• Title, Summary, Keyword: Yeast culture

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Automatic Counting of Yeast Cells in Baker's Yeast Culture Using PC Camera and Conventional Light Microscope (PC카메라와 일반광학현미경을 이용한 빵효모 배양액의 효모세포 자동계수)

  • Lee, Hyeong-Choon
    • KSBB Journal
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    • v.26 no.1
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    • pp.87-91
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    • 2011
  • Automatic counting of yeast cells in baker's yeast culture was tried using a conventional light microscope equipped with a pc camera. Relatively good binary image was obtained by using white LED as microscope light source, but uneven brightness distribution in original image hindered counting accuracy. A block binarization method using local thresholds proportional to local brightnesses was used to get improved binary images. The brightnesses of the blocks were expressed as the value component in HSV color model. Good quality binary images were obtained by binarization on $8{\times}6$ blocks of original images and connected-component labelling of the binarized images produced reliable counting results in the concentration range $1.4{\times}10^5/mL{\sim}1.4{\times}10^7\;cells/mL$.

Supplemental Enzymes, Yeast Culture and Effective Micro-organism Cultureto Enhance the Performance of Rabbits Fed Diets Containing High Levels of Rice Bran

  • Shanmuganathan, T.;Samarasinghe, K.;Wenk, C.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.5
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    • pp.678-683
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    • 2004
  • An experiment was carried out to study the effects of exogenous enzymes (cellulases and proteases), yeast culture and effective micro-organism (EM) culture on feed digestibility and the performance of rabbits fed rice bran rich diets over a period of ten weeks. Twenty four, 8 to 9 weeks old male and female New Zealand White rabbits were allotted to 4 dietary treatments; a basal (control) feed containing 43% rice bran, basal feed supplemented with either enzymes, yeast culture or EM. Individual feed intake, body weight gain, nutrient digestibility, carcass characteristics and feed cost were studied. Sex of the rabbits had no significant (p<0.05) influence on the parameters studied. The control group showed the lowest daily feed intake (104.8 g), body weight gain (12.8 g) and the highest feed/gain ratio (8.20 g/g). The highest daily feed intake (114.3 g), body weight gain (20.42 g) and the lowest feed/gain ratio (5.60) were observed with enzymes. Compared to the control, yeast significantly (p<0.05) improved the feed intake, body weight gain and feed/gain ratio by 4.9, 34.4 and 22.0%, respectively, while EM improved (p<0.05) them by 4.0, 32.6 and 21.6%, respectively. All the additives improved (p<0.05) the digestibility of dry matter, crude protein, crude fiber and energy by 4.9-8.7, 3.6-10.7, 5.9-8.3 and 4.3-6.4%, respectively. Higher weights of pancreas (by 38.5-56.4%) and caecum (by 13.1-26.8%, compared to the control) were recorded with all additives but liver weight was increased only by yeast (24.5%) and enzymes (26.7%). Significantly (p<0.05) higher carcass recovery percentages were observed with enzymes (60.55), yeast (60.47) and EM (56.60) as compared to the control (48.52). Enzymes, yeast and EM reduced (p<0.05) the feed cost per kg live weight by 23.8, 15.9 and 15.5%, respectively. Results revealed that enzymes, yeast culture and EM can be used to improve the feeding value of agro-industrial by-products for rabbits in Sri Lanka and thereby to reduce the feed cost. Under the present feeding system, enzyme supplement was the best.

Effect of Feeding Yeast Culture from Different Sources on the Performance of Lactating Holstein Cows in Saudi Arabia

  • Alshaikh, M.A.;Alsiadi, M.Y.;Zahran, S.M.;Mogawer, H.H.;Aalshowime, T.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.3
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    • pp.352-356
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    • 2002
  • One hundred-fifty lactating, multiparous cow at post-peak of lactation were used to examine the effect of dietary yeast supplementation on milk production, milk composition and ruminal fermentation. The cows were randomly allocated to three groups of fifty cows each: a control group fed on a basal diet without yeast supplementation and two groups fed on basal diets supplemented with one of two commercial sources of yeast cultures, given at the rates of 15 g/head/d ($YC_1$) and 50 g/head/d ($YC_2$), respectively, as per manufacturers' recommendation. Daily milk production was recorded for all cows, while milk samples were taken randomly from ten cows per group for two consecutive days at two-week intervals for chemical analysis of the milk. Rumen fluids were also analyzed for ammonia nitrogen and volatile fatty acids. The results indicated that cows consuming diets supplemented with yeast culture tended to decrease their dry matter intake and to increase their milk yield. Cows fed $YC_2$ supplemented diet produced more milk and 4% fat corrected milk than those fed either $YC_1$-supplemented diet or the control. The highest milk fat percentage was obtained in cows fed $YC_2$ supplemented diet while the highest percentages of protein, lactose, total solids and solids not fat were recorded in cows fed $YC_1$. Rumen ammonia nitrogen concentration decreased significantly after yeast culture supplementation. Molar proportion of volatile fatty acids did not change significantly with yeast supplementation.

