Étude de la diversité des levures du genre Brettanomyces et de leur potentiel en fermentation brassicole

Authors: Ladrie, Myriam
Advisor: Labrie, Steve
Abstract: The yeasts of the genus Brettanomyces are often considered as a major contaminant in the wine and beer industries because of their production of phenolic off-flavors. Recently, few species of this genus, especially B. bruxellensis and B. anomalus, have been used in beers to enlarge the pool of aromatic compounds produced by the traditional Saccharomyces cerevisiae starter used for decades in breweries. The characterization of Brettanomyces species is therefore crucial to identify the strains showing interesting technological traits. However, to our knowledge, no fast method is currently available to evaluate the genetic diversity of the genus Brettanomyces which can be easily adapted in an industrial context. The aim of this study was to develop and optimize a new, fast and reliable typing method used for the species and strains differentiation of Brettanomyces spp. isolates and for the prediction of their brewing potential. Twenty-two (22) strains of Brettanomyces, one (1) Pichia kluyveri, one (1) Candida parapsilosis, one (1) Schizosaccharomyces pombe and one (1) Saccharomyces cerevisiae were isolated from beer, red wine, kombucha, sourdough, chicha and commercial starters and used for the development of a method based on the Random Amplification of Microsatellites (RAM)-PCR technique with (CGA)₅. This method was validated with the already existent and reliable Restriction Endonuclease Analysis coupled with Pulsed-Field Gel Electrophoresis (REA-PFGE) method. Further fermentation assays revealed that potential brewing isolates were clustered in the same phylogenetic group generated with RAM-PCR electrophoretic profiles. The study allowed the development of a useful tool for brewers and yeast suppliers for the identification at the species and strains levels and the brewing potential of various Brettanomyces spp. isolates, without the need for sequencing and laborious fermentation assays.
Document Type: Mémoire de maîtrise
Issue Date: 2021
Open Access Date: 29 March 2021
Permalink: http://hdl.handle.net/20.500.11794/68632
Grantor: Université Laval
Collection:Thèses et mémoires

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