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World Journal of Microbiology &... Feb 2024The bioprospection of indigenous microorganism strains with biotechnological potential represents a prominent trend. Metschnikowia yeasts exhibit diverse capabilities,...
The bioprospection of indigenous microorganism strains with biotechnological potential represents a prominent trend. Metschnikowia yeasts exhibit diverse capabilities, such as ethanol reduction in winemaking, biocontrol potential, and lipid production. In this work, local Metschnikowia strains were isolated from different fruits by their ability to produce pulcherrimic acid, a molecule that has been linked to biocontrol activity and that binds iron giving colored colonies. Five strains were selected, each from one of five distinct sources. All of them were identified as M. pulcherrima. All five were able inhibit other yeasts and one M. pulcherrima, called M7, inhibited the growth of Aspergillus nidulans. The selected strains accumulated lipid bodies in stationary phase. Certain non-conventional yeasts like Hanseniaspora vineae are very sensitive to biomass drying, but cell extracts from M. pulcherrima added to the growth media as a source of antioxidant lipids increased their tolerance to drying. All strains isolated showed good stress tolerance (particularly to heat) and have nutrient requirements similar to a commercial M. pulcherrima strain. In addition, the M7 strain had a good growth in sugarcane and beet molasses and behaved like Saccharomyces cerevisiae in a growth medium derived from agricultural waste, a persimmon hydrolysate. Therefore, the isolation of local strains of Metschnikowia able to grow in a variety of substrates is a good source of biocontrol agents.
Topics: Saccharomyces cerevisiae; Metschnikowia; Wine; Fruit; Lipids
PubMed: 38334894
DOI: 10.1007/s11274-024-03918-y -
Applied Microbiology and Biotechnology Jan 2024Honeybee (Apis mellifera) is an important agricultural pollinator and a model for sociality. In this study, a deep knowledge on yeast community characterizing the...
Honeybee (Apis mellifera) is an important agricultural pollinator and a model for sociality. In this study, a deep knowledge on yeast community characterizing the honeybees' environmental was carried out. For this, a total of 93 samples were collected: flowers as food sources, bee gut mycobiota, and bee products (bee pollen, bee bread, propolis), and processed using culture-dependent techniques and a molecular approach for identification. The occurrence of yeast populations was quantitatively similar among flowers, bee gut mycobiota, and bee products. Overall, 27 genera and 51 species were identified. Basidiomycetes genera were predominant in the flowers while the yeast genera detected in all environments were Aureobasidium, Filobasidium, Meyerozyma, and Metschnikowia. Fermenting species belonging to the genera Debaryomyces, Saccharomyces, Starmerella, Pichia, and Lachancea occurred mainly in the gut, while most of the identified species of bee products were not found in the gut mycobiota. Five yeast species, Meyerozyma guilliermondii, Debaryomyces hansenii, Hanseniaspora uvarum, Hanseniaspora guilliermondii, and Starmerella roseus, were present in both summer and winter, thus indicating them as stable components of bee mycobiota. These findings can help understand the yeast community as a component of the bee gut microbiota and its relationship with related environments, since mycobiota characterization was still less unexplored. In addition, the gut microbiota, affecting the nutrition, endocrine signaling, immune function, and pathogen resistance of honeybees, represents a useful tool for its health evaluation and could be a possible source of functional yeasts. KEY POINTS: • The stable yeast populations are represented by M. guilliermondii, D. hansenii, H. uvarum, H. guilliermondii, and S. roseus. • A. pullulans was the most abondance yeast detective in the flowers and honeybee guts. • Aureobasidium, Meyerozyma, Pichia, and Hanseniaspora are the main genera resident in gut tract.
Topics: Bees; Animals; Yeasts; Ascomycota; Pichia; Gastrointestinal Microbiome; Flowers
PubMed: 38276993
DOI: 10.1007/s00253-023-12942-1 -
Foods (Basel, Switzerland) Nov 2023This study identified and tested fruit-isolated yeasts against three major postharvest citrus pathogens, namely, , , and , and further evaluated the impact of FeCl on...
