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Abstract Background Along bacteria, yeasts are common in forages and forage fermentations as spoilage microbes or as additives, yet few studies exist with species-level data on these fungi’s occurrence in feedstuff. Active dry yeast and other yeast-based products are also common feed additives in animal husbandry. Here, we aimed to characterize both fermented and non-fermented milking cow feedstuff samples from Hungary to assess their microbial diversity in the first such study from Central Europe. Results We applied long-read bacterial metabarcoding to 10 fermented and 25 non-fermented types of samples to assess bacterial communities and their characteristics, surveyed culturable mold and yeast abundance, and identified culturable yeast species. Fermented forages showed the abundance of Aerococcaceae, Bacillaceae, Brucellaceae, Lactobacillaceae, Staphylococcaceae, and Thermoactinomycetaceae, non-fermented ones had Cyanothecaceae, Enterobacteriaceae, Erwiniaceae, Gomontiellaceae, Oxalobacteraceae, Rhodobiaceae, Rickettsiaceae, and Staphylococcaceae. Abundances of bacterial families showed mostly weak correlation with yeast CFU numbers, only Microcoleaceae (positive) and Enterococcaceae and Alcaligenaceae (negative correlation) showed moderate correlation. We identified 14 yeast species, most commonly Diutina rugosa, Pichia fermentans, P. kudriavzevii, and Wickerhahomyces anomalus. We recorded S. cerevisiae isolates only from animal feed mixes with added active dry yeast, while the species was completely absent from fermented forages. The S. cerevisiae isolates showed high genetic uniformity. Conclusion Our results show that both fermented and non-fermented forages harbor diverse bacterial microbiota, with higher alpha diversity in the latter. The bacterial microbiome had an overall weak correlation with yeast abundance, but yeasts were present in the majority of the samples, including four new records for forages as a habitat for yeasts. Yeasts in forages mostly represented common species including opportunistic pathogens, along with a single strain of Saccharomyces used as a feed mix additive.

The abundantly available waste banana pseudostem fibers have attracted the paper and textile industries, however the stem-sap extracted during fiber processing remains underutilized. Although this sap comprising cellulosic sugars holds potential as a feedstock, its commercial viability in the renewable energy sector remains a challenge. Our study delves into this untapped resource by mechanically extracting sap from banana pseudostems and enhancing its reducing sugar content to approximately 35.5 g/L through acid hydrolysis and detoxification without concentrating the sap. Using separate batch fermentations with pentose and hexose fermenting strains such as Pichia stipitis NCIM 3499 and Saccharomyces cerevisiae ATCC 2601, we achieved bioethanol production efficiencies of 67.5 % and 70.03 %, respectively. Yield and cost analyses confirmed the feasibility of this approach for industrial application in low-economy settings. Furthermore, gene-interaction network and functional enrichment analysis identified 63 key genes involved in carbohydrate metabolism and ethanol conversion pathways within the fermenting organisms. Among these, the PGK1 gene and its direct interactors emerged as promising targets for future biotechnological enhancements aimed at boosting bioethanol production. This study not only underscores the renewable energy potential of unconcentrated banana pseudostem sap but also paves the way for innovative genetic interventions to optimize bioethanol yields.

Abstract Background Over the last two decades, hybridization has been a powerful tool used to construct superior yeast for brewing and winemaking. Novel hybrids were primarily constructed using at least one Saccharomyces cerevisiae parent. However, little is known about hybrids used for other purposes, such as targeted flavor production, for example, 2-phenylethanol (2-PE). 2-PE, an aromatic compound widely utilised in the food, cosmetic, and pharmaceutical industries, presents challenges in biotechnological production due to its toxic nature. Consequently, to enhance productivity and tolerance to 2-PE, various strategies such as mutagenesis and genetic engineering are extensively explored to improved yeast strains. While biotechnological efforts have predominantly focused on S. cerevisiae for 2-PE production, other Saccharomyces species and their hybrids remain insufficiently described. Results To address this gap, in this study, we analysed a new interspecies yeast hybrid, II/6, derived from S. uvarum and S. kudriavzevii parents, in terms of 2-PE bioconversion and resistance to its high concentration, comparing it with the parental strains. Two known media for 2-PE biotransformation and three different temperatures were used during this study to determine optimal conditions. In 72 h batch cultures, the II/6 hybrid achieved a maximum of 2.36 ± 0.03 g/L 2-PE, which was 2–20 times higher than the productivity of the parental strains. Our interest lay not only in determining whether the hybrid improved in productivity but also in assessing whether its susceptibility to high 2-PE titers was also mitigated. The results showed that the hybrid exhibited significantly greater resistance to the toxic product than the original strains. Conclusions The conducted experiments have confirmed that hybridization is a promising method for modifying yeast strains. As a result, both 2-PE production yield and tolerance to its inhibitory effects can be increased. Furthermore, this strategy allows for the acquisition of non-GMO strains, alleviating concerns related to additional legislative requirements or consumer acceptance issues for producers. The findings obtained have the potential to contribute to the development of practical solutions in the future.

ABSTRACT Amoebae are environmental predators feeding on bacteria, fungi, and other eukaryotic microbes. Predatory interactions alter microbial communities and impose selective pressure toward phagocytic resistance or escape which may, in turn, foster virulence attributes. The ubiquitous fungivorous amoeba Protostelium aurantium has a wide prey spectrum in the fungal kingdom but discriminates against members of the Saccharomyces clade, such as Saccharomyces cerevisiae and Candida glabrata. Here, we show that this prey discrimination among fungi is solely based on the presence of ubiquinone as an essential cofactor for the predator. While the amoeba readily fed on fungi with CoQ presenting longer isoprenyl side chain variants CoQ8-10, such as those from the Candida clade, it failed to proliferate on those with shorter CoQ variants, specifically from the Saccharomyces clade (CoQ6). Supplementing non-edible yeast with CoQ9 or CoQ10 rescued the growth of P. aurantium, highlighting the importance of a long isoprenyl side chain. Heterologous biosynthesis of CoQ9 in S. cerevisiae by introducing genes responsible for CoQ9 production from the evolutionary more basic Yarrowia lipolytica complemented the function of the native CoQ6. The results suggest that the use of CoQ6 among members of the Saccharomyces clade might have originated as a predatory escape strategy in fungal lineages and could be retained in organisms that were able to thrive by fermentation.IMPORTANCEUbiquinones (CoQ) are universal electron carriers in the respiratory chain of all aerobic bacteria and eukaryotes. Usually 8-10 isoprenyl units ensure their localization within the lipid bilayer. Members of the Saccharomyces clade among fungi are unique in using only 6. The reason for this is unclear. Here we provide evidence that the use of CoQ6 efficiently protects these fungi from predation by the ubiquitous fungivorous amoeba Protostelium aurantium which lacks its own biosynthetic pathway for this vitamin. The amoebae were starving on a diet of CoQ6 yeasts which could be complemented by either the addition of longer CoQs or the genetic engineering of a CoQ9 biosynthetic pathway.

