The investment of several countries in developing renewable energy sources, that emit less air pollutants and increasing their ability to reuse, has become higher due to the knowledge of the scarcity of fossil fuels in the near future and the environmental consequences of the greenhouse effect by burning those. In Brazil, the main alternative source is ethanol, the result of fermentation performed by yeast in ethanol distilleries. However, problems such as increasing the concentration of ethanol inside the tank fermentation are stress factors to yeast, which affect the efficiency of fermentation and consequent production of alcohol. Genes and specific cellular processes involved in the response to this stress are induced by the yeast, allowing it to reach a certain tolerance to stressor. Studies have shown that this tolerance is partially performed in Saccharomyces cerevisiae by modification of fluidity of its cell membranes, indicating a possible correlation with genetic expression of OLE1, responsible gene which encoding the Ole1p enzyme and participate in the synthesis of unsaturated fatty acids that make up the membrane. This project seeks a better understanding of the role of OLE1 gene, as well as the nature of the mediating processes of transcription and expression levels, and investigate how its gene expression may be related to the tolerance to high ethanol concentration and temperature. For this purpose, will be selected wild strains isolated during industrial production of ethanol and grouped according to characteristics of resistance or sensitivity to temperature and ethanol. The ole1 gene expression analysis in these samples will be performed in order to determine whether a relationship exists between the expression of this gene and resistance to ethanol and temperature. We will do also attempts that promote overexpression of OLE1 gene in temperature and ethanol sensitive strains to verify if these strains acquire tolerance. With the experimental results, we hope to provide greater scientific background on the issue of OLE1 gene have or not the quality of resistance marker to ethanol or temperature. If so, the techniques used for overexpression may be explored in the framework of improve resistance in industrial yeasts currently used for production of ethanol.
News published in Agência FAPESP Newsletter about the scholarship: