In industrial processes, more robust and tolerant Saccharomyces cerevisiae strains are needed, as stress conditions can affect these microorganisms and cause cellular changes. Thus, this study aimed to evaluate the genetic and physiological effect of fermentation cycles in industrial strains of S. cerevisiae. A pre-inoculum was performed by inoculating 0.10 g of Pedra-2, FT858 and Fleischmann yeasts in YPD 2% liquid medium and incubated at 30°C for 10 hours at 250 rpm. The cells were recovered

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... nd the biomass obtained was inoculated in sugarcane juice with 22°Brix at a temperature of 30°C at 250 rpm for 10 hours being conducted with cell recycling. Aliquots were taken at each cycle for genotoxicity analysis by the comet test and physiological stress by ethanol quantification. THE yeast Fleischmann showed lower tolerance to the fermentation cycle, showing greater damage to deoxyribonucleic acid (DNA). The ethanol productivity of the Fleischman strain, in the first fermentation cycle, was similar to the Pedra-2 and FT858 yeasts. However, during the cycles, there was a reduction in the content of this metabolite.