Production of Yeast from the Acid Hydrolyzate of the Waste Composts of Oyster Mushroom (느타리버섯 폐상퇴비(廢床堆肥) 산가수분해액(酸加水分解液)을 이용(利用)한 효모생산(酵母生産))

  • Hong, Jai-Sik;Koh, Moo-Seok;Kim, Jeong-Sook;Lee, Keug-Ro
    • Applied Biological Chemistry
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    • v.27 no.4
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    • pp.231-237
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    • 1984
  • Culture conditions for yeast production from the acid hydrolyzate of the 2nd waste composts of oyster mushroom (Pleurotus ostreatus) were determined. Among the yeast strains tested, Candida quilliermondii JAFM 215, which was culture at $30^{\circ}C$, pH 5.0, showed good culture yield. Yeast production was the highest yield with the medium composition of 0.3% $NH_4Cl$, 0.15% $KH_2PO_4$, 0.02% $MgSO_4{\cdot}7H_2O$, and 0.05% $CaCl_2$. Yeast growth was increased at the concentration of 0.001 to 0.01% furfural, but at the higher concentration the yeast growth was inhibited. Utilization rate of sugar was 86.2%, and yield of yeast from sugar was 50.45%. Crude protein of yeast ranged from 50 to 52%.

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The Culture of free-swiming Copepod Secies Apocyclops sp. (Copepod; Cyclopoida)by baking Yeast (빵 이스트를 먹이로 이용한 부유성 코페포다 Apocyclops sp.(Copepod: Cyclopoida)의 배양)

  • Jung, Min-Min;Kim, Hyeung-Sin;Rho, Sum;Rumengan, Innke F.M.;Hagiwara, Atsushi
    • Journal of Aquaculture
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    • v.12 no.4
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    • pp.303-307
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    • 1999
  • Copepod is useful live food organism in the larval rearing. However of fin fish, culcures of copepod species (Specially calanoida and cyclopoida) were very difficult under artificial management conditions. In this study, we report successful culture of a free swimming cyclopodia copepod species (Apocyclops sp.) by easily baker's yeast as food. The maximum culture density of Apocyclops sp. was observed 11,200±2,660 ind/ℓ during the 30 days culture periods in the 1.5ℓ culture tanks. The nauplii were growth up maximum density 6,400±432 ind/ℓ on day 16th. The number of egg carring female was observed maximum density (666.7 ind./ℓ) of two times after 6days and 28 days of initial culture.

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Expression and Secretion of Human Serum Albumin in the Yeast Saccharomyces cerevisae

  • Kang, Hyun-Ah;Jung, Moon-Soo;Hong, Won-Kyoung;Sohn, Jung-Hoon;Choi, Eui-Sung;Rhee, Sang-Ki
    • Journal of Microbiology and Biotechnology
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    • v.8 no.1
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    • pp.42-48
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    • 1998
  • In order to maximize the secretory expression of human serum albumin (HSA) in the yeast Saccharomyces cerevisiae, a series of HSA expression vectors were constructed with a combination of different promoters, 5' untranslated regions (5'UTR), and secretion signal sequences. The expression vector composed of the galactose-inducible promoter GALl0, the natural 5'UTR, and the natural signal sequence of HSA directed the most efficient expression and secretion of HSA among the constructed vectors when introduced into several S. cerevisiae strains. Although the major form of HSA expressed and secreted in the yeast transformants was the mature form of 66 kDa, the truncated form of 45 kDa was also detected both in the cell extract and in the culture supernatant. The level of the intact HSA protein in the culture supernatant reached up to 30 mg/l at 24 h of cultivation in a shake-flask culture but began to decrease afterwards, indicating that the secreted HSA protein was unstable in a prolonged culture of yeast.

