Saccharomyces cerevisiae strain adaptation

Figure 9.14 Potential targets for wine yeast strain development. The primary role of wine yeast is to conduct the alcoholic fermentation during which grape sugars (mainly glucose and fructose) are converted into ethanol, carbon dioxide and other minor, but important, metabolites. The main emphasis in strain development programmes is on the development of Saccharomyces cerevisiae strains with improved fermentation, processing and biopreservation abilities, and the capacity to enhance the wholesomeness and sensory quality of wine. It is hoped that such genetically improved yeast strains could enhance cost-effective production of wine with minimised resource inputs, improved quality and low environmental impact. Adapted from Pretorius (2000).

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.)... 

Ockert, P.H.A. and Kock, J.L.F. 1989. Differentiation of yeast species, and strains within a species, by cellular fatty acid analysis. 1. Application of an adapted technique to differentiate between strains of Saccharomyces cerevisiae. J. Microbiol. Methods 10, 9-23. 

Figure 6.5. Growth of Saccharomyces cerevisiae Epernay (open circles) and Lactobacillus kunkeei strain YH-15 (closed squares) in a Chardonnay juice. Adapted from Huang et al. (1996) with the kind permission of the American Journal ofEnology and Viticulture.

Tian, S., Luo, X., Yang, X., Zhu, J., 2010. Robust ceUulosic ethanol production from SPORL-pretreated lodgepole pine using an adapted strain Saccharomyces cerevisiae without detoxification. Bioresource Technology 101 (22), 8678—8685. 

With a few exceptions (Nisiotou et al., 2007), Saccharomyces strains dominate fermentation sooner or later, as in nonbotrytized wine. A special feature of botrytized fermentations is that, beside various S. cerevisiae races, S. uvarum (formerly known as S. bayanus var. uvarum) is typically isolated from these wines (Antunovics et al., 2003 Magyar et al., 2008 Minarik and Laho, 1962 Naumov et al., 2000, 2002 Sipiczki et al., 2001 Tosi et al., 2009). This species seems to be well adapted to sweet wine fermentations, particularly, but not exclusively, in cooler climates. 

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