Developing non-dairy functional beverages based on probiotics is a potential alternative for vegan consumers. It also becomes a big challenge since microorganisms can easily change chemical composition, acidity, color, and consumers’ acceptability. In this work, the probiotic yeast Saccharomyces boulardii was used to elaborate a fermented barley wort beverage. For the beverage formulations, the use of two flavors strawberry (SPB) and nutty (NPB) and two different inoculum concentrations (1 × 103 (SPB or NPB103) and 1 × 104 CFU/mL (SPB or NPB 104)) were considered. The fermentation was carried out at 37 °C under anaerobic conditions. The effect of the inoculum concentration was evaluated over reducing sugar consumption, the concentration of soluble solids, and pH. The best formulation was selected through a sensory evaluation. The profile of oligosaccharides and the resistance of the yeast to gastrointestinal conditions were determined only in the nutty flavor formulation (NPB 104). During the fermentation process, the content of oligosaccharides was increased compared to the unfermented wort, which improved the nutritional value. The analysis of resistance to simulated gastrointestinal conditions showed a decrease from 8.0 × 107 to 1.5 × 107 CFU/mL in the NPB 104 beverage. Barley wort is a potential medium to produce probiotic beverages with the yeast S. boulardii.

In fermentation processes, changes in yeast cell count and substrate concentration are indicators of yeast performance. Therefore, monitoring the composition of the biological suspension, particularly the dispersed solid phase (i.e., yeast cells) and the continuous liquid phase (i.e., medium), is a prerequisite to ensure favorable process conditions. However, the available monitoring methods are often invasive or restricted by detection limits, sampling requirements, or susceptibility to masking effects from interfering signals. In contrast, ultrasound measurements are non-invasive and provide real-time data. In this study, the suitability to characterize the dispersed and the liquid phase of yeast suspensions with ultrasound was investigated. The ultrasound signals collected from three commercially available Saccharomyces yeast were evaluated and compared. For all three yeasts, the attenuation coefficient and speed of sound increased linearly with increasing yeast concentrations (0.0–1.0 wt%) and cell counts (R2 > 0.95). Further characterization of the dispersed phase revealed that cell diameter and volume density influence the attenuation of the ultrasound signal, whereas changes in the speed of sound were partially attributed to compositional variations in the liquid phase. This demonstrates the ability of ultrasound to monitor industrial fermentations and the feasibility of developing targeted control strategies.

Experiments exposing Saccharomyces cerevisiae to glucose limitation (calorie restriction) are widely used to determine impacts on cell health as a model for aging. Using growth on plates and in liquid culture, we demonstrated that calorie restriction reduces fitness in subsequent nutrient-limited environments. Yeast grown in a calorie-restricted environment took longer to emerge from the lag phase, had an extended doubling time and had a lower percentage of culturability. Cells grown under moderate calorie restriction were able to withstand a gradual heat stress in a similar manner to cells grown without calorie restriction but fared less well with a sudden heat shock. Yeast grown under extreme calorie restriction were less fit when exposed to gradual heating or heat shock. Using RNAseq analysis, we provide novel insight into the mechanisms underlying this response, showing that in the absence of calorie restriction, genes whose products are involved in energy metabolism (glycolysis/gluconeogenesis and the citrate cycle) are predominantly overexpressed when yeasts were exposed to gradual heating, whereas this was not the case when they were exposed to shock. We show that both the culture history and the current environment must be considered when assaying physiological responses, and this has wider implications when developing strategies for the propagation, preservation or destruction of microbial cells.

One of the most fatal diseases that harm Allium species is purple blotch, which is brought on by Alternaria porri. As the disease's severity rises, crop production may decrease. In this study, 12 isolates of A. porri exhibiting purple blotch symptoms have been isolated from diseased onion plants. Sequencing of the internal transcribed spacer region (ITS) allowed for the identification of the isolate that was the most virulent and caused a disease severity of 85.93%. Under greenhouse and field growing conditions, the efficiency of two bio-agents, Trichoderma asperellum T34 and Saccharomyces cerevisiae AUMC 10203, as well as three doses (50, 25, and 12.5 ppm) of their green-synthesized silver nanoparticles (AgNPs) against purple blotch disease was assessed. For avoiding or treating purple blotch disease in onion plants, it has been demonstrated that the T. asperellum T34 spore suspension was the most effective resulting in a 76% reduction in disease severity. The spore suspension of S. cerevisiae and a 50-ppm dosage of AgNPs were the top contenders for T. asperellum. When compared to the control plants, the plants treated with bio-agents and AgNPs showed a significant decline in disease incidence and disease severity. Additionally, improvements were made to the broadness of inflorescences, the number of flowers and seeds, the weight of seeds per inflorescence, and the seed productivity. Therefore, it is recommended in this study to use T. asperellum T34 spore suspension as a potent bio-agent to manage the symptoms of purple blotch on onions.

Introduction: Approximately 10–40 million travelers get Traveler's Diarrhea (TD) yearly. A significant decrease in TD incidence has not been achieved by depending solely on antibiotic prophylaxis and educational initiatives. Using prebiotics to prevent TD has also not been examined in previous evaluations of probiotics for TD, which failed to consider the strain-specificity of probiotic efficacy. This review investigates the overall effects of probiotics on preventing TD, including the impact of dosage, duration, and age. Methods: Standard literature databases were searched without restriction on publication year or language. The following criteria are included: randomized controlled trials (RCTs) in English or non-English unrestricted to publication year, excluding animal and observational studies. This systematic review applied the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Results: Of the 166 screened papers, 10 RCTs were included. Lactobacillus acidophilus showed no efficacy in preventing TD except when mixed with other strains. Other genera of lactobacilli showed a protection rate of up to 39% against TD. Similarly, Saccharomyces cerevisiae and Saccharomyces boulardii have been effective in preventing TD. Conclusion: Studies investigating probiotics as a preventive measure for TD remain limited. Only a few probiotics that reduce TD risk exist. Based on this systematic review and meta-analysis, specific probiotic strains, including L. acidophilus, L. rhamnosus, L. fermentum, S. cerevisiae, and S. boulardii, may prevent TD. The effect of additional probiotic strains on TD prevention must be further investigated.

Nowadays, the wine industry carries out fermentations at low temperatures because this oenological practice clearly improves the aromatic complexity of the final wines. In addition, nitrogen content of the must also influences the quality of the wine. In this study, we carried out a phenotypic and fermentative analysis of two industrial wine Saccharomyces cerevisiae strains (P5 and P24) at 15 and 28 °C and three nitrogen concentrations (60, 140 and 300 mg N/L) in synthetic must. Our results show that both parameters, temperature and nitrogen, are interrelated and clearly determine the competitiveness of the wine strains and their ability to adapt at low temperatures. The best adapted strain at low temperatures decreased its competitiveness at lower nitrogen concentrations. In addition, our results show that it is not only the quantity of nitrogen transported that is important but also the quality of the nitrogen source used for wine yeast adaptation at low temperatures. The presence of some amino acids, such as arginine, branched chain amino acids, and some aromatic amino acids can improve the growth and fermentation activity of wine yeasts at low temperatures. These results allow us to better understand the basis of wine yeast adaptation to fermentation conditions, providing important information for winemakers to help them select the most appropriate yeast strain, thus reducing the economic costs associated with long and sluggish fermentations. The correlation between some amino acids and better yeast fermentation performance could be used in the future to design inactive dry yeast enriched in some of these amino acids, which could be added as a nutritional supplement during low temperature fermentations.

