scholarly journals Viability-PCR Allows Monitoring Yeast Population Dynamics in Mixed Fermentations Including Viable but Non-Culturable Yeasts

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1373
Author(s):  
Yurena Navarro ◽  
María-Jesús Torija ◽  
Albert Mas ◽  
Gemma Beltran
Keyword(s):  
Population Dynamics ◽  
Alcoholic Fermentation ◽  
Yeast Species ◽  
Culture Media ◽  
Microbial Interactions ◽  
Fast Method ◽  
Yeast Population ◽  
Final Population ◽  
Differential Medium ◽  
Yeast Interactions

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.

scholarly journals Yeast Population Dynamics during the Fermentation and Biological Aging of Sherry Wines

2001 ◽  
Vol 67 (5) ◽  
pp. 2056-2061 ◽  
Author(s):  
B. Esteve-Zarzoso ◽  
M. J. Peris-Torán ◽  
E. Garcı́a-Maiquez ◽  
F. Uruburu ◽  
A. Querol
Keyword(s):  
Population Dynamics ◽  
Alcoholic Fermentation ◽  
Specific Pattern ◽  
Internal Transcribed Spacers ◽  
Biological Aging ◽  
Rrna Gene ◽  
Native Strain ◽  
Yeast Population ◽  
Sherry Wine ◽  
Wine Aging

ABSTRACT Molecular and physiological analyses were used to study the evolution of the yeast population, from alcoholic fermentation to biological aging in the process of “fino” sherry wine making. The four races of “flor” Saccharomyces cerevisiae (beticus, cheresiensis, montuliensis, and rouxii) exhibited identical restriction patterns for the region spanning the internal transcribed spacers 1 and 2 (ITS-1 and ITS-2) and the 5.8S rRNA gene, but this pattern was different, from those exhibited by non-florS. cerevisiae strains. This flor-specific pattern was detected only after wines were fortified, never during alcoholic fermentation, and all the strains isolated from the velum exhibited the typical flor yeast pattern. By restriction fragment length polymorphism of mitochondrial DNA and karyotyping, we showed that (i) the native strain is better adapted to fermentation conditions than commercial strains; (ii) two different populations of S. cerevisiaestrains are involved in the process of elaboration, of fino sherry wine, one of which is responsible for must fermentation and the other, for wine aging; and (iii) one strain was dominant in the flor population integrating the velum from sherry wines produced in González Byass wineries, although other authors have described a succession of races of flor S. cerevisiae during wine aging. Analyzing all these results together, we conclude that yeast population dynamics during biological aging is a complex phenomenon and differences between yeast populations from different wineries can be observed.

scholarly journals Mechanisms Involved in Interspecific Communication between Wine Yeasts

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1734
Author(s):  
Ana Mencher ◽  
Pilar Morales ◽  
Jordi Tronchoni ◽  
Ramon Gonzalez
Keyword(s):  
Alcoholic Fermentation ◽  
Yeast Species ◽  
Interspecific Interactions ◽  
Interference Competition ◽  
Weighted Average ◽  
Starter Cultures ◽  
Simple Consequence ◽  
Wine Yeasts ◽  
Exploitation Competition ◽  
Metabolic Intermediates

In parallel with the development of non-Saccharomyces starter cultures in oenology, a growing interest has developed around the interactions between the microorganisms involved in the transformation of grape must into wine. Nowadays, it is widely accepted that the outcome of a fermentation process involving two or more inoculated yeast species will be different from the weighted average of the corresponding individual cultures. Interspecific interactions between wine yeasts take place on several levels, including interference competition, exploitation competition, exchange of metabolic intermediates, and others. Some interactions could be a simple consequence of each yeast running its own metabolic programme in a context where metabolic intermediates and end products from other yeasts are present. However, there are clear indications, in some cases, of specific recognition between interacting yeasts. In this article we discuss the mechanisms that may be involved in the communication between wine yeasts during alcoholic fermentation.

scholarly journals The Oleaginous Yeast Metschnikowia pulcherrima Displays Killer Activity against Avian-Derived Pathogenic Bacteria

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1227
Author(s):  
Robert H. Hicks ◽  
Mauro Moreno-Beltrán ◽  
Deborah Gore-Lloyd ◽  
Christopher J. Chuck ◽  
Daniel A. Henk
Keyword(s):  
Pathogenic Bacteria ◽  
Low Cost ◽  
Industrial Applications ◽  
Microbial Interactions ◽  
Bacterial Strains ◽  
Bacterial Killing ◽  
Killer Activity ◽  
Metschnikowia Pulcherrima ◽  
Livestock Health ◽  
Yeast Interactions

