Isolation, identification and characterization of regional indigenous Saccharomyces cerevisiae strains

Comparative adaptability of 307 Saccharomyces cerevisiae strains from winemaking and Mantou fermentation

Domesticated Saccharomyces cerevisiae is one of the most significant microbial populations in human civilization due to its remarkable diversity and high adaptability to human environments. However, the adaptability mechanisms underlying this population ecological behavior remain unclear. This study explored the adaptive behaviors of S. cerevisiae strains from the Wine and Mantou genetic lineages under both artificial stress conditions and natural or near-natural environments. A total of 307 diploid S. cerevisiae strains were analyzed, including 169 strains derived from grape sources and 138 from sourdough sources. Various stress factors, including sodium chloride, tannins, ethanol, pH, temperature, and sulfur dioxide (SO2), as well as different substrates (natural grape juice, simulated grape juice, and simulated dough), were applied to evaluate adaptability. The results demonstrated that Wine population exhibited superior performance in grape juice environments, characterized by higher CO2 production. The biomass of both the Wine and Mantou populations in the simulated dough was significantly higher than that in the simulated grape juice. In the simulated grape juice environment, the adaptability of the Wine population was significantly superior to that of the Mantou population. In contrast, in the simulated dough environment, the Mantou population exhibited better adaptability than the Wine population. Furthermore, Wine population displayed higher tolerance to ethanol, extreme temperatures, tannins, and sodium chloride in YPD medium compared to Mantou population. Diploid strains also exhibited greater stress tolerance than haploid strains. These findings offer valuable insights into the distinct adaptive mechanisms of domesticated S. cerevisiae lineages.

Flocculation Mechanisms in Brettanomyces bruxellensis: Influence of ethanol and sulfur dioxide on FLO gene expression

The mechanisms underlying flocculation in Brettanomyces bruxellensis, unlike the well-characterized FLO-family gene regulation in Saccharomyces cerevisiae, remain largely unexplored. This study investigates the flocculant phenotypes of 99 B. bruxellensis strains, revealing that only a minority exhibits this clumping behavior and confirms its strain-dependent attitude. Focusing on two strains, CBS2499 (flocculant) and UMY321 (non-flocculant), genetic analysis uncovered polymorphisms and distinct allelic heterozygosity in the FLO1 and FLO11 genes, potentially linked to the phenotypic differences. To further examine these traits, Response Surface Methodology (RSM) was used to simulate oenological conditions, testing the impact of pH, ethanol, and sulfur dioxide (SO₂) levels on flocculation and gene expression. The findings revealed that environmental stressors, especially ethanol and SO₂, significantly increase the expression of FLO1 and FLO11 in CBS2499, indicating a regulatory role in flocculation under stress. These insights broaden our understanding of stress adaptation in B. bruxellensis, especially its survival strategies in wine environments. By elucidating factors influencing flocculation, this study contributes valuable knowledge for managing B. bruxellensis spoilage, potentially aiding in the development of targeted approaches to reduce its impact on wine quality.

Selection of indigenous Saccharomyces cerevisiae strains with good oenological and aroma characteristics for winemaking in Ningxia China

Ningxia is one of the well-known wine producing regions in China. However, the oenological and aroma characteristics of indigenous yeasts remains hidden. The fermentative and oenological properties including stress resistance, hydrogen sulfide, foam production levels; killer phenotype, and flocculation of 89 Ningxia indigenous Saccharomyces cerevisiae isolates and ten commercial yeasts were evaluated. The fermentative and oenological properties of the tested strains varied significantly. They could resist 500 g/L glucose, 300 mg/L SO2, 14% (v/v) ethanol and pH 2.8, and produce more esters. They also produce low levels of ethanol and could conduct fermentations vigorously and at a high rate. Cabernet Sauvignon wines made with NXU 21-24 showed the high intensity of tropical fruit, dry fruit, temperate fruit, and spicy flavor. The floral flavor in NXU 21-102 fermented wine is very intense. The indigenous S. cerevisiae strains of NXU 21-102 and NXU 21-24 exhibited potential use as starter cultures in wine production.

