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International Journal of Food... Feb 2022Oenococcus oeni is the main agent responsible for malolactic fermentation (MLF) in wine. This usually takes place in red wines after alcoholic fermentation (AF) carried...
Oenococcus oeni is the main agent responsible for malolactic fermentation (MLF) in wine. This usually takes place in red wines after alcoholic fermentation (AF) carried out by Saccharomyces cerevisiae. In recent years, there is an increasing interest in using non-Saccharomyces yeast, usually in combination with S. cerevisiae, to improve wine quality. Current studies report a stimulatory effect of non-Saccharomyces on MLF, generally related to a decrease in the inhibitor compounds found in wine. In this work, we followed a comparative multi-omics approach, including transcriptomic and proteomic analysis, to study the molecular adaptation of O. oeni in wines fermented with Torulaspora delbrueckii and Metschnikowia pulcherrima, two of the most frequently used non-Saccharomyces, in sequential inoculation with S. cerevisiae. We compared the results to the adaptation of O. oeni in S. cerevisiae wine to determine the main changes arising from the use of non-Saccharomyces. The duration of MLF was shortened when using non-Saccharomyces, to half the time with T. delbrueckii and to a quarter with M. pulcherrima. In this work, we observed for the first time how O. oeni responds at molecular level to the changes brought about by non-Saccharomyces. We showed a differential adaptation of O. oeni in the wines studied. In this regard, the main molecular functions affected were amino acid and carbohydrate transport and metabolism, from which peptide metabolism appeared as a key feature under wine-like conditions. We also showed that the abundance of Hsp20, a well-known stress protein, depended on the duration time. Thus, the use of non-Saccharomyces reduced the abundance of Hsp20, which could mean a less stressful wine-like condition for O. oeni.
Topics: Fermentation; Malates; Oenococcus; Proteomics; Saccharomyces cerevisiae; Wine
PubMed: 34844030
DOI: 10.1016/j.ijfoodmicro.2021.109490 -
Microorganisms Nov 2021Whey is the main byproduct of the dairy industry and contains sugars (lactose) and proteins (especially serum proteins and, at lesser extent, residual caseins), which...
Whey is the main byproduct of the dairy industry and contains sugars (lactose) and proteins (especially serum proteins and, at lesser extent, residual caseins), which can be valorized by the fermentative action of yeasts. In the present study, we characterized the spoilage yeast population inhabiting natural whey starter (NWS), the undefined starter culture of thermophilic lactic acid bacteria used in Parmigiano Reggiano (PR) cheesemaking, and evaluated thermotolerance, mating type, and the aptitude to produce ethanol and bioactive peptides from whey lactose and proteins, respectively, in a selected pool of strains. PCR-RFLP assay of ribosomal ITS regions and phylogenetic analysis of 26S rDNA D1/D2 domains showed that PR NWS yeast population consists of the well-documented , as well as of other species (, , and ), with multiple biotypes scored within each species as demonstrated by (GTG)-based MSP-PCR. Haploid and diploid strains were identified through genotyping, while thermotolerance assay allowed the selection of strains suitable to grow up to 48 °C. In whey fermentation trials, one thermotolerant strain was suitable to release ethanol with a fermentation efficiency of 86.5%, while another candidate was able to produce the highest amounts of both ethanol and bioactive peptides with potentially anti-hypertensive function. The present work demonstrated that PR NWS is a reservoir of ethanol and bioactive peptides producer yeasts, which can be exploited to valorize whey, in agreement with the principles of circularity and sustainability.
PubMed: 34835414
DOI: 10.3390/microorganisms9112288 -
Journal of Fungi (Basel, Switzerland) Nov 2021Fungal Oligopeptide Transporters (Fot) Fot1, Fot2 and Fot3 have been found in wine strains, but not in strains from other environments. In the wine strain EC1118, Fot1...
Fungal Oligopeptide Transporters (Fot) Fot1, Fot2 and Fot3 have been found in wine strains, but not in strains from other environments. In the wine strain EC1118, Fot1 and Fot2 are responsible for a broader range of oligopeptide utilization in comparison with strains not containing any Fot. This leads to better fermentation efficiency and an increased production of desirable organoleptic compounds in wine. Despite the benefits associated with Fot activity in within the wine environment, little is known about this family of transporters in yeast. The presence of Fot1, Fot2 and Fot3 in wine strains is due to horizontal gene transfer from the yeast , which harbors Fot2Tm, FotX and FotY proteins. Sequence analyses revealed that Fot family members have a high sequence identity in these yeast species. In this work, we aimed to further characterize the different Fot family members in terms of subcellular localization, gene expression in enological fermentation and substrate specificity. Using CRISPR/Cas9, we constructed wine strains containing each different Fot as the sole oligopeptide transporter to analyze their oligopeptide preferences by phenotype microarrays. The results of oligopeptide consumption show that Fot counterparts have different di-/tripeptide specificities, suggesting that punctual sequence divergence between genes can be crucial for substrate recognition, binding and transport activity. gene expression levels in different wine strains during enological fermentation, together with predicted binding motifs for transcriptional regulators in nitrogen metabolism, indicate that these transporters may be under the control of the Nitrogen Catabolite Repression (NCR) system. Finally, we demonstrated that Fot1 is located in the yeast plasma membrane. This work contributes to a better understanding of this family of oligopeptide transporters, which have demonstrated a key role in the utilization of oligopeptides by in enological fermentation.
