Heterolog expression of putative xylose transporters from Candida sojae in Saccharomyces cerevisae aiming the 2G ethanol production

Abstract

The world energy matrix is composed mainly of fossil compounds such as oil, gas and coal. However, in the past decades, the global community expressed great concern with the consequences of the intense use of these compounds, as the increase of greenhouse gases. Thus, alternatives for energy production as sustainable energy are needed. One of these possibilities, the second-generation ethanol (2G) produced from agricultural residues like straw and bagasse of sugar cane, emerge with a great potential for the future. The biggest challenge in the 2G technology implementation is the development of a robust microorganism capable of converting sugars from the lignocellulosic material in ethanol. The employed industrial strains of 1G ethanol industry do not have the capability to ferment 5-carbon sugars like xylose, present in abundance in lignocellulosic biomass. Many researchers made efforts to obtain yeasts capable to ferment xylose to ethanol. However, one of the limitations in xylose consume is its uptake, due to the low affinity of the sugar transporters to xylose. Thus, this project aims the prospection and characterization of four new putative xylose transporters from the yeast Candida sojae. The heterologous expression of a transporter that fasten xylose uptake rate of the cell will enable second generation strains to be used in the conversion of the sugars present in lignocellulosic hydrolysates in ethanol.