One of the biggest challenges in the food industry is the incorporation of probiotics into food products while maintaining their properties, both in the processing phases and in the gastrointestinal tract. The production of this type of functional food, which has been used to prevent and/or help in the treatment of some diseases, needs improvements at the technological and economic levels. This review provides a comprehensive view of the main techniques used to encapsulate probiotic yeasts and analyzes the main variables involved in the industrial process. A systematic review and meta-analysis were carried out, considering the most current technical recommendations for this type of study, as well as the standardized criteria for the eligibility of articles. From a total of 1269 initial articles, only 14 complete articles, published in high-impact journals over the years 2013 to 2019 and focused on in vitro assays with probiotic yeasts, were considered in the analysis performed. In general, microencapsulation was efficient in maintaining yeast survival after gastrointestinal tests, viability studies, and thermal resistance in distilled water and food. Many variables can affect microencapsulation, but they are not always described or properly elucidated, leading to the conclusion that better delineated research is needed. Examples of these challenges include selecting appropriate encapsulating materials, optimizing encapsulation techniques, and ensuring the stability and viability of probiotics during processing and storage. Due to these challenges, the industrial application of probiotic microencapsulation is not yet well established; however, it holds promising potential.

Se realizó el experimento en Itacurubí de la Cordillera, Paraguay, desde julio de 2021a enero de 2022, donde se evaluó el efecto de la aplicación foliar de un extracto de estevia (Stevia rebaudiana Bertoni) y de un bioestimulante comercial formulado con agua y miel conteniendo 4,05x108UFC.mL-1deLactobacillussp.yde Saccharomycessp., y 3,1x109UFC.mL-1de Streptomyces scabies, comparados con un testigo, sobre el rendimiento de sandía variedad Crimson Sweet. Se utilizó el diseño experimental de bloques completamente al azar con cuatro repeticiones. La primera aplicación de los tratamientos se realizó en el semillero, cuando la plántula contenía 8 hojas definitivas, luego del trasplante, se realizó una aplicación cada 8 días hasta completar 10 aplicaciones en total. Se evaluó el peso promedio de los frutos, el número de frutos por planta y el rendimiento. Los datos fueron sometidosa un análisis de varianza (ANAVA), cuando hubo diferencias significativas entre las medias de los tratamientos, se aplicó la prueba de comparación de medias de Tukey al 5% de probabilidad de error. Con el extracto de estevia se obtuvo 1,9 frutos por planta, con peso promedio de 10 kg y rendimiento de 9119 kg.ha-1, mientras que con el bioestimulante comercial se obtuvo 1,6 frutos por planta, con peso promedio de 8,3 kg y rendimiento de 7325 kg.ha-1. Con el testigo se obtuvo 0,9 frutos por planta con 4,6 kg y un rendimiento de 4044 kg.ha-1. El extracto de estevia ofrece una mayor productividad en el cultivo de sandía. Se sugiere la realización de más estudios para evaluar diferentes dosis de los extractos y considerar variables relacionadas a la fitosanidad y a la calidad postcosecha

Abstract Background Horizontal gene transfer (HGT) is an evolutionary mechanism of adaptive importance, which has been deeply studied in wine S. cerevisiae strains, where those acquired genes conferred improved traits related to both transport and metabolism of the nutrients present in the grape must. However, little is known about HGT events that occurred in wild Saccharomyces yeasts and how they determine their phenotypes. Results Through a comparative genomic approach among Saccharomyces species, we detected a subtelomeric segment present in the S. uvarum, S. kudriavzevii, and S. eubayanus species, belonging to the first species to diverge in the Saccharomyces genus, but absent in the other Saccharomyces species. The segment contains three genes, two of which were characterized, named DGD1 and DGD2. DGD1 encodes dialkylglicine decarboxylase, whose specific substrate is the non-proteinogenic amino acid 2-aminoisobutyric acid (AIB), a rare amino acid present in some antimicrobial peptides of fungal origin. DGD2 encodes putative zinc finger transcription factor, which is essential to induce the AIB-dependent expression of DGD1. Phylogenetic analysis showed that DGD1 and DGD2 are closely related to two adjacent genes present in Zygosaccharomyces. Conclusions The presented results show evidence of an early HGT event conferring new traits to the ancestor of the Saccharomyces genus that could be lost in the evolutionary more recent Saccharomyces species, perhaps due to loss of function during the colonization of new habitats.

Durango State has the denomination of origin for the production of mezcal, which is made from Agave durangensis, mainly in an artisanal way; therefore, differences in the fermentation process affect the quality of the final product. The main objective of the present study was to evaluate the diversity of culturable yeasts involved in the artisanal and semi-technified process of mezcal production in the State of Durango. Three distilleries with different production processes were monitored at different fermentation stages (beginning, mid-fermentation, and end of fermentation) in the spring and summer seasons. A greater diversity was found in the distillery of Nombre de Dios in both the spring and summer production seasons (H’ = 1.464 and 1.332, respectively), since it maintains an artisanal production process. In contrast, the distillery of Durango, where a Saccharomyces cerevisiae commercial inoculum is used to start fermentation, presented low diversity indexes (H’ = 0.7903 and 0.6442) and only S. cerevisiae, Kluyveromyces marxianus, and, sporadically, Pichia manshurica were found. Results suggest that the yeast microbiota involved in mezcal fermentation during the different seasons is affected by the type of inoculum; changes include the presence of some species that were only identified during a specific season in alcoholic fermentation, such as Torulaspora delbrueckii and Pichia kluyveri.

Koumiss, a traditional fermented dairy product made from fresh mare milk, is a sour beverage that contains an abundance of microbial communities, including lactic acid bacteria, yeast and others. Firstly, probiotics such as Lacticaseibacillus in koumiss can induce the secretion of immunoglobulin G in serum and interleukin-2 in the spleen while beneficial Saccharomyces can secrete antibacterial compounds such as citric acid and ascorbic acid for specific immunopotentiation. Additionally, more isoflavone in koumiss can regulate estrogen levels by binding to its receptors to prevent breast cancer directly. Bile salts can be converted into bile acids such as taurine or glycine by lactic acid bacteria to lower cholesterol levels in vivo. Butyric acid secretion would be increased to improve chronic gastrotis by regulating intestinal flora with lactic acid bacteria. Finally, SCFA and lCFA produced by Lacticaseibacillus inhibit the reproduction of pathogenic microorganisms for diarrhea prevention. Therefore, exploring the mechanisms underlying multiple physiological functions through utilizing microbial resources in koumiss represents promising avenues for ameliorating chronic diseases.