PubMed: 34829250
DOI: 10.3390/jof7110963 -
Foods (Basel, Switzerland) Nov 2021Recent research has showed a breakthrough in investigating the effect of non- yeast on wine quality and sensory properties. The aim of this study was to compare the...
Recent research has showed a breakthrough in investigating the effect of non- yeast on wine quality and sensory properties. The aim of this study was to compare the influence of conventional yeast, , vs. that of the non- on the sensory profile of the white wine , and to establish if there are any differences in physical-chemical properties in regards to the applied yeast. Sample One was inoculated with both yeasts, while Sample Two was inoculated only with . The results indicated that a combination of and resulted in somewhat higher ethanol content in the finished wine. Sensory evaluation showed no significant discrepancies for any of the wines. Aspect and flavor were graded similarly, but the quality and intensity of the bouquet of Sample One was graded somewhat higher (14 and 6.6) than Sample Two (13.6 and 6.4). These findings open a very wide gate for future research in white wines.
PubMed: 34829033
DOI: 10.3390/foods10112752 -
Mycoscience 2021In this study, we isolated 741 wild budding yeast strains from the flowers of 45 rose cultivars growing in Fukuyama city, Hiroshima, Japan. Of these 741 strains, 21 were...
Isolation, identification, and characterization of wild budding yeasts from rose flowers in Fukuyama city, Hiroshima, Japan, and their application in bread and wine production.
In this study, we isolated 741 wild budding yeast strains from the flowers of 45 rose cultivars growing in Fukuyama city, Hiroshima, Japan. Of these 741 strains, 21 were found to have high fermentation abilities in yeast extract-peptone-dextrose (YPD) medium. Four of the 21 strains were able to ferment bread dough to make bread. These yeasts were identified as , , , and a sp. based on DNA sequences from the 26S rDNA D1/D2 regions. The CO production profiles of the bread dough generated by the rose yeasts were evaluated using a Fermograph. FRY2915 exhibited the highest fermentation capacity. Furthermore, FRY2915 was able to ferment grape juice to produce wine, yielding an alcohol concentration of more than 12%. The four rose yeasts isolated during this study have the potential to produce various types of unique fermented foods, thus enhancing the value of the microbiota associated with rose flowers.
PubMed: 37090174
DOI: 10.47371/mycosci.2021.10.003 -
Yeast (Chichester, England) Jan 2022Yeasts have broad importance as industrially and clinically relevant microbes and as powerful models for fundamental research, but we are only beginning to understand...
Yeasts have broad importance as industrially and clinically relevant microbes and as powerful models for fundamental research, but we are only beginning to understand the roles yeasts play in natural ecosystems. Yeast ecology is often more difficult to study compared to other, more abundant microbes, but growing collections of natural yeast isolates are beginning to shed light on fundamental ecological questions. Here, we used environmental sampling and isolation to assemble a dataset of 1962 isolates collected from throughout the contiguous United States of America (USA) and Alaska, which were then used to uncover geographic patterns, along with substrate and temperature associations among yeast taxa. We found some taxa, including the common yeasts Torulaspora delbrueckii and Saccharomyces paradoxus, to be repeatedly isolated from multiple sampled regions of the USA, and we classify these as broadly distributed cosmopolitan yeasts. A number of yeast taxon-substrate associations were identified, some of which were novel and some of which support previously reported associations. Further, we found a strong effect of isolation temperature on the phyla of yeasts recovered, as well as for many species. We speculate that substrate and isolation temperature associations reflect the ecological diversity of and niche partitioning by yeast taxa.
Topics: Ecosystem; Temperature; Torulaspora; Yeasts
PubMed: 34741351
DOI: 10.1002/yea.3679 -
Brazilian Journal of Microbiology :... Dec 2021Yeast isolates from flowers and fruits from a Brazilian forest were studied. The yeasts were identified at species and strain level by PCR-RFLP and PCR-RAPD,...
