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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 -
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 -
Frontiers in Microbiology 2022Non-conventional yeasts such as () have been proposed for sparkling winemaking. Unfortunately, this yeast has poor efficiency in completing wine fermentation as...
Non-conventional yeasts such as () have been proposed for sparkling winemaking. Unfortunately, this yeast has poor efficiency in completing wine fermentation as compared to (). New mutants with increased resistance to SO, ethanol, and high CO pressure were previously isolated from spore clones of . Although these mutants showed improved capability for base wine fermentation, there is still room for genetic improvement of yeasts until the fermentative capacity of is achieved. As an alternative approach, yeast mixture for eventual hybridization of with was assayed in this study. The new yeast mixture clones (-mixed ) showed an intermediate phenotype between both parent yeasts for some relevant biotechnological properties, such as resistance to SO, ethanol, copper, high CO pressure, and high temperature, as well as flocculation potential. These properties varied depending on the specific -mixed clone. Several mixture clones showed improved capability for base wine fermentation as compared to the parent strain, approaching the fermentation capability of the parent strain. The organoleptic quality of sparkling wine was also improved by using some mixture clones and this improved quality coincided with an increased amount of acetate and ethyl esters. The genetic stability of some -mixed clones was good enough for commercial yeast production and winery applications.
PubMed: 36274726
DOI: 10.3389/fmicb.2022.1006978 -
Food Research International (Ottawa,... Apr 2022Ethyl carbamate (EC) is a potential carcinogen that is mainly produced by the spontaneous reaction between urea and ethanol during rice wine brewing. Huzhou rice wine...
Ethyl carbamate (EC) is a potential carcinogen that is mainly produced by the spontaneous reaction between urea and ethanol during rice wine brewing. Huzhou rice wine (HZRW) is a traditional Chinese rice wine, but the correlation between its urea content and the microbial communities present during the fermentation process has not yet been evaluated. In this study, high-throughput sequencing technology was used to monitor the microbial community composition of HZRW in the different fermentation stages. The correlations between the microbial community and the physical and chemical properties and EC, urea and arginine contents were evaluated using the redundancy analysis (RDA) method. The metabolic profiles of key genes in the arginine and urea metabolic pathways were obtained via phylogenetic investigation of the communities by reconstruction of unobserved states (PICRUSt). The results showed that the fungal genera Saccharomyces, Issatchenkia, Torulaspora and Rhizopus were dominant during the fermentation of HZRW. Weissella and Acinetobacter were the dominant bacterial genera in the early stage, while Weissella, Staphylococcus, Leuconostoc and Streptophyta were the dominant bacterial genera in the late stage. Urea and arginine were positively correlated with Saccharomyces, Lactobacillus and Staphylococcus. In addition, the dominant genera of both fungi and bacteria were involved in the metabolism of arginine and urea. Finally, the relationships between the dominant microorganisms and key genes of the arginine and urea metabolic pathways were established. The obtained results are helpful in better understanding the mechanisms of metabolism of arginine and urea during rice wine fermentation and therefore improving the safety profile of rice wine.
Topics: Fermentation; Microbiota; Oryza; Phylogeny; Urethane; Wine
PubMed: 35337566
DOI: 10.1016/j.foodres.2022.111001 -
Food Research International (Ottawa,... Sep 2020Soy (tofu) whey is a by-product commonly disposed of by tofu manufacturers around the world. Due to its nutritious nature, direct disposal of soy whey into the sewage...
Soy (tofu) whey is a by-product commonly disposed of by tofu manufacturers around the world. Due to its nutritious nature, direct disposal of soy whey into the sewage can result in a detrimental impact on the environment in the long-run. In this study, soy whey supplemented with four individual amino acids (valine, leucine, isoleucine and phenylalanine) equivalent to 120 mg N/L was fermented with a yeast Torulaspora delbrueckii Biodiva. The supplementation of an individual amino acid resulted in faster sugar utilization and lower levels of residual sugar than the unsupplemented whey but did not result in a significantly higher amount of ethanol (7-8% v/v) at the end of fermentation. Isoleucine supplementation resulted in a slightly slower initial yeast growth rate when compared to the control while the other three amino acids had identical yeast growth kinetics to the control. Isoleucine supplementation also resulted in slower sugar utilization during the first four days. Therefore, isoleucine is least preferred by the yeast. The supplementation of amino acids resulted in greater formation of higher alcohols and their corresponding alcohol-derived esters. Overall, the supplementation of a single amino acid enhanced sugar utilization and impacted flavor compounds of the resultant soy whey alcoholic beverage.