ABSTRACT Polycystic ovary syndrome (PCOS) is a serious disease characterized by high androgen, insulin resistance (IR), hyperglycemia, and obesity, leading to infertility. The gut mycobiota has been reported to evolve in metabolic diseases including obesity, hyperglycemia, and fatty liver. However, little is known about the gut mycobiota and PCOS. In the current study, we recruited 17 PCOS patients and 17 age-matched healthy controls for community structure and functional analysis of the gut mycobiota. The results showed that PCOS patients have reduced diversity and richness of the gut microbiota compared with healthy controls. β-Diversity analysis showed that the community structure of the gut microbiota of patients with PCOS was significantly different from healthy controls. At the phylum level, PCOS patients have reduced Basidiomycota and increased Ascomycota compared with healthy controls. At the family level, the higher relative abundance of Saccharomycetaceae and lower Trichosporonaceae and Ascomycota_unclassified were detected in PCOS patients than in healthy controls. At the genus level, different microbial compositions were also observed between PCOS patients and healthy controls. In addition, PICRUSt2 showed that patients with PCOS have different microbial functions in the gut compared with healthy controls. LEfSe indicated that Saccharomyces and Lentinula were enriched in the fecal samples of PCOS patients, while Aspergillus was depleted compared with healthy controls. Our finding indicates that PCOS patients have different community structures and functions of the gut mycobiota, which provides new insight into PCOS pathogenesis and intervention. IMPORTANCE It was found that intestinal fungi as well as serum metabolites in PCOS patients were significantly different from those in healthy subjects. However, no studies have been done to show exactly which fungus interacts with which bacteria in humans or which fungus acts alone. As fungal research progresses, it will be possible to fill this gap.

This study aimed to investigate controlled fermentation of cocoa beans with selected yeasts as starter cultures via integrating microbiological, biochemical, and chromatographic analyses. The steps involved in the yeast starter culture test were of the following order: 1) counting, isolation, purification, and biochemical identification of yeasts, 2) selection of ethanol-producing yeasts, 3) selection of thermotolerant yeasts, and 4) evaluation of physicochemical parameters of the selected yeasts in controlled fermentation of cocoa (F1 – Saccharomyces ssp. and Hanseniaspora ssp. and F2 – spontaneous fermentation — control). A total of 32 yeasts were isolated from three sampling points (M1, M2, and M3), which comprised 50% Candida ssp., 9.4% Rhodotorula ssp., 18.8% Saccharomyces ssp., and 18.8% Hanseniaspora ssp. The yeasts identified as Saccharomyces ssp. (n = 6) were subjected to the ethanol production test. Saccharomyces spp. CLV09 showed the highest concentration of ethanol in the simulated cocoa medium (3.5% v/v). Hanseniaspora spp. CVL20 and CVL19 strains showed the highest thermotolerance at 42̊C after 72 h of growth. The starter cultures with Saccharomyces ssp. and Hanseniaspora ssp. showed a similar growth rate of the mesophilic aerobic population in both F1 and F2. Fermentation of the starter culture showed a higher production of organic acids than spontaneous fermentation (F2). Thus, Saccharomyces ssp. and Hanseniaspora ssp. can be used as a starter culture in cocoa fermentation.

The purpose of the present work was to identify and characterize several yeast strains useful in fermentation process and present in the Stefanesti-Arges vineyards. The biological material used was freshly squeezed grape must from the white wine grape cultivar, 'Fetească regală' one of the most widespread and appreciated cultivars for wine in the Arges region. In this study is described the procedure of obtaining the pure isolates and are presented the macroscopic and microscopic characteristics of these isolates retained on the culture medium. By microscopy and molecular analyses was confirmed that the selected isolates in pure culture belongs to the genus Saccharomyces. The morphological characteristics, complemented by the molecular ones of the PCR amplification of the region ITS1-5,8S -ITS2, as well as the analysis of the "killer" profile of the selected strains, proved that the four isolates obtained and analyzed are identical and belong to the species Saccharomyces cerevisiae.

The relationship between climate change and viticulture has become increasingly apparent in recent years. Rising temperatures have been a critical factor in early grape ripening. This, in turn, has led to wines with imbalanced acidity and, more importantly, higher alcohol content and pH values. Today, consumers demand high-quality and healthy products, and this trend has extended to wine consumption. Consumers prefer wines with reduced alcohol content due to the health risks associated with alcohol consumption. To meet this demand, researchers have developed modified yeast strains that reduce wine alcohol content during fermentation. These strains ferment less sugar or redirect carbon metabolism. However, their use may pose challenges, such as producing undesired secondary metabolites that can affect wine characteristics. Additionally, consumers are still divided on using genetically modified organisms (GMOs) in food and beverages. This review examines the impact of climate change on wine quality and consumer perception, taking into account new technologies used to reduce wine alcohol content or produce low-alcohol-content wines, such as low-cost techniques like bio-dealcoholization performed by non-GMO wine yeast, Saccharomyces, and non-Saccharomyces.

Saccharomyces cerevisiae var. boulardii (Sb) is currently receiving significant attention as a synthetic probiotic platform due to its ease of manipulation and inherent effectiveness in promoting digestive health. A comprehensive exploration of Sb and other S. cerevisiae strains (Sc) would shed light on the refinement and expansion of their therapeutic applications. This review aims to provide a thorough overview of Saccharomyces yeasts from their native health benefits to recent breakthroughs in the engineering of Saccharomyces yeasts as synthetic therapeutic platforms. Molecular typing and phenotypic assessments have uncovered notable distinctions, including the superior thermotolerance and acid tolerance exhibited by Sb, which are crucial attributes for probiotic functions. Moreover, parabiotic and prebiotic functionalities originating from yeast cell wall oligosaccharides have emerged as pivotal factors influencing the health benefits associated with Sb and Sc. Consequently, it has become imperative to select an appropriate yeast strain based on a comprehensive understanding of its actual action in the gastrointestinal tract and the origins of the targeted advantages. Overall, this review underscores the significance of unbiased and detailed comparative studies for the judicious selection of strains.

A variety of yeast applications in the food and beverage industry require individual and reproducible yeast propagation at high yields and consistent quality. One quality-determining parameter for yeast propagation is effective aeration to avoid oxygen depletion. Therefore, this work investigated three important aeration parameters: airflow, pulse time, and oxygen concentration, for their influence on yeast propagation. The aeration of a propagator involves phase transitions which are gradient-driven processes and can be accelerated with higher gradients between the liquid medium and the gas bubbles. In this study, oxygen-enriched air generated with membrane filters was used to aerate the system in an easy and cost-efficient way without the need for expensive technical gas usage. Propagation experiments were carried out in a pilot-scale reactor equipped with a membrane filter system for enhanced oxygen concentrations in ingas and online sensors for representative monitoring of the process. The membrane filter system is based on the separation of nitrogen in compressed air, leading to oxygen enrichment. Using oxygen-enriched air for propagation aeration showed higher oxygen transfer into the medium and the anaerobic process time caused by oxygen depletion due to high cell numbers was reduced by an average of 7.4% for pulsed aeration. Additionally, we conducted experiments with controlled measures of dissolved oxygen using different oxygen concentrations for aeration. The main objective of this study is to present a new and affordable optimization of propagation aeration using membrane filtration to enrich process air. The results showed increased cell counts for higher ingas oxygen concentrations and no negative impact on cell vitality was observed. Hence, our investigations showed that using oxygen-enriched air reduced the frequency of pulsed aeration, thus hindering foam formation, a limiting factor of the yeast propagation process.

