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Pyracantha fortuneana (P. fortuneana), as a medicinal and edible plant resource, is rich in nutrients. In order to screen the high quality yeast used in Firebone fruit wine, 12 strains of yeast were isolated and purified from P. fortuneana fermentation broth by traditional pure culture method. They were identified by molecular biology as Pichia kudriavzevii (P. kudriavzevii) and Saccharomyces cerevisiae (S. cerevisiae), respectively. Strain HJ-2 could grow normally at 30℃, alcohol content 15%, SO 2 mass concentration 360 mg/L, pH 3.2, sucrose mass concentration 400 g/L and glucose mass concentration 250 g/L. Strain HJ-6 could grow normally at 30℃, alcohol content 3%, SO 2 concentration 360 mg/L, pH 3.2, sucrose concentration 250 g/L, glucose concentration 300 g/L. Based on the technological characteristics of fruit wine, S. cerevisiae HJ-2 has the potential of brewing P. fortuneana fruit wine. P. kudriavzevii HJ-6 has a low tolerance to ethanol and is suitable for the production of fermented beverages such as low-alcohol wine or beer., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Saccharomyces cerevisiae has been considered a harmless yeast, but in recent years, increasing evidence has shown that it can cause disease in humans, especially invasive infections in infants/children and vulvovaginal infections in women. This study aimed to investigate the clinical information and antifungal susceptibility of clinical cases with S. cerevisiae and establish a foundation for the prevention and treatment of fungal infections., Methods: This study was conducted from May 2018 to May 2023 at a national regional medical center in Southwest China for women and children. The demographic and clinical characteristics of patients isolated with S. cerevisiae were collected and analyzed. All the isolates were cultured on Sabouraud medium plates and identified by MALDI-TOF MS. The antifungal susceptibility of S. cerevisiae to 10 agents (amphotericin B, fluconazole, itraconazole, voriconazole, micafungin, caspofungin, terbinafine and 5-flucytosine) was determined via the microdilution broth method to determine the minimum inhibitory concentrations (MICs)., Results: A total of 75 cases of S. cerevisiae isolated from patients with vulvovaginal candidiasis (VVC, 44 cases), pneumonia (13 cases), or diarrhea (18 cases) were included after data review. The MICs of voriconazole and flucytosine for S. cerevisiae isolated from different body sites differed, with higher resistance in intestinal isolates. In this study, S. cerevisiae caused VVC, but there was no clear evidence that it was involved in pneumonia or diarrhea. Compared with those of Candida albicans, the primary pathogen of VVC, the MICs of fluconazole (11.96 ± 5.78 µg/mL vs. 67.64 ± 16.62 µg/mL, p = 0.002), itraconazole (0.77 ± 0.19 µg/mL vs. 2.31 ± 0.53 µg/mL, p = 0.008), voriconazole (0.22 ± 0.09 µg/mL vs. 5.02 ± 1.09 µg/mL, p < 0.001), and terbinafine (10.41 ± 0.84 µg/mL vs. 14.93 ± 4.77 µg/mL, p < 0.001) for S. cerevisiae (isolated from the genital tract) were significantly lower, while those of micafungin (0.14 ± 0.01 µg/mL vs. 0.06 ± 0.01 µg/mL, p < 0.001) and caspofungin (0.27 ± 0.04 µg/mL vs. 0.06 ± 0.01 µg/mL, p < 0.001) were significantly greater., Conclusion: Azoles remain the recommended regimen for S. cerevisiae-related VVC, and the use of amphotericin B vaginal effervescent tablets could be considered for the treatment of azole-resistant isolates. The antifungal susceptibility of S. cerevisiae varies according to the isolated source, and the pathogenicity trend of S. cerevisiae should be studied., (© 2024. The Author(s).)

Aim: In this study, we investigated culturable yeast community, present in grape must sampled from vineyards with apiaries on the borders, and in honey bees collected in these apiaries., Methods and Results: To this aim, yeasts isolated from spontaneously fermented grapes randomly collected in two vineyards (P1 and P2) with apiaries on the borders (A1 and A2) were compared to those isolated from spontaneously fermented grapes collected from a vineyard without apiary (P4). At the same time, yeast community was analyzed on bees collected in each apiary placed in the vineyards, in comparison to yeasts isolated from an apiary (A3) located far from the vineyards. The analysis was performed for two consecutive years (2021 and 2022). The isolated yeasts were identified by restriction analysis of amplified ITS region, followed by sequencing of ITS fragment.Our research showed that the presence of apiaries seems to increase yeast counts of grape must, in particular of Saccharomyces cerevisiae; furthermore, the permanence of apiaries in the vineyards allowed the recovering of these yeasts also from bees., Conclusions: Our findings seem to corroborate the role of bees as vectors and reservoirs of oenologically relevant yeasts, such as a source of non-conventional yeasts with potential biotechnological applications., (© The Author(s) 2024. Published by Oxford University Press on behalf of Applied Microbiology International.)

Yeast, which plays a pivotal role in the brewing, food, and medical industries, exhibits a close relationship with human beings. In this study, we isolated and purified 60 yeast strains from the natural fermentation broth of Sidamo coffee beans to screen for indigenous beneficial yeasts. Among them, 25 strains were obtained through morphological characterization on nutritional agar medium from Wallerstein Laboratory (WL), with molecular biology identifying Saccharomyces cerevisiae strain YBB-47 and the remaining 24 yeast strains identified as Pichia kudriavzevii. We investigated the fermentation performance, alcohol tolerance, SO 2 tolerance, pH tolerance, sugar tolerance, temperature tolerance, ester production capacity, ethanol production capacity, H 2 S production capacity, and other brewing characteristics of YBB-33 and YBB-47. The results demonstrated that both strains could tolerate up to 3% alcohol by volume at a high sucrose mass concentration (400 g/L) under elevated temperature conditions (40 ℃), while also exhibiting a remarkable ability to withstand an SO 2 mass concentration of 300 g/L at pH 3.2. Moreover, S. cerevisiae YBB-47 displayed a rapid gas production rate and strong ethanol productivity. whereas P. kudriavzevii YBB-33 exhibited excellent alcohol tolerance. Furthermore, this systematic classification and characterization of coffee bean yeast strains from the Sidamo region can potentially uncover additional yeasts that offer high-quality resources for industrial-scale coffee bean production., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The use of yeast respiratory metabolism has been proposed as a promising approach to solve the problem of increasing ethanol content in wine, which is largely due to climate change. The use of S. cerevisiae for this purpose is mostly hampered by acetic acid overproduction generated under the necessary aerobic conditions. However, it was previously shown that a reg1 mutant, alleviated for carbon catabolite repression (CCR), showed low acetic acid production under aerobic conditions. In this work directed evolution of three wine yeast strains was performed to recover CCR-alleviated strains, expecting they will also be improved concerning volatile acidity. This was done by subculturing strains on galactose, in the presence of 2-deoxyglucose for around 140 generations. As expected, all evolved yeast populations released less acetic acid than their parental strains in grape juice, under aerobic conditions. Single clones were isolated from the evolved populations, either directly or after one cycle of aerobic fermentation. Only some clones from one of three original strains showed lower acetic acid production than their parental strain. Most clones isolated from EC1118 showed slower growth. However, even the most promising clones failed to reduce acetic acid production under aerobic conditions in bioreactors. Therefore, despite the concept of selecting low acetic acid producers by using 2-deoxyglucose as selective agent was found to be correct, especially at the population level, the recovery of strains with potential industrial utility by this experimental approach remains a challenge., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Beer is the world's third most popular fermented beverage. It is typically made from malted barley. Tropical countries must import barley from temperate countries for brewing, which is an expensive process. Therefore, it is critical to investigate alternative possible substrates for beer production in order to meet the growing demand for high-nutritional-quality beer. The current study involves the creation of a fermented beverage from anthocyanin-rich black wheat with the help of yeast, Saccharomyces cerevisiae CMS12, isolated from fruit waste. Characterization (UV, HPLC, NMR, FTIR, and ICPMS) was then performed, as well as a comparative study with white (amber) wheat beer. Further, process parameters optimization included initial sugar concentration, inoculum size, and pH. Black wheat wort contained 568 mg GAE/L total phenolic content, 4.67 mg/L anthocyanin concentration, 6.8% (v/v) alcohol content, and a pH of 4.04. The sensory analysis revealed that black wheat beer was more acceptable than white wheat beer. The developed fermented beverage has enormous commercialization potential., (© 2023. The Author(s).)

