process economics (Bai et al., 2008). However, wild S. cerevisiae
strains are unable to metabolise lactose. Nevertheless, S. cerevisiae
can utilize galactose, which is taken up by a permease encoded by the
gene GAL2 (Nehlin et al., 1989). Once inside the cell, catabolism of
galactose proceeds through the Leloir pathway.
Thus, the first applications of S. cerevisiae in whey fermentations
involved the pre-hydrolysis of lactose and further fermentation of