In Vitro Probiotic Characterization of Yeasts with their Postbiotics' Antioxidant Activity and Biofilm Inhibition Capacity.

This study evaluated the in vitro probiotic potential and postbiotic properties of yeast strains isolated from traditional fermented foods, emphasizing antioxidant activity (AOA) and biofilm inhibition capacity (BIC). The yeasts were molecularly confirmed using start codon targeted polymorphisms as Kluyveromyces lactis (n = 17), Saccharomyces cerevisiae (n = 9), Pichia kudriavzevii (n = 6), P. fermentans (n = 4), Wickerhamomyces anomalus (n = 2), and Torulaspora delbrueckii (n = 1). The probiotic assessment of live cells included viability in simulated gastric and pancreatic juices, autoaggregation, hydrophobicity, and AOA, using S. boulardii MYA-796 as reference. Additionally, cell-free supernatants (CFS) were tested for AOA and BIC against Cronobacter sakazakii, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus. Several strains exhibited significantly higher in vitro probiotic characteristics compared to S. boulardii MYA-796 (P < 0.05), particularly in gastric and pancreatic survival, hydrophobicity, and AOA. Notably, CFS exhibited greater AOA than live cells and strong BIC, especially against L. monocytogenes and S. aureus. Multivariate analysis identified K. lactis TC11, S. cerevisiae M33T1-2, P. kudriavzevii S96, W. anomalus OB7Y1, and T. delbrueckii KY31 as having superior probiotic properties, attributed to enhanced gastric survival, autoaggregation, and AOA. CFS of S. cerevisiae M33T1-2 and T. delbrueckii KY31 demonstrated significant BIC, with over 60% inhibition across all tested pathogens.

Yeast polysaccharides: The environmentally friendly polysaccharides with broad application potentials.

Yeast cell wall (YCW) polysaccharides, including ß-glucans, mannans, chitins, and glycogens, can be extracted from the waste of beer industry. They are environmentally friendly, abundant, inexpensive raw materials, and have shown broad biological activities and application potentials. The exploitation of yeast polysaccharides is of great importance for environmental protection and resource utilization. This paper reviews the structural features and preparation of YCW polysaccharides. The solubility and emulsification of yeast polysaccharides and the properties of binding metal ions are presented. In addition, biological activities such as blood glucose and lipid lowering, immune regulation, antioxidant, promotion of intestinal health, and promotion of wound healing are proposed, highlighting the beneficial effects of yeast polysaccharides on human health. Through modification, the physical and chemical properties of yeast polysaccharides are changed, which emphasizes the promotion of their biological activities and properties. In addition, the food applications of yeast polysaccharides, including the food packaging film, emulsifier, thickening agent, and fat alternatives, are focused and discussed.

The Role of Indigenous Yeasts in Shaping the Chemical and Sensory Profiles of Wine: Effects of Different Strains and Varieties.

The microbial terroir is an indispensable part of the terroir panorama, and can improve wine quality with special characteristics. In this study, eight autochthonous yeasts (Saccharomyces cerevisiae), selected in Huailai country, China, were trailed in small-scale and pilot fermentations for both white (Riesling and Sémillon) and red (Cabernet Sauvignon and Syrah) wines and evaluated by GC-MS analysis and the rate-all-that-apply (RATA) method. Compared to commercial yeast strains, the indigenous yeasts were able to produce higher concentrations of ethyl esters and fatty acid ethyl esters, and higher alcohol, resulting in higher odor activity values of fruity, floral attributes. Marked varietal effects were observed in the pilot fermentation, but yeast strains exerted a noticeable impact in modulating wine aroma and sensory profile. Overall, indigenous yeast could produce more preferred aroma compounds and sensory characteristics for both white and red wines, demonstrating the potential for improving wine quality and regional characteristics.

Neonatal Fungemia by Non-Candida Rare Opportunistic Yeasts: A Systematic Review of Literature.