Yeast morphology and counting are highly important in fermentation as they are often associated with productivity and can be influenced by process conditions. At present, time-consuming and offline methods are utilized for routine analysis of yeast morphology and cell counting using a haemocytometer. In this study, we demonstrate the application of an in situ microscope to obtain a fast stream of pseudohyphae images from agitated sample suspensions of a Saccharomyces cerevisiae strain, whose morphology in cell clusters is frequently found in the bioethanol fermentation industry. The large statistics of microscopic images allow for online determination of the principal morphological characteristics of the pseudohyphae, including the number of constituent cells, cell-size, number of branches, and length of branches. The distributions of these feature values are calculated online, constituting morphometric monitoring of the pseudohyphae population. By providing representative data, the proposed system can improve the effectiveness of morphological characterization, which in turn can help to improve the understanding and control of bioprocesses in which pseudohyphal-like morphologies are found., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Aim: Tyrosol, a quorum sensing molecule in yeasts, was reported to reduce lag phase and induces hyphae formation during cell proliferation. However, evidence of any enhancing effect of tyrosol in cellular proliferation within fermentative environment is unclear. In this investigation, selected yeast cells were assessed for their ability to synthesize tyrosol followed by examining the role of the molecule during fermentation., Methods and Results: Tyrosols were characterized in four fermentative yeasts viz., Saccharomyces cerevisiae, Wickerhamomyces anomalus, Candida glabrata and Candida tropicalis isolated from traditional fermentative cakes of northeast India. All the isolates synthesized tyrosol while C. tropicalis exhibited filamentous growth in response to tyrosols retrieved from other isolates. Purified tyrosols showed protective behaviour in C. tropicalis and S. cerevisiae under ethanol mediated oxidative stress. During fermentation, tyrosol significantly enhanced growth of W. anomalus in starch medium while C. tropicalis exhibited growth enhancement in starch and glucose sources. The chief fermentative yeast S. cerevisiae showed notable enhancement in fermentative capacity in starch medium under the influence of tyrosol con-commitment of ethanol production., Conclusion: The study concludes that tyrosol exerts unusual effect in cellular growth and fermentative ability of both Saccharomyces and non-Saccharomyces yeasts., Significance and Impact of the Study: This is the first report of expression of tyrosol by non-conventional yeasts, where the molecule was found to exert enhancing effect during fermentation, thereby augmenting the process of metabolite production during traditional fermentation., (© 2020 The Society for Applied Microbiology.)

Saccharomyces cerevisiae sub-species diastaticus (S. diastaticus) is the main fungal cause of spoilage of carbonated fermented beverages in the brewing industry. Here, prevalence of S. diastaticus in nature and breweries was assessed as well as the spoilage capacity of its vegetative cells and spores. S. diastaticus could only be enriched from 1 out of 136 bark and soil samples from the Netherlands, being the first described natural isolate of this yeast outside South America. On the other hand, it was identified by PCR and selective enrichment in 25 and 21 out of 54 biofilm samples from beer filling halls in Asia, Africa, Europe and North America. ITS sequencing revealed that S. cerevisiae (including S. diastaticus) represented <0.05% of fungal DNA in 17 out of 20 samples, while it represented 0.1, 2 and 32% in samples VH6, VH1 and VH3 respectively. Next, vegetative cells and ascospores of the natural S. diastaticus isolate MB523 were inoculated in a variety of beer products containing 0.0-5.0% alcohol (v/v). Ascospores spoiled all beer products, while vegetative cells did not grow in Radler lemon 0.0, Radler lime mint 0.0 and Radler lemon lime 0.0. Notably, vegetative cells could spoil these Radlers when they first had been grown in alcohol free beer either or not mixed with Radler lemon lime 0.0. Conversely, vegetative cells that had been grown in Radler lemon lime lost their spoilage potential of this beer product when they had grown in YPD medium for more than 24 h. In addition, it was shown that cells grown in alcohol free beer were more heat resistant than cells grown in YPD (D 52 40 min and ≤ 10.3 min, respectively). Together, these data show that S. diastaticus is a less prevalent variant of S. cerevisiae in nature, while it accumulates in breweries in mixed biofilms. Data also show that both vegetative cells and spores can spoil all tested beer products, the latter cell type irrespective of its environmental history., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Nitrogen requirements by S. cerevisiae during wine fermentation are highly strain-dependent. Different approaches were applied to explore the nitrogen requirements of 28 wine yeast strains. Based on the growth and fermentation behaviour displayed at different nitrogen concentrations, high and low nitrogen-demanding strains were selected and further verified by competition fermentation. Biomass production with increasing nitrogen concentrations in the exponential fermentation phase was analysed by chemostat cultures. Low nitrogen-demanding (LND) strains produced a larger amount of biomass in nitrogen-limited synthetic grape musts, whereas high nitrogen-demanding (HND) strains achieved a bigger biomass yield when the YAN concentration was above 100 mg/L. Constant rate fermentation was carried out with both strains to determine the amount of nitrogen required to maintain the highest fermentation rate. Large differences appeared in the analysis of the genomes of low and high-nitrogen demanding strains showed for heterozygosity and the amino acid substitutions between orthologous proteins, with nitrogen recycling system genes showing the widest amino acid divergences. The CRISPR/Cas9-mediated genome modification method was used to validate the involvement of GCN1 in the yeast strain nitrogen needs. However, the allele swapping of gene GCN1 from low nitrogen-demanding strains to high nitrogen-demanding strains did not significantly influence the fermentation rate., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Bollo is a traditional Goan fermented food in which coarse wheat/wheat and finger millet is leavened with toddy. We here isolated 42 yeast strains from Bollo batter. Initial screening of the isolates with probiotic properties yielded four yeast isolates (DABRP1, DABRP2, DABRP5 and DABRP12). These isolates exhibited tolerance to high bile salt concentration and acidic pH and resistance to various antibiotics, which indicated their probiotic nature. All these yeast isolates were identified as Saccharomyces cerevisiae through D1D2-LSU-rDNA sequencing. These yeast isolates also showed higher percent hydrophobicity towards chloroform followed by n-hexadecane and o-xylene indicating their mucosal surface-adhesive property. To evaluate the safety of the isolates for them to be called as generally recognized as safe, the pathogenic behavior of the isolates determined through the in vitro hemolysis assay and evaluation of DNase and gelatinase activities. None of the isolates exhibited hemolysis or produced DNase or gelatinase and thus were considered potentially safe. In terms of beneficial effects, the most potent isolate S. cerevisiae DABRP5 showed antibacterial activity against the test pathogens. It also showed excellent antioxidant activity with DPPH free radical scavenging activity of 68.85 ± 0.69%, anti-inflammatory activity with 60.39 ± 0.34% inhibition of protein denaturation, and antidiabetic activity with 71.75 ± 0.45% inhibition of α-amylase activity. The isolate produced α-amylase, lipase, and β-galactosidase. The probiotic potential of the isolate S. cerevisiae DABRP5 was similar to that of the reference strain (Saccharomyces boulardii CNCM I-745) used in this study. The results thus indicate that yeast isolates from Bollo batter have probiotic potential.