Abstract Background Polyploidy and heterokaryosis are common and consequential genetic phenomena that increase the number of haplotypes in an organism and complicate whole-genome sequence analysis. Allele balance has been used to infer polyploidy and heterokaryosis in diverse organisms using read sets sequenced to greater than 50× whole-genome coverage. However, sequencing to adequate depth is costly if applied to multiple individuals or large genomes. Results We developed VCFvariance.pl to utilize the variance of allele balance to infer polyploidy and/or heterokaryosis at low sequence coverage. This analysis requires as little as 10× whole-genome coverage and reduces the allele balance profile down to a single value, which can be used to determine if an individual has two or more haplotypes. This approach was validated using simulated, synthetic, and authentic read sets from the oomycete species Bremia lactucae and Phytophthora infestans, the fungal species Saccharomyces cerevisiae, and the plant species Arabidopsis arenosa. This approach was deployed to determine that nine of 21 genotyped European race-type isolates of Bremia lactucae were inconsistent with diploidy and therefore likely heterokaryotic. Conclusions Variance of allele balance is a reliable metric to detect departures from a diploid state, including polyploidy, heterokaryosis, a mixed sample, or chromosomal copy number variation. Deploying this strategy is computationally inexpensive, can reduce the cost of sequencing by up to 80%, and used to test any organism.

Assaying changes in the amount of DNA in single cells is a well-established method for studying the effects of various perturbations on the cell cycle. A drawback of this method is the need for a fixation procedure that does not allow for in vivo study nor simultaneous monitoring of additional parameters such as fluorescence of tagged proteins or genetically encoded indicators. In this work, we report on a method of Histone Abundance Quantification (HAQ) of live yeast harboring a GFP-tagged histone, Htb2. We show that it provides data highly congruent with DNA levels, both in Saccharomyces cerevisiae and Ogataea polymorpha yeasts. The protocol for the DNA content assay was also optimized to be suitable for both Ogataea and Saccharomyces yeasts. Using the HAQ approach, we demonstrate the expected effects on the cell cycle progression for several compounds and conditions and show usability in conjunction with additional fluorophores. Thus, our data provide a simple approach that can be utilized in a wide range of studies where the effects of various stimuli on the cell cycle need to be monitored directly in living cells.

This study examined the effect of simultaneous fermentations of Saccharomyces cerevisiae and Pichia kluyveri, Lactobacillus plantarum and Oenococcus oeni on the chemical composition of apple cider from two apple varieties—Topaz and Red Topaz. Analytical techniques (HPLC-RID, HPLC-VWD, GC/MS, GC/FID, HPLC-DAD ESI+) were employed to analyze glucides, organic acids, volatile compounds, amino acids and phenolic compounds, respectively. Statistical analysis and and PCA were conducted to assess the correlations among samples based on the compounds identified. In the mixed fermentations, such as Saccharomyces cerevisiae + Lactobacillus plantarum and Saccharomyces cerevisiae + Oenococcus oeni, the amount of lactic acid was higher compared to the other samples, thus proving the effectiveness of malolactic fermentation simultaneous to alcoholic fermentation. The fermentation of Saccharomyces cerevisiae + Pichia kluyveri resulted in the formation of greater amounts of certain volatile compounds. Moreover, the sensory analysis revealed that Saccharomyces cerevisiae + Pichia kluyveri distinguished apple-like, fruity and floral notes. This study suggests that the simultaneous inoculation of Saccharomyces and non-Saccharomyces yeasts results in a more complex-flavored cider. The mixed fermentation of yeast and lactic acid bacteria is a sustainable method given the shortened fermentation duration and can be successfully applied in the cider industry.

Saccharomyces cerevisiae is commonly used for the production of alcoholic beverages, including cider. In this study, we examined indigenous S. cerevisiae and S. uvarum strains, both species commonly found in cider from Hardanger (Norway), for their strain-specific abilities to produce volatile and non-volatile compounds. Small-scale fermentation of apple juice with 20 Saccharomyces strains was performed to evaluate their aroma-producing potential as a function of amino acids (AAs) and other physicochemical parameters under the same experimental conditions. After fermentation, sugars, organic acids, AAs, and biogenic amines (BAs) were quantified using the HPLC–UV/RI system. A new analytical method was developed for the simultaneous determination of nineteen AAs and four BAs in a single run using HPLC–UV with prior sample derivatization. Volatile compounds were determined using HS-SPME-GC-MS. Based on 54 parameters and after the removal of outliers, the nineteen strains were classified into four groups. In addition, we used PLS regression to establish a relationship between aroma compounds and predictor variables (AAs, BAs, organic acids, sugars, hydrogen sulfide (H2S) production, CO2 release) of all 19 strains tested. The results of the VIP show that the main predictor variables affecting the aroma compounds produced by the selected yeasts are 16, belonging mainly to AAs.

Traditional yeast (Saccharomyces cerevisiae) has been used for its benefits in various fermentation processes; the benefits of non-Saccharomyces yeast as a material for food, feed, and pharmaceuticals have been studied recently. This study evaluated the anti-inflammatory activity and extracellular functional characteristics of wild-type yeasts isolated from traditional fermented foods (doenjang (common name: soybean paste) and nuruk) in Korea. The viability of the yeast and lipopolysaccharide (LPS)-stimulated RAWBlue™ cells was improved, similar to unstimulated RAWBlue™ cells, and the isolates demonstrated NF-κB inhibitory activity. Yeast suppressed the nitric oxide production in LPS-stimulated RAWBlue™ cells, which was attributed to the inhibition of iNOS or COX-2 mRNA expression depending on the strain. Although there were differences depending on the strain, the production of anti-inflammatory cytokines was reduced in the yeast and LPS-stimulated RAWBlue™ cells, some of which were demonstrated at the mRNA level. In addition, the isolates exhibited high antioxidant and antihypertensive activities (similar to the positive control), which varied depending on the strain. This suggests that yeast can be used for fermentation with enhanced antioxidant and antihypertensive activities. Furthermore, the isolates inhibited the growth of pathogenic Gram-negative bacteria, indicating that yeast can inhibit food spoilage and the growth of pathogenic bacteria during fermentation. Consequently, utilizing raw materials to cultivate yeast strains could be a promising avenue for developing functional foods to prevent and treat inflammatory reactions; such foods may exhibit antioxidant, antihypertensive, and antibacterial properties.

ObjectivesMounting evidence suggests that bacterial dysbiosis and immunity disorder are associated with patients with chronic kidney disease (CKD), but the mycobiome is beginning to gain recognition as a fundamental part of our microbiome. We aim to characterize the profile of the mycobiome in the gut of CKD patients and its correlation to serum immunological profiles.Methods and materialsNinety-two CKD patients and sex–age–body mass index (BMI)–matched healthy controls (HCs) were recruited. Fresh samples were collected using sterile containers. ITS transcribed spacer ribosomal RNA gene sequencing was performed on the samples. An immunoturbidimetric test was used to assess the serum levels of immunological features.ResultsThe CKD cohort displayed a different microbial community from that in the HC cohort according to principal coordinate analysis (PCoA). (P=0.001). The comparison of the two cohorts showed that the CKD cohort had significantly higher gut microbial richness and diversity (P

Probiotics are vital and beneficial organisms which offers the health benefits to the host organisms. The fungal probiotic field is one of the developing fields nowadays. Yeast has an enormous and diverse group of microorganisms that is attracting and expanding the attention from researchers and industries. Saccharomyces boulardii, the only patented strain belonging to yeast genera for the human use, has been broadly evaluated for its probiotic effect. Yeasts belonging to the genera Debaryomyces, Pichia, Yarrowia, Meyerozyma, Kluyveromyces etc.., have attained more interest because of their beneficial and probable probiotic features. These yeast probiotics produce VOCs (Volatile organic compounds), mycocins and antimicrobials which shows the antagonistic effect against pathogenic fungi and bacteria. Additionally, those yeasts have been recorded as good plant growth promoting microorganisms. Yeast has an important role in environmental applications such as bioremediation and removal of metals like chromium, mercury, lead etc., from waste water. Probiotic yeasts with their promising antimicrobial, antioxidant, anticancer properties, cholesterol assimilation and immunomodulatory effects can also be utilized as biotherapeutics. In this review article we have made an attempt to address important yeast probiotic attributes.

