The analysis on efficiency of ethanol biosynthesis by Saccharomyces yeast

Ethanol as a raw material or a basic product is widely used in different food industry branches, including the manufacturing of distilled beverages (60 %), alcoholisation (17 %), food flavours, fragrances and cosmetics. It is also often used for extracts and disinfectants. The alcohol technology is based on fermentation of carbohydrate-containing raw materials to ethanol by microorganisms. Saccharomyces yeast serves as a main ethanol producer. The alcohol yeast race should conform to quite strict requirements of fermentation activity; a degree of fermentation of carbohydrate stability to the products of own exchange (namely to ethanol). The effective development of alcohol technology is largely associated with the advancement in applied research studies, including specific processes of alcohol production. The research was aimed to study the technological properties of two yeast races, i.e. Saccharomyces cerevisiae S-04 and Saccharomyces uvarum (Carlsbergensis) for ethanol biosynthesis compared to the physiology of cells and their rate of living. In the study, both dry and rehydrated yeast was used. The paper presents the microscopy results of stained and unstained preparation of yeast. The analysis of fermentation activity, assessed by a quick-detection technique, and in the simulative conditions of fermentation on the beer wort, was conducted. The obtained results demonstrated that the examined yeast strains are absolutely different in terms of their fermentation activity. The researchers observed different effects of rehydration on yeast: for Saccharomyces uvarum (Carlsbergensis) this process had a positive influence, but the fermentation activity of Saccharomyces cerevisiae S-04 decreased. The authors concluded about the significant difference in the fermentation activity analysed by the quick-detection technique and using the beer wort.