Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/7321
Título: In search of role of yeast regulatory pathways during the last stages of wine fermentation
Autor: Viana, Tiago Monteiro Lomba
Orientador: Prista, Catarina Geoffroy
Dias, Maria da Conceição Loureiro
Arneborg, Nils
Palavras-chave: proton homeostasis
regulatory pathways
Saccharomyces cerevisiae
stress response
wine fermentation
Data de Defesa: 2014
Editora: ISA/UL
Citação: Viana, T.M.L. - In search of role of yeast regulatory pathways during the last stages of wine fermentation. Lisboa: ISA, 2014, 230 p.
Resumo: While searching for roles of Saccharomyces cerevisiae regulatory pathways during the late stages of wine fermentation, a peculiar H+ homeostasis was found in an industrial wine strain, while fermenting natural grape must (NGM). Intracellular pH (pHi) of the population remained in the range 6.0 – 6.4, decreasing by the end of glucose fermentation (pHi 5.2 at 15oC), although cells remained viable. The plasma membranes of late stationary cells became almost impermeable to H+. To ensure replicability of subsequent experiments, a synthetic grape must was designed (ISA-SGM), in which we obtained similar fermentative profiles as in NGM for the wine strain and for laboratory strains. Fluorescence Ratio Imaging Microscopy (FRIM) was used to estimate pHi of individual cells of strain BY4741. Even at the end of fermentation, we found subpopulations with “healthy” cytosolic pH (i.e. pHi 6-7). Sixty-two single-deletion mutants of BY4741 were screened to identify genes required for optimal wine fermentation performance, leading to the identification of 10 determinants whose absence improved fermentation performance, while 37 were deleterious. Principal Component Analysis revealed that deletion of some genes involved in transcription, cell cycle and stress response led to improved performance, while reduced performance was associated mainly with genes involved in membrane functions.
Descrição: Doutoramento em Engenharia Alimentar - Instituto Superior de Agronomia
URI: http://hdl.handle.net/10400.5/7321
Aparece nas colecções:BISA - Teses de Doutoramento / Doctoral Thesis

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