Fungal colonization poses a significant risk for neonates, leading to invasive infections such as fungemia. While Candida species are the most commonly identified pathogens, other rare yeasts are increasingly reported, complicating diagnosis and treatment due to limited data on antifungal pharmacokinetics. These emerging yeasts, often opportunistic, underscore the critical need for early diagnosis and targeted therapy in neonates. This systematic review aims to comprehensively analyze all published cases of neonatal fungemia caused by rare opportunistic yeasts, examining geographical distribution, species involved, risk factors, treatment approaches, and outcomes. Searching two databases (PubMed and SCOPUS), 89 relevant studies with a total of 342 cases were identified in the 42-year period; 62% of the cases occurred in Asia. Pichia anomala (31%), Kodamaea ohmeri (16%) and Malassezia furfur (15%) dominated. Low birth weight, the use of central catheters, prematurity, and the use of antibiotics were the main risk factors (98%, 76%, 66%, and 65%, respectively). 22% of the cases had a fatal outcome (80% in Asia). The highest mortality rates were reported in Trichosporon beigelii and Trichosporon asahii cases, followed by Dirkmeia churashimamensis cases (80%, 71%, and 42% respectively). Low birth weight, the use of central catheters, the use of antibiotics, and prematurity were the main risk factors in fatal cases (84%, 74%, 70%, and 67%, respectively). 38% of the neonates received fluconazole for treatment but 46% of them, died. Moreover, the rare yeasts of this review showed high MICs to fluconazole and this should be taken into account when planning prophylactic or therapeutic strategies with this drug. In conclusion, neonatal fungemia by rare yeasts is a life-threatening and difficult-to-treat infection, often underestimated and misdiagnosed.

The bacterial and yeast microbiota in livestock forages in Hungary.

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.

Effects of yeast-enriched functionalized canola meal supplementation on apparent total tract macronutrient digestibility and fecal characteristics, fecal microbiota, and immune function of healthy adult dogs.

Brewer's dried yeast has a high nutritional value and has long been utilized by the animal feed industry as a source of protein, B-complex vitamins, and minerals. Brewer's dried yeast is also rich in bioactive compounds and may thereby be used as a functional ingredient, providing benefits beyond that of its nutrient content. Canola meal is a high-fiber ingredient that also has unique properties, especially when it is wetted and dried using a proprietary drying system that creates a "functionalized" canola meal. The objective of this experiment was to evaluate the effects of a yeast-enriched functionalized canola meal (FCM) on apparent total tract digestibility (ATTD) and the fecal quality, metabolite concentrations, and microbiota populations, and immune function of healthy adult dogs. Twelve adult female beagles (body weight [BW] = 7.6 ±â€…0.7 kg; age = 5.8 ±â€…1.3) were used in a replicated 4 × 4 Latin square design with 28-d periods. Each experimental period consisted of a 22-d adaptation phase, 5 d of total and fresh fecal collection, and blood collection on the last day. To start, all dogs were fed a basal diet to maintain BW for 14 d. Following fecal and blood collections at baseline (-1 d) to confirm health status, experimental periods began testing the following dietary treatments using a Latin square design experiment: 1) FCM only (no yeast inclusion), 2) FCM + low yeast dose, 3) FCM + medium yeast dose, and 4) FCM + high yeast dose. All treatments were top-dressed onto the basal diet at a rate estimated to be 1% of daily intake (as-is basis). Statistical analysis was performed using the PROC MIXED procedure of SAS with the main effect of treatment and the random effect of dog. Significance was declared at P ≤ 0.05, and trends reported if 0.05 < P ≤ 0.10. Supplementation with yeast-enriched FCM had no significant effect on the ATTD of macronutrients or energy or the fecal characteristics, metabolite concentrations, and microbiota populations of dogs. Additionally, no significant differences were observed in circulating immune cell counts or response to Toll-like receptor agonists among treatments. Our results suggest that the yeast-enriched FCM could be included in canine diets without negatively affecting stool quality, fecal metabolite concentrations, or ATTD. Further research is necessary to determine the effective dose of yeast-enriched FCM, potential mechanisms of action, and other potential implications it has on canine health.

