ABSTRACT
The history of yeast started 9000 years ago in the production of food. Bread, wine, sake, and beer are made with the essential contribution of yeasts, especially from the species Saccharomyces cerevisiae. Yeasts were rst used in the Caucasian and Mesopotamian regions approximately 7000 BC (Lin and Tanaka 2006). However, there was no recorded information about yeast until Louis Pasteur discovered that it could produce CO2 and ethanol from sugar. After the discovery of fermentation by Pasteur, yeast fermentation became famous and by the end of the nineteenth century, the production of bread and beer become a common practice. Wine producers are more disinclined to change their traditional practices and only began using exogenous yeast inocula in the 1950s, especially in countries with less wine tradition. In the 1960s, yeast biomass production, which was used in European countries, contributed to the technology of producing large amounts of dry yeast (Reed and Nagodawithana 1988). Efcient and protable processes have been developed to produce yeast biomass at the laboratory and plant scale. The standard process has
12.1 Introduction ........................................................................................................................ 279 12.2 Yeast .....................................................................................................................................280