This study identified and tested fruit-isolated yeasts against three major postharvest citrus pathogens, namely, , , and , and further evaluated the impact of FeCl on the biocontrol efficiency of pulcherrimin-producing strains. Based on the characterization of the pigmented halo surrounding the colonies and the analysis of the D1/D2 domain of 26S rDNA, a total of 46 sp. were screened and identified. All 46 strains significantly inhibited the hyphal growth of , , and , and effectively controlled the development of green mold, blue mold and sour rot of citrus fruit. The introduction of exogenous FeCl at certain concentrations did not significantly impact the pulcherriminic acid (PA) production of pigmented strains, but notably diminished the size of pigmented zones and the biocontrol efficacy against the three pathogens. Iron deficiency sensitivity experiments revealed that and exhibited higher sensitivity compared to , indicating that iron dependence varied among the three pathogens. These results suggested that strains, capable of producing high yields of PA, possessed great potential for use as biocontrol agents against postharvest citrus diseases. The biocontrol efficacy of these yeasts is mainly attributed to their ability to competitively deplete iron ions in a shared environment, with the magnitude of their pigmented halo directly correlating to their antagonistic capability. It is worth noting that the level of sensitivity of pathogens to iron deficiency might also affect the biocontrol effect of pulcherrimin-producing .
PubMed: 38231683
DOI: 10.3390/foods12234249 -
FEMS Yeast Research Jan 2024Pulcherrimin is an iron (III) chelate of pulcherriminic acid that plays a role in antagonistic microbial interactions, iron metabolism, and stress responses. Some...
Pulcherrimin is an iron (III) chelate of pulcherriminic acid that plays a role in antagonistic microbial interactions, iron metabolism, and stress responses. Some bacteria and yeasts produce pulcherriminic acid, but so far, pulcherrimin could not be produced in Saccharomyces cerevisiae. Here, multiple integrations of the Metschnikowia pulcherrima PUL1 and PUL2 genes in the S. cerevisiae genome resulted in red colonies, which indicated pulcherrimin formation. The coloration correlated positively and significantly with the number of PUL1 and PUL2 genes. The presence of pulcherriminic acid was confirmed by mass spectrometry. In vitro competition assays with the plant pathogenic fungus Botrytis caroliana revealed inhibitory activity on conidiation by an engineered, strong pulcherrimin-producing S. cerevisiae strain. We demonstrate that the PUL1 and PUL2 genes from M. pulcherrima, in multiple copies, are sufficient to transfer pulcherrimin production to S. cerevisiae and represent the starting point for engineering and optimizing this biosynthetic pathway in the future.
Topics: Saccharomyces cerevisiae; Botrytis; Metschnikowia; Iron
PubMed: 38140959
DOI: 10.1093/femsyr/foad053 -
Life (Basel, Switzerland) Dec 2023Consumers today seek safe functional foods with proven health-promoting properties. Current evidence shows that a healthy diet can effectively alleviate oxidative stress...
Consumers today seek safe functional foods with proven health-promoting properties. Current evidence shows that a healthy diet can effectively alleviate oxidative stress levels and reduce inflammatory markers, thereby preventing the occurrence of many types of cancer, hypertension, and cardiovascular and neurological pathologies. Nevertheless, as fruits and vegetables are mainly consumed fresh, they can serve as vectors for the transmission of pathogenic microorganisms associated with various disease outbreaks. As a result, there has been a surge in interest in the microbiome of fruits and vegetables. Therefore, given the growing interest in sweet cherries, and since their microbial communities have been largely ignored, the primary purpose of this study is to investigate their culturome at various maturity stages for the first time. A total of 55 microorganisms were isolated from sweet cherry fruit, comprising 23 bacteria and 32 fungi species. Subsequently, the selected isolates were molecularly identified by amplifying the 16S rRNA gene and ITS region. Furthermore, it was observed that the communities became more diverse as the fruit matured. The most abundant taxa included and among the bacteria, and , , and among the fungi.
PubMed: 38137924
DOI: 10.3390/life13122323 -
Foods (Basel, Switzerland) Dec 2023Interest in () is growing in the world of winemaking. is used both to protect musts from microbial spoilage and to modulate the aromatic profile of wines. Here, we...
Interest in () is growing in the world of winemaking. is used both to protect musts from microbial spoilage and to modulate the aromatic profile of wines. Here, we describe the isolation, characterization, and use of an autochthonous strain of in the vinification of Chasselas musts from the 2022 vintage. was used in co-fermentation with at both laboratory and experimental cellar scales. Our results showed that does not ferment sugars but has high metabolic activity, as detected by flow cytometry. Furthermore, sensory analysis showed that contributed slightly to the aromatic profile when compared to the control vinifications. The overall results suggest that our bioprospecting strategy can guide the selection of microorganisms that can be effectively used in the winemaking process.
PubMed: 38137289
DOI: 10.3390/foods12244485 -
Anais Da Academia Brasileira de Ciencias 2023Harsh and extreme environments, such as Antarctica, offer unique opportunities to explore new microbial taxa and biomolecules. Given the limited knowledge on microbial...
