Nitrogen catabolite repression in Saccharomyces cerevisiae during wine fermentations

We carried out fermentations with several nitrogen sources in different concentrations and studied nitrogen regulation by following the transcriptional profile of the general amino-acid permease (GAPI) and the ammonium permeases (MEP1, MEP2, MEP3). In wine fermentations the cells evolve from a nitrogen-repressed situation at the beginning of the process to a nitrogen-derepressed situation as the nitrogen is consumed. These nitrogen-repressed/derepressed conditions determined the different patterns of ammonium and amino-acid consumption. Arginine and alanine were hardly used under the repressed conditions, while the uptake of branched-chain and aromatic amino acids increased. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.