Enzymatic activities produced by mixed Saccharomyces and non-Saccharomyces cultures: relationship with wine volatile composition

Abstract

During certain wine fermentation processes, yeasts, and mainly non-Saccharomyces strains, produce and secrete enzymes such as β-glucosidases, proteases, pectinases, xylanases and amylases. The effects of enzyme activity on the aromatic quality of wines during grape juice fermentation, using different co-inoculation strategies of non-Saccharomyces and Saccharomyces cerevisiae yeasts, were assessed in the current study. Three strains with appropriate enological performance and high enzymatic activities, BSc562 (S. cerevisiae), BDv566 (Debaryomyces vanrijiae) and BCs403 (Candida sake), were assayed in pure and mixed Saccharomyces/non-Saccharomyces cultures. β-Glucosidase, pectinase, protease, xylanase and amylase activities were quantified during fermentations. The aromatic profile of pure and mixed cultures was determined at the end of each fermentation. In mixed cultures, non-Saccharomyces species were detected until day 4-5 of the fermentation process, and highest populations were observed in MSD2 (10% S. cerevisiae/90% D. vanrijiae) and MSC1 (1% S. cerevisiae/99% C. sake). According to correlation and multivariate analysis, MSD2 presented the highest concentrations of terpenes and higher alcohols which were associated with pectinase, amylase and xylanase activities. On the other hand, MSC1 high levels of β-glucosidase, proteolytic and xylanolytic activities were correlated to esters and fatty acids. Our study contributes to a better understanding of the effect of enzymatic activities by yeasts on compound transformations that occur during wine fermentation.

Microbial Resources and Enological Significance: Opportunities and Benefits

“…Similarly, wines of the grape variety Syrah obtained by mixed and sequential fermentation with C. cantarellii and S. cerevisiae showed 44.3 to 52.8% glycerol content higher than the control wines (Toro and Vazquez, 2002). C. sake increased concentrations of terpenes and higher alcohols in Pedro Gimenez wines (Maturano et al, 2015). …”

Grape Microbiome: Potential and Opportunities as a Source of Starter Cultures

“…Despite the fact that non-Saccharomyces species that grow during fermentation have a low fermentative capacity, they play a key role in wine flavour as they produce flavour compounds such as esters, higher alcohols, acetic acid and acetaldehyde. Therefore, the identification and differentiation between S. cerevisiae and non-Saccharomyces species allows the creation of specific mixtures which are used to improve the sensory quality of the wine [7]. The discrimination of different strains is also of ecological interest.…”

“…Moreover, it is well known that the enzymes secreted by non-Saccharomyces yeasts have the ability to transform compounds coming from the grapes to various aromatic precursors which are positively influencing the sensorial profile of the produced wines [45]. More specifically, during wine fermentation different non-Saccharomyces species secrete significant amounts of proteases which produce odorous compounds such as terpenes, C13-norisoprenoids, esters and ketones and affect the aromatic quality of the produced wine [7]. Therefore, by screening and measuring the proteolytic activity of non-Saccharomyces strains, suitable mixtures of Saccharomyces and nonSaccharomyces strains can be created in order to facilitate the production of wines with improved aroma and flavour [46].…”

“…The survival of non-Saccharomyces species during the fermentation process is regulated by ethanol production as the main Saccharomyces cerevisiae metabolic product. Specific species of Hanseniaspora, Candida, Pichia, Kluyveromyces, Metschnikowia and Issatchenkia isolated from grapes and must are sensitive in high ethanol concentrations (more than 5-7%), and that is probably the reason for their decline and finally their death, as the fermentation progresses [7]. Surviving indigenous microorganisms seem to be better adapted to the environmental conditions of a given wine producing area, as well as to the cellar where the winemaking process takes place.…”

Purification and Properties of Yeast Proteases Secreted by Wickerhamomyces anomalus 227 and Metschnikovia pulcherrima 446 during Growth in a White Grape Juice

“…Non-Saccharomyces wine yeasts, also called "wild" yeasts, can enhance the analytical composition and aroma profile of wine by production of secondary metabolites and secretion of enzymes [3][4][5]. Yeasts of the genera Kloeckera, Candida, Debaryomyces, Rhodotorula, Pichia, Wickerhamomyces, Zygosaccharomyces, Hanseniaspora, Kluyveromyces and Metschnikowia produce hydrolytic exoenzymes (esterases, lipases, glycosidases, glucanases, pectinases, amylases, and proteases) that interact with grape compounds [6].…”