Washing, of yeast

Figure 8.4 The effect of fluorophore labeling and suspension washing of yeast suspensions. A Unwashed fluorophore labeled suspension concentration 0.50gL , A unwashed nonlabeled suspension concentration O.SOgL, washed fluorophore labeled suspension concentration 0.37gL ,...

FIGURE 13.3 Raw and deconvoluted mass spectra of a yeast ribosomal protein (L16) from a 2DLC(SCX/RP)/MS experiment were obtained, where mass spectral adducts were observed because of insufficient washing of the second-dimension RP column (Panel a, 7 column volumes of wash). Panel b shows mass spectra for the same protein from an experiment with sufficient second-dimension wash volumes (Panel b, 14 column volumes of wash). 

The liquid was then evaporated in vacuo to a small volume and two volumes of 95% ethanol were added. A small amount of flocculent precipitate, probably consisting of yeast polysaccharides, was removed by centrifugation, and the solution was concentrated to a sirup in a vacuum oven at 40°. This colorless sirup, when treated with hot absolute alcohol and stirred, set to a crystalline mass. The crystals were filtered, washed with alcohol and ether and dried in vacuo at 70°. The yield was 2.8 g. 

In a 500 ml flask with a shoulder was separately charged 50 ml of medium (pH 7.0) containing 0.5 g/dl of yeast extract, 1.0 g/dl of peptone, 1.0 g/dl of meat extract and 0.5 g/dl of NaCI followed by sterilization. One platinum loop of each microorganism shown in Table which had been preincubated in bouillon agar medium at 30°C for 16 hours was inoculated on the medium followed by shake culture at 30°C for 16 hours. After the cells were isolated from the obtained culture solution by centrifugal separation, the cells were washed with 0.05 M Tris-HCI buffer (pH 7.2) and further centrifuged to give washed cells. 

Presented below are four flow diagrams representing processes for washing the concentrated yeast suspension (the suspension concentrated from the fermentation medium by centrifugation). Which of these processes do you think would be suitable for washing the yeast suspension ... 

Yeast Food Product—The high percentage of nutritive material in yeast has led to its use as a food product since dried yeast contains 45 per cent, of albumenoids derived from the protoplasm of the ceUs. Yeast extract, prepared by heating well-washed beer yeast and evaporating in a vacuum pan to a syrupy consistency, has the appearance... 

In the early stages of fermentation there is a rapid development of yeast, for which the best temperature is about 17° to 21° C. the temperature rises as the operation proceeds, and the main fermentation in which the maltose and dextrose are transformed into alcohol occurs best at 26° to 30° C. At this temperature a secondary reaction also occurs, any dextrins which remain are acted upon by the diastase and gradually converted into fermentable sugars, which are then attacked by the yeast. The chief fermentation is over in about 48 hours, but the wort, now known as wash, is allowed to remain another day at 25° to 26° C. to complete the process. 

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