Mixed yeast communities contribute to regionally distinct wine attributes

There is evidence that vineyard yeast communities are regionally differentiated, but the extent to which this contributes to wine regional distinctiveness is not yet clear. This study represents the first experimental test of the hypothesis that mixed yeast communities-comprising multiple, region-specific, isolates, and species-contribute to regional wine attributes. Yeast isolates were sourced from uninoculated Pinot Noir fermentations from 17 vineyards across Martinborough, Marlborough, and Central Otago in New Zealand. New methodologies for preparing representative, mixed species inoculum from these significantly differentiated regional yeast communities in a controlled, replicable manner were developed and used to inoculate Pinot Noir ferments. A total of 28 yeast-derived aroma compounds were measured in the resulting wines via headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. Yeast community region of origin had a significant impact on wine aroma, explaining ∼10% of the observed variation, which is in line with previous reports of the effects of region-specific Saccharomyces cerevisiae isolates on Sauvignon Blanc ferments. This study shows that regionally distinct, mixed yeast communities can modulate wine aroma compounds in a regionally distinct manner and are in line with the hypothesis that there is a microbial component to regional distinctiveness, or terroir, for New Zealand Pinot Noir.

Screening and Enzymatic Evaluation of Saccharomyces cerevisiae Populations from Spontaneous Fermentation of Organic Verdejo Wines

Microbial populations in spontaneous winemaking contribute to the distinctiveness and quality of the wines. In this study, molecular methods were applied to 484 isolated yeasts to survey the diversity of the Saccharomyces cerevisiae population in spontaneous fermentations of organic Verdejo grapes. Identification was carried out at strain level for samples from different vineyards correct.and stages of the winemaking process over the course of two vintages, establishing 54 different strains. The number of isolates belonging to each strain was not homogeneous, as two predominant strains represented more than half of the isolates independent of vineyard or vintage. Regarding the richness and abundance, differences among the stages of fermentation were confirmed, finding the highest diversity values in racked must and in the end of fermentation stages. Dissimilarity in S. cerevisiae communities was found among vineyards and vintages, distinguishing representative groups of isolates for each of the populations analysed. These results highlight the effect of vineyard and vintage on yeast communities as well as the presence of singular strains in populations of yeasts. Oenologically relevant enzymatic activities, β-lyase, protease and β-glucanase, were detected in 83.9%, 96.8% and 38.7% of the isolates, respectively, which may be of interest for potential future studies.

Indigenous Saccharomyces cerevisiae Could Better Adapt to the Physicochemical Conditions and Natural Microbial Ecology of Prince Grape Must Compared with Commercial Saccharomyces cerevisiae FX10

Indigenous Saccharomyces cerevisiae, as a new and useful tool, can be used in fermentation to enhance the aroma characteristic qualities of the wine-production region. In this study, we used indigenous S. cerevisiae L59 and commercial S. cerevisiae FX10 to ferment Prince (a new hybrid variety from Lion Winery) wine, detected the basic physicochemical parameters and the dynamic changes of fungal communities during fermentation, and analyzed the correlations between fungal communities and volatile compounds. The results showed that the indigenous S. cerevisiae L59 could quickly adapt to the specific physicochemical conditions and microbial ecology of the grape must, showing a strong potential for winemaking. Compared with commercial S. cerevisiae FX10, the wine fermented by indigenous S. cerevisiae L59 contained more glycerol and less organic acids, contributing to a rounder taste. The results of volatile compounds indicated that the indigenous S. cerevisiae L59 had a positive effect on adding rosy, honey, pineapple and other sweet aroma characteristics to the wine. Overall, the study we performed showed that selection of indigenous S. cerevisiae from the wine-producing region as a starter for wine fermentation is conducive to improving the aroma profile of wine and preserving the aroma of the grape variety.

Bioprospecting and Diversity of Yeast Producing Ethanol Isolated from Indonesia

Bioethanol is considered the most environmentally friendly as renewable fuels. Indonesia has abundant microbe diversity which is potential for bioprospecting such as fermenting agents using agriculture product as raw materials for producing bioethanol. This study aims to isolate, characterise and molecular identify of 15 isolates of bioethanol-producing yeasts from various sources. Characterisation based on ethanol production, cell morphology and various substrate utilisation has been carried out. Molecular characterisation of 15 yeast isolates using tree sets of primers had been carried out. Amplification in the internal area of transcribe spacers (ITS) was successfully carried out with an amplitude of 400 bp-900 bp. Amplifiers in the D1/D2 26s rDNA domain are 250 bp. Amplification with ScerF2 and ScerR2 specific primers was carried out successfully and proved that there were two isolates which were not Saccharomyces cerevisiae analysis of yeast genetic diversity showed 12 yeast isolates classified as S. cerevisiae and the rest belonged to the genus Clavispora, Candida and Kodamaea (Pichia).

Current Ethanol Production Requirements for the Yeast Saccharomyces cerevisiae

An increase in global energy demand has caused oil prices to reach record levels in recent times. High oil prices together with concerns over CO₂ emissions have resulted in renewed interest in renewable energy. Nowadays, ethanol is the principal renewable biofuel. However, the industrial need for increased productivity, wider substrate range utilization, and the production of novel compounds leads to renewed interest in further extending the use of current industrial strains by exploiting the immense, and still unknown, potential of natural yeast strains. This review seeks to answer the following questions: (a) which characteristics should S. cerevisiae have for the current production of first- and second-generation ethanol? (b) Why are alcohol-tolerance and thermo-tolerance characteristics required? (c) Which genes are related to these characteristics? (d) What are the advances that can be achieved with the isolation of new organisms from the environment?

Optimized Ensiling Conditions and Microbial Community in Mulberry Leaves Silage With Inoculants

Mulberry leaves (ML) are a promising alternative fodder source due to their high protein content and the abundance of active components. A test of three inoculants in various combinations revealed that high-quality ML silage was produced at an inoculum ratio of 1:1:0 (50% Saccharomyces cerevisiae, 50% Lactobacillus plantarum, and 0% Bacillus subtilis). Using dry matter (DM) loss, pH, ammonia-N and amino acid contents, total antioxidant activity, and total flavonoids content to evaluate silage quality, this inoculant mixture was shown to produce high-quality silage within a range of inoculum size (5–15%), moisture contents (50–67%), ensiling temperatures (27–30°C), and ensiling duration (14–30 days). A third trial comparing silages produced after 30 days at 28°C and 50% moisture content revealed that silage E, prepared using an L. plantarum inoculant alone, displayed the lowest DM loss and pH, and low bacterial diversity, and it was dominated by Lactobacillus (88.6%), with low abundance of Enterobacter (6.17%). In contrast, silage B5, prepared with equal ratios of L. plantarum and S. cerevisiae, was dominated by Enterococcus (67.16%) and Lactobacillus (26.94%), with less marked yeast persistence, and reducing the DM content from 50 to 40% altered these relative abundances to 5.47 and 60.61, respectively. Control silages produced without an inoculant had the highest pH and ammonia-N content (indicative of poor quality), had the lowest antioxidant activity, had higher bacterial diversity, and were dominated by Carnobacterium (74.28%) and Enterococcus (17.3%). In summary, ensiling of ML conditions with proper inoculants yielded high-quality silage with a favorable microbial community composition.

Prospection of indigenous yeasts from Uruguayan Tannat vineyards for oenological applications

Prospection of yeasts from oenological environments can provide knowledge of new native strains that are capable of fermenting must and positively influence the composition and sensory characteristics of the wine. This work addressed the biotechnological characterization of indigenous yeasts of Tannat must, an emblematic and widespread vineyard of Uruguay. Fifty-three yeast isolates were morphologically characterized and further identified by amplification and sequencing of ITS and D1-D2 regions, grouping into a total of fifteen species. One isolate of each species was randomly chosen and evaluated for its technological traits. In presence of ethanol (6 to 16% v/v) and sulfur dioxide (40 mg/L), native Saccharomyces cerevisiae 3FS presented the best growth rates and minor lag phase. Regarding non-Saccharomyces strains, Starmerella bacillaris 3MS stood out for its behavior in vinification conditions, more closely related to S. cerevisiae strains. Saccharomyces cerevisiae 3FS, Starmerella bacillaris 3MS, and Saturnispora diversa 1FS conducted a successful fermentation process reaching a final ethanol concentration ≥ 10% v/v and presenting a killer and resistant phenotype, suggesting that they could be used as pure starter cultures, as well as in mixed culture fermentations. This preliminary screening and oenological characterization of indigenous Saccharomyces cerevisiae and non-Saccharomyces yeasts might be a useful tool to identify some strains as potential candidates for wine vinification.