Water kefir is a sparkling, slightly acidic fermented beverage produced by fermenting a solution of sucrose, to which dried fruits have been added, with water kefir grains. These gelatinous grains are a symbiotic culture of bacteria and yeast embedded in a polysaccharide matrix. Lactic acid bacteria, yeast and acetic acid bacteria are the primary microbial members of the sugary kefir grain. Amongst other contributions, species of lactic acid bacteria produce the exopolysaccharide matrix from which the kefir grain is formed, while yeast assists the bacteria by a nitrogen source that can be assimilated. Exactly which species predominate within the grain microbiota, however, appears to be dependent on the geographical origin of the grains and the fermentation substrate and conditions. These factors ultimately affect the characteristics of the beverage produced in terms of aroma, flavour, and acidity, for example, but can also be controlled and exploited in the production of a beverage of desired characteristics. The production of water kefir has traditionally occurred on a small scale and the use of defined starter cultures is not commonly practiced. However, as water kefir increases in popularity as a beverage - in part because of consumer lifestyle trends and in part due to water kefir being viewed as a health drink with its purported health benefits - the need for a thorough understanding of the biology and dynamics of water kefir, and for defined and controlled production processes, will ultimately increase. The aim of this review is to provide an update into the current knowledge of water kefir., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Saccharomyces cerevisiae fungemia: risk factors, outcome and links with S. boulardii-containing probiotic administration., Objective: The aim of our study was to review cases of S. cerevisiae fungemia along with the corresponding risk factors (including S. boulardii probiotic intake), treatment and outcomes., Patients and Methods: Retrospective study (2005-2017) of S. cerevisiae fungemia. All the data were extracted from medical files., Results: We identified 10 patients with S. cerevisiae fungemia. Mean age was 59.4 years (range 21-88). Four fifths (80%) were on total parenteral or enteral nutrition, 70% had a central venous line, and 30% were admitted in an Intensive Care Unit (ICU). S. boulardii-containing probiotic prescription was identified in 6 subjects. Three patients with no risk factors such as ICU or central venous catheter were 80 years old or more. Mortality rate was 50%., Conclusion: S. cerevisiae fungemia is a rare but life-threatening infection, associated with intake of probiotics containing S. boulardii. Besides classical risk factors, older age should be a contraindication for these probiotics., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Saccharomyces cerevisiae(S. cerevisiae) has been classically used as a treatment for diarrhea and diarrhea-related diseases. However, cases of the fungal infections caused by S. cerevisiae have been increasing in the last two decades among immunocompromised patients, while a long time was spent on S. cerevisiae isolation clinically so it was difficult to achieve timely diagnosis the diseases. Here, a novel approach for isolation and selection of S. cerevisiae is proposed by designing a microfluidic chip with an optically induced dielectrophoresis (ODEP) system. S. cerevisiae was isolated from the surroundings by ODEP due to different dielectrophoretic forces. Two special light images were designed and used to block and separate S. cerevisiae, respectively, and several manipulation parameters of ODEP were experimentally optimized to acquire the maximum isolation efficiency of S. cerevisiae. The results on the S. cerevisiae isolation declared that the purity of the S. cerevisiae selected by the method was up to 99.5 % ±0.05, and the capture efficiency was up to 65.0 % ±2.5 within 10 min. This work provides a general method to isolate S. cerevisiae as well as other microbial cells with high accuracy and efficiency and paves a road for biological research in which the isolation of high-purity cells is required.

Numerous transcription factor genes associated with stress response are upregulated in Saccharomyces cerevisiae grown in the presence of inhibitors that result from pretreatment processes to unlock simple sugars from biomass. To determine if overexpression of transcription factors could improve inhibitor tolerance in robust S. cerevisiae environmental isolates as has been demonstrated in S. cerevisiae haploid laboratory strains, transcription factors were overexpressed at three different expression levels in three S. cerevisiae environmental isolates. Overexpression of the YAP1 transcription factor in these isolates did not lead to increased growth rate or reduced lag in growth, and in some cases was detrimental, when grown in the presence of either lignocellulosic hydrolysates or furfural and 5-hydroxymethyl furfural individually. The expressed Yap1p localized correctly and the expression construct improved inhibitor tolerance of a laboratory strain as previously reported, indicating that lack of improvement in the environmental isolates was due to factors other than nonfunctional expression constructs or mis-folded protein. Additional stress-related transcription factors, MSN2, MSN4, HSF1, PDR1, and RPN4, were also overexpressed at three different expression levels and all failed to improve inhibitor tolerance. Transcription factor overexpression alone is unlikely to be a viable route toward increased inhibitor tolerance of robust environmental S. cerevisiae strains., (© 2020 American Institute of Chemical Engineers.)

Yeast Saccharomyces cerevisiae ( S. Cerevisiae ) is one of the most attractive microbial species used for industrial production of value-added products and is an important model organism to understand the biology of the eukaryotic cells and humans. S. Cerevisiae has different shapes, such as spherical singlets, budded doublets, and clusters, corresponding to phases of the cell cycle, genetic, and environmental factors. The ability to obtain high-purity populations of uniform-shaped S. Cerevisiae cells is of significant importance for a wide range of applications in basic biological research and industrial processes. In this work, we demonstrate shape-based separation and enrichment of S. Cerevisiae using a coflow of viscoelastic and Newtonian fluids in a straight rectangular microchannel. Due to the combined effects of lift inertial and elastic forces, this label-free and continuous separation arises from shape-dependent migration of cells from the Newtonian to the non-Newtonian viscoelastic fluid. The lateral position of S. Cerevisiae cells with varying morphologies is found to be dependent on cell major axis. We also investigate the effects of sheath and sample flow rate, poly(ethylene oxide) (PEO) concentration and channel length on the performance of the viscoelastic microfluidic device for S. Cerevisiae enrichment and separation by shape. Moreover, the separation efficiency, cell extraction yield, and cell viability after sorting operations are studied.