Brewer's dried yeast has a high nutritional value and has long been utilized by the animal feed industry as a source of protein, B-complex vitamins, and minerals. Because yeast is rich in polyphenols, mannanoligosaccharides, and ß-glucans, it may also be used as a functional ingredient, providing benefits beyond that of its nutrient content. Canola meal is a high-fiber ingredient that also has unique properties, especially when it is wetted and dried using a proprietary drying system that creates a "functionalized" canola meal. In this experiment, functionalized canola meal was enriched with different levels of brewer's dried yeast, then fed to dogs to evaluate its effects on nutrient digestibility, stool characteristics, microbiota populations, and immunity. The results showed that the yeast-enriched functionalized canola meal had no impact on nutrient digestibility or fecal characteristics. Additionally, no differences were observed in immune cell counts or immune cell activation after challenge. In conclusion, yeast-enriched functionalized canola meal may be supplemented in canine diets without negatively affecting stool quality, fecal metabolite concentrations, or digestibility. Further research is necessary to determine the effective dose of yeast-enriched functionalized canola meal, potential mechanisms of action, and other potential implications it has on canine health.

Mechanistic divergences of endocytic clathrin-coated vesicle formation in mammals, yeasts and plants.

Clathrin-coated vesicles (CCVs), generated by clathrin-mediated endocytosis (CME), are essential eukaryotic trafficking organelles that transport extracellular and plasma membrane-bound materials into the cell. In this Review, we explore mechanisms of CME in mammals, yeasts and plants, and highlight recent advances in the characterization of endocytosis in plants. Plants separated from mammals and yeast over 1.5 billion years ago, and plant cells have distinct biophysical parameters that can influence CME, such as extreme turgor pressure. Plants can therefore provide a wider perspective on fundamental processes in eukaryotic cells. We compare key mechanisms that drive CCV formation and explore what these mechanisms might reveal about the core principles of endocytosis across the tree of life. Fascinatingly, CME in plants appears to more closely resemble that in mammalian cells than that in yeasts, despite plants being evolutionarily further from mammals than yeast. Endocytic initiation appears to be highly conserved across these three systems, requiring similar protein domains and regulatory processes. Clathrin coat proteins and their honeycomb lattice structures are also highly conserved. However, major differences are found in membrane-bending mechanisms. Unlike in mammals or yeast, plant endocytosis occurs independently of actin, highlighting that mechanistic assumptions about CME across different systems should be made with caution.

Recent Advances in the Biosynthesis of Mid- and Long-Chain Dicarboxylic Acids Using Terminally Oxidizing Unconventional Yeasts.

As high-performance monomers for the manufacture of polyamide materials, mid- and long-chain dicarboxylic acids (DCAi, i ≥ 6) have received extensive attention from researchers. Biosynthesis is gradually replacing chemical synthesis due to its outstanding advantages in the industrial production of mid- and long-chain dicarboxylic acids, which is mostly achieved by using the strong terminal oxidation ability of nonmodel microorganisms such as Candida tropicalis to oxidize hydrophobic substrates such as alkanes. Here, we first summarize the metabolic pathways of oxidative alkane conversion into dicarboxylic acid by terminally oxidizing unconventional yeasts and the corresponding metabolic engineering strategies. Then, we summarize the research progress on new dicarboxylic acid production processes. Finally, the future development directions in the biosynthesis of mid- and long-chain dicarboxylic acids are prospected from synthetic biology and bioprocess engineering, which can also provide a reference for the synthesis of other biobased chemicals and biomaterials.

Polysaccharides from bile Arisaema exert an antipyretic effect on yeast-induced fever rats through regulating gut microbiota and metabolic profiling.

