The impact of saccharomyces cerevisiae on a wine yeast consortium in natural and inoculated fermentations
Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Frontiers Media
Abstract
Natural, also referred to as spontaneous wine fermentations, are carried out by
the native microbiota of the grape juice, without inoculation of selected, industrially
produced yeast or bacterial strains. Such fermentations are commonly initiated by
non-Saccharomyces yeast species that numerically dominate the must. Community
composition and numerical dominance of species vary significantly between individual
musts, but Saccharomyces cerevisiae will in most cases dominate the late stages of
the fermentation and complete the process. Nevertheless, non-Saccharomyces species
contribute significantly, positively or negatively, to the character and quality of the
final product. The contribution is species and strain dependent and will depend on
each species or strain’s absolute and relative contribution to total metabolically active
biomass, and will therefore, be a function of its relative fitness within the microbial
ecosystem. However, the population dynamics of multispecies fermentations are not
well understood. Consequently, the oenological potential of the microbiome in any given
grape must, can currently not be evaluated or predicted. To better characterize the
rules that govern the complex wine microbial ecosystem, a model yeast consortium
comprising eight species commonly encountered in South African grape musts and an
ARISA based method to monitor their dynamics were developed and validated. The
dynamics of these species were evaluated in synthetic must in the presence or absence
of S. cerevisiae using direct viable counts and ARISA. The data show that S. cerevisiae
specifically suppresses certain species while appearing to favor the persistence of other
species. Growth dynamics in Chenin blanc grape must fermentation was monitored only
through viable counts. The interactions observed in the synthetic must, were upheld
in the natural must fermentations, suggesting the broad applicability of the observed
ecosystem dynamics. Importantly, the presence of indigenous yeast populations did not
appear to affect the broad interaction patterns between the consortium species. The
data show that the wine ecosystem is characterized by both mutually supportive and
inhibitory species. The current study presents a first step in the development of a model
to predict the oenological potential of any given wine mycobiome.
Description
CITATION: Bagheri, B., Bauer, F. F. & Setati, M. E. 2017. The impact of saccharomyces cerevisiae on a wine yeast consortium in natural and inoculated fermentations. Frontiers in Microbiology, 8:1988, doi:10.3389/fmicb.2017.01988.
The original publication is available at https://www.frontiersin.org
The original publication is available at https://www.frontiersin.org
Keywords
Saccharomyces, Saccharomyces cerevisiae, Saccharomyces cerevisiae -- Biotechnology
Citation
Bagheri, B., Bauer, F. F. & Setati, M. E. 2017. The impact of saccharomyces cerevisiae on a wine yeast consortium in natural and inoculated fermentations. Frontiers in Microbiology, 8:1988, doi:10.3389/fmicb.2017.01988