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| Author(s): |
Sheila Tiemi Nagamatsu
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2019-04-05 |
| Examining board members: |
Marcelo Falsarella Carazzolle;
Anderson Ferreira da Cunha;
Marcelo Mendes Brandão;
Gabriela Felix Persinoti;
Jose Eduardo Krieger
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| Advisor: | Marcelo Falsarella Carazzolle |
| Abstract | |
The excessive use of petroleum has several negative points, being two more relevant: economic dependence and environmental damage. In this context, ethanol was included as one of the most promising renewable energy sources and this reflect in publications and patents in this theme. Currently, two types of production has been applied in industry: first generation (1G), which uses fermentable sugars, and second generation (2G), using biomass as feedstock. Therefore, 2G production faces the biggest challenge due to biomass deconstruction, which require a pre-treatment step to release sugars. Among the challenges, we can mention the presence of non-fermentable sugars by Saccharomyces cerevisiae, mainly xylose, and the generation of toxic compounds, such as furfural, hydroxymethylfurfural (HMF), acetic acid and phenolic compounds. Thus, the selection of more resistant strains and the development of yeasts by genetic engineering and evolutionary techniques emerges as a fundamental step to increase fermentation efficiency. In this scenario, this project reaches two issues: xylose consumption and resistance to HMF. In the first issue, genomic and transcriptomic analyzes of engineered yeasts for xylose consumption were performed in order to identify metabolic bottlenecks that increased the efficiency of industrial fermentation. Then, were identified genes related to iron metabolism (including ISU1), indicating an association between this metal and xylose isomerase, the enzyme responsible for conversion of xylose to xylulose. While, to study mechanisms of resistance to HMF, were analyzed the genome of resistant and susceptible strains of industrial yeast SA-1 so the contrasting phenotypes could be compared. To conclude this work, SA-1 resistance genome was compared to other industrial yeasts in order to identify genes that underwent beneficial changes during evolution of Brazilian yeasts. Therefore were identified genes under positively selection related to iron homeostasis and to stresses. Accordingly, this work identified several metabolic routes that may be tested for construction of a more efficient 2G industrial strain and can be used industrially (AU) | |
| FAPESP's process: | 14/26905-2 - Bioinformatic analysis of QTLs mapping by high-throughput sequencing to identification of robustness mechanisms of industrial yeast |
| Grantee: | Sheila Tiemi Nagamatsu |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |