The Geographic Distribution of Saccharomyces cerevisiae Isolates within three Italian Neighboring Winemaking Regions Reveals Strong Differences in Yeast Abundance, Genetic Diversity and Industrial Strain Dissemination

Strain prevalence and killer factor only partially influence the fermentation activity of pairwise Saccharomyces cerevisiae wine strains inoculation

Commercial Saccharomyces cerevisiae starters are single-strain cultures widely used in winemaking to optimise the fermentation process and improve the organoleptic quality of wine. Unfortunately, the worldwide extensive use of a limited number of industrial strains led to the standardisation of the sensory properties, reducing the identity of wines. Therefore, the use of multi-strain S. cerevisiae starters can be an alternative tool to alter the sensory profile of wines, increasing the diversity of wine styles. However, this strategy may be interesting only if the overall fermentation kinetics is not affected. To date, there is a lack of information regarding the influence of multi-strain starters on the overall fermentation process in wine. In this context, killer toxins, affecting the viability of sensitive strains, can play a significant role. This study aimed to evaluate the effects of pairing eight wine strains of S. cerevisiae (two sensitive, three neutral and three killer) in co-fermentations compared to single-strain fermentations. Results evidenced that, among co-fermentations where the strain prevalence was significant, the killer strains constituted 79% to 100% of the total yeast population when co-inoculated with a sensitive one. However, in most of the cases, co-fermentations kinetics were similar to those of sensitive strains or worse than both strains. Thus, the presence of a killer strain alone is not sufficient to predict the overall fermentation progress, which is an essential information in winemaking. Interestingly, the neutral strain P304.4 was always prevalent, regardless of the second strain and, in most of the co-fermentations, the overall fermentation trend was similar to the P304.4 single-strain fermentation. Regardless of killer activity, our results suggest that the effect of strains on fermentative kinetics is still unpredictable, and further studies are needed to thoroughly explore strain to strain interactions in winemaking.

Detection of Microbiota during the Fermentation Process of Wine in Relation to the Biogenic Amine Content

Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra, Eastern Slovakia, and Tokaj. This study focuses on the detection of microbiota in soil samples, grape leaves and berries, and samples taken from fermenting must and young wine (the variety Tramín červený) in relation to the detected concentrations of biogenic amines during the fermentation process. In the examined samples, the number of yeasts and molds (from 3.8 to 6.8 log cfu/g or mL) and TVC (from 3.7 to 6.5 log cfu/g or mL) were determined via culture examination. At the same time, the number of LAB (from ˂3.0 to 4.4 log cfu/g or mL) was determined, which was the highest on day 4 of the must fermentation process and was related to the detected of the highest concentration of biogenic amines (histamine and tyramine) on day 6 in the investigated must samples using the UHPLC system. Mycobiota species were identified by MALDI-TOF MS, PCR, ITS-PCR-RFLP, and PCR sequencing of the amplified products. The study confirmed the presence of the yeasts Saccharomyces cerevisiae, Metschnikowia pulcherrima, Hanseniospora uvarum, Pichia kudriavzevii, Pichia kluyveri, Pichia fermentas, Torulaspora delbrueckii, and Candida tenuis. At the same time, the presence of molds (Cladosporium herbarum, Cladosporium cladosporioides, Penicillium granulatum, Penicillium mononematosum, Botritis cinerea, and Penicillium glabrum) was also confirmed in soil samples, leaves, grape berries, and fresh grape must. The study confirmed the reduction in the species diversity of the microbiota during the must fermentation process, which resulted in decreases in the concentrations of the monitored biogenic amines in the early stages of the must fermentation process and young wine of the variety Tramín červený.

Yeast Diversity during Spontaneous Fermentations and Oenological Characterisation of Indigenous Saccharomyces cerevisiae for Potential as Wine Starter Cultures

Diversity of regional yeast can be influenced by geography, grape cultivars and the use of SO₂, but at single vineyard scale in China, the impact of these factors on yeast population, particularly Saccharomyces cerevisiae, is not well studied. Here, we characterised yeast species and dynamics during spontaneous fermentations with/without SO₂ using eight typical grape cultivars from Yuma vineyard in Ningxia wine region of China. Results show that distribution and abundance of yeast species varied by grape varieties, fermentation stage and SO₂ treatment. A number of 290 S. cerevisiae isolates were further classified into 33 genotypes by Interdelta fingerprinting. A prevailing role of grape varieties in shaping the genetic divergence of S. cerevisiae in Yuma vineyard was observed, as compared to the impacts of fermentation stage and SO₂ treatment. Pre-selected S. cerevisiae strains were subjected to vinification with Cabernet Sauvignon and Chardonnay. All strains completed fermentations but the physiochemical parameters and volatile profiles of wines were strain-specific. Some indigenous S. cerevisiae yielded more desirable aroma compounds compared to the commercial strains, among which NX16 and NX18 outcompeted others, therefore having potential for use as starters. This study provides comprehensive analysis on yeast diversity at vineyard scale in Ningxia. Information on the vinification using indigenous S. cerevisiae is of great value for improving Ningxia wine regionality.

The effect of vine variety and vintage on wine yeast community structure of grapes and ferments

AIMS

The yeast community structure associated with grapes is an essential part of the wine-growing chain with a significant effect on wine quality. The aim of the present study was to evaluate the effect of the varietal factor on the yeast community assembly on grapes and during must fermentation.

METHODS AND RESULTS

We analysed the wine yeast populations associated with four different grape varieties from the Greek national collection vineyard of Lykovryssi. The vintage effect was also considered by sampling the grapes for two consecutive years. Fourteen yeast species were recovered and genotyped to distinct subpopulations. A relatively stable yeast community structure was detected across vintages, with Hanseniaspora guilliermondii being the core species of the vineyard under study. The detected species subpopulations shared a relatively high genetic similarity with several genotypes persisting across vintages.

CONCLUSIONS

It was shown that different grape cultivars were associated with distinct yeast communities, pointing to their possible implication on wine chemical diversity.

SIGNIFICANCE AND IMPACT OF THE STUDY

Present findings show that the varietal factor is an important sharpener of the vineyard-associated wine yeast community, which may interfere with the organoleptic profile of the resulting wines.

Lebanon's Native Oenological Saccharomyces cerevisiae Flora: Assessment of Different Aspects of Genetic Diversity and Evaluation of Winemaking Potential

A total of 296 isolates of Saccharomyces cerevisiae sampled from naturally fermenting grape musts from various locations in Lebanon were typed by interdelta fingerprinting. Of these, 88 isolates were compared with oenological strains originating from various countries, using microsatellite characterization at six polymorphic loci. These approaches evidenced a large diversity of the natural oenological Lebanese flora over the territory as well as in individual spontaneous fermentations. Several cases of dominance and perenniality of isolates were observed in the same wineries, where fermentations appeared to involve lineages of sibling isolates. Our work thus evidenced a “winery effect” on strains’ relatedness. Similarly, related or identical strains were also detected in vicinal wineries, suggesting strain circulation within small geographical areas and a further “vicinity effect”. Moreover, and despite its diversity, the Lebanese flora seemed interrelated, on the basis of microsatellite loci analysis, in comparison to worldwide communities. We finally tested the ability of 21 indigenous strains to act as potential starters for winemaking. Seven of them passed our pre-selection scheme and two of them at least may be good candidates for use provided pilot-scale assays confirm their suitability.

Sources and Assembly of Microbial Communities in Vineyards as a Functional Component of Winegrowing