Wild Saccharomyces Produced Differential Aromas of Fermented Sauvignon Blanc Must

Nine Saccharomyces strains, previously isolated from vineyards in Southern Brazil, were used as starter cultures in fermentations of Sauvignon Blanc (SB) must at laboratory scale, to study inter-strain differences in aroma profiles. The molecular profiles differentiated the following isolates from the reference strain (SC2048), which is typically used in wine production: 06CE, 11CE, 33CE, 01PP, 12M, 13PP, 26PP, 28AD, and 41PP. Under the same conditions, each of these strains produced different concentrations and combinations of metabolites, which significantly influenced the aroma of the fermented SB must. Volatile compounds such as octanoic acid, diethyl succinate, and ethyl lactate were associated with the strains 26PP, 41PP, 01PP, and 12M, while strains 33CE, 28AD, 13PP, and 06CE were associated with the production of ethyl acetate and 1-hexanol. Strain 06CE produced 592.87 ± 12.35 µg/L 1-hexanol. In addition, the olfactory activity values (OAVs; we considered only values >1) allowed us to evaluate the participation of each compound in the aroma of the final fermented SB. In conclusion, the selected wild strains are promising candidates for improving the regional characteristics of wine.

Enological potential of non-Saccharomyces yeast strains of enological and brewery origin from Ukrainian Collection of Microorganisms

Non-conventional wine yeasts are extensively studied as promising producers of hydrolytic enzymes and as potential starter cultures in winemaking due to their ability to improve organoleptic properties of wine. Thirty-six yeast strains of enological and brewery origin from the Ukrainian Collection of Microorganisms belonging to Torulaspora, Kloeckera, Candida, Metschnikowia, Pichia, and Zygosaccharomyces genera have been screened for the production of extracellular hydrolases, stress tolerance, fermentative activity, and other traits of enological interest. This study revealed the high incidence of lipolytic, proteolytic, and β-glucosidase activities among the yeasts, while no pectinase activity was detected. Esterase, cellulase and glucanase activities were found in a small proportion of yeasts (8.33–16.66%). Several Pichia anomala, Kloekera javanica, Pichia membranifaciens, and Metschnikowia pulcherrima strains demonstrated a wide range of hydrolytic activities. High tolerance to stress factors (ethanol, osmotic, and oxidative stress) present during alcoholic fermentation was detected in P. anomala and M. pulcherrima strains. Fermentative activity of several yeast strains was evaluated in microfermentations in a model semi-synthetic medium. Strain P. anomala UCM Y-216 was selected as the most promising culture for winemaking due to its hydrolytic activities, tolerance to stress factors and other valuable metabolic traits. This study represents the first step for selecting a non-conventional yeast strain of enological origin as a potential co-culture for winemaking.

Winemaking Characteristics of Red-Fleshed Dragon Fruit from Three Locations in Guizhou Province, China

The aim of this study was to identify the locations and harvest months in Guizhou province, China, producing the most suitable red dragon fruit (Hylocereus polyrhizus) for winemaking. Fruit from Guanling, Luodian and Zhenfeng counties was harvested separately from successive fruit cycles in August, September and October, respectively. The key traits measured were fruit weight, pulp yield, soluble solids content, and titratable acid. Wine characteristics measured were alcohol content, total carbohydrates, titratable acidity, volatile acidity, and betacyanin content. The overall suitability of fruit from each location for winemaking was evaluated using a multi-factor, unweighted, scorecard. On that basis, fruit from Guanling county harvested in August was the most suitable. Fruit from Luodian, and Zhenfeng was most suitable when harvested in August and September, and September, respectively. These results provide a preliminary guide for the sourcing of red dragon fruit from Guizhou for wine production.

Fungal Genomic Resources for Strain Identification and Diversity Analysis of 1900 Fungal Species

Identification and diversity analysis of fungi is greatly challenging. Though internal transcribed spacer (ITS), region-based DNA fingerprinting works as a “gold standard” for most of the fungal species group, it cannot differentiate between all the groups and cryptic species. Therefore, it is of paramount importance to find an alternative approach for strain differentiation. Availability of whole genome sequence data of nearly 2000 fungal species are a promising solution to such requirement. We present whole genome sequence-based world’s largest microsatellite database, FungSatDB having >19M loci obtained from >1900 fungal species/strains using >4000 assemblies across globe. Genotyping efficacy of FungSatDB has been evaluated by both in-silico and in-vitro PCR. By in silico PCR, 66 strains of 8 countries representing four continents were successfully differentiated. Genotyping efficacy was also evaluated by in vitro PCR in four fungal species. This approach overcomes limitation of ITS in species, strain signature, and diversity analysis. It can accelerate fungal genomic research endeavors in agriculture, industrial, and environmental management.

Physiological characterization of a new thermotolerant yeast strain isolated during Brazilian ethanol production, and its application in high-temperature fermentation

BACKGROUND

The use of thermotolerant yeast strains can improve the efficiency of ethanol fermentation, allowing fermentation to occur at temperatures higher than 40 °C. This characteristic could benefit traditional bio-ethanol production and allow simultaneous saccharification and fermentation (SSF) of starch or lignocellulosic biomass.

RESULTS

We identified and characterized the physiology of a new thermotolerant strain (LBGA-01) able to ferment at 40 °C, which is more resistant to stressors as sucrose, furfural and ethanol than CAT-1 industrial strain. Furthermore, this strain showed similar CAT-1 resistance to acetic acid and lactic acid, and it was also able to change the pattern of genes involved in sucrose assimilation (SUC2 and AGT1). Genes related to the production of proteins involved in secondary products of fermentation were also differentially regulated at 40 °C, with reduced expression of genes involved in the formation of glycerol (GPD2), acetate (ALD6 and ALD4), and acetyl-coenzyme A synthetase 2 (ACS2). Fermentation tests using chemostats showed that LBGA-01 had an excellent performance in ethanol production in high temperature.

CONCLUSION

The thermotolerant LBGA-01 strain modulates the production of key genes, changing metabolic pathways during high-temperature fermentation, and increasing its resistance to high concentration of ethanol, sugar, lactic acid, acetic acid, and furfural. Results indicate that this strain can be used to improve first- and second-generation ethanol production in Brazil.

Isolation, screening, identification and tolerance of yeast in cherry wine lees

In this study, yeast was isolated from cherry wine lees by rose Bengal medium, and its species was identified through three-stage screening, morphological observation and molecular biological identification. Moreover, the tolerance of screened strains was studied. The results showed that 30 strains of yeast were isolated from cherry wine lees, and five strains of yeast were selected, which were named YJN10, YJN16, YJN18, YJN19 and YJN28. After preliminary appraisal, strain YJN10 was Saccharomyces kudriavzevii, strain YJN16 was Saccharomyces paradoxus, and strains YJN18, YJN19, YJN28 were Saccharomyces cerevisiae. In the tolerance study, the tolerable sugar concentrations of the five strains were 650, 650, 550, 600 and 600 g/L. The tolerable alcohol volume fractions were 20, 20, 16, 18 and 18%. The tolerable molar concentration of potassium chloride was 1.8, 1.8, 1.5, 1.5 and 1.5 mol/L. Finally, strains YJN10, YJN16, YJN19 and YJN28 showed good tolerance, which laid a foundation for subsequent application in cherry wine fermentation.

Anti-infective nitazoxanide disrupts transcription of ribosome biogenesis-related genes in yeast

BACKGROUND

Nitazoxanide is a broad-spectrum, anti-parasitic, anti-protozoal, anti-viral drug, whose mechanisms of action have remained elusive.

OBJECTIVE

In this study, we aimed to provide insight into the mechanisms of action of nitazoxanide and the related eukaryotic host responses by characterizing transcriptome profiles of Saccharomyces cerevisiae exposed to nitazoxanide.

METHODS

RNA-Seq was used to investigate the transcriptome profiles of three strains of S. cerevisiae with dsRNA virus-like elements, including a strain that hosts M28 encoding the toxic protein K28. From the strain with M28, an additional sub-strain was prepared by excluding M28 using a nitazoxanide treatment.

RESULTS

Our transcriptome analysis revealed the effects of nitazoxanide on ribosome biogenesis. Many genes related to the UTP A, UTP B, Mpp10-Imp3-Imp4, and Box C/D snoRNP complexes were differentially regulated by nitazoxanide exposure in all of the four tested strains/sub-strains. Examples of the differentially regulated genes included UTP14, UTP4, NOP4, UTP21, UTP6, and IMP3. The comparison between the M28-laden and non-M28-laden sub-strains showed that the mitotic cell cycle was more significantly affected by nitazoxanide exposure in the non-M28-laden sub-strain.

CONCLUSIONS

Overall, our study reveals that nitazoxanide disrupts regulation of ribosome biogenesis-related genes in yeast.

Comparative transcriptional analysis of flavour-biosynthetic genes of a native Saccharomyces cerevisiae strain fermenting in its natural must environment, vs. a commercial strain and correlation of the genes' activities with the produced flavour compounds

Background

During alcoholic fermentation, Saccharomyces cerevisiae synthesizes more than 400 different compounds with higher alcohols, acetate esters of higher alcohols and ethyl esters of medium-chain fatty acids being the most important products of its metabolism, determining the particular flavour profile of each wine. The concentration of the metabolites produced depends to a large extent on the strain used. The use of indigenous strains as starting cultures can lead to the production of wines with excellent organoleptic characteristics and distinct local character, superior in quality when compared to their commercial counterparts. However, the relationship of these wild-type genotypes, linked to specific terroirs, with the biosynthetic profiles of flavour metabolites is not completely clarified and understood. To this end, qRT-PCR was employed to examine, for the first time on the transcriptional level, the performance of an indigenous Saccharomyces cerevisiae strain (Z622) in its natural environment (Debina grape must). The expression of genes implicated in higher alcohols and esters formation was correlated with the concentrations of these compounds in the produced wine. Furthermore, by applying the same fermentation conditions, we examined the same parameters in a commercial strain (VL1) and compared its performance with the one of strain Z622.

Results

Strain Z622, exhibited lower concentrations of 2-methylbutanol, 3-methylbutanol and 2-phenyl ethanol, than VL1 correlating with the elevated expression levels of transaminase and decarboxylase genes. Furthermore, the significantly high induction of ADH3 throughout fermentation of Z622 probably explains the larger population numbers reached by Z622 and reflects the better adaptation of the strain to its natural environment. Regarding acetate ester biosynthesis, Z622 produced higher concentrations of total acetate esters, compared with VL1, a fact that is in full agreement with the elevated expression levels of both ATF1 and ATF2 in strain Z622.

Conclusions

This study provides evidence on the transcriptional level that indigenous yeast Z622 is better adapted to its natural environment able to produce wines with desirable characteristics, i.e. lower concentrations of higher alcohol and higher ester, verifying its potential as a valuable starter for the local wine-industry.

Electronic supplementary material

The online version of this article (10.1186/s40709-019-0096-8) contains supplementary material, which is available to authorized users.

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.

Isolation and Identification of the Indigenous Yeast Population during Spontaneous Fermentation of Isabella (Vitis labrusca L.) Grape Must

Grape must harbors a complex community of yeast species responsible for spontaneous alcoholic fermentation. Although there are detailed studies on the microbiota of Vitis vinifera L. grapes, less is known about the diversity and behavior of yeast communities present on fermenting grape must from other species of Vitis. In this work, we used a culture-dependent method to study the identity and dynamics of the indigenous yeast population present during the spontaneous fermentation of Isabella (Vitis labrusca L.) grape must. Alcoholic fermentation was conducted using standard enological practices, and the associated non-Saccharomyces and S. cerevisiae yeast community was analyzed using selective growth media and 5.8-ITS DNA sequencing. Candida californica, Candida hellenica, Starmerella bacillaris (synonym Candida zemplinina), Hanseniaspora uvarum, and Hanseniaspora vineae were the main non-Saccharomyces species identified on Isabella fermenting must. Issatchenkia hanoiensis, a yeast species rarely found on Vitis vinifera L. grapes, was also recognized on Isabella grape must. Candida azymoides, Candida californica and Pichia cecembensis, identified in this work on Isabella fermenting must, have not previously been found on Vitis vinifera L. grape must. Interestingly, C. azymoides, I. hanoiensis and P. cecembensis have recently been isolated from the surface of Vitis labrusca L. grapes from vineyards in the Azores archipelago, suggesting that specific Vitis-yeast species associations are formed independently of geographic origin. We suggest that C. azymoides, C. californica, and P. cecembensis are yeast species preferentially associated with Vitis labrusca L. grapes. Specific biological interactions between grapevines and yeast species may underlie the assembly of differential Vitis-microbial communities.