1. The study screened the flocculant yeast Saccharomyces cerevisiae NCYC 1195 for tolerance to high ethanol concentrations using gamma ray radiation mutagenesis. 2. Mutant yeast strains Y7 and Y8 showed higher tolerance to ethanol (5% concentration) compared to the wild type (2.5% concentration). 3. Mutant Y8 demonstrated 15.9% higher cell growth and sugar consumption compared to the wild type yeast under growth profile testing.