Dominance and Persistence of PE strains (Saccharomyces Sensu Stricto) in Brazilian Bioethanol Fermentation Tanks (One Unit Four Seasons)

Claudia Steckelberg, Patricia R. Kitaka, Silvio R. Andrietta, Maria G.S. Andrietta

The use of select yeasts as inoculum at the start of the season of bioethanol production has been a recurring practice in Brazilian distilleries. The Saccharomyces sensu stricto strain mostly used to start the process in distilleries is know as Pedra (PE). In this work, we assessed four different seasons (2009, 2010, 2011, 2012) at the same unit, which started the process with the PE strain in all years. The dominance and persistency capacity of the PE strain varied from season to season, but in none of the seasons we noted the presence of this strain the end of the activities, even though this strain was found to have considerable capacity to remain in the process. The data presented in this study elucidate that one selected strain is replaced by the other, or even by more than one originated from feedstock. We have also noted that yeast dynamics behavior in tanks is variable from season to season, suggesting the influence of feedstock in yeast selection.