Controlled mixed culture fermentation: a new perspective on the use of non-Saccharomyces  yeasts in winemaking

Abstract

Mixed fermentations using controlled inoculation of Saccharomyces cerevisiae starter cultures and non-Saccharomyces yeasts represent a feasible way towards improving the complexity and enhancing the particular and specific characteristics of wines. The profusion of selected starter cultures has allowed the more widespread use of inoculated fermentations, with consequent improvements to the control of the fermentation process, and the use of new biotechnological processes in winemaking. Over the last few years, as a consequence of the re-evaluation of the role of non-Saccharomyces yeasts in winemaking, there have been several studies that have evaluated the use of controlled mixed fermentations using Saccharomyces and different non-Saccharomyces yeast species from the wine environment. The combined use of different species often results in unpredictable compounds and/or different levels of fermentation products being produced, which can affect both the chemical and the aromatic composition of wines. Moreover, possible synergistic interactions between different yeasts might provide a tool for the implementation of new fermentation technologies. Thus, knowledge of the Saccharomyces and non-Saccharomyces wine yeast interactions during wine fermentation needs to be improved. To reach this goal, further investigations into the genetic and physiological background of such non-Saccharomyces wine yeasts are needed, so as to apply '-omics' approaches to mixed culture fermentations.

Directed metabolomic approaches for the characterization and development of new yeast strains

“…Current taxonomies recognize 149 yeast genera comprising nearly 1500 species [24]. Of these, more than 40 species have been isolated from grape must [3,21] but not all of them are welcome to the fermentation process. It should be noted that some yeast species found in grapes and must, like Aureobasidium pullulans or Cryptococcus amylolentus, are enzymatically interesting showing a wide range and intensity of hydrolytic activities but have a low incidence on fermentation development.…”

“…Some enzymatic properties (glycosidases, β-lyase, etc.) and the release of some interesting metabolites such as glycerol, mannoproteins and other aromatic compounds justify the interest in these combined fermentations [21,22]. Such fermentations are a very useful tool to improve wine productions in which aromatic complexity of spontaneous fermentations and the safety of industrial targeted fermentations are joined [19,21].…”

Sequential fermentation using non-Saccharomycesyeasts for the reduction of alcohol content in wine

“…The inoculum for immobilized cells was 2-4 × 10 8 cells per ml (10% [wt/vol] of the amount of beads in the medium). Fermentations were carried out in duplicate at 25 • C in synthetic grape juice (SGJ) [4] containing 220 g/L sugar. All fermentation trials completed alcoholic fermentation with less than 2 g/L residual sugar.…”

“…Following numerous studies on the influence of non-Saccharomyces yeast in winemaking, there has been a re-evaluation of the role of these yeasts. Indeed, some non-Saccharomyces yeast can enhance the overall profile of the wine, and for this reason the use of controlled multi-starter fermentation using selected cultures of non-Saccharomyces and S. cerevisiae yeast strains has been encouraged [4]. Indeed, nowadays one of the most recent technological advances in winemaking is the practice of co-inoculation of grape a Corresponding author: m.ciani@ univpm.it juice with selected culture of non-Saccharomyces coupled with S. cerevisiae starter strain [5].…”

Evaluation of different co-inoculation time of non-Saccharomyces/Saccharomycesyeasts in order to obtain reduced ethanol wines

“…In this context, the use of nonSaccharomyces wine yeasts could be attractive to reduce alcohol content in wine. However, most nonSaccharomyces yeasts are not able to consume all sugars present in grape must and, therefore, they need to be used as part of sequential, mixed or multistarter inoculation with S. cerevisiae strains [7][8][9][10]. For this reason, it is interesting to analyze the interval between the first and the second inoculation (sequential culture) and inoculation a e-mail: victoria mestref@hotmail.com * Both authors contributed equally to this work proportions (mixed cultures) due to possible interactions between Saccharomyces and non-Saccharomyces yeasts.…”