Identifier: TFG:9103
Authors: García García, Aida
Abstract:
In this work, we characterized the effect of the PYK2 gene deletion in the wine strain Saccharomyces cerevisiae Lalvin Clos, with the aim of evaluating its influence on growth and metabolic adaptation to different fermentable and non-fermentable carbon sources. Growth parameters, substrate consumption, and metabolite production were compared between the Δpyk2 mutant strain and the control strain, and the expression of key genes involved in fermentative and respiratory pathways, such as CAT8, PDC2, and CYC1, was also analyzed. The Δpyk2 strain showed similar growth to the Lalvin Clos strain in media with fermentable carbon sources, but was unable to grow on nonfermentable sources or to reuse the ethanol generated after fermentation for the diauxic growth observed in the parental strain. In contrast, when compared with a laboratory strain, both the parental strain and its Δpyk2 mutant were able to grow on non-fermentable sources and consume ethanol. During the experimental process, the presence of a mitochondrial mutation was detected in the mutant strain. Unlike the PYK2 deletion, which according to the literature does not affect growth in different carbon sources, it does cause a significant change in growth, especially in media with respiratory sources. The presence of this unexpected mutation limits the interpretation of the results obtained. Therefore, although differences in metabolic and adaptive capacity were observed between the PYK2 mutant and the parental strain, it was not possible to establish a conclusive causal relationship between these differences and the loss of PYK2 function. This study lays the groundwork for future research to more precisely isolate and analyze the specific role of PYK2 in S. cerevisiae metabolism, especially in its interaction with the glycolytic complex and melatonin, relevant elements in cellular metabolic regulation.
Repositori URV