The Genus Metschnikowia in Enology

Abstract

Over the last decade, several non-Saccharomyces species have been used as an alternative yeast for producing wines with sensorial properties that are distinctive in comparison to those produced using only Saccharomyces cerevisiae as the classical inoculum. Among the non-Saccharomyces wine yeasts, Metschnikowia is one of the most investigated genera due to its widespread occurrence and its impact in winemaking, and it has been found in grapevine phyllospheres, fruit flies, grapes, and wine fermentations as being part of the resident microbiota of wineries and wine-making equipment. The versatility that allows some Metschnikowia species to be used for winemaking relies on an ability to grow in combination with other yeast species, such as S. cerevisiae, during the first stages of wine fermentation, thereby modulating the synthesis of secondary metabolites during fermentation in order to improve the sensory profile of the wine. Metschnikowia exerts a moderate fermentation power, some interesting enzymatic activities involving aromatic and color precursors, and potential antimicrobial activity against spoilage yeasts and fungi, resulting in this yeast being considered an interesting tool for use in the improvement of wine quality. The abovementioned properties have mostly been determined from studies on Metschnikowia pulcherrima wine strains. However, M. fructicola and M. viticola have also recently been studied for winemaking purposes.

The Use of Raman Spectroscopy to Monitor Metabolic Changes in Stressed Metschnikowia sp. Yeasts

“…In 2020, shell-isolated nanoparticle-enhanced Raman spectroscopy was successfully applied for characterization of pulcherrimin [ 34 ]. Advances in genus Metschnikowia have been illustrated in two recent publications [ 35 , 36 ].…”

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

“…Z. bisporus is closely related to Z. bailii and Z. pseudobailii [ 83 , 84 ]. It was described as spoilage yeast with intermediate features between Z. rouxii and Z. bailii [ 71 , 72 ] and has been isolated from both healthy grapes [ 54 ] and rotten grapes [ 85 ]. From one of the bottled Essence wines, only Z. lentus was isolated.…”

“…The analysis of the genome sequences of certain strains of the pulcherrima clade revealed that their rDNA is fragmented and thus evolves via the birth-and-death mechanism rather than via homogenisation, which is unusual in yeasts [ 68 ]. Yeasts belonging to this clade are ubiquitous on/in fruits, beverages and fruit-based food products (e.g., [ 85 , 95 ]) and were also found in botrytised grapes from the Tokaj region [ 42 , 96 ]. As the fermentation power of Metschnikowia is lower than that observed for other non- Saccharomyces species [ 15 ], the strains found in the Essence wines are not likely to significantly contribute to the fermentation process but they may modulate the composition of the wine.…”

“…As the fermentation power of Metschnikowia is lower than that observed for other non- Saccharomyces species [ 15 ], the strains found in the Essence wines are not likely to significantly contribute to the fermentation process but they may modulate the composition of the wine. Strains of the pulcherrima clade have been found to affect wine quality, both positively and negatively (for recent reviews, see [ 15 , 85 ]).…”

“…Given their low abundance in the yeast biota, they are unlikely to affect the fermentation but may modulate certain sensorial properties of the wine. All low-abundance yeast species found in this study are known to have favourable abilities that can be exploited to improve the wine quality when inoculated in the wine as components of mixed starters (for recent reviews, see, e.g., [ 11 , 14 , 85 , 100 ]).…”