Microbiomes are integral to viticulture and winemaking – collectively termed winegrowing – where diverse fungi and bacteria can exert positive and negative effects on grape health and wine quality. Wine is a fermented natural product, and the vineyard serves as a key point of entry for quality-modulating microbiota, particularly in wine fermentations that are conducted without the addition of exogenous yeasts. Thus, the sources and persistence of wine-relevant microbiota in vineyards critically impact its quality. Site-specific variations in microbiota within and between vineyards may contribute to regional wine characteristics. This includes distinctions in microbiomes and microbiota at the strain level, which can contribute to wine flavor and aroma, supporting the role of microbes in the accepted notion of terroir as a biological phenomenon. Little is known about the factors driving microbial biodiversity within and between vineyards, or those that influence annual assembly of the fruit microbiome. Fruit is a seasonally ephemeral, yet annually recurrent product of vineyards, and as such, understanding the sources of microbiota in vineyards is critical to the assessment of whether or not microbial terroir persists with inter-annual stability, and is a key factor in regional wine character, as stable as the geographic distances between vineyards. This review examines the potential sources and vectors of microbiota within vineyards, general rules governing plant microbiome assembly, and how these factors combine to influence plant-microbe interactions relevant to winemaking.

Capturing yeast associated with grapes and spontaneous fermentations of the Negro Saurí minority variety from an experimental vineyard near León

‘Microbial terroir’ relates to the influence of autochthonous yeasts associated with a grape cultivar on the resultant wine. Geographic region, vineyard site and topography, climate and vintage influence the biodiversity of these microbial communities. Current research focus attempts to correlate their ‘microbial fingerprint’ to the sensorial and chemical characteristics of varietal wines from distinct geographical wine regions. This study focuses on the minor red grape variety, Negro Saurí, which has seen a resurgence in the León Appellation of Origin in Spain as a varietal wine. An experimental vineyard at Melgarajo S.A. (42° 15′ 48.68_N 5° 9′ 56.66_W) was sampled over four consecutive vintages, with autochthonous yeasts being isolated from grapes, must and pilot-scale un-inoculated fermentations, and identified by ITS sequencing. Forty-nine isolates belonging to Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora uvarum and Torulaspora delbrueckii were isolated from grapes and must, and early stages of fermentation dependent on seasonal variation. Saccharomyces cerevisiae predominated throughout fermentation, as a heterogeneous and dynamic population, with seven major biotypes identified amongst 110 isolates across four consecutive vintages. Twenty-four S. cerevisiae isolates representing five strains dominated in two or more vintages. Their persistence through fermentation warrants further validation of their oenological properties as starter cultures.

Whole-genome sequencing from the New Zealand Saccharomyces cerevisiae population reveals the genomic impacts of novel microbial range expansion

Saccharomyces cerevisiae is extensively utilized for commercial fermentation, and is also an important biological model; however, its ecology has only recently begun to be understood. Through the use of whole-genome sequencing, the species has been characterized into a number of distinct subpopulations, defined by geographical ranges and industrial uses. Here, the whole-genome sequences of 104 New Zealand (NZ) S. cerevisiae strains, including 52 novel genomes, are analyzed alongside 450 published sequences derived from various global locations. The impact of S. cerevisiae novel range expansion into NZ was investigated and these analyses reveal the positioning of NZ strains as a subgroup to the predominantly European/wine clade. A number of genomic differences with the European group correlate with range expansion into NZ, including 18 highly enriched single-nucleotide polymorphism (SNPs) and novel Ty1/2 insertions. While it is not possible to categorically determine if any genetic differences are due to stochastic process or the operations of natural selection, we suggest that the observation of NZ-specific copy number increases of four sugar transporter genes in the HXT family may reasonably represent an adaptation in the NZ S. cerevisiae subpopulation, and this correlates with the observations of copy number changes during adaptation in small-scale experimental evolution studies.

Quantifying the effect of human practices on S. cerevisiae vineyard metapopulation diversity

Saccharomyces cerevisiae is the main actor of wine fermentation but at present, still little is known about the factors impacting its distribution in the vineyards. In this study, 23 vineyards and 7 cellars were sampled over 2 consecutive years in the Bordeaux and Bergerac regions. The impact of geography and farming system and the relation between grape and vat populations were evaluated using a collection of 1374 S. cerevisiae merlot grape isolates and 289 vat isolates analyzed at 17 microsatellites loci. A very high genetic diversity of S. cerevisiae strains was obtained from grape samples, higher in conventional farming system than in organic one. The geographic appellation and the wine estate significantly impact the S. cerevisiae population structure, whereas the type of farming system has a weak global effect. When comparing cellar and vineyard populations, we evidenced the tight connection between the two compartments, based on the high proportion of grape isolates (25%) related to the commercial starters used in the cellar and on the estimation of bidirectional geneflows between the vineyard and the cellar compartments.

Spontaneous fermentation in wine production as a controllable technology

This study focuses on the isolation of a consortium of microorganisms from spontaneously fermenting must that naturally contain lactic acid bacteria, non-saccharomyces yeasts, and saccharomyces yeasts. To collect the greatest diversity of microorganisms, the consortium was taken from the point of micro-sparkling. Based on the growth curves, isolation was performed using individual special nutrient media, and the isolates were subsequently multiplied in the nutrient medium. Individual isolates were then used for fermentation tests to monitor the percentage of fermented sugar and hydrogen sulphide production. The highest fermentation abilities were achieved in the isolates containing Saccharomyces cerevisiae and Zygosaccharomyces bailii. The smallest amount of ethanol was formed from the isolates containing Hanseniaspora uvarum, while Candida sake isolate produced the lowest amount of hydrogen sulphide and Zygosaccharomyces bailii produced the highest. The other isolates produced an average amount. Based on these results, a consortium containing the given isolates in a certain ratio was compiled.

Saccharomyces cerevisiae Strain Diversity Associated with Spontaneous Fermentations in Organic Wineries from Galicia (NW Spain)

Yeast play an essential role in wine quality. The dynamics of yeast strains during fermentation determine the final chemical and sensory characteristics of wines. This study aims to evaluate the Saccharomyces cerevisiae strains diversity in organic wineries from Galicia (NW Spain). Samples from spontaneous fermentations were taken in five wineries over three consecutive years (2013 to 2015). The samples were transported to the laboratory and processed following standard methodology for yeast isolation. S. cerevisiae strains were differentiated by mDNA-RFLPs. A total of 66 different strains were identified. Some of them presented a wide distribution and appeared in several wineries. However, other strains were typical from a specific winery. Similarity analysis using two different statistical tests showed significant differences in strain diversity among wineries. The results also revealed high biodiversity indexes; however, only some strains showed an important incidence in their distribution and frequency. Our findings confirmed that spontaneous fermentation favored the existence of a high S. cerevisiae strain diversity in organic wineries from Galicia. The presence of different yeasts during fermentation, specially winery-specific strains, contribute to increased wine complexity and differentiation.

Characterization of Sub-Regional Variation in Saccharomyces Populations and Grape Phenolic Composition in Pinot Noir Vineyards of a Canadian Wine Region

Wine is a product of grape juice fermentation by yeast. Terroir is a term that encompasses all environmental factors and interactions at a specific geographical site, resulting in the development of regional-specific microbial strains and grape metabolites. In this study we determine the distribution of vineyard-associated wine yeast strains and characterize the flavonoid profile of Pinot Noir grapes among 3 sub-regions in the Okanagan Valley (OV), a major wine region in British Columbia, Canada. Pinot Noir grape samples were collected from 13 vineyards among 3 sub-regions of the OV, namely Kelowna (KE), Naramata-Penticton (NP) and Oliver-Osoyoos (OO), within a week prior to the winery harvesting date in 2016 and 2017. A total of 156 spontaneous Pinot Noir fermentations were conducted and vineyard-associated Saccharomyces strains were isolated from fermentations that reached two-thirds sugar depletion. Using microsatellite genotyping, we identified 103 Saccharomyces cerevisiae strains and 9 Saccharomyces uvarum strains. We also identified Saccharomyces paradoxus in one vineyard using ITS sequencing. We developed a microsatellite database of 160 commercial S. cerevisiae strains to determine the identity of the isolated strains and we include the database herein. Commercial strains were widely distributed across the three sub-regions. Forty-two of our 103 S. cerevisiae strains were equivalent or highly similar to commercial strains whereas the remaining 61 were considered as ‘unknown’ strains. Two S. uvarum strains were previously isolated in other OV studies and none matched the S. uvarum commercial strain BMV58. S. cerevisiae population structure was driven by sub-region, although S. cerevisiae populations did not differ significantly across vintages. S. uvarum and S. paradoxus were only identified in the 2017 vintage, demonstrating dynamic wine yeast populations between vintages. We found that the flavonoid profile of Pinot Noir grapes from the same 13 vineyards was also affected by sub-regional terroir. The anthocyanin content was lower and the proportion of methoxylated anthocyanins and flavonols was higher in Pinot Noir grapes from OO, the warmer sub-region as compared to KE, the cooler sub-region. Our study demonstrates that both yeast populations and metabolites associated with the Pinot Noir variety have sub-regional variation within a viticultural area.

