Influence of SNF1 Gene on Glycolytic Flux Addressed to Aerobic Fermentation (Crabtree Effect) of Saccharomyces cerevisiae

The alcoholic fermentation is a biotechnological process, which has been employed for more than one hundred years. Despite the ample researches carry out about this, there are specific aspects that are still not fully understood, an example of this is the Crabtree effect. The Crabtree effect is a metabolic phenomenon that occurs when the concentration of fermentable sugars in the medium is higher than 0.015% (w/v) and is characterized by the increase of glycolytic flux, an augment in the production of metabolites of fermentation and respiration repression. In spite of the wide quantity of information on the Crabtree effect is still not clear the molecular basis by which originates. It has been proposed that sucrose non‐fermenting protein‐1 (Snf1p) plays a key role in the unleashing of the Crabtree effect. Since in high concentrations of glucose, Snf1p is found dephosphorylated; while in low concentrations of glucose the protein Snf1p is phosphorylated and participate in the de‐repression of genes repressed by glucose. However, it has been suggested that both Snf1p phosphorylated and dephosphorylated have an essential participation in the metabolic transition of fermentative metabolism to the respiratory metabolism. This study aimed to evaluate the influence of the deletion of SNF1 gene in the glycolytic flux addressed to the Crabtree effect of S. cerevisiae . For this purpose, we use the Saccharomyces cerevisiae genetic background BY4742 and its mutant in the gene SNF1 ( snf1Δ ). Here, we provide evidence that snf1Δ mutants grown in YPD medium supplemented with 10% glucose did not present any effect upon glycolytic flux. In this regard, NADH/NAD+ ratio, extracellular acidification rate and transcription levels of genes HXK2 and PFK1 did not show a significative difference between strains snf1Δ and wild‐type. Surprisingly, the strain with the deletion in the gen SNF1 exhibits an increased oxygen consumption in comparison with wild‐type. The results obtained in this study suggest by first time that even when Snf1p is found dephosphorylated in high concentrations of glucose could be necessary for carrying out the repression of the respiration. Support or Funding Information PRODEP partially funded this work (project number: ITESCH‐EXB‐002). This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .