Author, as appears in the article.: Navarro Y; Torija MJ; Mas A; Beltran G

Department: Bioquímica i Biotecnologia

URV's Author/s: Beltran Casellas, Gemma / Mas Baron, Alberto / Navarro García, Yurena de los Ángeles / Torija Martínez, María Jesús

Keywords: Wine yeast Viable but non culturable Viability qpcr Saccharomyces cerevisiae Propidium monoazide Non-saccharomyces yeast Non-saccharomyces Listeria-monocytogenes Hanseniaspora-uvarum Ethidium monoazide Cerevisiae Cell-cell contact Alcoholic fermentation Acid bacteria

Abstract: © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). The use of controlled mixed inocula of Saccharomyces cerevisiae and non-Saccharomyces yeasts is a common practice in winemaking, with Torulaspora delbrueckii, Lachancea thermotolerans and Metschnikowia pulcherrima being the most commonly used non-Saccharomyces species. Although S. cerevisiae is usually the dominant yeast at the end of mixed fermentations, some non-Saccharomyces species are also able to reach the late stages; such species may not grow in culture media, which is a status known as viable but non-culturable (VBNC). Thus, an accurate methodology to properly monitor viable yeast population dynamics during alcoholic fermentation is required to understand microbial interactions and the contribution of each species to the final product. Quantitative PCR (qPCR) has been found to be a good and sensitive method for determining the identity of the cell population, but it cannot distinguish the DNA from living and dead cells, which can overestimate the final population results. To address this shortcoming, viability dyes can be used to avoid the amplification and, therefore, the quantification of DNA from non-viable cells. In this study, we validated the use of PMAxx dye (an optimized version of propidium monoazide (PMA) dye) coupled with qPCR (PMAxx-qPCR), as a tool to monitor the viable population dynamics of the most common yeast species used in wine mixed fermentations (S. cerevisiae, T. delbrueckii, L. thermotolerans and M. pulcherrima), comparing the results with non-dyed qPCR and colony counting on differential medium. Our results showed that the PMAxx-qPCR assay used in this study is a reliable, specific and fast method for quantifying these four yeast species during the alcoholic fermentation process, being able to distinguish between living and dead yeast populations. Moreover, the entry into VBNC status was observed for the first time in L. thermotolerans and S. cerevisiae during alcoholic fermentation. Further studies are needed to unravel which compounds trigger this VBNC state during alcoholic fermentation in these species, which would help to better understand yeast interactions.

Thematic Areas: Plant science Microbiology Health professions (miscellaneous) Health (social science) Food science & technology Food science

licence for use: https://creativecommons.org/licenses/by/3.0/es/

Author's mail: yurenadelosangeles.navarro@urv.cat albert.mas@urv.cat mjesus.torija@urv.cat gemma.beltran@urv.cat

Author identifier: 0000-0002-0763-1679 0000-0001-6419-0745 0000-0002-7071-205X

Record's date: 2023-03-11

Papper version: info:eu-repo/semantics/publishedVersion

Link to the original source: https://www.mdpi.com/2304-8158/9/10/1373

Licence document URL: http://repositori.urv.cat/ca/proteccio-de-dades/

Papper original source: Foods. 9 (10):

APA: Navarro Y; Torija MJ; Mas A; Beltran G (2020). Viability-PCR allows monitoring yeast population dynamics in mixed fermentations including viable but non-culturable yeasts. Foods, 9(10), -. DOI: 10.3390/foods9101373

Article's DOI: 10.3390/foods9101373

Entity: Universitat Rovira i Virgili

Journal publication year: 2020

Publication Type: Journal Publications