Saccharomyces cerevisiae inoculation with

Romani et al. (2011) also evaluated the yeast population dynamics and fermentation kinetics, and their influences on the analytical profiles of Vin Santo obtained at industrial scale utilizing in separate trials two non-Saccharomyces yeasts, T. delbrueckii and Z. bailii. These results were compared with those obtained both with spontaneous fermentation and with an inoculum of a S. cerevisiae yeast strain. The standard kinetics of fermentations were observed in all of the trials, also if a higher fermentation rate was observed in the trials inoculated with S. cerevisiae compared to those inoculated with the two non-Saccharomyces yeasts, and in the spontaneous one. A rapid decrease in non-Saccharomyces yeast was observed in the trials inoculated with S. cerevisiae. In these last ones, after 6 months, 18.4% ethanol was reached versus 16% of the trials inoculated with the non-Saccharomyces strains. No substantial differences were seen for the higher alcohols or other byproducts assayed. 

The shermat is inoculated with an active culture of Saccharomyces beticus or similar flor yeast. [As of 1981, this will be classified as S. cerevisiae, Ed.] Dehydrated flor yeast is not acclimated to ethanol and must be fermented to produce a yeast that will grow in 14.5 percent ethanol media. 

Figure 8.21 The content of different PolyP fractions in Saccharomyces cerevisiae cells in the process of growth after re-inoculation of late-logarithmic cells on the fresh medium with a high initial culture density (a) re-inoculation from a P -limited medium (with 1 mM P ) to a complete Reader medium (with 18 mM P ) (b) re-inoculation from a complete Reader medium to a fresh one (o) polyP(I) (A) polyP(II) ( ) polyP(III) (a) polyP(IV) (x) polyP(V). The growth curves are shown below in Figure 8.23(c).

Torrea, D., Fraile, R, Garde, T, Ancin, C. (2003) Rroduction of volatile compounds in the fermentation of chardonnay musts inoculated with two strains of Saccharomyces cerevisiae with different nitrogen demands. Eood Control, 14, 565-571. 

In many countries, alcoholic fermentation is induced by inoculation with a yeast starter culture of Saccharomyces selected for its desirable winemaking qualities (Kunkee, 1984 Kunkee and Bisson, 1993 Rainieri and Pretorius, 2000 Reed and Chen, 1978 Reed and Nagodawithana, 1988). Starter cultures of S. cerevisiae strains are generally used because of to their increased ethanol and sulfur dioxide resistance and production of desirable aromas and flavors (Boulton et al., 1996 Ebeler, 2001 Nykanen, 1986 Reed and Chen, 1978 Reed and Nagodawithana, 1988). 

FIG. 5 Viability of Saccharomyces cerevisiae (o) and Oenococcus oeni strain EQ-54 ( ) inoculated into a Chardonnay juice with the bacteria prepared using a diluted grape juice medium (A) or a lyophilized culture (B). (Adapted from Semon et al, 2001 and with the permission of the Australian Journal of Grape and Wine Research.)... 

Owen conducted experiments on sucrose inoculated with yeast and with organisms of the potato group, e. g., B. mesenterieus, B. vulgatus, and found that levan formation was very markedly reduced by excessive inversion in the presence of the yeast (or of yeast invertase) or by the addition of excess invert sugar. Apparently the nascent D-fructose liberated by yeast is not in a suitable condition for polymerization to levan. On the other hand (page 217), symbiotic association of L. mesenteroides with Saccharomyces cerevisiae produces much larger yields of dextran. ... 

Continuous SSF processes are usually operated in plug flow mode. Such processes will require pasteurization or sterilization of the substrate as it enters the bioreactor, mixing with an inoculum, and at the outlet end of the bioreactor, continuous removal of spent substrate. Such a process was operated on a pilot scale for the production of ethanol from fodder beets by Saccharomyces cerevisiae [81,82]. The bioreactor had a screw within a 4.7 m long and 15.25 cm diameter tube. The screw was rotated intermittently to mix the substrate and move it along the tube. At the front end was a hammer-mill and a pasteurization chamber for substrate preparation and a port for inoculation. New substrate was added, inoculated, and the screw rotated at 12-h intervals, resulting in a residence time of 72 h. 

Wine fermentation may occur spontaneously due to the presence of various desirable wine yeasts and wild yeasts found on the surface of grapes. Fermentation can also be conducted after must pasteurization by inoculation of the must with a pure culture of a selected strain of wine yeast. Wild yeasts include Saccharomyces apiculatus and exiguus, while the pure selected yeasts are derived from Saccharomyces cerevisiae var. ellip-soides or pastorianus. The pure wine yeast possesses various desirable fermentation properties. High fermenting strains are used to give high alcohol wines (up to 145 g/1) and those which are resistant to tannin and high alcohol levels are used... 

In an unsulfited and non-inoculated must, contamination yeasts can begin to develop within a few hours of filling the tank. Apiculated yeasts (Kloechera, Hanseniaspora) are the most frequently encountered. Aerobic yeasts also develop (Candida, Pichia, Hansenula), producing acetic acid and ethyl acetate. Brettanomyces and its characteristic animal-like odors are rare in must. Although such yeasts can be relatively resistant to sulfur dioxide (Fleet, 1992), sulfiting followed by inoculating with a selected strain of Saccharomyces cerevisiae constitute, in practice, an effective means of avoiding contamination (Section 3.5.4). 

Rossouw, D., Du Toit, M., and Bauer, F.F. (2012) The impact of co-inoculation with Oenococcus oeni on the trancrip-tome of Saccharomyces cerevisiae and on the flavour-active metabolite profiles during fermentation in synthetic must. Food Microbiol 29, 121-131. 

Samah, O.A., Ptih, M.F., and Selamat, J. (1992) Biochemical changes during fermentation of cocoa beans inoculated with Saccharomyces cerevisiae (wild strain). J Food Sci Technol 29, 341-343. 

Ten small scale fermentations were established with 5 L of crushed grapes from Vitis vinifera L cv. Cabernet Sauvignon. Each must was inoculated wiA a population of 10 cfii/mL of one of the ten yeast strains, all these belonged to Saccharomyces bayanus or cerevisiae. Three yeast strains of each regions were isolated from grapes collected in the Spanish apellation controUe regions of La... 

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