Saccharomyces species

SSB, Saccharomyces species, RAD strains, differential toxicity + + 100 Sharp Parry (1981a)... 

Saccharomyces species other than S. cerevisiae have often been found during spontaneous fermentation of sweet wines, such as S. bayanus and S. paradoxus during the natural fermentation of Tokaj wine (Naumov et al., 2000,2002 Sipiczki et al., 2001) and S. uvarum in the natural fermentation for the production of Recioto and Amarone wines (Dellaglio et al., 2003 Torriani et al., 1999 Tosi et al., 2009 Zapparoli et al., 2003). 

Using direct isolation, without enrichment, Saccharomyces species were not found on Tokaj aszu berries (Csoma, 2008 Magyar, 2006 Magyar and Bene, 2006), although Naumov et al. (2002) reported the presence of S. uvarum and S. cerevisiae on Tokaj grapes (method of isolation unknown). During spontaneous fermentations, however, diverse Saccharomyces populations can be detected in botrytized musts (see Section IV.C). 

These results suggest that non-Saccharomyces species may contribute significantly to the fermentation of botrytized wines. C. zemplinina seems not to produce excess volatile compounds nor any specific aroma compounds (Toth-Markus et al., 2002). Its main contribution to the chemical composition might be an increase in glycerol content and in the G F ratio. C. zemplinina and C. stellata have proven to be very fructo-philic yeasts (Mills et al., 2002 Magyar and Toth, 2011 Magyar et al., 2008). 

Carbohydrase (Saccharomyces species) Produced as a white to tan, amorphous powder by controlled fermentation using a number of species of Saccharomyces traditionally used in the manufacture of food. Soluble in water (the solution is usually light yellow), but practically insoluble in alcohol, in chloroform, and in ether. Major active principles (1) in-vertase and (2) lactase. Typical applications used in the manufacture of candy and ice cream and in the modification of dairy products. 

Carbohydrase (Saccharomyces species) Produced as a white to tan, amorphous powder by controlled fermentation using a number of species of Saccharomyces traditionally used in the manufacture of food. Soluble in water (the solution is usually light... 

GA3P is subsequently converted, in a number of steps, into pyruvate (PYR), which is the branch-point between fermentation and respiration. Saccharomyces species are particularly well adapted to the anaerobic production of ethanol, via decarboxylation and reduction of PYR, to the near-exclusion of other metabolites. On account of this latter characteristic, as well as its high ethanol tolerance, Saccharomyces is the preferred organism to produce ethanol from hexoses. 

This intractable problem may now be close to being solved. A Saccharomyces species that expressed the xylose isomerase gene from an anaerobic fungus was found to grow slowly on pentoses [29]. Improvement resulted from a combination of rational engineering - overexpression of the pentose phosphate-converting enzymes (see Fig. 8.5) - and classical strain improvement [30]. The authors conclude The kinetics of xylose fermentation are no longer a bottleneck in the industrial production of ethanol with yeast ... 

Lopandic K, Prillinger H, Molnar O, Gimenez-Jurado G Molecular characterization and genotypic identification of Metschnikowia species. Syst Appl Microbiol 1996 19 393-402. Molnar O, Messner R, Prillinger H, Stahl U, Slavikova E Genotypic identification of Saccharomyces species using random amplified polymorphic DNA analysis. Syst Appl Microbiol 1995 18 136-145. 

Torrija, M.J., Beltran, G., Novo, M.T., Poblet, M., Guillamon, J.M., Mas, A., Rozes, N. (2003) Effect of fermentation temperature and Saccharomyces species on the cell fatty acid composition and presence of volatile compounds in wine. Int. J. Food Microbiol., 85, 127-136. 

The term flavour will be used in its broadest sense to incorporate aroma, taste, and mouth-feel. Yeast taxonomy is according to Kurtzman and Fell (1998), with the exception of the former species Saccharomyces uvarum, for which species status is still unresolved (Nguyen and Gaillardin 2005), and will therefore be recorded as Saccharomyces species bayanus/uvarum Yeast gene and enzyme notations are according to the Saccharomyces Genome Database (http //yeastgenome.org). 

Table 8D.7 General properties of Saccharomyces species cerevisiae, bayanus/uvarum and paradoxus ...

Table 8D.9 Comparison of aroma descriptors for Chardonnay wines made with Saccharomyces cerevisiae and non-Saccharomyces species...

Aroma group Saccharomyces cerevisiae Non-Saccharomyces species ... 

Several examples of how the novel properties of non-Saccharomyces yeasts can be used to improve the composition and aroma properties of wine will be discussed according to yeast species. The salient characteristics of several non-Saccharomyces species are summarised in Table 8D.10. 

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