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Isolation of Ethanol-tolerant Strains of Yeast in Relation to Their Tolerant Mechanism (에탄올 내성 효모의 선별과 그의 에탄올 내성 기작)

  • 지계숙;박소영;이지나;이영하;민경희
    • Korean Journal of Microbiology
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    • v.29 no.2
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    • pp.136-142
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    • 1991
  • The selection of ethanol-tolerant strains was applied to enrichment culture of YPD broth medium containing various concentrations of ethanol. Isolates were identified to be Saccharomyces cerevisiae, the others as S. dairensis, S. exiguus, S. telluris, Saccharomycodes ludwigii, Schwanniomyces occidentalis var. occidentalis and Zygosaccharomyces florentinus. Among isolates S. cerevisiae YO-1 was screened as having the highest ethanol tolerance and produced 18% (v/v) ethanol after 4 days fermentation. The change of fatty-acyl residues represents that a progressive decrease in fatty-acyl unsaturation and a proportional increase in saturation in phospholipids of yeast cells during fermentation affected the yeast viability. Supplementation ethanol to the cultures led to an increase of unsaturated fatty-acyl residues, especially $C_{16}$ or $C_{18}$ residues, along with a decrease in the proportion of saturated residues in cellular phospholipids. Increasing the amount of soy flour led to an increase in the maximum number of viable yeast cells and ethanol production. It was possible in 4 days to reach 21% (v/v) ethanol by adding 4% soy flour as source of unsaturated fatty-acyl residues to the fermentation medium. Soy flour not only increased yeast population but also enhanced the physiological properties of yeast cells to be ethanol tolerant in the anaerobic culture.

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Biocatalytic Production of Aldehyde by a Methanol Utilizing Yeast, Hansenula nonfermentans KYP-l Grown in Methanol-limited Continuous Culture

  • Yoon, Byung-Dae;Kim, Hee-Sik;Kwon, Tae-Jong;Yang, Ji-Won;Kwon, Gi-Seok;Lee, Hyun-Sun;Ahn, Jong-Seog;Mheen, Tae-Ick
    • Journal of Microbiology and Biotechnology
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    • v.2 no.4
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    • pp.278-283
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    • 1992
  • Aldehyde production by cells of a methanol utilizing yeast, Hansenula nonfermentans KYP-1 was improved when they were grown in a methanol-limited continuous culture, in comparison with cells grown in a batch culture. A higher cell yield was also obtained in continuous culture than in batch culture. This could be due to the fact that a lower methanol concentration was maintained in the jar fermentor to minimize growth inhibition by methanol. A maximum cell productivity of 0.219 g.$liter^{-1}.hr^{-l}$ and a cell yield of 47% were obtained at dilution rates of 0.1 $hr{-1}$ and 0.06 hr{-1}, respectively. The greatest amount of aldehyde was measured at a dilution rate of 0.08 $hr{-1}$. Under optimum reaction conditions, 915.7 mM of acetaldehyde was produced from 1.5 M ethanol after 21 hours reaction, with a conversion rate of 61%. Propionaldehyde and acrolein were produced with conversion rates of 32.7% and 44%, respectively.

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Nutritional Conditions of Xylanase Production from Xylose Fermenting Yeast (Xylose 발효효모의 Xylanase 생성)

  • 배명애;김남순;방병호;서정훈
    • Microbiology and Biotechnology Letters
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    • v.17 no.2
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    • pp.85-87
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    • 1989
  • Cultural conditions for the formation of extracellular xylanase by Candida sp. X-6-41 were investigated. The xylanase was not produced in culture medium containing polypeptone or yeast extract as a nitrogen source, respectively, whereas the enzyme w8s produced in chemically defined medium containing (NH$_4$)$_2$SO$_4$as a sole nitrogen source. The xylanase production was affected by the amino acids such as isoleucine and tryptophan. The enzyme production of the strain was completely inhibited by the addition of isoleucine in the culture medium, but enhanced by tryptophan below the concentration of 25$\mu$g/$m\ell$.

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Optimum culture conditions of cell growth and polysaccharide production by Paecilomyces japonicain batch culture

  • Park, Seok-Jae;Byeon, Hak-Gyu;Han, Dae-Seok;Hong, Eok-Gi
    • 한국생물공학회:학술대회논문집
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    • pp.287-290
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    • 2000
  • To examine effects of agitation and aeration as well as adding of glucose and yeast extract on cell growth and polysaccharide production by Paecilomyces japonica, batch culture was carried out at 5L jar fermenter at $27^{\circ}C$ with the initial pH 7 for 7 days cultivation(innoculum size 2%, working volume 3L). Media compositions(g/L) were 30 glucose, 20 yeast extract, 0.5 $KH_2PO_4$, $0.1\;CuCl_2\;{\cdot}\;2H_2O$. Optimum culture conditions of agitation and aeration in batch culture were 400 rpm and 1.0 vvm, resulting in 23.1 g/L biomass and 2.5 g/L polysaccharide. Additional feeding of glucose and yeast extract with a pulse mode conferred an advantage on cell growth and polysaccharide production with showing the results of 29.2 g/L and 3.3 g/L, respectively.

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