Ecological Distribution and Oenological Characterization of Native Saccharomyces cerevisiae in an Organic Winery

The relation between regional yeast biota and the organoleptic characteristics of wines has attracted growing attention among winemakers. In this work, the dynamics of a native Saccharomyces cerevisiae population was investigated in an organic winery. In this regard, the occurrence and the persistence of native S. cerevisiae were evaluated in the vineyard and winery and during spontaneous fermentation of two nonconsecutive vintages. From a total of 98 strains, nine different S. cerevisiae biotypes were identified that were distributed through the whole winemaking process, and five of them persisted in both vintages. The results of the oenological characterization of the dominant biotypes (I and II) show a fermentation behavior comparable to that exhibited by three common commercial starter strains, exhibiting specific aromatic profiles. Biotype I was characterized by some fruity aroma compounds, such as isoamyl acetate and ethyl octanoate, while biotype II was differentiated by ethyl hexanoate, nerol, and β-damascenone production also in relation to the fermentation temperature. These results indicate that the specificity of these resident strains should be used as starter cultures to obtain wines with distinctive aromatic profiles

Yeast interactions and molecular mechanisms in wine fermentation: A comprehensive review

Wine can be defined as a complex microbial ecosystem, where different microorganisms interact in the function of different biotic and abiotic factors. During natural fermentation, the effect of unpredictable interactions between microorganisms and environmental factors leads to the establishment of a complex and stable microbiota that will define the kinetics of the process and the final product. Controlled multistarter fermentation represents a microbial approach to achieve the dual purpose of having a less risky process and a distinctive final product. Indeed, the interactions evolved between microbial consortium members strongly modulate the final sensorial properties of the wine. Therefore, in well‐managed mixed fermentations, the knowledge of molecular mechanisms on the basis of yeast interactions, in a well‐defined ecological niche, becomes fundamental to control the winemaking process, representing a tool to achieve such objectives. In the present work, the recent development on the molecular and metabolic interactions between non‐Saccharomyces and Saccharomyces yeasts in wine fermentation was reviewed. A particular focus will be reserved on molecular studies regarding the role of nutrients, the production of the main byproducts and volatile compounds, ethanol reduction, and antagonistic actions for biological control in mixed fermentations

Metschnikowia pulcherrima in Cold Clarification: Biocontrol Activity and Aroma Enhancement in Verdicchio Wine

Non-Saccharomyces wine yeasts are not only proposed to improve the sensory profile of wine but also for several distinctive promising features. Among them, biocontrol action at different steps of the wine production chain could be a suitable strategy to reduce the use of sulfur dioxide. In this work, the activity of a selected strain of Metschnikowia pulcherrima was evaluated as inoculum in cold clarification with the aim to reduce SO2 and improve the aromatic profile of the wine. Fermentation processes were carried out at the winery level for two consecutive vintages using a pied de cuve as the starter inoculum coming from indigenous Saccharomyces cerevisiae strains. M. pulcherrima revealed an effective bio-protectant action during the pre-fermentative stage even if the timely and appropriate starter inoculum in the two years permitted the effective control of wild yeasts during the fermentation also in the control trials. In general, the main oenological characters did not show differences if compared with an un-inoculated trial, while the inoculum of M. pucherrima in cold clarification determined an enhancement of ethyl hexanoate, isobutanol, acetaldehyde, and geraniol even if they are considered in different amounts for each year. Indeed, the analytical and sensory profiles of wines were also influenced by the vintage and variation pied the cuve population. Nonetheless, the overall results indicated that M. pulcherrima led to biocontrol action and an improvement of the aromatic and sensory profile of the wine

Purification and characterization of WA18, a new mycocin produced by wickerhamomyces anomalus active in wine against brettanomyces bruxellensis spoilage yeasts

Wickerhamomyces anomalus strain 18, isolated from a natural underground cheese ripening pit, secretes a mycocin named WA18 that inhibits wine spoilage yeasts belonging to Brettanomyces bruxellensis species, with a broad-spectrum of activity. WA18 was purified, and the purified protein was digested with specific restriction enzymes (lysine K and arginine R cut sites). The LC–MS and LC–MS/MS analysis after enzymatic digestions revealed a molecular weight of 31 kDa. Bioinformatics processing and database research of digested pure killer protein showed 99% identity with a UDP-glycosyltransferase protein. Competitive inhibition assay of killer activity by cell-wall polysaccharides suggests that branched glucans represent the first receptor site of the toxin on the envelope of the sensitive target. The WA18 partially purified crude extract (PPCE) showed high stability of antimicrobial activity at the physicochemical conditions suitable for the winemaking process. Indeed, in wine WA18 was able to counteract B. bruxellensis and control the production of ethyl phenols. In addition, the strain WA18 was compatible with Saccharomyces cerevisiae in co-culture conditions with a potential application together with commercial starter cultures. These data suggest that WA18 mycocin is a promising biocontrol agent against spoilage yeasts in winemaking, particularly during wine storage