Environmental shaping of the bacterial and fungal community in infant bed dust and correlations with the airway microbiota

BACKGROUND

From early life, children are exposed to a multitude of environmental exposures, which may be of crucial importance for healthy development. Here, the environmental microbiota may be of particular interest as it represents the interface between environmental factors and the child. As infants in modern societies spend a considerable amount of time indoors, we hypothesize that the indoor bed dust microbiota might be an important factor for the child and for the early colonization of the airway microbiome. To explore this hypothesis, we analyzed the influence of environmental exposures on 577 dust samples from the beds of infants together with 542 airway samples from the Copenhagen Prospective Studies on Asthma in Childhood₂₀₁₀ cohort.

RESULTS

Both bacterial and fungal community was profiled from the bed dust. Bacterial and fungal diversity in the bed dust was positively correlated with each other. Bacterial bed dust microbiota was influenced by multiple environmental factors, such as type of home (house or apartment), living environment (rural or urban), sex of siblings, and presence of pets (cat and/or dog), whereas fungal bed dust microbiota was majorly influenced by the type of home (house or apartment) and sampling season. We further observed minor correlation between bed dust and airway microbiota compositions among infants. We also analyzed the transfer of microbiota from bed dust to the airway, but we did not find evidence of transfer of individual taxa.

CONCLUSIONS

Current study explores the influence of environmental factors on bed dust microbiota (both bacterial and fungal) and its correlation with airway microbiota (bacterial) in early life using high-throughput sequencing. Our findings demonstrate that bed dust microbiota is influenced by multiple environmental exposures and could represent an interface between environment and child. Video Abstract.

The impact of CUP1 gene copy-number and XVI-VIII/XV-XVI translocations on copper and sulfite tolerance in vineyard Saccharomyces cerevisiae strain populations

In wine production, sulfites are widely used as antimicrobials and antioxidants, whereas copper is associated with fungicides and wine fining treatments. Therefore, wine yeasts are constantly exposed to these agents. Copper tolerance is related to the copy number of the CUP1 gene, encoding for a metallothionein involved in copper detoxification. In wine yeasts, sulfite resistance mainly depends on the presence of the translocation t(XVI;VIII) in the promoter region of the SSU1 gene. This gene encodes for a plasma membrane sulfite pump involved in sulfite metabolism and detoxification. Recently, a new translocation, t(XVI;VIII), was identified. In this work, 253 Saccharomyces cerevisiae strains, representing three vineyard populations from two different continents, were analyzed, along with 20 industrial starters. Copper and sulfites tolerance as well as distribution of CUP1 gene copy-number, t(XVI;VIII)and t(XVI;XV) of SSU1 gene were studied to evaluate the impact of these genomic variations on population phenotypes. The CUP1 gene copy-number was found to be highly variable, ranging from zero to 79 per strain. Moreover it differently impacted the copper tolerance in the populations of the two continents. The diffusion of t(XVI;VIII) and, for the first time, t(XVI;XV) was determined in the three vineyard populations. The correlation between the presence of the translocation and strain sulfite tolerance levels was significant only for the t(XVI;VIII).

