Analysis of genetic and physiological determinants involved in the production of aromatic amino acid derived compounds (aadc) in saccharomyces cerevisiae

• Autores: Ricardo Bisquert Alcaraz
• Directores de la Tesis: José Manuel Guillamón Navarro (dir. tes.)
• Lectura: En la Universitat de València ( España ) en 2023
• Idioma: inglés
• Número de páginas: 243
• Tribunal Calificador de la Tesis: Daniel Ramón Vidal (presid.), Gemma Beltran Casellas (secret.), Paola Branduardi (voc.)
• Programa de doctorado: Programa de Doctorado en Biomedicina y Biotecnología por la Universitat de València (Estudi General)
• Materias:
  • Ciencias de la vida
    • Microbiología
      • Metabolismo microbiano
      • Micología (levaduras)
• Enlaces
  • Tesis en acceso abierto en: TESEO
• Resumen

  • The recently established relation between the metabolism of aromatic amino acids and the synthesis of bioactive molecules such as melatonin, serotonin and hydroxytyrosol in Saccharomyces cerevisiae brings interesting applications in the field of food and pharmacological industry but also poses a great challenge. The synthesis of these molecules is attributed to yeast during the fermentation process but the underlying mechanisms or the responsible genes remain unknown. In this context, the main hypothesis in this thesis is: Through the study of the synthesis of bioactive aromatic amino acid-derived compounds and their underlying mechanisms in S. cerevisiae it is possible to promote an increase of these metabolites in fermented foods and beverages as a result of yeast metabolism, but it is also possible to rationally tune the production of these compounds of interest for a massive and yet sustainable production in a yeast cell factory. From this approach, the main objective of this thesis is to broaden the knowledge about the molecular determinants responsible for the synthesis of bioactive compounds derived from aromatic amino acids, especially melatonin and hydroxytyrosol, and explore yeasts overproducing capacity of these metabolites by different genetic improvement approaches, such as adaptive laboratory evolution, metabolic engineering and synthetic biology. With that aim in this thesis a sensitive and cost-effective method to detect and quantitate melatonin directly from growth media samples is adapted and optimized, enabling an accessible method to perform extensive screenings to discern spontaneous melatonin production in multiple yeast strains. The objective of shedding light on the genes responsible for the synthesis of melatonin in S. cerevisiae led to the conclusion of the involvement of "moonlighting" proteins in the synthesis of melatonin in yeast and a new gene candidate, HPA2, is revealed as implicated on melatonins biosynthesis due to its capacity of acetylating melatonins precursors. The production of aromatic amino acid derived compounds by yeast is also addressed from two different approaches, on the one hand a novel adaptive laboratory evolution was carried out on an industrial yeast strain to obtain a new phenotype, majorly concerning its metabolomic profile, and specially the synthesis of antioxidants and bioactive aromatic amino acid derived compounds. On the other hand the utilization of yeast as a cell factory is explored by the development of a hydroxytyrosol producer strain, capable to produce a high-value product such as hydroxytyrosol using glucose as the main substrate.