Starmerella bombicola and saccharomyces cerevisiae in wine sequential fermentation in aeration condition: Evaluation of ethanol reduction and analytical profile

In the last few decades, the increase of ethanol in wine, due to global climate change and consumers’ choice is one of the main concerns in winemaking. One of the most promising approaches in reducing the ethanol content in wine is the use of non-Saccharomyces yeasts in co-fermentation or sequential fermentation with Saccharomyces cerevisiae. In this work, we evaluate the use of Starmerella bombicola and S. cerevisiae in sequential fermentation under aeration condition with the aim of reducing the ethanol content with valuable analytical profile. After a preliminary screening in synthetic grape juice, bench-top fermentation trials were conducted in natural grape juice by evaluating the aeration condition (20 mL/L/min during the first 72 h) on ethanol reduction and on the analytical profile of wines. The results showed that S. bombicola/S. cerevisiae sequential fermentation under aeration condition determined an ethanol reduction of 1.46% (v/v) compared with S. cerevisiae pure fermentation. Aeration condition did not negatively affect the analytical profile of sequential fermentation S. bombicola/S. cerevisiae particularly an overproduction of volatile acidity and ethyl acetate. On the other hand, these conditions strongly improved the production of glycerol and succinic acid that positively affect the structure and body of wine

Metschnikowia pulcherrima as biocontrol agent and wine aroma enhancer in combination with a native Saccharomyces cerevisiae

One of the main objectives for a sustainable winemaking process is the reduction of the use of sulfur dioxide. In this regard, non-Saccharomyces wine yeasts are proposed as biocontrol agent in different steps of wine production chain. Here, a selected strain of Metschnikowia pulcherrima (DiSVA 269) and a native Saccharomyces cerevisiae low sulfite producer strain (DiSVA 708) were investigated. After preliminary laboratory trials, winemaking process at industrial level showed an effective biocontrol action (reduction of c.a. 1 Log order of wild yeasts) of M. pulcherrima inoculated at prefermentative stage in cold clarification (48 h at 10 ◦C) and during the subsequent fermentation process. The combination of M. pulcherrima/S. cerevisiae led a distinctive aromatic profile of wines both in laboratory and winery trials with a significant enhancement of ethyl butyrate, ethyl hexanoate, isoamyl acetate and β-phenyl ethanol. Moreover the use of the two selected strains was the best combination to enhance volatile thiols (3-mercaptohexan-1-ol and 3-mercaptoexil acetate) that well correlate with the sensory analysis (tropical fruits). The overall results indicate that the combined use of M. pulcherrima DiSVA 269 and native S. cerevisiae DiSVA 708 led a biocontrol action and an improvement of aromatic and sensorial profile of wine with low SO2 content

Characterization of wild yeasts isolated from artisan dairies in the Marche region, Italy, for selection of promising functional starters

Ninety-two yeasts isolated from cheeses and different dairies in the Marche region (Italy) were identified and characterized as potential functional co-starter cultures. The prevalent isolates were Debaryomyces hansenii (58%), Candida zeylanoides (25%) and Yarrowia lipolytica (5.5%), while other species belonging to the Candida, Kluyveromyces, Moniliella and Yamadazyma genera were minorities. The yeasts identified were subjected to typing analysis with the purpose of clustering the biotypes to detect the strain specificity for each dairy. Furthermore, the occurrence of some functional and/or probiotic properties was evaluated. D. hansenii, C. zeylanoides and Y. lipolytica showed 16, 4 and 2 different biotypes, respectively. Y. lipolytica biotype II and Candida parapsilosis biotype I exhibited high antioxidant activities. The unique Kluyveromyces lactis biotype showed a minimal ability to grow in the presence of bile salts at 37 °C and pH 2.5, but it exhibited high antioxidant activity. Most of the D. hansenii and C. zeylanoides biotypes showed relevant preliminary probiotic and technological traits. Thus, considering these preliminary evaluations, selected strains of C. zeylanoides, Y. lipolytica and K. lactis could be proposed in association with lactic acid bacteria as innovative co-starters that are able to develop functional cheeses characterized by a distinctive aroma