Yeast isolates from flowers and fruits from a Brazilian forest were studied. The yeasts were identified at species and strain level by PCR-RFLP and PCR-RAPD, respectively. The 46 isolated yeasts were classified into 11 different species belonging to the genera Candida, Diutina, Hanseniaspora, Meyerozyma, Pichia, Rhodotorula, and Torulaspora. A total of 20 different strains were found. In order to ascertain the probiotic potential, the resistance to gastrointestinal conditions, autoaggregation, and hydrophobicity assays were studied, along with the capacity to form biofilm. The results indicate that, although most of the strains presented better results than Saccharomyces boulardii (the only strain recognized as a probiotic yeast), four strains were the most promising, namely, Rhodotorula mucilaginosa 32, Meyerozyma caribbica 35, and Diutina rugosa 12 and 45, according to the Duncan test. Several biotechnological properties were evaluated. D. rugosa inhibited Dekkera bruxellensis. The assimilation or fermentation of seven sugars was tested, and only five of the yeasts did not show a capacity to assimilate any of the sugars under aerobic conditions. However, all strains were able to ferment at least one of the sugars under anaerobic conditions. As far as enzyme production is concerned, positive results were only found for the enzymes' amylase, pectinase, and protease. D. rugosa 42 and Hanseniaspora opuntiae 18, followed of Pichia kluyveri 26, showed high values for the production of melatonin. In conclusion, the results of this study show that several non-Saccharomyces present probiotic characteristics, and these have good potential for industrial applications in the food or biotechnology industries.
Topics: Biotechnology; Ecosystem; Fermentation; Fruit; Probiotics; Random Amplified Polymorphic DNA Technique; Sugars; Yeasts
PubMed: 34595728
DOI: 10.1007/s42770-021-00541-z -
Journal of Fungi (Basel, Switzerland) Aug 2021has attracted interest in recent years, especially due to its biotechnological potential, arising from its flavor- and aroma-enhancing properties when used in wine,... (Review)
Review
has attracted interest in recent years, especially due to its biotechnological potential, arising from its flavor- and aroma-enhancing properties when used in wine, beer or bread dough fermentation, as well as from its remarkable resistance to osmotic and freezing stresses. In the present review, genomic, biochemical, and phenotypic features of are described, comparing them with other species, particularly with the biotechnologically well-established yeast, . We conclude about the aspects that make this yeast a promising biotechnological model to be exploited in a wide range of industries, particularly in wine and bakery. A phylogenetic analysis was also performed, using the core proteome of , to compare the number of homologous proteins relative to the most closely related species, understanding the phylogenetic placement of this species with robust support. Lastly, the genetic tools available for improvement are discussed, focusing on adaptive laboratorial evolution and its potential.
PubMed: 34575750
DOI: 10.3390/jof7090712 -
Mycology 2021Non-conventional wine yeasts are extensively studied as promising producers of hydrolytic enzymes and as potential starter cultures in winemaking due to their ability to...
Non-conventional wine yeasts are extensively studied as promising producers of hydrolytic enzymes and as potential starter cultures in winemaking due to their ability to improve organoleptic properties of wine. Thirty-six yeast strains of enological and brewery origin from the Ukrainian Collection of Microorganisms belonging to , and genera have been screened for the production of extracellular hydrolases, stress tolerance, fermentative activity, and other traits of enological interest. This study revealed the high incidence of lipolytic, proteolytic, and β-glucosidase activities among the yeasts, while no pectinase activity was detected. Esterase, cellulase and glucanase activities were found in a small proportion of yeasts (8.33-16.66%). Several , and strains demonstrated a wide range of hydrolytic activities. High tolerance to stress factors (ethanol, osmotic, and oxidative stress) present during alcoholic fermentation was detected in and strains. Fermentative activity of several yeast strains was evaluated in microfermentations in a model semi-synthetic medium. Strain UCM Y-216 was selected as the most promising culture for winemaking due to its hydrolytic activities, tolerance to stress factors and other valuable metabolic traits. This study represents the first step for selecting a non-conventional yeast strain of enological origin as a potential co-culture for winemaking.
PubMed: 34552811
DOI: 10.1080/21501203.2020.1837272 -
Food Chemistry Feb 2022Black currants (Ribes nigrum) were fermented with Saccharomyces and non-Saccharomyces yeasts without added sugar to yield low-ethanol-content beverages. The effects of...
Comparison of volatile compounds and sensory profiles of alcoholic black currant (Ribes nigrum) beverages produced with Saccharomyces, Torulaspora, and Metschnikowia yeasts.
Black currants (Ribes nigrum) were fermented with Saccharomyces and non-Saccharomyces yeasts without added sugar to yield low-ethanol-content beverages. The effects of yeasts on the volatile compounds and sensory characteristics were analysed by HS-SPME-GC-MS, GC-O, and generic descriptive analysis. Ninety-eight volatile compounds were identified from the black currant juice and fermented beverages. Significant increases in the contents of esters (131 %), higher alcohols (391 %), and fatty acids (not present in juice sample) compared to initial juice were observed depending on the yeasts used. GC-O analysis revealed the higher impact of esters on the sensory properties of Saccharomyces bayanus-fermented beverage compared to the Torulaspora delbrueckii-fermented beverage. In the sensory evaluation, non-Saccharomyces yeasts resulted in a higher 'black currant odour'. However, all beverages were intensely sour, which can be a significant challenge in the development of alcoholic berry beverages.
Topics: Alcoholic Beverages; Fermentation; Metschnikowia; Ribes; Saccharomyces; Torulaspora; Wine; Yeasts
PubMed: 34520974
DOI: 10.1016/j.foodchem.2021.131049