We used yeast proteome microarrays (∼5800 purified proteins) to conduct a high-throughput and systematic screening of PI5P-interacting proteins with PI5P-tagged fluorescent liposomal nanovesicles. Lissamine rhodamine B-dipalmitoyl phosphatidylethanol was incorporated into the liposome bilayer to provide the nanovesicles with fluorescence without any encapsulants, which not only made the liposome fabrication much easier without the need for purification but also improved the chip-probing quality. A special chip assay was washed very gently without the traditional spin-dry step. Forty-five PI5P-interacting proteins were identified in triplicate with this special chip assay. Subsequently, we used flow cytometry to validate these interactions, and a total of 41 PI5P-interacting proteins were confirmed. Enrichment analysis revealed that these proteins have significant functions associated with ribosome biogenesis, rRNA processing, ribosome binding, GTP binding, and hydrolase activity. Their component enrichment is located in the nucleolus. The InterPro domain analysis indicated that PI5P-interacting proteins are enriched in the P-loop containing nucleoside triphosphate hydrolases domain (P-loop). Additionally, using the MEME program, we identified a consensus motif (IVGPAGTGKSTLF) that contains the Walker A sequence, a well-known nucleotide-binding motif. Furthermore, using a quartz crystal microbalance, both the consensus motif and Walker A motif showed strong affinities to PI5P-containing liposomes but not to PI5P-deprived liposomes or PI-containing liposomes. Additionally, the glycine (G6) and lysine (K7) residues of the Walker A motif (-GPAGTG 6 K 7 S-) were found to be critical to the PI5P-binding ability. This study not only identified an additional set of PI5P-interacting proteins but also revealed the strong PI5P-binding affinity ( K d = 1.81 × 10 -7 M) of the Walker A motif beyond the motif's nucleotide-binding characteristic.

In order to phenotypically characterized Saccharomyces cerevisiae strains isolated from sorghum beer and palm wines for a possible selection of a starter culture, 30 strains were tested for killer activity, temperature resistance, ethanol tolerance, carbohydrate fermentation, enzyme profile and sorghum wort fermentation. Of the tested strains, three showed a killer profile, while four showed a neutral profile and 23 were found to be sensitive to K2 toxin. Temperatures of 40 °C and 44 °C allowed to distinguish strains into four thermal groups with only three strains may grow at 44 °C. Almost tested strains were tolerant to 5% ethanol with viability rates up to 73%. But at 10% and 15% ethanol, respectively 18 and 7 strains were tolerant. Carbohydrate fermentation revealed 13 fermentation profiles, including one typical and 12 atypical profiles. The typical profile strains (16.13% of the strains) fermented glucose, galactose, fructose, sucrose, maltose, trehalose and raffinose. Most of the strains secreted lipases (mainly esterase and esterase-lipase), proteases (mainly valine and cysteine arylamidase, chrymotrypsin) and phosphatases (mainly acid phosphatase and naphthol phosphohydrolase). On contrary, only five strains isolated from sorghum beer exhibited glucosidase activity, mainly α-glucosidase. The analyse of fermented sorghum wort revealed that fermentative performance is strain dependent. Furthermore, the Hierarchical Cluster Analysis showed that the strains were separated in three distinct clusters with the strains from sorghum beer clustered separately.

The role of the yeast community in Chinese strong-flavor baijiu fermentation was investigated by culture-independent and culture-dependent methods based on 26S rDNA sequence analysis. 92 yeast species belonging to 54 genera were found by Illumina sequencing during the fermentation of strong-flavor baijiu "Wuliangye" and 306 strains belonging to 28 species, which covered all species with more than 1% of relative abundance, were isolated and identified. Kazachstania exigua, Geotrichum silvicola, Pichia kudriavzevii, Saccharomyces cerevisiae, Zyosaccharomyces bailii, and K. humilis were found to be the first six dominant species, and their proportion varied with different fermentation stages. K. exigua was the most important yeast species responsible for the production of ethanol with the assistance of P. kudriavzevii and Z. bailii in the vigorous stage and P. kudriavzevii and G. silvicola in the continuous fermentation stage. Higher alcohols were mainly produced by K. exigua, P. kudriavzevii, S. cerevisiae, and Z. bailii in the vigorous fermentation stage, which was stimulated by more oxygen in the grains of the upper strata. K. exigua, P. kudrizevii, S. cerevisiae, Z. bailii, G. silvicola, and Trichosporon ovoides promoted the formation of ethyl alcohol. The results revealed the key roles of K. exigua, G. silvicola, and P. kudriavzevii in the fermentation of strong-flavor baijiu. The functions of these species should be confirmed by a further study based on the fermentation characteristics of isolated yeast strains gathered in this study. Distribution and function of dominant yeast species in the fermentation of strong flavor baijiu.

In this study, we tested the feces of children with ASD and those of healthy children, and the overall changing of the gut fungal community was observed in ASD children compared with controls. However, there were no abundant fungi populations showed significant variations between the ASD and Control group both at phylum and class level. Among the 507 genera identified, Saccharomyces and Aspergillus showed significant differences between ASD (59.07%) and Control (40.36%), indicating that they may be involved in the abnormal gut fungal community structure of ASD. When analyzed at the species level, a decreased abundance in Aspergillus versicolor was observed while Saccharomyces cerevisiae was increased in children with ASD relative to controls. Overall, this study characterized the fungal microbiota profile of children with ASD and identified potential diagnostic species closely related to the immune response in ASD.

The study focused on the production of wine from date palm fruits (Phoenix dactylifera L.) using a strain of yeast isolated from selected Nigerian locally fermented beverages ('pito', 'brukutu' and palm wine). Seven (7) distinct yeasts were isolated and identified using cultural, microscopy and biochemical tests (temperature tolerance, flocculation, ethanol tolerance, H 2 S production and killer toxin production and the ability to assimilate and ferment sugars. The yeast isolates were screened using refractometric and spectrophotometric methods to select the isolate with the best ability for wine production. This isolate was molecularly characterized, grown in 1 L of potatoes dextrose broth, freeze dried and used for wine production. The population of yeast, bacteria and the physicochemical analysis of the must were monitored during fermentation. Populations of bacteria in the wine were assessed by standard pour plate count. The proximate content and physicochemical properties of the produced wine before and after ageing, as well as the sensorial quality of the produced wine was determined. All the yeast isolates possessed the ability to flocculate, tolerate ethanol concentration of between 5 and 20% and temperature range of 30-45 °C, produced low concentration of H 2 S and does not produce killer toxins. A palm wine isolate, identified as Saccharomyces cerevisiae X01 was selected as the best isolate with the most ability for wine production. The total yeast count increases as the period of fermentation progressed while the total viable bacterial count reduced as the fermentation period progressed. There was a significant difference (P < 0.05) in the physicochemical properties of the must during fermentation. At the end of the fermentation, the produced wine had 5.22% and 4.86% ethanol content for S. cerevisiae QA23 and S. cerevisiae X01 respectively. There was no significant difference (P > 0.05) between the proximate and physicochemical compositions of the produced wine before and after ageing using Saccharomyces cerevisiae X01 when compared to the control S. cerevisiae QA23. This study revealed that the Nigerian locally sourced S. cerevisiae X01 can be used as an alternative substrate for industrial scale production of wine with a mild alcoholic content.

