The global interest in minimizing the obstacles associated with the use of fossil fuels requires new low-cost renewable energy sources. In this scenario, second-generation ethanol (2G) emerges as a promising alternative by using lignocellulosic biomasses rich in fermentable sugars as sources of raw materials. However, Saccharomyces cerevisiae, the main microorganism employed in the production of 2G ethanol, lacks specific transporters for some fundamental sugars of these biomasses such as pentoses. To mitigate the problems with sugar uptake, genetic engineering arises as a valuable tool for heterologous expression of transporters on S. cerevisiae. Microorganisms that naturally consume these sugars, such as Trichoderma reesei fungus, are essential in the search for new transporters, once they have efficient systems to transport sugars and other nutrients. Therefore, this project proposes the characterization of eight transporters identified by in silico analysis of RNA-seq data during the cultivation of T. reesei on sugarcane bagasse and glucose in S. cerevisiae knockout strain for sugar sensors and transporters. Later, candidate transporters with better efficiency in the uptake of different sugars will be used for genetic transformation of an industrial S. cerevisiae strain. The transformed industrial strains will be evaluated regarding their 2G ethanol productive capacity, through fermentative assays mimicking industrial conditions. Therefore, it is expected with this work to develop robust and efficient strains of S. cerevisiae in the uptake and fermentation of the different lignocellulose sugars and thus contribute to the advances and economic viability of ethanol 2G production.
News published in Agência FAPESP Newsletter about the scholarship: