γ-aminobutyric acid effect in yeast under wine-type

Identifier:  TFM:271

Handle: https://hdl.handle.net/20.500.11797/TFM271

Authors:  Alvarez Ossorio Serrano, Carmen

Abstract:
Wine-making is a process increasingly controlled by human. Low nitrogen source grape musts are one of the most important problems in current oenology. Yeast assimilable nitrogen (YAN) consists of ammonium and α-amino acids; however yeast controls the nitrogen metabolism depending on the presence of preferred compound. This mechanism is called nitrogen catabolite repression (NCR). Nitrogen assimilation efficiency by wine yeast is the key for avoiding stuck fermentation on account of nitrogen source deficiency. The metabolism of γ-aminobutyric acid (GABA), a non-proteinogenic amino acid, has been elucidated but the role in wine yeast of this nitrogen source is still unknown. In this study we followed wine-type fermentation in synthetic wine must in absence and presence of GABA. The aim of this study is to detect differences in the kinetic and/or yeast metabolisms of the process promoted by GABA. We have analysed fermentation by Saccharomyces and non-Saccharomyces wine yeast. We determined the chemical composition of fermented media by high performance liquid chromatography (HPLC) and enzymatic reactions, and the yeast cell metabolome by gas chromatography coupled to mass spectroscopy (GC-MS).