Fino wine is one of the most important Sherry wines and it is obtained through a complex and dynamic biological aging system. In this study, wine and veil of flor samples from fifty-two barrels with different aging levels and distributed in three different wineries from the Jerez-Xèrés-Sherry winemaking area have been analyzed during two years. Some of the wine compounds most deeply involved in flor yeast metabolism were analyzed to take into account the blending effect of this system. On the other hand, veil of flor was analyzed by molecular methods, finding five different species: S. cerevisiae, W. anomalus, P. membranaefaciens, P. kudriavzevii and P. manshurica, being the first time that the three last species have been reported in this biological aging system. Since S. cerevisiae was the vast majority of the isolates, its intraspecies variability was also analyzed by the simultaneous amplification of three microsatellite loci, obtaining nine different S. cerevisiae genotypes, also differentiated according to their physiological properties. Biodiversity analysis showed there were significant differences between the three wineries in the three aging scales, although the overall diversity was relatively low. Moreover, variations in the relative frequency of the different S. cerevisiae genotypes were found to be seasonal-dependent., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Icewine produced in China is becoming popular, but there is only limited knowledge available on the yeast population that occurs during fermentation and also on the selection of indigenous Saccharomyces cerevisiae strains for its production. In this work, we first investigated yeast species and the evolution of yeast population in spontaneous fermentations of icewine produced in the Qilian region of China and then analyzed the biodiversity and important enological properties of S. cerevisiae isolates., Results: Seven species of five genera including S. cerevisiae, S. uvarum, Torulaspora delbrueckii, Hanseniaspora uvarum, Lachancea thermotolerans, Metschnikowia aff. fructicola and H. osmophila were identified by the colony morphology on Wallerstein Laboratory Nutrient medium and sequence analysis of the 26S rRNA gene D1/D2 domain. Saccharomyces cerevisiae, H. uvarum and L. thermotolerans were the dominant species, representing almost 87% of the total yeast isolates. Microvinification with seven preselected S. cerevisiae strains were performed on Vidal. All selected strains could complete fermentations, and the enochemical parameters were within the acceptable ranges of the wine industry. W5B3 produced higher amounts of ethyl hexanoate and ethyl octanoate than other strains. R3A10 was a low volatile acid producer and the corresponding icewine presented the highest values on some odorants including β-damascenone, 1-octen-3-ol, ethyl 2-methylbutyrate, and isoamyl alcohol. Vidal icewines fermented with R3A10, R3A16 and W5B3 were well accepted by the judges because of superior sensory quality., Conclusion: Three indigenous strains (R3A10, R3A16 and W5B3) could be used as starters and could potentially improve the regional character of the icewine in Qilian. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

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

In this work the potential of comparative transcriptomics was explored of Saccharomyces (S.) cerevisiae and S. pastorianus for their discrimination. This way an alternative should be demonstrated to comparative genomics, which can be difficult as a result of their aneuoploid genomes composed of mosaics of the parental genomes. Strains were selected according to their application in beer brewing, i.e. top and bottom fermenting yeasts. Comparative transcriptomics was performed for four strains each of commercially available S. cerevisiae (top fermenting) and Saccharomyces pastorianus (bottom fermenting) brewing yeasts grown at two different temperatures to mid-exponential growth phase. A non-reference based approach was chosen in the form of alignment against a de novo assembled brewery-associated pan transcriptome to exclude bias introduced by manual selection of reference genomes. The result is an analysis workflow for self-contained comparative transcriptomics of Saccharomyces yeasts including, but not limited to, the analysis of core and accessory gene expression, functional analysis and metabolic classification. The functionality of this workflow is demonstrated along the principal differentiation of accessory transcriptomes of S. cerevisiae versus S. pastorianus strains. Hence, this work provides a concept enabling studies under different brewing conditions., Competing Interests: The authors have declared that no competing interests exist.

The Saccharomyces cerevisiae has been used for many years in the elaboration of food and beverage products, mainly associated with fermentation processes. The objective of this study was to characterize different indigenous S. cerevisiae strains and guide the notable strains for potential use in productions of fermented maize-based beverages. Initially, 81 strains isolated from different spontaneous food fermentations were evaluated. About 31% of strains showed phytase activity, an important characteristic for their application in cereals beverages production. All strains were able to grow in pH values 2.0, 3.0, and 5.0 and the presence of 5, 15, and 30% of glucose, but none could grow at 42 °C. Only 29.6% of the evaluated strains were able to efficiently grow in up to 1.0 mol L -1 of NaCl. The Rep-PCR and RAPD-PCR tools showed that the strains were differently grouped by the two techniques, and the grouping was not completely correlated with isolation source. A total of 65 volatile compounds were identified from the maize beverage produced. The profiles of volatile compounds produced by the strains were strain specific. S. cerevisiae strains isolated from the same source showed different chemical and genetic profiles, emphasize the importance to characterize the performance of each strain when searching for starter culture to develop or improve fermented beverages.

Cabernet Sauvignon grape produced in Xinjiang (China) is often overripe, with unusually high sugar content, which impedes utilization. We aimed to establish the optimal combination of indigenous yeast strains to produce a new sweet wine from the overripe grape. Five yeast strains with pronounced enological characteristics were selected from 88 indigenous yeast isolates. Using a series of co-fermentation experiments with different inoculated strategies, we achieved optimal co-fermentation with a combination of strains SC19 and NS68, later identified as Saccharomyces cerevisiae and Pichia kudriavzevii, respectively, simultaneously inoculated in a 1:1 ratio at the early stage of fermentation. The combination was characterized by vigorous fermentation with high resistance to 457.13 g/L sugar and high alcohol yield (16.01% vol). The sweet wine contained 17 aromatic compounds with odor activity value (OAV) ≥ 1 and pronounced sweet fruit, floral, herbaceous, and caramel odors. The co-fermentation has a good potential for utilization of overripe Cabernet Sauvignon grape.

Aims: To provide information on the time-dependent behaviour of microbe staining by fluorescent dyes in the order of seconds, which is important in terms of the recent rapid and online techniques for microbe measurements and/or environmental microbe analysis., Methods and Results: For combinations of yeast (Saccharomyces cerevisiae) and typical dyes, including DAPI (4',6-diamidino-2-phenylindole) and Auramine-O, a suspension of yeast cells in ultrapure water was injected into a dye solution in a micro cuvette placed inside a spectrofluorometer and the fluorescence intensity of the resulting solution was measured at 1 s intervals, starting immediately after the mixing and continued until the time for the maximum intensity using various concentrations of yeast and dyes. The relaxation time τ, which corresponds to ~63·2% of the maximum fluorescence intensity, was shown to decrease to below 1 s with increasing DAPI concentration, whereas it remained constant for 2-3 s with increasing Auramine-O concentration, for example at a yeast concentration of 100 µg ml -1 ., Conclusions: For the conditions of yeast >10 µg ml -1 , DAPI >1 µg ml -1 and Auramine-O >0·1 µg ml -1 , τ could be adjusted to below 5 s to achieve a rapid and stable staining., Significance and Impact of the Study: Design and operating conditions for rapid and online measurements of microbes can be optimized., (© 2020 The Society for Applied Microbiology.)