Metschnikowia pulcherrima is a non-conventional yeast with potential to be used in biotechnological processes, especially those involving low-cost feedstock exploitation and biocontrol applications. The combination of traits that supports these industrial applications in M. pulcherrima also makes it an attractive option to study in the context of livestock health. In this study, we examined the specific interactions between M. pulcherrima and multiple avian pathogenic bacteria. We tested individual bacteria–yeast interactions and bacterial combinations in both solid and liquid media and in variable nutrient environments. Across multiple isolates of M. pulcherrima, we observed different levels of antimicrobial activity, varying from supporting the growth of competing bacteria through suppression and bacterial killing, and we found that these responses varied depending on the bacterial strains and media. We identified multiple molecular routes, including proteins produced by M. pulcherrima strains, that acted to control these microbial interactions. Furthermore, protein screening revealed that M. pulcherrima strains were induced to produce proteins specifically when exposed to bacterial strains, suggesting that fine-tuned mechanisms allow M. pulcherrima to function as a potential lynchpin in a microbial community.

scholarly journals Yeast–Yeast Interactions: Mechanisms, Methodologies and Impact on Composition

2020 ◽  
Vol 8 (4) ◽  
pp. 600 ◽  
Author(s):  
Fanny Bordet ◽  
Alexis Joran ◽  
Géraldine Klein ◽  
Chloé Roullier-Gall ◽  
Hervé Alexandre
Keyword(s):  
Alcoholic Fermentation ◽  
Integrated Approach ◽  
Culture Conditions ◽  
Matrix Composition ◽  
Wine Composition ◽  
The Matrix ◽  
Composition Modification ◽  
Underlying Mechanisms ◽  
Yeast Interactions ◽  
Wine Matrix

During the winemaking process, alcoholic fermentation is carried out by a consortium of yeasts in which interactions occurs. The consequences of these interactions on the wine matrix have been widely described for several years with the aim of controlling the winemaking process as well as possible. In this review, we highlight the wide diversity of methodologies used to study these interactions, and their underlying mechanisms and consequences on the final wine composition and characteristics. The wide variety of matrix parameters, yeast couples, and culture conditions have led to contradictions between the results of the different studies considered. More recent aspects of modifications in the composition of the matrix are addressed through different approaches that have not been synthesized recently. Non-volatile and volatile metabolomics, as well as sensory analysis approaches are developed in this paper. The description of the matrix composition modification does not appear sufficient to explain interaction mechanisms, making it vital to take an integrated approach to draw definite conclusions on them.

Influence of climatic and nutritional factors on yeast population dynamics in the phyllosphere of wheat

1992 ◽  
Vol 23 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Aleid J. Dik ◽  
Nyckle J. Fokkema ◽  
Johannes A. van Pelt
Keyword(s):  
Population Dynamics ◽  
Nutritional Factors ◽  
Yeast Population

scholarly journals Investigations of the mechanisms of interactions between four non-conventional species withSaccharomyces cerevisiaein oenological conditions

2018 ◽  
Author(s):  
Oliver Harlé ◽  
Judith Legrand ◽  
Catherine Tesnière ◽  
Martine Pradal ◽  
Jean-Roch Mouret ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Rational Design ◽  
Yeast Species ◽  
Ecological Engineering ◽  
Joint Effect ◽  
Wine Fermentation ◽  
Specific Cell ◽  
Lipid Uptake ◽  
Modeling Tools ◽  
Yeast Cultures

AbstractFermentation by microorganisms is a key step in the production of traditional food products such as bread, cheese, beer and wine. In these fermentative ecosystems, microorganisms interact in various ways, namely competition, predation, commensalism and mutualism. Traditional wine fermentation is a complex microbial process performed bySaccharomycesand non-Saccharomyces(NS) yeast species. To better understand the different interactions occurring within wine fermentation, isolated yeast cultures were compared with mixed co-cultures of one reference strain ofS. cerevisiaewith one strain of four NS yeast species (Metschnikowia pulcherrima, M. fructicola, Hanseniaspora opuntiae and H. uvarum). In each case, we studied population dynamics, resource consumed and metabolites produced from central carbon metabolism. This phenotyping of competition kinetics allowed us to confirm the main mechanisms of interaction between strains of four NS species.S. cerevisiaecompeted withH. uvarumandH. opuntiaefor resources although bothHanseniasporaspecies were characterized by a strong mortality either in isolated or mixed fermentations.M. pulcherrimaandM. fructicoladisplayed a negative interaction with theS. cerevisiaestrain tested, with a decrease in viability in co-culture, probably due to iron depletion via the production of pulcherriminic acid. Overall, this work highlights the importance of measuring specific cell populations in mixed cultures and their metabolite kinetics to understand yeast-yeast interactions. These results are a first step towards ecological engineering and the rational design of optimal multi-species starter consortia using modeling tools. In particular the originality of this paper is for the first times to highlight the joint-effect of different species population dynamics on glycerol production and also to discuss on the putative role of lipid uptake on the limitation of some non-conventional species growth although interaction processes.

Phenotypic characterization of cell-to-cell interactions between two yeast species during alcoholic fermentation

2021 ◽  
Vol 37 (11) ◽  
Author(s):  
Natasha Alethea Luyt ◽  
Sandra Beaufort ◽  
Benoit Divol ◽  
Mathabatha Evodia Setati ◽  
Patricia Taillandier ◽  
...  
Keyword(s):  
Alcoholic Fermentation ◽  
Yeast Species ◽  
Cell Interactions ◽  
Phenotypic Characterization
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