NAGIOS: RODERIC FUNCIONANDO

Nitrogen Metabolism of Saccharomyces and Non-Saccharomyces Wine Strains: Phenotypic and Genomic Characterisation

Repositori DSpace/Manakin

IMPORTANT: Aquest repositori està en una versió antiga des del 3/12/2023. La nova instal.lació está en https://roderic.uv.es/

Nitrogen Metabolism of Saccharomyces and Non-Saccharomyces Wine Strains: Phenotypic and Genomic Characterisation

dc.contributor.advisor	Guillamón Navarro, José Manuel
dc.contributor.advisor	Querol Simón, Amparo
dc.contributor.author	Su, Ying
dc.contributor.other	Departament de Bioquímica i Biologia Molecular	es_ES
dc.date.accessioned	2020-10-14T07:54:54Z
dc.date.available	2021-01-13T05:45:06Z
dc.date.issued	2020	es_ES
dc.date.submitted	08/10/2020	es_ES
dc.identifier.uri	https://hdl.handle.net/10550/75795
dc.description.abstract	S. cerevisiae is the most important yeast species for winemaking. In our study, different approaches were applied to evaluate the nitrogen requirement of a set of commercial S. cerevisiae strains. The selected high and low nitrogen demanding strains were sequenced and genomic differences were compared. Allele swapping of GCN1 gene revealed that the polymorphism of this gene is not the main reason for the nitrogen requirement differences in our strains. The cryotolerante Saccharomyces species such as S. uvarum, S. eubayanus and S. kudriavzevii are becoming more and more popular for wine making. However, the nitrogen requirements of these species is unclear. We studied the fermentation behaviour of Saccharomyces non-cerevisiae yeast species under different nitrogen concentrations and temperatures. The selected cryotolerant Saccharomyces species, particularly S. eubayanus showed lower nitrogen requirement than our control S. cerevisiae strain especially when the fermentations were carried out at low temperature. Although the cryotolerant yeast species possess many beneficial characteristics for fermentations at low temperature, they have lower tolerance to ethanol and sometimes are not able to finish the fermentation when used as pure culture. In our study, hybrids between cryotolerant species and S. cerevisiae were constructed. The fermentation capacity of the hybrid strains was tested under four conditions by combining two temperatures, 12°C and 28°C, and two nitrogen concentrations, 60 mg/L and 300 mg/L. The hybrid strains conferred better fermentation rates under low-temperature or low-nitrogen conditions and also produced larger amounts of acetate esters and higher alcohols, which increase aroma intensity and complexity in wine. The utilisation of non-Saccharomyces yeast strains in wine fermentation diversifies the characteristics of wine and improves wine quality. However, their nitrogen requirements and nitrogen source preferences are not well known. Our study explored the nitrogen utilisation profile of three popular non-Saccharomyces species: Torulaspora delbrueckii, Metschnikowia pulcherrima and Metschnikowia fructicola. The nitrogen source preferences to support growth and fermentation as well as the uptake order of different nitrogen sources during wine fermentation were investigated. While T. delbrueckii and S. cerevisiae strains shared the same nitrogen source preferences, Metschnikowia sp. displayed a lower capacity to efficiently use the preferred nitrogen compounds, but were able to assimilate a wider range of amino acids. The other important question is how nitrogen sources are metabolised and redistributed after entering the cell. A quantitative analysis using 15N-labelled NH4Cl, arginine, and glutamine, and 13C-labelled leucine and valine revealed the specificities of the nitrogen metabolism pattern of two non-Saccharomyces species, Torulaspora delbrueckii and Metschnikowia pulcherrima.	es_ES
dc.format.extent	419 p	es_ES
dc.language.iso	en	es_ES
dc.subject	nitrogen	es_ES
dc.subject	wine	es_ES
dc.subject	fermentation	es_ES
dc.subject	saccharomyces	es_ES
dc.subject	growth	es_ES
dc.title	Nitrogen Metabolism of Saccharomyces and Non-Saccharomyces Wine Strains: Phenotypic and Genomic Characterisation	es_ES
dc.type	doctoral thesis	es_ES
dc.subject.unesco	UNESCO::CIENCIAS DE LA VIDA	es_ES
dc.embargo.terms	3 months	es_ES