Superabsorbent polymers (SAPs) are most often used in hygienic goods or in the agricultural sector but the range of their application is much broader, including the utilization in advanced building materials. Although SAPs were studied widely during the last decades, the data related to the interactions between the natural environment and various organisms occurring on their surface are still lacking. In addition, SAPs can create a variable gel-forming matter in the presence of water but standard ecotoxicological bioassays are mostly not suitable for testing such type of materials. In this study, the SAPs potential for reducing/supporting unwanted indoor microorganism settlement was analyzed by biological methods under controlled laboratory conditions. Three commonly used SAPs (Cabloc CT, Creasorb SIS, Hydropam) were exposed to selected organisms representing green algae (Hematococcus pluvialis), cyanobacteria (Nostoc sp.), yeasts (Saccharomyces cerevisiae), wood-destroying fungi (Gleophyllium trabeum), and aerial molds. The obtained results indicated that Hydropam provided favorable conditions for Hematococcus pluvialis, Nostoc sp., and Saccharomyces cerevisiae. All three tested SAPs inhibited, both with and without nutrient addition, the growth of Gleophyllium trabeum and aerial molds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

This study focused on the microbial communities found in JIUYAO, the fermentation starter traditionally used in Shaoxing-jiu, and elucidated their relationship with the fermentation activities and volatile compounds involved in winemaking. The microbial communities found in all JIUYAO samples tested were dominated by Pediococcus and Weissella bacteria and Saccharomycopsis and Rhizopus fungi. Saccharifying power showed significant positive correlations with the presence of Pedioccoccus, Saccharomycopsis, and Rhizopus, whereas acid production capacity was strongly associated with Pedioccoccus, Weissella, and Rhizopus. Alcohol production capacity positively correlated with the presence of Pedioccoccus and Rhizopus. Fifteen important volatile compounds (odor-activity values ≥ 1) including esters, alcohols, acids, and aldehydes were identified in Huangjiu samples fermented with JIUYAO. Positive correlations were found between Saccharomycopsis and phenylethanol/ethyl butyrate, Rhizopus and ethyl propionate/ethyl laurate/ethyl butyrate, Pedioccoccus and ethyl laurate/acetic acid, and Weissella and decanoic acid/isopentanol. These results imply that these microorganisms significantly contribute to the fermentation activities and flavor of Shaoxing-jiu. Finally, the results showed that a combination of five core microbes with Saccharomyces cerevisiae could be used as a starter in winemaking. To conclude, this study provides a comprehensive overview of the core microbes found in JIUYAO and strategies for the selection of beneficial microorganisms to improve the quality and flavor of Shaoxing-jiu., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A reliable method for quantification of non-viable microbe-based nutritional and zootechnical additives introduced into feed is essential in order to ensure regulatory compliance, feed safety and product authenticity in industrial applications. In the present work, we developed a novel real-time quantitative polymerase chain reaction (qPCR) -based analysis protocol for monitoring two microbial additives in feed matrices. To evaluate the applicability of the method, pelleted wheat- and maize-based broiler chicken diets containing a non-viable phytase-producing strain of Aspergillus niger produced in solid state fermentation (150 or 300 g/t) and a non-viable selenium-enriched Saccharomyces cerevisiae (100 or 200 g/t) as model feed ingredients, were manufactured and subjected to analysis. Power analysis of the qPCR results indicated that 2 to 6 replicate feed samples were required to distinguish the product doses applied, which confirms that the microbial DNA was efficiently recovered and that potential PCR inhibitors present in the feed material were successfully removed in DNA extraction. The analysis concept described here was shown to be an accurate and sensitive tool for monitoring the inclusion levels of non-viable, unculturable microbial supplements in animal diets., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Yeasts involved in the spontaneous fermentation of traditional beverages like chicha (indigenous Andean beer) may have the potential to be used as starter cultures to improve the quality and microbiological safety of these products, but also as non-conventional alternatives to other food alcoholic fermentations. In this research, we isolated, identified and characterised yeast strains from four Ecuadorian chichas made by using four different raw materials: rice (RC), oat (OC), grape (GC) and a mixture of seven corn varieties (yamor, YC). Finally, 254 yeast isolates were obtained and identified by molecular methods. Eleven yeast genera and 16 yeast species were identified with relatively few isolates belonging to Saccharomyces cerevisiae (9.1% belonging to 6 strains) and Torulaspora delbrueckii (18.6% belonging to 2 strains). In order to select good candidates for fermentative starter production, different analyses were performed. The results of the stress response tests showed a wide variability between species and strains, and identified some yeasts displaying high stress tolerance, similarly to commercial wine strains. Amylase production was screened as being indicative of the capacity to degrade and ferment starch-rich substrates. A Cryptococcus sp. isolate showed the highest amylase activity. The growth rate and fermentative capacity in molasses medium was measured for three S. cerevisiae, T. delbrueckii and Candida sp. strains as tests for yield and performance in biomass production. Based on their excellent behaviour, three S. cerevisiae strains and one T. delbrueckii strain were selected for further analyses, including dehydration tolerance and invertase activity as additional desired traits for chicha starters. All the S. cerevisiae strains exhibited high invertase activity and one also displayed high resistance to dehydration. The yeasts selected in this study can thus be suitably used as dry starters for the microbiologically controlled production of traditional beverages, and also for other alcoholic fermentations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The consumption of probiotics has increased due to the reported health benefits, mainly in preventing or treating gastrointestinal pathology. This study investigated the antimicrobial capacity of yeasts, Saccharomyces cerevisiae and Pichia kluyveri, previously isolated from fermented foods (indigenous beverage, kefir and cocoa) against the adhesion of foodborne pathogens to Caco-2 cells. Co-aggregation of yeasts with pathogens and were evaluated by quantitative analysis and using scanning electron and laser confocal microscopies. All yeasts strains were able to co-aggregate with the tested pathogens, however, this activity was strain-dependent. The inhibition tests showed that the adhesion of Escherichia coli EPEC, Listeria monocytogenes and Salmonella Enteritidis to Caco-2 was reduced by all the yeasts studied. Most of the evaluated yeasts showed inhibition rates equal to or greater than the commercial probiotic Saccharomyces boulardii. The yeasts were able to reduce up to 50% of the bacterial infection, as observed for CCMA0615 towards EPEC in exclusion assay; CCMA0731, CCMA0732 and CCMA0615 towards L. monocytogenes in exclusion and competition assays; and CCMA0731 in exclusion and CCMA0731, CCMA0732, CCMA0615 in competition assay towards S. Enteritidis. No antimicrobial compounds were produced by the yeasts, showing that competition for nutrients and/or receptors in the intestinal mucosa was the mechanism to bacterial inhibition., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2020. Published by Elsevier Ltd.)

