸) 소다의 효과(效果)도 약하였다. 4. 동결(凍結) 건조(乾燥)시킨 빵 효모(酵母)의 세포(細胞)는 생세포(生細胞)의 경우 보다 높은 용해(溶解) 감수성(感受性)을 보였다. 그러나 동결(凍結) 건조(乾燥) 세포(細胞)의 경우, S. sake나 빵 효모(酵母)의 그 어느 세포(細胞)도 아유산(亞硫酸) 소-다에 의한 용해(溶解) 감수성(感受性)의 영향(影響)은 인정(認定)되지 않았다. 5. 효모(酵母) 세포벽(細胞壁) 용해(溶解)에 있어서, 그 반응(反應) 속도(速度)와 조효소(粗酵素)의 농도(濃度)와의 관계(關係)는 효소(酵素) 반응(反應) 속도론(速度論)에 준(準)하는 경향(傾向)을 보이는 것 같았으나, 반응(反應) 속도(速度)와 효모(酵母) 세포(細胞)의 농도(濃度)와의 관계(關係)는 효소(酵素) 반응(反應) 속도론(速度論)과는 다른 패턴을 보여주었다. 6. 0.05 M phoshate buffer (pH 7.5)에 용해(溶解)시킨 zymolyase 조세포(粗細胞) 표품(標品)을 $7^{\circ}C$에서 10일간(日間) 보존(保存) 시킨 결과(結果), 용해(溶解) 활성(活性)의 잔존(殘存)율은 약(約) 80 %였다.

• 한국미생물·생명공학회지
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• 제14권6호
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• pp.467-471
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• 1986

Fusarium moniliforme으로부터 순모세포벽 분해효소를 생산하고 분리, 정제하여 효소특성 및 protoplast 제조실험을 하였다. Ammonium nitrate를 0.2％ 첨가한 Baker's yeast 배지에서 7일간 진탕배양으로 효소를 생산한 후 Ammonium sulfate로 분획하고 Sephadex(G-100) column chromatography하여 세개의 peak를 얻었다 첫 번째 peak는 proteolytic, lytic activity 및 laminarin 분해력가를 보였으며, 두 번째 Peak는 lytic activity와 laminarin 분해력가를 동시에 가지고 있었으며, 세 번째 peak는 lytic activity만을 가지고 있었다. 분리된 세개의 peak를 혼합하였을때 개개의 peak보다 훨씬 높은 역가을 나타내어 상승효과를 보였고 또한 환원제에 의한 효소력가의 상승효과도 있었다. protoplast 수율은 99.2％정도였다

• Fisheries and Aquatic Sciences
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• 제8권4호
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• pp.235-242
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• 2005

Baker's yeast, Saccharomyces cerevisiae, has been widely used as a food organism for rotifers used in the larval production of marine fish. However, the nutritional value of the yeast is relatively poor compared with that of the marine alga Chlorella. We examined the nutritional value of another yeast, Candida utilis, and whether its food value could be increased through manipulation such as a cell wall treatment. Candida utilis and S. cerevisiae and their manipulated varieties were assessed with regard to the growth and nutrition of the rotifer Brachianus plicatilis. Larvae of the flounder Paralichthys alivaceus were cultured with rotifers fed on the yeast species, and the dietary value of the rotifers for the larvae was examined. Rotifers that were fed C. utilis grew faster than those provided with S. cerevisiae. Rotifers grew slightly faster on manipulated yeast than on non-manipulated yeast varieties. Of the two yeast species, C. utilis had better dietary value for rotifers. Flounder larvae cultured with rotifers that had fed on C. utilis displayed better growth and survival ($\%$) than did those cultured with rotifers that had fed on S. cerevisiae. Although the manipulated variety of C. utilis was better than the non-manipulated variety in terms of rotifer growth, the flounder larvae survived ($\%$) and grew better when they were fed rotifers that had eaten non-manipulated C. utilis. However, the nutritional value of this yeast species was still lower than that of Chlorella.

• 한국수산과학회지
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• 제30권3호
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• pp.319-328
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• 1997

연안해역에서 호기성 광합성 세균 Erythrobacter sp. $S\;\pi-I$I를 분리 및 동정하여 rotifer, Brachionus plicatilis의 먹이로 투여하였을 때 개체수, 체장, 체중 및 지방산 조성과 아미노산 조성을 분석한 결과를 요약하면 아래와 같다. 1. Erythrobacter sp. $S\;\pi-I$ 은 지방산의 함량중 $C_{18:1\omega9}$가 $36.5\%,\;C_{18:1\omega7}$이 $13.3\%\;C_{18:3\omega3}\;8.6\%$ 함유하였고 아미노산은 glutamic acid가 $61.6\;mg\%$, aspartic acid가 $45.2\;mg\%$, alanine이 $43.7\;mg\%$, lysine이 $28.7\;mg\%$ 등 높은 함량을 보였다. 2. Erythrobacter sp. $S\;\pi-I$을 rotifer, Brachionus plicatilis에 투여했을 때 (초기 개체수 5개체/$m\ell$) 개체수는 5일째 9개체/$m\ell$, 9일째 20개체/$m\ell$, 13일째는 43개체/$m\ell$로 증가하였다. 또한 체중은 초기 140ng/개체에서 5일째 280ng/개체, 9일째 560ng/개체, 13일째 610ng/개체로 증가하였으며, 체장은 초기 $150{\pm}7{\mu}m\;(length),\;85{\pm}14{\mu}m\;(width)$에서 5일째 $160{\pm}18{\mu}m\;(length),\;92{\pm}15{\mu}m\;(width)$, 9일째 $170{\pm}17{\mu}m\;(length),\;94{\pm}14{\mu}m\;(width)$, 13일째는 $184{\pm}17{\mu}m\;(length),\;100{\pm}12{\mu}m\;(width)$로 성장하였다. 3. Rotifer 개체당 24시간내에 $10^4\~10^5$개체의 세균을 섭취하였다. 4. Erythrobacter sp. $S\;\pi-I$을 rotifer에 먹이로 투여했을때 EPA, DHA가 증가하였다. 비교실험에 사용한 Chlorella sp. PSB, yeast에 비하여 EPA와 DHA의 함량이 높았다. 특히DBHA는 $S\;\pi-I$과 Chlorella sp.에서만 분석되었으며 $S\;\pi-I$이 높았다. 5. Erythrobacter sp. $S\;\pi-I$과 비교로서 PSB, Chlorella sp., yeast를 rotifer에 먹이로 투여했을 때 $S\;\pi-I$에서 lysine이 가장 높았고, PSB, Chlorellaal sp. 순으로 분석되었다. yeast에서는 검출되지 않았다.