There were isolated 41 yeast strains, for isolation being used both natural and special prepared laboratory media. 10 yeast strains were studied as regards their capacity to produce high ethanol concentration, to ferment different raw materials and to be resistant to high ethanol concentration, in order to be used to produce bioethanol from starchy raw-material (mainly corn). This selection was performed based on the fermentation properties specific for every yeast strain and the main parameter was the ethanol content in fermented mash.
For every yeast strain tested in pilot installation three successive repetitions were performed in the case of molasses as raw material and five successive repetitions were performed in the case of corn as raw material. The working conditions at laboratory and pilot levels were similar as regards the technology and equipment.