Although infrequent in our laboratory, growth of bacterial colonies has been observed on top of the purified cultures of yeasts. In this study, the likelihood of bacterial excision from yeast under aging and starvation stresses was assessed using 10 gastric and 10 food-borne yeasts. Yeasts were identified as members of Candida or Saccharomyces genus by amplification and sequencing of D1/D2 region of 26S rDNA. For aging stress, yeasts were cultured on brain heart infusion agar supplemented with sheep blood and incubated at 30 °C for 3-4 weeks. For starvation stress, yeasts were inoculated into distilled water and incubated similarly. After seven days, starved yeasts were cultured on yeast extract glucose agar, incubated similarly and examined daily for appearance of bacterial colonies on top of the yeast's growth. Outgrowth of excised bacteria was observed on top of the cultures of 4 yeasts (Y1, Y3, Y13 and Y18) after 3-7 days. The excised bacteria (B1, B3, B13 and B18) were isolated and identified at the genus level according to their biochemical characteristics as well as amplification and sequencing of 16S rDNA. B1 (Arthrobacter) were excised from Y1 (Candida albicans) upon aging and B3 (Staphylococcus), B13 (Cellulomonas) and B18 (Staphylococcus) were excised from their respective yeasts; Y3 (Candida tropicalis), Y13 (Saccharomyces cerevisiae) and Y18 (Candida glabrata) upon starvation. DNA from yeasts was used for detection of 16S rDNA of their intracellular bacteria and sequencing. Amplified products from yeasts showed sequence similarity to those of excised bacteria. Under normal conditions, yeast exerts tight control on multiplication of its intracellular bacteria. However, upon aging and starvation the control is no longer effective and bacterial outgrowth occurs. Unlimited multiplication of excised bacteria might provide yeast with plenty of food in close vicinity. This could be an evolutionary dialogue between yeast and bacteria that ensures the survival of both partners., Competing Interests: Declaration of Competing Interest None., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Saccharomyces cerevisiae is an emerging pathogen within the immunocompromised. We present a 4-year-old boy with acute lymphoblastic leukemia presenting with polymerase chain reaction-confirmed hepatosplenic S. cerevisiae infection and significant immune reconstitution symptoms. We explore the challenges of monitoring treatment efficacy using C-Reactive protein, β-D-glucan, and imaging and the administration of chemotherapy alongside antifungals and steroids for control of immune reconstitution syndrome.

The use of appropriate yeast strains allows to better control the fermentation during beverage production. Bee products, especially of stingless bees, are poorly explored as sources of fermenting microorganisms. In this work, yeasts were isolated from honey and pollen from Tetragonisca angustula (Jataí), Nannotrigona testaceicornis (Iraí), Frieseomelitta varia (Marmelada), and honey of Apis mellifera bees and screened according to morphology, growth, and alcohol production. Bee products showed to be potential sources of fermenting microorganisms. From 55 isolates, one was identified as Papiliotrema flavescens, two Rhodotorula mucilaginosa, five Saccharomyces cerevisiae, and nine Starmerella meliponinorum. The S. cerevisiae strains were able to produce ethanol and glycerol at pH 4.0-8.0 and temperature of 10-30 °C, with low or none production of undesirable compounds, such as acetic acid and methanol. These strains are suitable for the production of bioethanol and alcoholic beverages due to their high ethanol production, similar or superior to the commercial strain, and in a broad range of conditions like as 50% (m/v) glucose, 10% (v/v) ethanol, or 500 mg L -1 of sodium metabisulfite.

In most yeast-driven biotechnological applications, biomass is separated from the aqueous phase after fermentation or production has finished. During winemaking, yeasts are removed after fermentation by racking, filtration, or centrifugation, which add costs to the overall process and may reduce product yield. Theoretically, clarification and filtration can be aided through use of yeast strains that form flocs due to cell-cell binding, a process known as flocculation. However, because early flocculation can cause stuck/sluggish fermentations, this phenotype is not common amongst commercially available wine yeasts. In this study we sought to identify wine strains that exhibit late-fermentation flocculant behaviour using two complementary approaches; a high-throughput sedimentation rate assay of individual strains and a competitive sedimentation assay using a barcoded yeast collection. Amongst 103 wine strains, several exhibited strong sedimentation at the end of the wine fermentation process under various environmental conditions. Two of these strains, AWRI1688 and AWRI1759, were further characterised during red winemaking trials. Shiraz wines produced with both strains displayed improved filtration-related properties. AWRI1759 produced wines with greater filterability, whereas AWRI1688 enabled the recovery of larger wine volumes after racking. Thus, this study demonstrates the effective use of sedimentation screening assays to identify wine yeasts with practical winemaking applications.

The lactic acid bacteria (LAB) and yeast strains with phytate degrading ability were isolated from Iranian traditional sourdough, and based on the acid and bile tolerance, three LAB and three yeast strains were selected and molecularly identified. In this study, baker's yeast (Saccharomyces cerevisiae) was considered as a positive control strain to investigate the nutritional and technological properties of the isolated strains. All of the identified microorganisms were characterized based on additional probiotic properties and were evaluated for nutritional and technological characteristics. The functional features are associated with degradation of phytate, antioxidant capacity, exopolysaccharides, phenolic compound content and in vitro starch digestion. Among all the tested strains the highest amount of phytase production capacity (1.64 Unit/ml) and lowest phytate content (17.49 mg/5 g) belonged to Kluyveromyces marxianus. According to the results, the bread prepared by using Kluyveromyces aestuarii possessed the highest porosity percentage (70.43%), and the lowest hardness (508.71 g)., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Deionized water and glucose without yeast and with yeast ( Saccharomyces cerevisiae ) of optical density OD 600 that ranges from 4 to 16 has been put in the ring electrode region of six different types of impedance biochips and impedance has been measured in dependence on the added volume (20, 21, 22, 23, 24, 25 µL). The measured impedance of two out of the six types of biochips is strongly sensitive to the addition of both liquid without yeast and liquid with yeast and modelled impedance reveals a linear relationship between the impedance model parameters and yeast concentration. The presented biochips allow for continuous impedance measurements without interrupting the cultivation of the yeast. A multiparameter fit of the impedance model parameters allows for determining the concentration of yeast (c y ) in the range from c y = 3.3 × 10 7 to c y = 17 × 10 7 cells/mL. This work shows that independent on the liquid, i.e., DI water or glucose, the impedance model parameters of the two most sensitive types of biochips with liquid without yeast and with liquid with yeast are clearly distinguishable for the two most sensitive types of biochips.

High glycosidase-producing strains of Aspergillus luchuensis were isolated from 2-deoxyglucose (2-DG) resistant mutants. α-Amylase, exo-α-1,4-glucosidase, β-glucosidase and β-xylosidase activity in the mutants was ~3, ~2, ~4 and ~2.5 times higher than the parental strain RIB2604 on koji-making conditions, respectively. Citric acid production and mycelia growth of the mutants, however, approximately halved to that of the parent. Compared to the parent, the alcohol yield from rice and sweet potato shochu mash of the mutant increased ~5.7% and 3.0%, respectively. The mutant strains showed significantly low glucose assimilability despite the fructose one was almost normal, and they had a single missense or nonsense mutation in the glucokinase gene glkA . The recombinant strain that was introduced at one of the mutations, glkA Q300K, demonstrated similar but not identical phenotypes to the mutant strain. This result indicates that glkA Q300K is one of the major mutations in 2-DG resistant strains.

