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Prospection of 2G ethanol production associated genes using comparative genomics approach

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Author(s):
Guilherme Borelli
Total Authors: 1
Document type: Master's Dissertation
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
Defense date:
Examining board members:
Raquel Miranda Cadete; Mariana Freitas Nery
Advisor: Gonçalo Amarante Guimarães Pereira
Abstract

The planetary change of the energetic matrix is raised as partial solution at many international meetings that discuss the global warming. Substituting gasoline to ethanol could render a request for increasing its production, that probably in the future will account on second generation (2G) plants. Low volumetric productivity of constructed yeasts in industry is an obstacle to economic feasibility of the process. The most employed solution is constructing Saccharomyces cerevisiae strains in laboratory, using exogenous genes. In the present work, we searched xylose-related genes from isolated wild yeasts and performed a comparative genomic analysis. We obtained from plague-insects from energy cane and other cultivars, about 1300 yeast colonies, identified as 13 species. A comparative growth analysis in xylose indicated Candida sojae as a good candidate to donate new putative xylose transporters, since its fastest consumption rate between our isolates. C. sojae genomic analysis pointed to 4 possible xylose transporters, which are being tested. The comparison among other yeasts¿ genomes highlighted a xylose-consumers¿ exclusive gene family, predicted as transporter genes. From this family, two representatives were chosen and are also being tested. At the same time, we investigated xylose-related enzymes evolution and found, for the first time, positive selection clues in wild xylose-fermenter yeasts. Another gene family containing positive selection clues in our analysis, is a methylglyoxal reductase family We hypothesized that this enzyme might be related to cofactor balance regulation in these yeasts. Our findings lead to new possibilities in cofactor imbalance researches, and indicate genes with potential of industrial utilization and improvement of 2G ethanol production (AU)