Identification of systemic signatures associated to ethanol tolerance in Saccharomyces cerevisiae strains

Author(s)

Ivan Rodrigo Wolf

• Document type: Doctoral Thesis
• Press: Botucatu. 2019-07-17.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu
• Defense date: 2019-07-01
• Advisor: Guilherme Targino Valente

Abstract

The increasing demand and economic instabilities related to the use of fossil fuels raised interest in the development of biofuels such as bioethanol. The most common bioethanol production process is from the first generation technology, in which the most widely used organism is the yeast Saccharomyces cerevisiae. However, the high concentration of ethanol generates toxicity to S. cerevisiae and this is one of the limiting factors in the bioethanol production. Thus, the production of more resistant strains to this stressor is crucial to the development of biotechnological processes related to bioethanol. The systems analyzes are poorly explored to understand the ethanol tolerance phenomenon, leading the search for candidate genes labor intensive and expensive. Thus, the differences between low tolerant (LT) and high tolerant (HT) strains to ethanol (EtOH) were analyzed using bioinformatics tools like systems biology and transcriptome analysis. The results showed that HT and LT strains initially used a common stress response system but due to changes in the network structure of metabolic, regulatory, and protein-protein interactions of each strain, different mechanisms of stress response are activated in each group. LT strains maintain the cellular homeostasis activating cell cycle, and adjusting metabolisms, despite activation of transposable elements and disruption of important anti-oxidant agents production, allowing the occurrence of DNA damage. HT strains disrupt the cell cycle and most of metabolisms, but maintaining protein production and repair to stabilize cell membranes and control reactive oxygen species (ROS), working together with the ethanol metabolism. Moreover, HTs are using the EtOH to obtain carbon in the citric acid cycle, thus, it may be the reason of HT strains surpass high ethanol concentration. Altogether, the knowledge here generated may be used to enrich future discussions about the studied phenomenon and to provide biotechnological development. (AU)

• FAPESP's process: 15/19211-7 - Identification of systemic signatures associated to ethanol tolerance in Saccharomyces cerevisiae strains
• Grantee: Ivan Rodrigo Wolf
• Support Opportunities: Scholarships in Brazil - Doctorate