In our previous study, bile Arisaema was elucidated to have a significant anti-febrile effect, but the pharmacodynamic material basis of this effect remains uncertain. Herein, we found that the soluble polysaccharide fraction from bile Arisaema presents a remarkable antipyretic effect through balancing the gut microbiota and regulating metabolic profiling. Bile Arisaema polysaccharide (BAP) was characterized for its monosaccharide composition with arabinose, galactose, glucose, mannose and xylose (0.028:0.072:0.821:0.05:0.029, molar ratios) and amino acid composition with arginine, threonine, alanine, glycine, serine, proline and tyrosine (109.33, 135.78, 7.22, 8.86, 21.07, 4.96, 12.31 µg/mg). A total of 50 peptides were identified from BAP using Ltq-Orbitrap MS/MS. The oral administration of 100 mg/kg BAP significantly increased the antipyretic effect in yeast-induced fever rats by comparing the rectal temperature. Mechanistically, the inflammation and disorders of neurotransmitters caused by fever were improved by treatment with BAP. The western blotting results suggested that BAP could suppress fever-induced inflammation by down-regulating the NF-κB/TLR4/MyD88 signaling pathway. We also demonstrated that BAP affects lipid metabolism, amino acid metabolism and carbohydrate metabolism and balances the gut microbiota. In summary, the present study provides a crucial foundation for determining polysaccharide activity in bile Arisaema and further investigating the underlying mechanism of action.

European farmhouse brewing yeasts form a distinct genetic group.

The brewing industry is constantly evolving, driven by the quest for novel flavours and fermentation characteristics that cater to evolving consumer preferences. This study explores the genetic and phenotypic diversity of European farmhouse yeasts, traditionally used in rural brewing practices and maintained outside of pure culture industrial yeast selection. We isolated landrace brewing yeast strains from diverse geographical locations across Europe, including Norway, Lithuania, Latvia, and Russia, and also included African farmhouse brewing strains from Ghana. Our genomic analysis using long-read and short-read whole genome sequencing uncovered a genetically distinct group that diverges from industrial brewing yeasts. This group, which is closely related to ale brewing strains, is preliminarily named the 'European Farmhouse' group and shows greater predicted admixture from Asian fermentation strains. Through genomic and phenotypic analyses, including flavour metabolite analysis via headspace gas chromatography-mass spectrometry, sugar metabolite analysis via high-performance liquid chromatography, and wort fermentation analysis, we found a broad spectrum of fermentation capabilities, from rapid and efficient fermentation to unique aroma and flavour compound profiles, potentially offering novel traits for brewing applications. This study highlights the importance of preservation of brewing cultural heritage knowledge and resources including yeast cultures. KEY POINTS: • A large set of geographically diverse farmhouse brewing strains were characterized • Norwegian and Baltic farmhouse brewing strains form a distinct genetic group • Farmhouse strains show considerable diversity in fermentation and flavour formation.

Kombucha with yam: Comprehensive biochemical, microbiological, and sensory characteristics.

Consumer demand for functional foods has increased, helping to popularize and increase the consumption of Kombucha. Other substrates have been used together with tea to improve the functional and sensory properties of the beverage. Thus, this study evaluated the comprehensive biochemical, microbiological, and sensory characteristics of kombuchas fermented with green tea (Camellia sinensis) and different concentrations of yam (0, 10, and 20 % w/v). Based on pre-tests to detect the best concentration of yam in the beverage (10, 20, 30, and 40 %) and fermentation time (5, 7, and 14 days),the concentrations of 10 and 20 % of yam and five days of fermentation were selected through pH, °Brix, and sensory analysis. During the kombucha fermentation, there was a decrease in °Brix and pH. Sucrose, glucose, fructose, citric, and succinic acids were related to the beginning of fermentation, and lactic and acetic acids were more related to the end of fermentation in the treatment containing 20 % yam. The fermentation time did not change the color of the kombucha. Fatty acids, phenols, terpenoids, and alcohols were the volatile groups with the most compounds identified. Only two yeast genera were identified (Brettanomyces bruxellensis and Pichia membranifaciens), and bacteria of the genera Acetobacter, Lactobacillus, Pantoea, Pseudomonas, Azospirillum, and Enterobacter. The beverage control showed less turbidity and more clear. The fruity descriptor was more perceived in treatments with yam. However, the perception of the apple descriptor decreases as the yam concentration increases. The yam's concentration alters the kombucha's microbiota and sensory characteristics, mainly appearance and acidity. Kombucha fermentation using yam extract is viable, and the product is sensorially accepted. However, technological improvements, such as yam flour, could be made mainly for appearance and taste attributes.

Biodiversity and probiotic potential of yeasts isolated from sumbawa horse milk.

