Abstract:Better knowledge about the expression of some genes encoding the flocculent phenotype which could be useful to select suitable starter cultures to improve sparkling wine technology was achieved. A step forward in understanding the complexity and strain-specific nature of flocculation phenotype was done.
“…Beyond its physiological relevance as a protective mechanism to enhance the survival under environmental stresses (Marika et al, 1993), flocculation is a desirable technological feature allowing the separation of cells from media in fermentation processes such as brewing and winemaking (Pretorius, 2000;Soares, 2011), in particular sparkling wine obtained by the so-called Method Champenoise. This characteristic allows the rapid clarification and reduction of the handling of final products, with a significant decrease in production costs (Tofalo et al, 2016b;Vigentini et al, 2017). Moreover, yeast flocculation seems to be associated with the enhancement of ester production (Pretorius, 2000).…”
A current trend in winemaking has highlighted the beneficial contribution of non-Saccharomyces yeasts to wine quality. Hanseniaspora uvarum is one of the more represented non-Saccharomyces species onto grape berries and plays a critical role in influencing the wine sensory profile, in terms of complexity and organoleptic richness. In this work, we analyzed a group of H. uvarum indigenous wine strains as for genetic as for technological traits, such as resistance to SO 2 and β-glucosidase activity. Three strains were selected for genome sequencing, assembly and comparative genomic analyses at species and genus level. Hanseniaspora genomes appeared compact and contained a moderate number of genes, while rarefaction analyses suggested an open accessory genome, reflecting a rather incomplete representation of the Hanseniaspora gene pool in the currently available genomes. The analyses of patterns of functional annotation in the three indigenous H. uvarum strains showed distinct enrichment for several PFAM protein domains. In particular, for certain traits, such as flocculation related protein domains, the genetic prediction correlated well with relative flocculation phenotypes at lab-scale. This feature, together with the enrichment for oligo-peptide transport and lipid and amino acid metabolism domains, reveals a promising potential of these indigenous strains to be applied in fermentation processes and modulation of wine flavor and aroma. This study also contributes to increasing the catalog of publicly available genomes from H. uvarum strains isolated from natural grape samples and provides a good roadmap for unraveling the biodiversity and the biotechnological potential of these non-Saccharomyces yeasts.
“…Beyond its physiological relevance as a protective mechanism to enhance the survival under environmental stresses (Marika et al, 1993), flocculation is a desirable technological feature allowing the separation of cells from media in fermentation processes such as brewing and winemaking (Pretorius, 2000;Soares, 2011), in particular sparkling wine obtained by the so-called Method Champenoise. This characteristic allows the rapid clarification and reduction of the handling of final products, with a significant decrease in production costs (Tofalo et al, 2016b;Vigentini et al, 2017). Moreover, yeast flocculation seems to be associated with the enhancement of ester production (Pretorius, 2000).…”
A current trend in winemaking has highlighted the beneficial contribution of non-Saccharomyces yeasts to wine quality. Hanseniaspora uvarum is one of the more represented non-Saccharomyces species onto grape berries and plays a critical role in influencing the wine sensory profile, in terms of complexity and organoleptic richness. In this work, we analyzed a group of H. uvarum indigenous wine strains as for genetic as for technological traits, such as resistance to SO 2 and β-glucosidase activity. Three strains were selected for genome sequencing, assembly and comparative genomic analyses at species and genus level. Hanseniaspora genomes appeared compact and contained a moderate number of genes, while rarefaction analyses suggested an open accessory genome, reflecting a rather incomplete representation of the Hanseniaspora gene pool in the currently available genomes. The analyses of patterns of functional annotation in the three indigenous H. uvarum strains showed distinct enrichment for several PFAM protein domains. In particular, for certain traits, such as flocculation related protein domains, the genetic prediction correlated well with relative flocculation phenotypes at lab-scale. This feature, together with the enrichment for oligo-peptide transport and lipid and amino acid metabolism domains, reveals a promising potential of these indigenous strains to be applied in fermentation processes and modulation of wine flavor and aroma. This study also contributes to increasing the catalog of publicly available genomes from H. uvarum strains isolated from natural grape samples and provides a good roadmap for unraveling the biodiversity and the biotechnological potential of these non-Saccharomyces yeasts.
“…The natural reservoir of FLO genes in S. cerevisiae strains was proposed as a reservoir to improve beverage industry because it allows green biomass separation 29 , 40 , 41 . For this reason, this study was first focused on FLO 1, FLO 5 and FLO 8 genes in four S. cerevisiae wine strains (primers’ sequences and PCR conditions are reported in Supplementary Table S1 ).…”
Section: Resultsmentioning
confidence: 99%
“…Haploid segregants obtained with the flocculent hybrid PDG 42 that had inherited the FLO 1 gene from F6789 were not able to achieve flocculation. It could be due to the mutations in this region or to the different expression of Flo1p 29 , 40 . Further studies are necessary to explain these data.…”
Flocculation is an important feature for yeast survival in adverse conditions. The natural diversity of flocculating genes in Saccharomyces cerevisiae can also be exploited in several biotechnological applications. Flocculation is mainly regulated by the expression of genes belonging to the FLO family. These genes have a similar function, but their specific contribution to flocculation ability is still unclear. In this study, the distribution of FLO1, FLO5 and FLO8 genes in four S. cerevisiae wine strains was investigated. Subsequently, both FLO1 and FLO5 genes were separately deleted in a flocculent S. cerevisiae wine strain. After gene disruption, flocculation ability and agar adhesion were evaluated. FLO1 and FLO5 genes inheritance was also monitored. All strains presented different lengths for FLO1 and FLO5 genes. Results confirm that in S. cerevisiae strain F6789, the FLO5 gene drives flocculation and influences adhesive properties. Flocculation ability monitoring after a cross with a non-flocculent strain revealed that FLO5 is the gene responsible for flocculation development.
“…Selection of β-lyase-producing yeasts improves aromatic thiol release and, consequently, the sensory properties of wines (Belda et al, 2016), whereas the selection of yeasts specializing in certain processes such as flocculation may improve the fermentation of special wines such as sparkling wines (Tofalo et al, 2016). In turn, the current trend of using non- Saccharomyces strains, which in the past were considered yeasts of secondary importance or yeasts that produced undesirable changes, has positively impacted the vinification process, given the ability of the strains to produce enzymes, secondary metabolites, glycerol, ethanol, and other compounds that can increase the organoleptic complexity of wines (Padilla et al, 2016).…”
Over thousands of years, modernization could be predicted for the use of microorganisms in the production of foods and beverages. However, the current accelerated pace of new food production is due to the rapid incorporation of biotechnological techniques that allow the rapid identification of new molecules and microorganisms or even the genetic improvement of known species. At no other time in history have microorganisms been so present in areas such as agriculture and medicine, except as recognized villains. Currently, however, beneficial microorganisms such as plant growth promoters and phytopathogen controllers are required by various agricultural crops, and many species are being used as biofactories of important pharmacological molecules. The use of biofactories does not end there: microorganisms have been explored for the synthesis of diverse chemicals, fuel molecules, and industrial polymers, and strains environmentally important due to their biodecomposing or biosorption capacity have gained interest in research laboratories and in industrial activities. We call this new microbiology Technological Microbiology, and we believe that complex techniques, such as heterologous expression and metabolic engineering, can be increasingly incorporated into this applied science, allowing the generation of new and improved products and services.
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