Abstract In this study 10 local isolates of yeast Saccharomyces were obtained from the local markets of Mosul .The Isolates were diagnosed by morphological and cultural characters in addition to biochemical tests. the results of the tests showed that they belong to the Saccharomyces cerevisiae type . Local isolates were tested for resistance to 8 different types of antibiotics and 5 salts of heavy metals. all isolates were resistant to each of Chloramphenicol , Ampicillin , Tetracycline and Streptomycin at 100%. As for the Erythromycin antibiotic most of the local isolates were resistant except for the isolates (SY4 , SY5 , SY6) As well as Amoxicillin all isolates were resistant except for (SY4) . While the isolates showed sensitivity to Nystatin at 80% and for Flagyl at 90% . The isolates also showed resistance to all Zinc chloride ZnCl2 , Nickel chloride NiCl2 and Cobalt chloride CoCl2 at 100% , as for mercury chloride all isolates were resistant except for (SY2) which showed sensitivity to it . sensitivity of the isolates was clear to Cadmium chloride CdCl2 except for the isolates (SY3 , SY9 , SY10) .

Drinking wine is a processed beverage that offers high nutritional and health benefits. It is produced from grape must, which undergoes fermentation by yeasts (and sometimes lactic acid bacteria) to create a product that is highly appreciated by consumers worldwide. However, if only one type of yeast, specifically Saccharomyces cerevisiae, was used in the fermentation process, the resulting wine would lack aroma and flavor and may be rejected by consumers. To produce wine with a desirable taste and aroma, non-Saccharomyces yeasts are necessary. These yeasts contribute volatile aromatic compounds that significantly impact the wine’s final taste. They promote the release of primary aromatic compounds through a sequential hydrolysis mechanism involving several glycosidases unique to these yeasts. This review will discuss the unique characteristics of these yeasts (Schizosaccharomyces pombe, Pichia kluyveri, Torulaspora delbrueckii, Wickerhamomyces anomalus, Metschnikowia pulcherrima, Hanseniaspora vineae, Lachancea thermotolerans, Candida stellata, and others) and their impact on wine fermentations and co-fermentations. Their existence and the metabolites they produce enhance the complexity of wine flavor, resulting in a more enjoyable drinking experience.

In recent years, research on yeasts as probiotics has gained more and more interest, which will allow the development of “new” products in the probiotics market. In this context, seventeen yeast strains isolated from Rabilé, a traditional beer produced in Burkina Faso, were assessed for their probiotic attributes. The yeast identification was performed by molecular methods, including PCR-RFLP and 5.8S-ITS region sequencing. Saccharomyces cerevisiae (14 strains) was the predominantly identified species, followed by Pichia kudriavzevii (2 strains) and Rhodotorula mucilaginosa (1 strain). Except for R. mucilaginosa, all yeast strains grew well at human temperature. The yeast strains showed high resistance when they were exposed to simulated gastrointestinal conditions. Auto-aggregation ability was between 70.20 ± 10.53% and 91.82 ± 1.96%, while co-aggregation with E. coli ranged from 24.92 ± 3.96% to 80.68 ± 9.53% and with S. enterica serovar Typhimurium from 40.89 ± 8.18% to 74.06 ± 7.94%. Furthermore, the hydrophobicity of isolated strains toward n-hexane was in the range from 43.17 ± 5.07% to 70.73 ± 2.42%. All yeast strains displayed high antioxidant capabilities, and the strains did not show hemolysis halos, such that they can be considered safe. Additionally, S. cerevisiae strains strongly inhibited the growth of foodborne pathogens. This is the first preliminary study to identify and characterize the yeast strains isolated from Rabilé with interesting probiotic properties.

The aim of the long-term preservation of cells, tissues and organs is to maintain their cellular structures and biological functions for as long as possible. Cryopreservation is a process where biological material is stored and preserved at very low temperatures. However, freezing and thawing processes can cause irreversible cell damage, which is related to formation of ice crystals, osmotic stress, accumulation of reactive forms of oxygen, etc. Therefore the cell viability depends mainly on the freezing rate, the composition of the cryoprotective medium as well as on the thawing rate. Using a suitable cryoprotective medium can increase the viability rate of the yeasts after “revitalization“. Appropriate pre-cultivation before freezing also plays an important role. These facts show that cell freezing and thawing processes must be controlled to avoid cell damage.

An experiment was performed to investigate the probiotic effect of Saccharomyces boulardii and Saccharomyces cerevisiae on yield, antioxidant activity, and expression of interleukin-6 gene in Holstein calves. Sixteen calves were divided into 4 dietary treatments with 4 calves/treatment. Experimental treatment diets include 1) control (without probiotic use), 2) milk soluble probiotics based on S. boulardii (1 g/kg), 3) milk soluble probiotics based on S. cerevisiae (1 g/kg) and 4) A mixture of yeast probiotics S. boulardii and S. cerevisiae as a solution in dairy milk (1 g/kg each). The completely randomized design was used in this experiment. The results showed that feeding S. boulardii and S. cerevisiae did not have a significant effect on performance traits compared with control. There was no significant difference between the different treatments for the number of antioxidant enzymes compared to the controls. Superoxide dismutase (SOD) in the treatments used probiotics were higher than the control. The expression of interleukin-6 gene expression was increased significantly (P

Wine contains a large number of different chemical compounds, the interaction of which influences the formation of its quality defined by the intensity and quality of the color, its aromatic and taste properties. It is the presence of organic acids and their interrelationship that plays a significant role in the formation of taste quality whereby those with lower concentrations of certain acids will be palatably empty and dull, potentially more exposed to microbial contamination, while those with excessive acidity will taste rough and unbalanced. Tartaric, malic and citric acids are the main organic acids in grapes and wine and at the same time play the most important role in the formation of an acidity profile. However, during alcoholic fermentation, other organic acids such as succinic, pyruvic, lactic and acetic acids can also be produced by the yeasts and/or bacteria activity, thereby directly affecting the acidity profile of the wine. The contribution of Saccharomyces yeast to the change in the concentrations of individual organic acids is significantly lower compared to non-Saccharomyces species and is mainly related to the synthesis of succinic acid. In the past non-Saccharomyces species were treated exclusively as spoilage yeasts but nowadays it is somewhat different, with particular attention being paid to exploring their ability to modify the acidic profile of wine by increasing and/or reducing the synthesis of lactic, succinic, malic and pyruvic acid.