The yeast Saccharomyces cerevisiae var. boulardii is a biotherapeutic agent used for the prevention and treatment of several gastrointestinal diseases. We report a case of fungemia in a patient suffering from Clostridiumdifficile-associated diarrhea and treated with metronidazole and a probiotic containing S. cerevisiae var. boulardii. The yeasts isolated from the blood culture and capsules were identified by MALDI-TOF MS and API ID 32 C as S. cerevisiae, and showed the same appearance and color on CHROMAgar Candida. Treatment with fluconazole 400mg/day was initiated and the probiotic was stopped. The patient was discharged from hospital in good condition and was referred to a rehabilitation center. We suggest that the potential benefit of S. cerevisiae var. boulardii should be accurately evaluated, especially in elderly patients. Moreover, all physicians should be trained in the use of probiotic agents and enquire whether the use probiotics was included in the patients'medical histories., (Copyright © 2019 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

The world is facing a big problem of non-communicable diseases, such as obesity, cardiovascular disease and diabetes. An excessive sugar consumption is considered as a main factor, which triggers these diseases. The two main sources of sugar in processed products on the market are sugar-sweetened beverages and sweet bakery products. Sugar reduction is challenging, especially in baked goods, since it interacts significantly with all ingredients. These interactions cause an increase in gelatinization temperature, a delay in gluten network development, an increase or decrease in yeast activity depending on the sugar concentration, as well as an enhancement of emulsification. Reflecting the molecular interactions on the product quality characteristics of different types of baked goods, sugar also contributes to browning reactions and extension of microbial shelf life. During cake preparation, sugar supports the batter aeration which results in the typical soft cake crumb. Furthermore, it contributes to the spreading process of biscuits during baking and enhances surface cracking due to recrystallization. Sugar reduction requires the development of different strategies; Two well-known strategies are the replacement of added sugar by the combination of bulking agents and high-intensive sweeteners, or by sweet bulking ingredients, such as polyols. The in-situ production of polyols to enhance sweetness, and exopolysaccharides to improve texture, in a sourdough system shows high potential as sugar replacement. Lactobacillus sanfranciscensis, Leuconostoc mesenteroides and Leuconostoc citreum are high mannitol producing lactic acid bacteria (LAB) strains with yields of 70-98% and Leuconostoc oenos was found to produce erythritol. Furthermore, the yeast strain Candida milleri isolated from sourdough produces xylitol in the presence of xylose. Exopolysaccharides produced by LAB and/or yeasts are known to improve the texture and structure of bakery products and, thus, have high potential as natural functional ingredients to compensate quality loss in sweet bakery goods., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Cellular aging is best studied in the budding yeast Saccharomyces cerevisiae. As an example of a pleiotropic trait, yeast lifespan is influenced by hundreds of interconnected genes. However, no quantitative methods are currently available to infer system-level changes in gene networks during cellular aging., Results: We propose a parsimonious mathematical model of cellular aging based on stochastic gene interaction networks. This network model is made of only non-aging components: the strength of gene interactions declines with a constant mortality rate. Death of a cell occurs in the model when an essential node loses all of its interactions with other nodes, and is equivalent to the deletion of an essential gene. Stochasticity of gene interactions is modeled using a binomial distribution. We show that the exponential increase of mortality rate over time can emerge from this gene network model during the early stages of aging.We developed a maximal likelihood approach to estimate three lifespan-influencing network parameters from experimental lifespans: t 0 , the initial virtual age of the network system; n, the average lifespan-influencing interactions per essential node; and R, the initial mortality rate. We applied this model to yeast mutants with known effects on replicative lifespans. We found that deletion of SIR2, FOB1, and HXK2 considerably altered the initial virtual age but not the average lifespan-influencing interactions per essential node, suggesting that these mutations mainly influence the reliability of gene interactions but not the overall configurations of gene networks.We applied this model to investigate replicative lifespans of yeast natural isolates. We estimated that the average number of lifespan-influencing interactions per essential node is 7.0 (6.1-8) and the average estimated initial virtual age is 45.4 (30.6-74) cell divisions in these isolates. We also found that t 0 could potentially mediate the observed Strehler-Mildvan correlation in yeast natural isolates., Conclusions: Our theoretical model provides a parsimonious interpretation of experimental lifespan data from the perspective of gene networks. We hope that our work will stimulate more interest in developing network models to study aging as a pleiotropic trait.

Global outbreaks of drug-resistant fungi such as Candida auris are thought to be due at least in part to excessive use of antifungal drugs. Baker's yeast Saccharomyces cerevisiae has gained importance as an emerging opportunistic fungal pathogen that can cause infections in immunocompromised patients. Analyses of over 1000 S. cerevisiae isolates are providing rich resources to better understand how fungi can grow in human environments. A large percentage of clinical S. cerevisiae isolates are heterozygous across many nucleotide sites, and a significant proportion are of mixed ancestry and/or are aneuploid or polyploid. Such features potentially facilitate adaptation to new environments. These observations provide strong impetus for expanding genomic and molecular studies on clinical and wild isolates to understand the prevalence of genetic diversity and instability-generating mechanisms, and how they are selected for and maintained. Such work can also lead to the identification of new targets for antifungal drugs., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The variation in house dust mite microbial communities is important because various microorganisms modulate the production of allergens by their mite hosts and/or contaminate immunotherapeutic extracts. Temporal changes in mite microbiomes and the mite culture environment occurring at different stages of mite culture development are particularly understudied in this system. Here, we analyzed the dynamics of microbial communities during the culture growth of Dermatophagoides farinae. Changes in microbiomes were related to three key variables: the mite population density, microbial microcosm respiration and concentration of guanine (the mite nitrogenous waste metabolite). Mite populations exhibited the following phases: exponential growth, plateau and exponential decline. The intracellular bacterium Cardinium and the yeast Saccharomyces cerevisiae prevailed in the internal mite microbiomes, and the bacterium Lactobacillus fermentum was prevalent in the mite diet. The reduction in the mite population size during the late phases of culture development was related to the changes in their microbial profiles: the intracellular bacterium Cardinium was replaced by Staphylococcus, Oceanobacillus and Virgibacillus, and S. cerevisiae was replaced by the antagonistic fungi Aspergillus penicillioides and Candida. Increases in the guanine content were positively correlated with increases in the Staphylococcus and A. penicillioides profiles in the culture environment. Our results show that the mite microbiome exhibits strong, dynamic alterations in its profiles across different mite culture growth stages., (© FEMS 2019.)

Fungal adhesion is fundamental to processes ranging from infections to food production to bioengineering. Yet, robust, population-scale quantification methods for yeast surface adhesion are lacking. We developed a microfluidic assay to discriminate and separate genetically-related yeast strains based on adhesion strength, and to quantify effects of ionic strength and substrate hydrophobicity on adhesion. This approach will enable the rapid screening and fractionation of yeast based on adhesive properties for genetic protein engineering, anti-fouling surfaces, and a host of other applications.