BACKGROUND: The microbial composition of Sumbawa Horse Milk is influenced by various factors, including environmental elements that encompass geographical location, climate, and conditions specific to Sumbawa. This study aimed to determine the biodiversity and genetic diversity of the microbiome of Sumbawa Horse Milk, with an emphasis on yeast. METHODS: The diversity and group of yeast isolates were evaluated by the sequence-related amplified polymorphism (SRAP) method using ME2F-EM15R (1) and ME2F-EM12R (2) primers. Molecular identification using 18 S rRNA primers was then carried out on nine selected isolates (K_21, K_31, K_42, K_45, K_1, K_6, K_8, K_17, and K_19) to determine the type of yeast. Probiotic candidate tests were carried out on three isolates, namely K_1, K_6 and K_8. RESULTS: Analysis with NTSYS software on the SRAP results using Primer 1 revealed the presence of two major groups, where Group I was exclusively comprised of K_45 isolate, whereas the other isolates belonged to Group II. On the other hand, analysis with NTSYS software on the SRAP analysis with Primer 2 also showed two major groups with different compositions. Group I consisted of isolates K_39, 38, 37, 36, 35, 34, 33, 31, 29, 28, 27, 26, 25, 24, 23, 22, and 21, while the remaining isolates belonged to Group II. Results of 18 S rRNA analysis demonstrated that K_17 and K_19 had 99.8 and 100% similarity, respectively, and identified as Candida humilis. K_21, K_31, and K_45 were identified as having a 100% similarity to Clavispora lusitaniae, while K_42 had a 99.8% similarity to Candida parapsilosis. Three isolates were identified as belonging to the genus Ogataea, namely Ogataea polymorpha (K_6 and K_8) and Ogataea siamensis (K_1) with similarity of 100% and 99.8%, respectively. CONCLUSIONS: These findings suggest that the three yeast have potential as probiotics.

Yeast Proteins: Proteomics, Extraction, Modification, Functional Characterization, and Structure: A Review.

Proteins are essential for human tissues and organs, and they require adequate intake for normal physiological functions. With a growing global population, protein demand rises annually. Traditional animal and plant protein sources rely heavily on land and water, making it difficult to meet the increasing demand. The high protein content of yeast and the complete range of amino acids in yeast proteins make it a high-quality source of supplemental protein. Screening of high-protein yeast strains using proteomics is essential to increase the value of yeast protein resources and to promote the yeast protein industry. However, current yeast extraction methods are mainly alkaline solubilization and acid precipitation; therefore, it is necessary to develop more efficient and environmentally friendly techniques. In addition, the functional properties of yeast proteins limit their application in the food industry. To improve these properties, methods must be selected to modify the secondary and tertiary structures of yeast proteins. This paper explores how proteomic analysis can be used to identify nutrient-rich yeast strains, compares the process of preparing yeast proteins, and investigates how modification methods affect the function and structure of yeast proteins. It provides a theoretical basis for solving the problem of inadequate protein intake in China and explores future prospects.

Conventional and Unconventional Protein Secretion in Yeast and Animal Cells.

Protein secretion mediated by the secretory transport pathway is a sophisticated and highly regulated cellular process in eukaryotic cells. In the conventional secretory transport pathway, newly synthesized proteins pass through several endomembrane compartments to reach their destinations. This transport occurs via small, membrane-enclosed vesicles. To ensure the fidelity of trafficking, eukaryotic cells employ elaborate molecular machinery to accurately sort newly synthesized proteins into specific transport vesicles and precisely deliver them to respective acceptor compartments. Leaderless cargo proteins, lacking a signal peptide, follow an unconventional secretory pathway. This review encompasses the molecular machinery regulating both conventional and unconventional protein secretion in yeast and animal cells.

Effects of Fermentation with Kombucha Symbiotic Culture of Bacteria and Yeasts on Antioxidant Activities, Bioactive Compounds and Sensory Indicators of Rhodiola rosea and Salvia miltiorrhiza Beverages.