The aim of the present study was to investigate the production of extracellular enzymes in a number of twenty six autochtonous Saccharomyces and nonSaccharomyces strains selected in Dealu Mare region for wine production. The strains were screened for the production of extracellular b-glucosidase, esterase, pectinase and protease activity by inoculation the yeast strains onto selective media. All Saccharomyces tested strains showed at least two enzymatic activities while nonSaccharomyces strains showed activity at least for one enzyme. The weakest activity was recorded in case of β-glucosidase. Most of the tested strains exhibit more or less intense activity for polygalacturonase/pectinase and protease. This study put into evidence the potential of autochtonous and especially of non-Saccharomyces strains as source of production of secondary compounds which can play an important role in improving the quality of wines.

This study investigated the oenological potential of indigenous Saccharomyces and non-Saccharomyces yeasts isolated from different stages of the natural must fermentation process. Screening of extracellular enzymatic activities was performed on agarized media in which the following substrates were added: arbutin, cellobiose, Tween 80, tributyrin, casein and citrus pectin, to highlight the activity of enzymes: ßglucosidase, esterase, lipase, protease and pectinase. Among the 30 Saccharomyces cerevisae strains tested, 37% showed very low β-glucosidase activity, 100% showed esterase activity, 40% lipase activity, 90% protease activity and 53% pectinase activity. The non-Saccharomyces strain tested showed β-glucosidase, esteraseand protease activity. Tolerance to ethanol was assessed in YPD medium with ethanol concentrations of 5, 10 and 15% (v/v) by yeast culture development index. At 15% ethanol, development of all tested strains were inhibited. In the case of SO2 tolerance, decrease in strains development was inversely correlated with the increase in potassium metabisulphite concentration, up to 200 mg/L. Only four Saccharomyces strains showed specific oenological characteristics and were selected to be tested in mixed and/or sequential cultures to obtain wines with improved sensory features.

The two leading yeast pathogens of humans, Candida albicans and Cryptococcus neoformans, cause systemic infections in >1.4 million patients worldwide with mortality rates approaching 75%. It is thus imperative to study fungal virulence mechanisms, efficacy of antifungal drugs, and host response pathways. While this is commonly done in mammalian models, which are afflicted by ethical and practical concerns, invertebrate models, such as wax moth larvae and nematodes have been introduced over the last two decades. To complement existing invertebrate host models, we developed fifth instar caterpillars of the Tobacco Hornworm moth Manduca sexta as a novel host model. These caterpillars can be maintained at 37°C, are suitable for injections with defined amounts of yeast cells, and are susceptible to the most threatening yeast pathogens, including C. albicans, C. neoformans, C. auris, and C. glabrata. Importantly, fungal burden can be assessed daily throughout the course of infection in a single caterpillar’s feces and hemolymph. Infected caterpillars can be rescued by treatment with antifungal drugs. Notably, these animals are large enough for weight to provide a reliable and reproducible measure of fungal disease and to facilitate host tissue-specific expression analyses. M. sexta caterpillars combine a suite of parameters that make them suitable for the study of fungal virulence.

Many traits of industrial and basic biological interest arose long ago, and manifest now as fixed differences between a focal species and its reproductively isolated relatives. In these systems, extant individuals can hold clues to the mechanisms by which phenotypes evolved in their ancestors. We harnessed yeast thermotolerance as a test case for such molecular-genetic inferences. In viability experiments, we showed that extant Saccharomyces cerevisiae survived at temperatures where cultures of its sister species S. paradoxus died out. Then, focusing on loci that contribute to this difference, we found that the genetic mechanisms of high-temperature growth changed with temperature. We also uncovered an enrichment of low-frequency variants at thermotolerance loci in S. cerevisiae population sequences, suggestive of a history of non-neutral selective forces acting at these genes. We interpret these results in light of models of the evolutionary mechanisms by which the thermotolerance trait arose in the S. cerevisiae lineage. Together, our results and interpretation underscore the power of genetic approaches to explore how an ancient trait came to be.

Expression of a new fluorescent reporter protein called mNeonGreen, that is not based on the jellyfish green fluorescent protein (GFP) sequence, shows increased brightness and folding speed compared to enhanced GFP. However, in vivo brightness of mNeonGreen and its yeast-optimized variant ymNeonGreen in S. cerevisiae is lower than expected, limiting the use of this high quantum yield, fast-folding reporter in budding yeast. This study shows that secondary RNA structure near the start codon in the ymNeonGreen ORF inhibits expression in S. cerevisiae. Removing secondary structure, without altering the ymNeonGreen protein sequence, led to a 2 and 4-fold increase in fluorescence when expressed in S. cerevisiae and E. coli, respectively. In S. cerevisiae, increased fluorescence was seen with strong and weak promoters and led to higher transcript levels suggesting greater transcript stability and improved expression in the absence of stable secondary RNA structure near the start codon.

Traditional Norwegian Farmhouse ale yeasts, also known as kveik, have captured the attention of the brewing community in recent years. Kveik were recently reported as fast fermenting thermo- and ethanol tolerant yeasts with the capacity to produce a variety of interesting flavor metabolites. They are a genetically distinct group of domesticated beer yeasts of admixed origin with one parent from the “Beer 1” clade and the other unknown. While kveik are known to ferment wort efficiently at warmer temperatures, their range of fermentation temperatures and corresponding fermentation efficiencies, remain uncharacterized. In addition, the characteristics responsible for their increased thermotolerance remain largely unknown. Here we demonstrate variation in kveik strains at a wide range of fermentation temperatures and show not all kveik strains are equal in fermentation performance and stress tolerance. Furthermore, we uncovered an increased capacity of kveik strains to accumulate intracellular trehalose, which likely contributes to their increased thermo- and ethanol tolerances. Taken together our results present a clearer picture of the future opportunities presented by Norwegian kveik yeasts and offer further insight into their applications in brewing.

Mutations shape genetic architecture and thus influence the evolvability, adaptation and diversification of populations. Mutations may have different and even opposite effects on separate fitness components, and their rate of origin, distribution of effects and variance-covariance structure may depend on environmental quality. We performed an approximately 1,500-generation mutation-accumulation (MA) study in diploids of the yeast Saccharomyces cerevisiae in stressful (high-salt) and normal environments (50 lines each) to investigate the rate of input of mutational variation (Vm) as well as the mutation rate and distribution of effects on diploid and haploid fitness components, assayed in the normal environment. All four fitness components in both MA treatments exhibited statistically significant mutational variance and mutational heritability. Compared to normal-MA, salt stress increased the mutational variance in growth rate by more than sevenfold in haploids derived from the MA lines. This increase was not detected in diploid growth rate, suggesting masking of mutations in the heterozygous state. The genetic architecture arising from mutation (M-matrix) differed between normal and salt conditions. Salt stress also increased environmental variance in three fitness components, consistent with a reduction in canalization. Maximum-likelihood analysis indicated that stress increased the genomic mutation rate by approximately twofold for maximal growth rate and sporulation rate in diploids and for viability in haploids, and by tenfold for maximal growth rate in haploids, but large confidence intervals precluded distinguishing these values between MA environments. We discuss correlations between fitness components in diploids and haploids and compare the correlations between the two MA environmental treatments.

