The role of GAP1 gene in the nitrogen metabolism of Saccharomyces cerevisiae during wine fermentation

The aim of this study was to analyse the relevance of the general amino acid permease gene (GAP1) of the wine yeast Saccharomyces cerevisiae on nitrogen metabolism and fermentation performance. We constructed a gap1 mutant in a wine strain. We compared fermentation rate, biomass production and nitrogen consumption between the gap1 mutant and its parental strain during fermentations with different nitrogen concentrations. The fermentation capacity of the gap1 mutant strain was impaired in the nitrogen-limited and -excessive conditions. The nitrogen consumption rate between the wild strain and the mutant was different for some amino acids, especially those affected by nitrogen catabolite repression (NCR). The deletion of GAP1 gene also modified the gene expression of other permeases. The Gap1 permease seems to be important during wine fermentations with low and high nitrogen content, not only because of its amino acid transporter role but also because of its function as an amino acid sensor. A possible biotechnological advantage of a gap1 mutant is its scarce consumption of arginine, whose metabolism has been related to the production of the carcinogenic ethyl carbamate.