Patterns of Genetic Diversity and the Invasion of Commercial Starters in Saccharomyces cerevisiae Vineyard Populations of Santorini Island

Autochthonous Saccharomyces cerevisiae vineyard populations are important components of the grape/wine system. Besides their direct impact on winemaking, they also constitute an untapped reservoir of genotypes with special technological attributes for the wine industry. Research so far on S. cerevisiae populations has focused on spatial distribution on large scales, yet little is known about the genetic variability of populations within viticultural zones and their temporal genotypic variation. Here, S. cerevisiae populations from different vineyards in Santorini, a small Aegean island, were genotyped and their genetic diversity was assessed within and between vineyards during two consecutive years. Despite the relative geographical isolation of the island, a relatively high genetic diversity was uncovered. The vast majority of genotypes were vineyard-specific, while in one of the vintages, significant differences in the genotypic composition of vineyards were detected. Overall, higher differences were detected between vintages rather than among vineyards. Notably, only four genotypes were common for the two vintages, three of which were commercial S. cerevisiae strains, probably "escapees" from wineries. Nevertheless, the populations of the two vintages were not genetically distinct. Present results highlight the magnitude of genetic diversity in natural wine yeast populations on a small spatial scale, yet the invasion of commercial starters may constitute a potential risk for loss of local yeast biodiversity. However, present results show that industrial strains do not necessarily dominate over the natural strains or their high abundance may be temporary.

Genetic and Phenotypic Characterisation of a Saccharomyces cerevisiae Population of 'Merwah' White Wine

The study of yeast biodiversity represents an important step in the preservation of the local heritage, and this work in particular has an innovative character since no further studies have investigated 'Merwah', one of the main grape varieties used in winemaking in Lebanon. To gain deeper knowledge of the genetic diversity and population structure of native Saccharomyces cerevisiae wine strains, 202 isolates were collected during spontaneous alcoholic fermentation of eight must/wine samples of cultivar 'Merwah', over two consecutive years (2016, 2017) in a traditional winery in Mount Lebanon (1400 m a.s.l.). The isolates were identified as S. cerevisiae on the basis of their morphology and preliminary sequence analysis of their internal transcribed spacer (ITS) PCR. They were then characterised at the strain level by interdelta PCR and genotyped using multiplex PCR reactions of 12 microsatellite markers. High genetic diversity was observed for the studied population. To select potential yeast starter strains from this population, micro-fermentations were carried out for 22 S. cerevisiae strains that were selected as representative of the 'Merwah' wine yeast population in order to determine their technological and oenological properties. Three indigenous yeast strains might represent candidates for pilot-scale fermentation in the winery, based on relevant features such as high fermentation vigour, low production of volatile acidity and H₂S and low residual sugar content at the end of alcoholic fermentation.

Looking at the Origin: Some Insights into the General and Fermentative Microbiota of Vineyard Soils

In winemaking processes, there is a current tendency to develop spontaneous fermentations taking advantage of the metabolic diversity of derived from the great microbial diversity present in grape musts. This enological practice enhances wine complexity, but undesirable consequences or deviations could appear on wine quality. Soil is a reservoir of important microorganisms for different beneficial processes, especially for plant nutrition, but it is also the origin of many of the phytopathogenic microorganisms that affect vines. In this study, a meta-taxonomic analysis of the microbial communities inhabiting vineyard soils was realized. A significant impact of the soil type and climate aspects (seasonal patterns) was observed in terms of alpha and beta bacterial diversity, but fungal populations appeared as more stable communities in vineyard soils, especially in terms of alpha diversity. Focusing on the presence and abundance of wine-related microorganisms present in the studied soils, some seasonal and soil-dependent patterns were observed. The Lactobacillaceae family, containing species responsible for the malolactic fermentation, was only present in non-calcareous soils samples and during the summer season. The study of wine-related fungi indicated that the Debaryomycetaceae family dominates the winter yeast population, whereas the Saccharomycetaceae family, containing the most important fermentative yeast species for winemaking, was detected as dominant in summer.