An alternative to natural food shortage for honeybees is the provision of supplements. The objective of this research was to develop a method with ideal conditions for the fermentation of a protein supplement for honeybees. The microorganisms used were Lactobacilli, Bifidobacteria and Saccharomyces and the inulin prebiotic. There was an increase in lactic acid and a decrease in pH over a five-day fermentation period. The amount of acid bacteria present was 108–109 CFU/g of supplement. In the first phase the temperature and the humidity had significantly affected the fermentation but the variables inulin and probiotic didn’t. In the second phase, the lower temperatures and higher humidity produced the best effects on the fermentative responses. It was concluded that an ideal environment with temperature, humidity, inulin and probiotics could be created which allowed the fermentation of the protein supplement in five days obtaining final product fermentative characteristics close to bee bread.

Over the past decade, a large number of major studies have been published analysing the efficacy of including probiotics in the eradication therapy regimens of Helicobacter pylori (H. pylori) infection. One of the catalysts for scientific activity in this direction is undoubtedly the negative trend associated with the decrease in the effectiveness of classical eradication therapy regimens observed all over the world. To date, the results of several meta-analyses show that the addition of certain strains of probiotics to standard eradication therapy regimens increases the efficiency of eradication therapy as well as reduces the frequency of side effects of the gastrointestinal tract associated with the treatment. Mechanisms allowing to increase the efficacy of eradication therapy when using probiotics are still being actively studied. The antagonistic role of some strains of probiotics against H. pylori both in vitro and in vivo has been shown in some works. In particular, probiotics can secrete antibacterial substances including short-chain fatty acids, lactic acid, hydrogen peroxide and bacteriocin. Probiotics can prevent the colonization of H. pylori by competitively inhibiting the adhesion of the microorganism to the epithelial cells of the gastric mucosa. It should be separately noted that probiotics make an important contribution to strengthening the protective properties of the gastric mucosal barrier. Probiotics are able to increase the expression of MUC1, MUC2 and MUC3, as well as restore the compromised proteins of dense contacts of cells, thus stabilizing the structural and functional integrity of the mucous layer of the gastric barrier. Probiotics are able to modulate the immune response of the macroorganism, reducing the production of proinflammatory cytokines involved in the chemotaxis and activation of immunocompetent cells in the gastric mucosa.

This study aimed to investigate in vitro the probiotic potential of three yeasts strains (BB06, OBT05, and MT07) isolated from agro-food natural sources. Screening was performed, including several functional, technological, and safety aspects of the yeast strains, in comparison to a reference Saccharomyces boulardii, to identify the ones with suitable probiotic attributes in aquaculture. The yeast strains were identified by 5.8S rDNA-ITS region sequencing as Metschnikowia pulcherrima OBT05, Saccharomyces cerevisiae BB06, and Torulaspora delbrueckii MT07. All yeast strains were tolerant to different temperatures, sodium chloride concentrations, and wide pH ranges. S. cerevisiae BB06 showed a strong and broad antagonistic activity. Moreover, the S. cerevisiae strain exhibited a high auto-aggregation ability (92.08 ± 1.49%) and good surface hydrophobicity to hexane as a solvent (53.43%). All of the yeast strains have excellent antioxidant properties (>55%). The high survival rate in the gastrointestinal tract (GIT) can promote yeast isolates as probiotics. All yeast strains presented a resistance pattern to the antibacterial antibiotics. Non-hemolytic activity was detected. Furthermore, freeze-drying with cryoprotective agents maintained a high survival rate of yeast strains, in the range of 74.95–97.85%. According to the results obtained, the S. cerevisiae BB06 strain was found to have valuable probiotic traits.

Tequila and mezcal are both traditional Mexican liquors that are produced from cooked Agave spp. must fermentation and usually rely on spontaneous or pure Saccharomyces cerevisiae strain inoculation. In order to contribute to the rational selection of yeast starters for tequila and mezcal productions, we tested a collection of 25 yeasts originally isolated from mezcal musts, spanning 10 different yeast species. These strains were first characterized in a semi synthetic medium (labeled as M2, having 90 g/L fructose and 10 g/L glucose of initial hexoses) at 48 h of culture, observing a differential pattern in the consumption of sugars and productivity. Selected Saccharomyces strains left around 10 g/L of fructose and showed higher fermentation performance. However, some non-Saccharomyces strains, specifically from Torulospora (Td), Kluyveromyces (Km), and Zygosaccharomyces (Zb) genera, consumed almost all the sugar (i.e., Km1Y9 with

Dahi and chhurpi are the homemade, mildly acidic and mouthfeel fermented dairy products of Sikkim in India. Since yeasts co-exist among traditional fermented dairy foods, we believe that some species of yeasts may have some probiotic properties. Hence, the present study is aimed at screening some probiotic yeasts from dahi and chhurpi. A total of 3438 yeasts were isolated from 40 samples of dahi (1779 isolates) and 40 chhurpi (1659 isolates) and were preliminarily screened for probiotic properties on the basis of survival in low pH, resistance to bile salts and the percentage of hydrophobicity, out of which only 20 yeasts were selected for in vitro and genetic screening of probiotic properties. Saccharomyces cerevisiae DJT-2 and Debaryomyces prosopidis CPA-55 showed the highest hydrophobicity of 97.54% and 98.33%, respectively. S. cerevisiae DRC-42 and S. cerevisiae CGI-29 showed 93.88% and 91.69% auto-aggregation, respectively. All yeasts showed co-aggregation properties against pathogenic bacteria. Kluyveromyces marxianus DPA-41 and Pichia kudriavzevii CNT-3 showed excellent deconjugation activities. Probiotic genes for acid tolerance, bile tolerance, adhesion and antimicrobial activity were detected in S. cerevisiae DAO-17, K. marxianus DPA-41, S. cerevisiae CKL-10 and P. kudriavzevii CNT-3. Based on the results of in vitro and genetic screening of probiotic yeasts strains, S. cerevisiae DAO-17 (dahi), S. cerevisiae CKL-10 (chhurpi), P. kudriavzevii CNT-3 (chhurpi) and K. marxianus DPA-41(dahi) were selected as the potential probiotic yeasts.

Economic conversion of biomass to biofuels and chemicals requires efficient and complete utilization of xylose. Saccharomyces cerevisiae strains engineered for xylose utilization are still considerably limited in their overall ability to metabolize xylose. In this study, we identified causative mutations resulting in improved xylose fermentation of an adapted S. cerevisiae strain expressing codon-optimized xylose isomerase and xylulokinase genes from the rumen bacterium Prevotella ruminicola. Genome sequencing identified single-nucleotide polymorphisms in seven open reading frames. Tetrad analysis showed that mutations in both PBS2 and PHO13 genes were required for increased xylose utilization. Single deletion of either PBS2 or PHO13 did not improve xylose utilization in strains expressing the xylose isomerase pathway. Saccharomyces can also be engineered for xylose metabolism using the xylose reductase/xylitol dehydrogenase genes from Scheffersomyces stipitis. In strains expressing the xylose reductase pathway, single deletion of PHO13 did show a significant increase xylose utilization, and further improvement in growth and fermentation was seen when PBS2 was also deleted. These findings will extend the understanding of metabolic limitations for xylose utilization in S. cerevisiae as well as understanding of how they differ among strains engineered with two different xylose utilization pathways.