Topics: Alcoholic Beverages; Amino Acids; Fermentation; Kinetics; Soy Foods; Torulaspora; Whey
PubMed: 32527478
DOI: 10.1016/j.foodres.2020.109283 -
Genome Biology and Evolution Jul 2021Eukaryotic DNA replication begins at genomic loci termed origins, which are bound by the origin recognition complex (ORC). Although ORC is conserved across species, the...
Eukaryotic DNA replication begins at genomic loci termed origins, which are bound by the origin recognition complex (ORC). Although ORC is conserved across species, the sequence composition of origins is more varied. In the budding yeast Saccharomyces cerevisiae, the ORC-binding motif consists of an A/T-rich 17 bp "extended ACS" sequence adjacent to a B1 element composed of two 3-bp motifs. Similar sequences occur at origins in closely related species, but it is not clear when this type of replication origin arose and whether it predated a whole-genome duplication that occurred around 100 Ma in the budding yeast lineage. To address these questions, we identified the ORC-binding sequences in the nonduplicated species Torulaspora delbrueckii. We used chromatin immunoprecipitation followed by sequencing and identified 190 ORC-binding sites distributed across the eight T. delbrueckii chromosomes. Using these sites, we identified an ORC-binding motif that is nearly identical to the known motif in S. cerevisiae. We also found that the T. delbrueckii ORC-binding sites function as origins in T. delbrueckii when cloned onto a plasmid and that the motif is required for plasmid replication. Finally, we compared an S. cerevisiae origin with two T. delbrueckii ORC-binding sites and found that they conferred similar stabilities to a plasmid. These results reveal that the ORC-binding motif arose prior to the whole-genome duplication and has been maintained for over 100 Myr.
Topics: DNA Replication; DNA, Fungal; Origin Recognition Complex; Replication Origin; Saccharomyces cerevisiae; Saccharomycetales
PubMed: 34132803
DOI: 10.1093/gbe/evab137 -
Food Research International (Ottawa,... Mar 2024This study investigated the effects of co-fermentation of T. delbrueckii and S. cerevisiae on the volatile composition and sensory characteristics of blueberry wines....
This study investigated the effects of co-fermentation of T. delbrueckii and S. cerevisiae on the volatile composition and sensory characteristics of blueberry wines. Mixed fermentation led to higher levels of terpenes, higher alcohols, and esters compared to wines fermented with each yeast individually. Conversely, when T. delbrueckii were physically separated from S. cerevisiae in the double-compartment fermenter, contrasting outcomes emerged. The stronger fruity aroma induced by mixed fermentation were linked to higher ester concentrations, including isoamyl acetate, ethyl isovalerate, ethyl hexanoate, and diethyl succinate. The enhanced esters in mixed fermentation can be attributed to the upregulated alcohol acyltransferase activity and the expressions of ACC1, FAS2, ELO1 and ATF1 genes in late fermentation stage via the cell-cell contact between T. delbrueckii and S. cerevisiae. These findings can deepen the understanding of the interaction between non-Saccharomyces and S. cerevisiae in ester production, assisting wineries in effectively controlling wine aroma through mixed fermentations.
Topics: Saccharomyces cerevisiae; Fermentation; Wine; Torulaspora; Esters; Blueberry Plants
PubMed: 38342548
DOI: 10.1016/j.foodres.2024.114029 -
Journal of Agricultural and Food... Dec 2023The structure of yeast cell wall (CW) mannoproteins (MPs) influences their impact on wine properties. Yeast species produce a diverse range of MPs, but the link between...
