## 1 Introduction  
During winemaking, the consortium of microorganisms rapidly evolves and adapts to the environmental changes. A plethora of genera and species have been identified, and many biotic and abiotic factors shape their population structure and dynamics. The unique microbiota composition of each region is affected mainly by the microclimate, the viticulture and the winemaking techniques that are used. In this regard, the microorganisms play an essential role, which can affect the final product in a positive or negative way [1]. Without a doubt, _Saccharomyces cerevisiae_ is the yeast species that is considered to be adapted to the winemaking conditions, which is reflected in its ability to carry out the alcoholic fermentation and also create the ideal organoleptic profile that is demanded by the market and the consumers [2; 3]. In terms of the increasing insights into the grape and the wine microecosystem, the non-_Saccharomyces_ species dominate the population in the beginning of the alcoholic fermentation in spontaneously fermented wines, while their interactions at molecular and chemical levels with the \(S\). _cerevisiae_ strains can lead to wines with enhanced sensorial properties [4].  
The compatibility between the yeast species as well as their effect on the wine quality is far from being controlled in winemaking, even if several studies have been carried out. The interactions between the yeast species are mainly antagonistic, thus leading to off-flavor by-products or sluggish fermentations. The use of pure cultures results in the development of different metabolomic fingerprint compared to the respective resulting from the use of mixed cultures, while the metabolites that are produced may also be affected by cell-to-cell yeast contact in multi-starter wine fermentation [4; 5]. Additionally, other parameters, such as the temperature, the inoculation ratio, the available nitrogen sources and the amount of produced acetic acid may configure the microbial dynamics during winemaking [1; 4; 5; 6; 7].  
Sauvignon blanc is, worldwide, one of the most used varieties for the production of aromatic white wines, with a typical varietal profile due to the production of thiols. Three major aromatic volatile thiols, namely, 4-mercapto-4-methylpentan-2-one (4 MMP), 3-mercaptoethanol-1-ol (3 MH) and 3-mercaptoethanol acetate (3 MHA), were identified as being responsible for the box tree, grapefruit and passion fruit aromas, respectively, of Sauvignon blanc [8; 9]. The yeast strains that produced the highest levels of the volatile-free thiols fermented the wines with the highest perceived intensity of fruitiness, and these wines were the ones preferred by the tasting panels [10]. While the green character in the Sauvignon Blanc wines can be manipulated through vineyard management, the tropical fruity characters appear to be largely dependent on the wine yeast strain that is used during fermentation. Therefore, the choice of yeast strain for alcoholic fermentation offers great potential to modulate the wine aroma profiles as well as to direct the definable styles that are adapted to the consumer market specifications [11; 12].  
In our previous study [7] we have shown for the first time the oenological potential of the \(S\). _pastorianus_ species for Sauvignon blanc wine production as well as the effect of the inoculation scheme for the expression of varietal aromas. In our present study, we exhaustively studied the interaction between \(S\). _pastorianus_ and \(S\). _cerevisiae_ by comparing the pure and mixed cultures of the _Saccharomyces_ species under different inoculation ratios. One \(S\). _pastorianus_ strain was tested under five co-inoculation combinations schemes with two commercial \(S\). _cerevisiae_ strains in Sauvignon blanc must. For all fermentation trials, the population dynamics of the inoculated and indigenous yeasts, the aromatic compounds with high oenological interest and the sensory profile of the produced wines were analyzed.