Increased expression of the ectoenzyme CD38 in peripheral blood plasmablasts and plasma cells of patients with systemic sclerosis

Objective: CD38 is a type II glycoprotein highly expressed on plasmablasts and on short- and long-lived plasma cells, but weakly expressed by lymphoid, myeloid, and non-hematopoietic cells. CD38 is a target for therapies aimed at depleting antibody-producing plasma cells. Systemic sclerosis (SSc) is an immune-mediated disease with a well-documented pathogenic role of B cells. We therefore analyzed CD38 expression in different subsets of peripheral blood mononuclear cells (PBMCs) from a cohort of SSc patients. Methods: Cell surface expression of CD38 was evaluated on PBMCs from SSc patients using eight-color flow cytometry analysis performed with a FacsCanto II (BD). Healthy individuals were used as controls (HC). Results: Forty-six SSc patients (mean age 56, range 23-79 years; 38 females and 8 males), and thirty-two age- and sex-matched HC were studied. Twenty-eight patients had the limited cutaneous form and eighteen the diffuse cutaneous form of SSc. The mean disease duration was 7 years. Fourteen patients were on immunosuppressive therapy (14 MMF, 5 RTX). The total percentages of T, B and NK cells were not different between SSc and HC. Compared to HC, SSc patients had higher levels of CD3+CD38+ T cells (p<0.05), higher percentage (p<0.001) of CD3+CD4+CD25+FOXP3+ regulatory T cells, lower percentage (p<0.05) of CD3+CD56+ NK T cells. Moreover, SSc patients had higher levels of CD24highCD19+CD38high regulatory B cells than HC (p<0.01), while the amount of CD24+CD19+CD38+CD27+ memory B cells was lower (p<0.001). Finally, the percentages of circulating CD38highCD27+ plasmablasts and CD138+CD38high plasma cells were both higher in the SSc group than in HC (p<0.001). We did not observe any correlations between these immunophenotypes and disease subsets or duration, and ongoing immunosuppressive treatment. Conclusions: The increased expression of CD38 in peripheral blood plasmablasts and plasma cells of SSc patients may suggest this ectoenzyme as a candidate therapeutic target, under the hypothesis that depletion of these cells may beneficially downregulate the chronic immune response in SSc patients. Validation of this data in multicenter cohorts shall be obtained prior to clinical trials with existing anti-CD38 drugs

DataSheet_1_Increased expression of the ectoenzyme CD38 in peripheral blood plasmablasts and plasma cells of patients with systemic sclerosis.pdf

ObjectiveCD38 is a type II glycoprotein highly expressed on plasmablasts and on short- and long-lived plasma cells, but weakly expressed by lymphoid, myeloid, and non-hematopoietic cells. CD38 is a target for therapies aimed at depleting antibody-producing plasma cells. Systemic sclerosis (SSc) is an immune-mediated disease with a well-documented pathogenic role of B cells. We therefore analyzed CD38 expression in different subsets of peripheral blood mononuclear cells (PBMCs) from a cohort of SSc patients.MethodsCell surface expression of CD38 was evaluated on PBMCs from SSc patients using eight-color flow cytometry analysis performed with a FacsCanto II (BD). Healthy individuals were used as controls (HC).ResultsForty-six SSc patients (mean age 56, range 23-79 years; 38 females and 8 males), and thirty-two age- and sex-matched HC were studied. Twenty-eight patients had the limited cutaneous form and eighteen the diffuse cutaneous form of SSc. The mean disease duration was 7 years. Fourteen patients were on immunosuppressive therapy (14 MMF, 5 RTX). The total percentages of T, B and NK cells were not different between SSc and HC. Compared to HC, SSc patients had higher levels of CD3+CD38+ T cells (phighCD19+CD38high regulatory B cells than HC (phighCD27+ plasmablasts and CD138+CD38high plasma cells were both higher in the SSc group than in HC (pConclusionsThe increased expression of CD38 in peripheral blood plasmablasts and plasma cells of SSc patients may suggest this ectoenzyme as a candidate therapeutic target, under the hypothesis that depletion of these cells may beneficially downregulate the chronic immune response in SSc patients. Validation of this data in multicenter cohorts shall be obtained prior to clinical trials with existing anti-CD38 drugs.</p