Dominance and Persistence of PE strains (Saccharomyces sensu stricto) in Brazilian bioethanol fermentation tanks (three units, one season)

Maria da Graca S. Andrietta,Patricia R. Kitaka, Silvio R. Andrietta, Claudia Steckelberg

The purpose of this work was to follow up the dynamics of yeast population in fermentation tanks for ethanol production starting their processes with PE strain (Saccharomycessensustricto) as inoculum. This follow-up was carried out by using the pulsed-field technique. The results suggest that even though the replacement for indigenous strains took place at different times, the PE strain was unable to remain until the end of the season in the units assessed. In spite of the complete replacement of the PE strain, this fact cannot be associated with the entry of a certain strain, since those that eliminated the PE were also replaced by others at some point at the three units. Each process presents a different dynamics with regard to the yeast population in process, which changes depending on a number of biotic and abiotic factors favoring the installation of certain strains at different periods of the season.