Kombucha is a well-known fermented beverage traditionally made from black tea infusion. Recent studies have focused on finding alternative materials to create novel kombucha beverages with various health benefits. In this study, we prepared and evaluated two novel kombucha beverages using Rhodiola rosea and Salvia miltiorrhiza as materials. The effects of fermentation with the residue of these plants on the kombucha were also investigated. The antioxidant activities, total phenolic contents, and concentrations of the bioactive compounds of the kombucha beverages were determined by the Trolox equivalent antioxidant capacity test, ferric-reducing antioxidant power test, Folin-Ciocalteu method, and high-performance liquid chromatography, respectively. The results revealed that the kombucha beverages made with Rhodiola rosea and Salvia miltiorrhiza had strong antioxidant capacities and abundant phenolic contents. Additionally, the kombucha fermented with Rhodiola rosea residue had higher FRAP, TEAC and TPC values than that fermented without residue. On the other hand, the Salvia miltiorrhiza kombucha fermented with residue had similar FRAP and TEAC values but lower TPC values compared to that fermented without residue. The correlation analysis showed that gallic acid, salidroside, and tyrosol were responsible for the antioxidant abilities and total phenolic contents of the Rhodiola rosea kombucha, and salvianolic acid A and salvianolic acid B contributed to the antioxidant abilities of the Salvia miltiorrhiza kombucha. Furthermore, the kombucha fermented with Rhodiola rosea residue had the highest sensory scores among the kombucha beverages studied. These findings suggest that Rhodiola rosea and Salvia miltiorrhiza are suitable for making novel kombucha beverages with strong antioxidant abilities and abundant phenolic contents, which can be used in preventing and managing oxidative stress-related diseases.

Using Extracted Sugars from Spoiled Date Fruits as a Sustainable Feedstock for Ethanol Production by New Yeast Isolates.

This study focuses on investigating sugar recovery from spoiled date fruits (SDF) for sustainable ethanol production using newly isolated yeasts. Upon their isolation from different food products, yeast strains were identified through PCR amplification of the D1/D2 region and subsequent comparison with the GenBank database, confirming isolates KKU30, KKU32, and KKU33 as Saccharomyces cerevisiae; KKU21 as Zygosaccharomyces rouxii; and KKU35m as Meyerozyma guilliermondii. Optimization of sugar extraction from SDF pulp employed response surface methodology (RSM), varying solid loading (20-40%), temperature (20-40 °C), and extraction time (10-30 min). Linear models for sugar concentration (R1) and extraction efficiency (R2) showed relatively high R2 values, indicating a good model fit. Statistical analysis revealed significant effects of temperature and extraction time on extraction efficiency. The results of batch ethanol production from SDF extracts using mono-cultures indicated varying consumption rates of sugars, biomass production, and ethanol yields among strains. Notably, S. cerevisiae strains exhibited rapid sugar consumption and high ethanol productivity, outperforming Z. rouxii and M. guilliermondii, and they were selected for scaling up the process at fed-batch mode in a co-culture. Co-cultivation resulted in complete sugar consumption and higher ethanol yields compared to mono-cultures, whereas the ethanol titer reached 46.8 ± 0.2 g/L.

Exploring yeast biodiversity and process conditions for optimizing ethylene glycol conversion into glycolic acid.

Plastics have become an indispensable material in many fields of human activities, with production increasing every year; however, most of the plastic waste is still incinerated or landfilled, and only 10% of the new plastic is recycled even once. Among all plastics, polyethylene terephthalate (PET) is the most produced polyester worldwide; ethylene glycol (EG) is one of the two monomers released by the biorecycling of PET. While most research focuses on bacterial EG metabolism, this work reports the ability of Saccharomyces cerevisiae and nine other common laboratory yeast species not only to consume EG, but also to produce glycolic acid (GA) as the main by-product. A two-step bioconversion of EG to GA by S. cerevisiae was optimized by a design of experiment approach, obtaining 4.51 ± 0.12 g l-1 of GA with a conversion of 94.25 ± 1.74% from 6.21 ± 0.04 g l-1 EG. To improve the titer, screening of yeast biodiversity identified Scheffersomyces stipitis as the best GA producer, obtaining 23.79 ± 1.19 g l-1 of GA (yield 76.68%) in bioreactor fermentation, with a single-step bioprocess. Our findings contribute in laying the ground for EG upcycling strategies with yeasts.

