Identification and Characterization of Non-Saccharomyces Species Isolated from Port Wine Spontaneous Fermentations

Abstract

In winemaking, non-Saccharomyces yeast species contribute important organoleptic complexity. Current interest focuses on abundant and dominant strains characteristically present in the early phase of spontaneous alcoholic fermentations. Non-Saccharomyces species are particularly relevant in Port wine production such that the fermentation is prematurely stopped, after the metabolism of only one half of the available sugar, through fortification with aguardente. This work aimed to isolate, identify and characterize non-Saccharomyces species present in spontaneously fermenting Port. To accomplish these goals, yeasts were isolated from a selection of frozen must samples (2012–2016 harvests), using a pre-screening process choosing only the best candidates based on the organoleptic quality of the corresponding fortified wine. From five hundred non-Saccharomyces isolates, twelve species were identified. The three most abundant species, Hanseniaspora uvarum, Lachancea thermotolerans, and Metschnikowia pulcherrima, representing 89% of the isolates, exhibited particularly high diversity with high growth performance variability when exposed to typical stress conditions associated with common enological parameters. Less abundant species included Issatchenkia orientalis, Torulaspora delbrueckii, Hanseniaspora vineae, Hanseniaspora osmophila, Candida zemplinina, Rhodotorula mucilaginosa, Hanseniaspora guilliermondii, Issatchenkia occidentalis, and Zygosaccharomyces bisporus. This is the first study providing insights into the identification and characterization of non-Saccharomyces species responsible for spontaneous Port wine production.

Vinification without Saccharomyces: Interacting Osmotolerant and “Spoilage” Yeast Communities in Fermenting and Ageing Botrytised High-Sugar Wines (Tokaj Essence)

“…This strategy previously proved efficient in investigating yeast communities of botrytised grapes [ 42 ]. The analysis of the D1/D2 sequences amplified from 99 isolates identified 13 species that are all known to cause microbial spoilage in high-sugar beverages and food products (e.g., [ 6 , 33 , 71 , 72 , 73 , 74 ]) and occur in fermenting and aging wines of high sugar contents (e.g., [ 6 , 10 , 75 , 76 , 77 ]).…”

“…Both C. lactis-condensi and C. zemplinina were previously detected in sweet Tokaj wines, including Essence-type wines [ 23 , 24 , 49 , 88 , 89 , 90 ]. The latter has been found in many wine-growing regions of the world usually in botrytised [ 10 , 44 , 90 ] and sweet wines (e.g., [ 77 , 91 , 92 , 93 ]) and turned out to have a beneficial effect on wine quality in fermentations inoculated with mixed starters (for a review, see [ 94 ]). Because of these properties, it can be assumed to play a positive role in the fermentation of the Essence wines.…”

Botrytis cinerea and Table Grapes: A Review of the Main Physical, Chemical, and Bio-Based Control Treatments in Post-Harvest

“…Moreover, this antagonistic activity was enhanced by the addition in the formulation of salicylic acid or salts, such as sodium bicarbonate or ammonium molybdate [ 109 , 123 ]. Starmerella bacillaris (synonym Candida zemplinina ) is another species of interest, commonly isolated from grapevines/musts [ 124 , 125 ] and from wines fermented by using botrytized grapes [ 126 , 127 ]. Three Starm.…”

Ethanol Production from Wheat Straw Hydrolysate by Issatchenkia Orientalis Isolated from Waste Cooking Oil

“…Issatchenkia orientalis, also known as Pichia kudriavzevii, Candida krusei or Candida glycerinogenes [4], can be readily isolated from food and environmental sources and offers tolerance to various stresses like low pH, high salt and high temperature [5][6][7][8][9][10]. Hence, I. orientalis, which is also involved in wine fermentation [11][12][13], has been utilized to produce various value-added compounds and platform chemicals under highly acidic conditions [14][15][16][17][18]. Due to its outspoken tolerability to various stresses, I. orientalis has been considered a promising alternative for sustainable ethanol production [19,20].…”