The modern technological process of starch hydrolysis to fermentable sugars in the ethanol production from starch-containing raw materials is based on the use of amylolytic commercial enzyme preparations and the application of a low-temperature liquefaction stage for greater process efficiency, which significantly affects the final product’s cost. Under such conditions, the search for alternative ways to reduce the costs of these technological process’ components and, accordingly, the cost of the manufactured product is relevant. The purpose of the study was to investigate the use of a commercial mixture of microorganisms, namely alcohol yeast Saccharomyces cerevisiae and mould fungus Rhyzopus, as components of the commercial product Angel Leaven for a single-stage process of starch hydrolysis and fermentation of higher gravity wort based on starch-containing raw materials. The methods and processes for preparing raw materials generally accepted in ethyl alcohol production were used in the studies. The technological mode of single-stage starch hydrolysis and sugar fermentation in higher gravity wort by an association of mould fungus and alcohol yeast has been experimentally substantiated. It has been established that saccharification and starch fermentation by a mixed culture occurs in one stage and almost simultaneously at the temperature of 30-32°C, which creates prerequisites for energy saving and technological process simplification. The energy saving effect is enhanced by fermentation of higher gravity wort, obtained without the stage of low-temperature liquefaction, but with the stage of exposure with a proteolytic enzyme for 1 hour at the temperature of 50°C. This technological method is effective for a medium with a concentration of up to 306.6 g/dm3 of dry matter, which allows getting a wort with an ethanol content of up to 14.2% v/v. Increasing the concentration of the medium to 350 g/dm3 of dry matter does not allow getting the calculated ethanol content in mature wort in a single-stage process and requires further research to optimise the fermentation conditions. A set of technological solutions for optimising of starch hydrolysis and fermentation process with a mixed culture creates conditions for increasing the efficiency of raw materials and improving the energy efficiency of production process
amylolytic enzymes; starch hydrolysis; mature mash; Saccharomyces cerevisiae; association of microorganisms