Functional potential of a new plant-based fermented beverage: Benefits through non-conventional probiotic yeasts and antioxidant properties.

Functional foods represent one of the fastest-growing, newer food category, and plant sources with functional properties are increasingly used as analogues of fermented milk-based derivatives. In this study, blended wort-rooibos beverages fermented with probiotic yeasts are proposed for the first time. Benefits of functional, non-conventional Lachancea thermotolerans (Lt101), Kazachstania unispora (Kum3-B3), Meyerozyma guilliermondii (Mg112), Meyerozyma caribbica (Mc58) and Debaryomyces hansenii (Dh36) yeast strains and the content of bioactive metabolites were evaluated. Viability tests on the probiotic yeasts confirmed previous results obtained in other matrices. The functional footprint of probiotic yeasts Lt101, Mg112 and Dh36 was confirmed by a balanced nutritional profile of the final drinks, also supported by aromatic and sensory analyses. In vitro estimated glycaemic index ranged between 77 % and 87 % without any influence on glycaemic response. Strains Dh36, Mc58, Kum3-B3 and Mg112 showed high antioxidant capacity and high total phenolic content, supporting the health promoting effect of the beverages.

Molecular analysis of cutaneous yeast isolates in the mycobiota of children with atopic dermatitis.

The skin of patients with atopic dermatitis (AD) has a greater diversity of mycobiota. An observational, prospective, cross-sectional, analytical, and comparative study was conducted involving 80 patients with AD Group (ADG) and 50 individuals without AD (wADG) in a tertiary hospital in Brazil. Skin scale samples were collected from the frontal, cervical, fossae cubital, and popliteal regions and identified using molecular biology techniques. The results showed that 47.5% of ADG had identified yeasts compared to 0% of wADG (P < .001). The yeasts Rhodotorula mucilaginosa and Candida parapsilosis were the most abundant. The probability of colonization increased with age, showing values of 40% at 60 months and 80% at 220 months (P = .09). The cervical region (12.5%) was colonized to the greatest extent. Our findings revealed that positive mycology was not more probable when the scoring of atopic dermatitis or eczema area and severity index value increased (P = .23 and .53, respectively). The results showed that the sex, age, and different population types directly affected the composition of the mycobiota in the population analyzed. A higher frequency of colonization and greater diversity of yeast species were detected in the cutaneous mycobiota of children with AD.

Atopic dermatitis (AD) is a skin disease that can be colonized by microorganisms. We evaluated patients with and without the disease and found a higher frequency of colonization by Rhodotorula mucilaginosa and Candida parapsilosis on the skin of children with AD.

Yeasts, arthropods, and environmental matrix: a triad to disentangle the multi-level definition of biodiversity.

Our understanding of the spread of yeasts in natural ecosystems remains somewhat limited. The recent momentum of yeast ecology research has unveiled novel habitats and vectors that, alongside human activities, impact yeast communities in their natural environments. Yeasts, as non-airborne microorganisms, rely on animal vectors, predominantly insects. However, the overlooked actor in this interplay is the environmental matrix, a player potentially influencing yeast populations and their vectors. This study aims to delve deeper into the intricate, multi-layered connections between yeast populations and ecosystems, focusing on the interactions between the attributes of the environmental matrix, arthropod diversity, and the mycobiota within a renowned yeast-inhabited framework: the vineyard. To investigate these relationships, we sampled both invertebrate and yeast diversity in six organic and conventional vineyards described in terms of management and landscape composition. We identified 80 different invertebrate taxa and isolated 170 yeast strains belonging to 18 species. Notably, new species-specific yeast-insect associations were observed, including the exclusive association between Candida orthopsilosis and Hymenoptera and between Metschnikowia pulcherrima and Coleoptera. These newly identified potential associations provide valuable insights into insect and yeast physiology, hence holding the promise of enhancing our understanding of yeast and arthropod ecology and their collective impact on overall ecosystem health.