Dynamics of Saccharomyces cerevisiae Strains Isolated from Vine Bark in Vineyard: Influence of Plant Age and Strain Presence during Grape must Spontaneous Fermentations

In this study, two vineyards of different age were chosen. During three years, a sampling campaign was performed for isolating vineyard-associated Saccharomyces cerevisiae (S. cerevisiae) strains. Bark portions and, when present, grape bunches were regularly collected from the same vine plants during the overall sampling period. Each bark portion was added to a synthetic must, while each grape bunch was manually crushed, and fermentations were run to isolate S. cerevisiae strains. All collected yeasts were identified at different species and strain levels to evaluate the genetic variability of S. cerevisiae strains in the two vineyards and strains dynamics. Moreover, bark-associated strains were compared with those isolated from spontaneous fermentations of grapes collected during the two harvests. Regarding the youngest vineyard, no S. cerevisiae was identified on bark and grape surface, highlighting the importance of vine age on yeast colonization. Results reported the isolation of S. cerevisiae from vine bark of the old vineyard at all sampling times, regardless of the presence of the grape bunch. Therefore, this environment can be considered an alternative ecological niche that permanently hosts S. cerevisiae. Bark-associated strains were not found on grape bunches and during pilot-scale vinifications, indicating no significative strain transfer from vine bark to the grape must. Commercial starters were identified as well both in vineyards and during vinifications.

Genetic diversity and population structure of Saccharomyces cerevisiae strains isolated from traditional alcoholic beverages of Côte d'Ivoire

In order to assess the genetic diversity and population structure of indigenous S. cerevisiae from Côte d'Ivoire, a total of 170 strains were isolated from four traditional alcoholic beverages through nine regions. Microsatellite analysis performed at 12 loci revealed that strains of palm oil and raffia wine were genetically related, unlike those of tchapalo and ron wine which formed two s from palm oil wine and raffia wine were clearly inbred. In comparison with the European, North American, Asian and others West African populations, Ivorian population was well defined, although most of these strains were admixed. Among these strains, only isolates from raffia wine appeared to have alleles in common to all populations.

Yeast distribution in Grignolino grapes growing in a new vineyard in Piedmont and the technological characterization of indigenous Saccharomyces spp. strains

The aim of this study was to characterize the yeast consortium isolated from Grignolino grapes in a newly planted vineyard in Piedmont (Italy) via analysis of the intra-vineyard yeast distribution of grape samples from single rows. A two-phase approach allowed the identification of culturable yeasts present on grape skins and, through an enriching procedure via grape fermentation, the isolation of low frequency non-Saccharomyces and Saccharomyces spp. fermentative species, including S. paradoxus, which is highly unusual during grape fermentation, along with the intra-specific characterization of S. cerevisiae isolates. Culture-based molecular techniques revealed a grape yeast microbiota formed by (in order of abundance) Hanseniaspora uvarum, the yeast-like fungus Aerobasidium pullulans, Candida zemplinina, Pichia kluyveri, Candida californica, Curvibasidium cygneicollum, Meyerozima caribbica, Rhodotorula babjevae, Metschnikowia pulcherrima and Cryptococcus flavescens. Technological properties of isolated Saccharomyces spp. strains were analysed, identifying strains, including S. paradoxus, potentially suitable as an ecotypical starter for territorial wines.

Genetic variability and physiological traits of Saccharomyces cerevisiae strains isolated from "Vale dos Vinhedos" vineyards reflect agricultural practices and history of this Brazilian wet subtropical area

Vale dos Vinhedos appellation of origin has a very recent history as industrial wine making region. In this study we investigated the genetic and phenotypic variability of Saccharomyces cerevisiae strains isolated from South-Brazilian vineyards in order to evaluate strain fermentation aptitude and copper and sulphites tolerance. Merlot grape bunches were collected from three vineyards and yeast isolation was performed after single bunch fermentation. High genotypic variability was found and most of the genotypes revealed to be vine-specific. No industrial strain dissemination was present in the sampled vineyards, although it has been wildly reported in traditional winemaking countries. From the phenotypic traits analysis these Brazilian native strains showed good fermentation performances, good tolerance to sulphites and, in particular, a high copper tolerance level. Copper is the most important metal in the formulation of fungicides against downy mildew (Plasmopara viticola), one of the most harmful disease of the vines, and other fungal pests. The high tolerance to copper suggests an environmental adaptation to the strong use of copper-based fungicides, requested by the wet subtropical climate.