Fungal Diversity Analysis of Grape Musts from Central Valley-Chile and Characterization of Potential New Starter Cultures

Abstract

Autochthonous microorganisms are an important source of the distinctive metabolites that influence the chemical profile of wine. However, little is known about the diversity of fungal communities associated with grape musts, even though they are the source of local yeast strains with potential capacities to become starters during fermentation. By using internal transcribed spacer (ITS) amplicon sequencing, we identified the taxonomic structure of the yeast community in unfermented and fermented musts of a typical Vitis vinifera L. var. Sauvignon blanc from the Central Valley of Chile throughout two consecutive seasons of production. Unsurprisingly, Saccharomyces represented the most abundant fungal genus in unfermented and fermented musts, mainly due to the contribution of S. uvarum (42.7%) and S. cerevisiae (80%). Unfermented musts were highly variable between seasons and showed higher values of fungal diversity than fermented musts. Since microbial physiological characterization is primarily achieved in culture, we isolated nine species belonging to six genera of fungi from the unfermented must samples. All isolates were characterized for their potential capacities to be used as new starters in wine. Remarkably, only Metschnikowia pulcherrima could co-exist with a commercial Saccharomyces cerevisiae strain under fermentative conditions, representing a feasible candidate strain for wine production.

Fungal Diversity and Dynamics during Grape Wine Fermentations with Different Sulfite Levels and Yeast Inoculations

“…It is important to understand the dynamics of indigenous yeasts during spontaneous and inoculated fermentations as they can impact organoleptic properties specific to grape-growing regions. While recently research has been done using HTS to identify grape/wine microbiota and study dynamics of microorganisms during wine fermentation (Bokulich et al 2014, Portillo and Mas 2016, De Filippis et al 2017, Mezzasalma et al 2017, Chen et al 2020, Guzzon et al 2020, Mandakovic et al 2020, only a few focused on impact of sulfites levels or yeast inoculations on grape juice/wine microbiota (Bokulich et al 2015).…”

Metataxonomic Analysis of Grape Microbiota During Wine Fermentation Reveals the Distinction of Cyprus Regional terroirs

“…Several common genera were detected in an HTS study of unfermented must of the variety V. vinifera L. var. Sauvignon blanc in Chile, in which a commercial starter culture of S. cerevisiae was added ( Mandakovic et al, 2020 ). Apart from the genus Saccharomyces the genera Hanseniaspora , Torularospora , Botrytis , Penicillium , Cladosporium , Candida , and Aureobasidium were the most dominant in agreement with most of our findings.…”

“…This observation is in agreement with a recent study comparing the fungal diversity of typical Vitis vinifera L. var. Sauvignon blanc from Chile between prefermented and fermented musts (Mandakovic et al, 2020) and a metataxonomic study of Vino Santo mycobiota in the Italian Alps (Stefanini et al, 2016). During AF, yeast species such as S. cerevisiae ferment sugars producing ethanol (Stefanini et al, 2016).…”

Wild Yeast for the Future: Exploring the Use of Wild Strains for Wine and Beer Fermentation

“…Yeasts are naturally present in fermentation raw materials, such as grape musts (wine fermentation) and cereals (beer fermentation), representing a fraction of the natural microbiota of these carbon-rich environments. However, in most cases, the main microorganisms that could outcompete the others are species belonging to the Saccharomyces genus, mainly Saccharomyces cerevisiae (Sternes et al, 2017;Stefanini and Cavalieri, 2018;Mandakovic et al, 2020). S. cerevisiae is able to dominate the fermentation process, due to its high fermentative capacity and ability to tolerate different stresses, such as high osmotic stress, low pH, high ethanol levels, anerobiosis, and nutrient starvation (Warringer et al, 2011;Brice et al, 2014;García-Ríos et al, 2014;Kitichantaropas et al, 2016;Taymaz-Nikerel et al, 2016;Legras et al, 2018;García-Ríos and Guillamón, 2019).…”