The structure of yeast cell wall (CW) mannoproteins (MPs) influences their impact on wine properties. Yeast species produce a diverse range of MPs, but the link between properties and specific structural features has been ill-characterized. This study compared the protein and polysaccharide moieties of MP-rich preparations from four strains of four different enologically relevant yeast species, named (SB62), (SC01), (MF77), and (TD70), and a commercial MP preparation. Monosaccharide determination revealed that SB62 MPs contained the highest mannose/glucose ratio followed by SC01, while polysaccharide size distribution analyses showed maximum molecular weights ranging from 1349 kDa for MF77 to 483 kDa for TD70. Protein identification analysis led to the identification of unique CW proteins in SB62, SC01, and TD70, as well as some proteins shared between different strains. This study reveals MP composition diversity within wine yeasts and paves the way toward their industrial exploitation.
Topics: Saccharomyces cerevisiae; Wine; Phylogeny; Fermentation; Polysaccharides
PubMed: 38049383
DOI: 10.1021/acs.jafc.3c05742 -
International Journal of Food... Dec 2022Fungal spoilage limits the shelf life of fermented dairy products. To address the problem, this study explores the potential of lactic acid bacteria as antifungal...
Fungal spoilage limits the shelf life of fermented dairy products. To address the problem, this study explores the potential of lactic acid bacteria as antifungal adjunct cultures in dairy matrices. Strains of lactic acid bacteria (113) representing 19 species were screened for their activity against Penicillium caseifulvum, Aspergillus clavatus and Mucor racemosus in modified MRS medium, milk, and yogurt. Strains of Lactiplantibacillus plantarum, Furfurilactobacillus milii, and Lentilactobacillus parabuchneri inhibited the growth of mycelial fungi. The inhibitory effects of lactic acid bacteria against yeasts were also determined in yogurt with Candida sake, Saccharomyces bayanus, and Torulaspora delbrueckii as challenge strains. The inhibition of yeasts by lactic acid bacteria was strain-specific and unrelated to the activity towards mycelial fungi. Organic acids and hydroxy fatty acids were quantified by liquid chromatograph coupled with refractive index detector and tandem mass spectrometry, respectively. Principal component analysis indicated 10-OH 18: 1 fatty acids and acetate are the main antifungal metabolites and explained over 50 % of the antifungal activity. The correlation analysis of metabolites and mold-free shelf life of milk and yogurt confirmed the role of these compounds. The genomic study analysed genes related to the production of major antifungal metabolites and predicted the formation of 1,2-propanediol and acetate but not of hydroxy unsaturated fatty acids. The findings provide new perspectives on the selection of antifungal strains, the characterization of antifungal metabolites and the exploration of antifungal mechanisms among different species.
Topics: Lactobacillales; Antifungal Agents; Fermentation; Propylene Glycol; Lactobacillaceae; Yeasts; Acetates; Fatty Acids
PubMed: 36202011
DOI: 10.1016/j.ijfoodmicro.2022.109938 -
Food Science & Nutrition Sep 2019This study investigated the effects of monocultures of and as well as simultaneous and sequential cultures of and on the nonvolatile and volatile compounds in longan...
This study investigated the effects of monocultures of and as well as simultaneous and sequential cultures of and on the nonvolatile and volatile compounds in longan wines. The four cultures had similar characteristics in longan wines. The main amino acids in all the fermentations were glutamic acid, arginine, alanine, leucine, proline, and GABA. The main volatile compounds in longan wines were ethanol, isoamyl alcohol, isobutanol, 2-phenylethanol, isoamyl acetate, ethyl decanoate, ethyl octanoate, ethyl hexanoate, and ethyl acetate, which can contribute more desired aroma compounds in wines. Among the four treatments, the longan wine fermented with the simultaneous culture produced the highest total volatile aroma content (345.26 mg/L). The simultaneous culture also had a better ability to generate a high level of the main volatile compounds in longan wines and also could achieve a noticeable intensity of floral and fruity aromas of wine as evaluated by calculation of the odor activity values.
PubMed: 31572574
DOI: 10.1002/fsn3.1076