Induction of Melibiase in Yeast

Exposing yeast cells with a certain genotype to different inducers, the ability of the yeast cells (Saccharomyces cerevisiae) to obtain enhanced fermentation for carbohydrates was observed. Regardless of the preexposure to any substrate, the inherent character incapable of fermenting a certain carbohydrate was maintained, while utilization of carbohydrates by the cells with a certain gene markers was varied by the previous conditions where they were exposed. Galactose was the best inducer for the cells to elaborate melibiase, even the galactose was not utilized as a substrate. Preexposure to galactose seemed to be necessary for the cells to utilize galactose and melibiose. Galactose fermentation by GA cells was enhanced by the exposure of the cells to galactose, but not to melibiose, raffinose, sucrose or glucose. Delayed fermentation of sucrose by the cells exposed to glucose or melibiose, but not to galactose, was observed. Raffinose fermentation was obtained by the cells with either SU RAF or GA ME genes, but the enhanced fermentation of raffinose seemed to be dependent on which inducer the cells were exposed previously and enzymes induced by the inducer to break either one of the linkages of raffinose molecule, the alpha0galactosidic or the beta-fructo-furanosidic.