Investigating the Effect of Selected Non-Saccharomyces Species on Wine Ecosystem Function and Major Volatiles

Abstract

Natural alcoholic fermentation is initiated by a diverse population of several non-Saccharomyces yeast species. However, most of the species progressively die off, leaving only a few strongly fermentative species, mainly Saccharomyces cerevisiae. The relative performance of each yeast species is dependent on its fermentation capacity, initial cell density, ecological interactions as well as tolerance to environmental factors. However, the fundamental rules underlying the working of the wine ecosystem are not fully understood. Here we use variation in cell density as a tool to evaluate the impact of individual non-Saccharomyces wine yeast species on fermentation kinetics and population dynamics of a multi-species yeast consortium in synthetic grape juice fermentation. Furthermore, the impact of individual species on aromatic properties of wine was investigated, using Gas Chromatography-Flame Ionization Detector. Fermentation kinetics was affected by the inoculation treatment. The results show that some non-Saccharomyces species support or inhibit the growth of other non-Saccharomyces species in the multi-species consortium. Overall, the fermentation inoculated with a high cell density of Starmerella bacillaris displayed the fastest fermentation kinetics while fermentation inoculated with Hanseniaspora vineae showed the slowest kinetics. The production of major volatiles was strongly affected by the treatments, and the aromatic signature could in some cases be linked to specific non-Saccharomyces species. In particular, Wickerhamomyces anomalus at high cell density contributed to elevated levels of 2-Phenylethan-1-ol whereas Starm. bacillaris at high cell density resulted in the high production of 2-methylpropanoic acid and 3-Hydroxybutanone. The data revealed possible direct and indirect influences of individual non-Saccharomyces species within a complex consortium, on wine chemical composition.

Ecological interactions are a primary driver of population dynamics in wine yeast microbiota during fermentation

“…Thus, our data show that production of major volatiles is significantly affected by the yeast species composition and the ecological interactions among the species rather than temperature and SO 2. This result is in agreement with our previous work by Bagheri et al 13 , who confirmed that the aromatic profile of wine is significantly affected by the presence of some non-Saccharomyces (e.g. C. parapsilosis) in grape juice, irrespective of their rapid declines at an early stage of fermentation.…”

“…During the fermentation process, and dependent on the specific microbiota composition of each must, weakly fermentative yeast species such as Pichia terricola, Metschnikowia pulcherrima and Hanseniaspora uvarum are usually replaced by more strongly fermentative species such as Lachancea thermotolerans and Torulaspora delbrueckii, while Saccharomyces cerevisiae will generally complete the process when alcohol levels are high and oxygen is depleted [5][6][7][8][9][10] . Many of these weakly and more strongly fermentative species, however, can contribute significantly to the final composition of wine, and impact the sensory perception of the product [11][12][13] . The contribution of each individual species will depend on its numerical presence and length of persistence throughout alcoholic fermentation.…”

“…For instance, Alonso del Real et al 28 showed that cryotolerant Saccharomyces yeasts, such as Saccharomyces uvarum, compromise the relative fitness of S. cerevisiae at lower temperatures. Bagheri et al 8,13 reported that the presence of certain species can be detrimental to, or may improve, the survival and numerical persistence of other yeast species within the wine ecosystem.…”

The Wickerhamiella/Starmerella clade—A treasure trove for the study of the evolution of yeast metabolism

“…For example, S. bacillaris (formerly known as Candida zemplinina) is often isolated from wine fermentations and grapes (Grangeteau et al, 2016;Magyar & Toth, 2011). It has been studied as a possible costarter of wine fermentations, where it contributes to a lower ethanol concentration and a higher glycerol content in the final product (Bagheri, Zambelli, Vigentini, Bauer, & Setati, 2018;Binati et al, 2019;Castrillo, Rabunal, Neira, & Blanco, 2019;Englezos et al, 2016;Englezos et al, 2018;Lemos Junior et al, 2019). S. bombicola is the best-studied species in the W/S clade as it is used for the industrial production of sophorolipids, a class of environmentally friendly biosurfactants used in the cleaning and cosmetic industries, as well as for bioremediation of soil pollution by hydrocarbons (Van Bogaert et al, 2013).…”

Microbial Resources as a Tool for Enhancing Sustainability in Winemaking

“…During the crushing stage, the strategy to bioprotect must as soon as possible at the biochemical level, avoiding undesired microorganisms' metabolism, by inoculating selected starter cultures is increasingly being employed [18]. Indeed, it has been shown that some non-Saccharomyces species support or inhibit the growth of other non-Saccharomyces and Saccharomyces species in multispecies consortiums, and that the relative performance of each yeast species is dependent on its fermentation capacity, initial cell density, and ecological interactions as well as tolerance to environmental factors [58]. A large number of research work has addressed this topic in recent years, most of which focused on the limitation of spoilage occurrence, mainly due to Brettanomyces bruxellensis growth (for reviews, see [17,39,59]).…”