Stress resistance during the lag phase of wine fermentation and development of optimized yeasts

Ferreira, David

Stress resistance during the lag phase of wine fermentation and development of optimized yeasts

dc.check.date	2023-09-13T10:38:18Z
dc.check.embargoformat	Apply the embargo to both hard bound copy and e-thesis (If you have submitted an e-thesis and a hard bound thesis and want to embargo both)	en
dc.check.entireThesis	Entire Thesis Restricted
dc.check.info	Restricted to everyone for five years	en
dc.check.opt-out	Not applicable	en
dc.check.reason	Releasing this thesis would cause substantial prejudice to the commercial interests of the sponsor of the postgraduate research	en
dc.contributor.advisor	Morrissey, John P.	en
dc.contributor.advisor	Dequin, Sylvie	en
dc.contributor.author	Ferreira, David
dc.contributor.funder	Seventh Framework Programme	en
dc.date.accessioned	2018-09-14T10:38:18Z
dc.date.issued	2017
dc.date.submitted	2017
dc.description.abstract	Saccharomyces cerevisiae has been used for millennia to perform wine fermentation due to its endurance and unmatched qualities and is nowadays widely used as wine yeast starter. Nevertheless, at the moment of inoculation, wine yeasts must cope with specific stress factors that can compromise the fermentation start. The objective of this work was to elucidate the metabolic and molecular bases of multi-stress resistance during wine fermentation lag phase. We first characterized a set of commercialized wine yeast strains by focusing on stress factors typically found at this stage in red wines and in white wines. Temperature and osmotic stress had a drastic impact in lag phase for all strains whereas SO2, low lipids and thiamine had a more strain dependent effect. Based on these data, we developed two parallel approaches. Using an evolutionary engineering approach where selective pressures typically present in lag phase were applied, we obtained evolved strains with a shorter lag phase in winemaking conditions. Whole genome sequencing allowed to identify several de novo mutations potentially involved in the evolved phenotype. In parallel, a QTL mapping approach was conducted, combining an intercross strategy, industrial propagation and drying of the progeny populations and selection of the first budding cells by FACS. Both strategies allowed the identification of several allelic variants involved in cell wall, glucose transport, cell cycle and stress resistance, as important in lag phase phenotype. Overall, these results provide a deeper knowledge of the diversity and the genetic bases of yeast adaptation to wine fermentation lag phase and a framework for improving yeast lag phase. Additionally, we showed that K. marxianus has potential for mixed cultures and positive aromatic contributions under oenological conditions, opening new possibilities for further studies.	en
dc.description.status	Not peer reviewed	en
dc.description.version	Accepted Version
dc.format.mimetype	application/pdf	en
dc.identifier.citation	Ferreira, D. 2017. Stress resistance during the lag phase of wine fermentation and development of optimized yeasts. PhD Thesis, University College Cork.	en
dc.identifier.endpage	298	en
dc.identifier.uri	https://hdl.handle.net/10468/6786
dc.language.iso	en	en
dc.publisher	University College Cork	en
dc.relation.project	info:eu-repo/grantAgreement/EC/FP7::SP3::PEOPLE/606795/EU/Yeast Cell Factories: Training Researchers to Apply Modern Post-Genomic Methods In Yeast Biotechnology/YEASTCELL	en
dc.rights	© 2017, David Ferreira.	en
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/	en
dc.subject	Wine fermentation	en
dc.subject	Yeast	en
dc.subject	Lag phase	en
dc.subject	Multi-stress resistance	en
dc.subject	QTL	en
dc.subject	Adaptive evolution	en
dc.subject	K. marxianus	en
dc.thesis.opt-out	false
dc.title	Stress resistance during the lag phase of wine fermentation and development of optimized yeasts	en
dc.title.alternative	Résistance au stress lors de la phase de latence en fermentation oenologique et développement de levures optimisées	en
dc.type	Doctoral thesis	en
dc.type.qualificationlevel	Doctoral	en
dc.type.qualificationname	PhD	en
ucc.workflow.supervisor	j.morrissey@ucc.ie