Harsh and extreme environments, such as Antarctica, offer unique opportunities to explore new microbial taxa and biomolecules. Given the limited knowledge on microbial diversity, this study aimed to compile, analyze and compare a subset of the biobank of Antarctic fungi maintained at the UNESP's Central of Microbial Resources (CRM-UNESP). A total of 711 isolates (240 yeasts and 471 filamentous fungi) from marine and terrestrial samples collected at King George Island (South Shetland Islands, Antarctica) were used with the primary objective of investigating their presence in both marine and terrestrial environments. Among the yeasts, 13 genera were found, predominantly belonging to the phylum Basidiomycota. Among the filamentous fungi, 34 genera were represented, predominantly from the phylum Ascomycota. The most abundant genera in the marine samples were Metschnikowia, Mrakia, and Pseudogymnoascus, while in the terrestrial samples, they were Pseudogymnoascus, Leucosporidium, and Mortierella. Most of the genera and species of the CRM-UNESP biobank of Antarctic fungi are being reported as an important target for biotechnological applications. This study showed the relevance of the CRM-UNESP biobank, highlighting the importance of applying standard methods for the preservation of the biological material and associated data (BMaD), as recommended in national and international standards.
Topics: Antarctic Regions; Biological Specimen Banks; Fungi; Yeasts; Ascomycota; Basidiomycota
PubMed: 38126380
DOI: 10.1590/0001-3765202320230603 -
Frontiers in Microbiology 2023Eukaryotic life depends on the functional elements encoded by both the nuclear genome and organellar genomes, such as those contained within the mitochondria. The...
INTRODUCTION
Eukaryotic life depends on the functional elements encoded by both the nuclear genome and organellar genomes, such as those contained within the mitochondria. The content, size, and structure of the mitochondrial genome varies across organisms with potentially large implications for phenotypic variance and resulting evolutionary trajectories. Among yeasts in the subphylum Saccharomycotina, extensive differences have been observed in various species relative to the model yeast , but mitochondrial genome sampling across many groups has been scarce, even as hundreds of nuclear genomes have become available.
METHODS
By extracting mitochondrial assemblies from existing short-read genome sequence datasets, we have greatly expanded both the number of available genomes and the coverage across sparsely sampled clades.
RESULTS
Comparison of 353 yeast mitochondrial genomes revealed that, while size and GC content were fairly consistent across species, those in the genera and trended larger, while several species in the order Saccharomycetales, which includes , exhibited lower GC content. Extreme examples for both size and GC content were scattered throughout the subphylum. All mitochondrial genomes shared a core set of protein-coding genes for Complexes III, IV, and V, but they varied in the presence or absence of mitochondrially-encoded canonical Complex I genes. We traced the loss of Complex I genes to a major event in the ancestor of the orders Saccharomycetales and Saccharomycodales, but we also observed several independent losses in the orders Phaffomycetales, Pichiales, and Dipodascales. In contrast to prior hypotheses based on smaller-scale datasets, comparison of evolutionary rates in protein-coding genes showed no bias towards elevated rates among aerobically fermenting (Crabtree/Warburg-positive) yeasts. Mitochondrial introns were widely distributed, but they were highly enriched in some groups. The majority of mitochondrial introns were poorly conserved within groups, but several were shared within groups, between groups, and even across taxonomic orders, which is consistent with horizontal gene transfer, likely involving homing endonucleases acting as selfish elements.
DISCUSSION
As the number of available fungal nuclear genomes continues to expand, the methods described here to retrieve mitochondrial genome sequences from these datasets will prove invaluable to ensuring that studies of fungal mitochondrial genomes keep pace with their nuclear counterparts.
PubMed: 38075892
DOI: 10.3389/fmicb.2023.1268944 -
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 -
BMC Bioinformatics Nov 2023Use of alternative non-Saccharomyces yeasts in wine and beer brewing has gained more attention the recent years. This is both due to the desire to obtain a wider variety...
BACKGROUND
Use of alternative non-Saccharomyces yeasts in wine and beer brewing has gained more attention the recent years. This is both due to the desire to obtain a wider variety of flavours in the product and to reduce the final alcohol content. Given the metabolic differences between the yeast species, we wanted to account for some of the differences by using in silico models.
RESULTS
We created and studied genome-scale metabolic models of five different non-Saccharomyces species using an automated processes. These were: Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora osmophila, Torulaspora delbrueckii and Kluyveromyces lactis. Using the models, we predicted that M. pulcherrima, when compared to the other species, conducts more respiration and thus produces less fermentation products, a finding which agrees with experimental data. Complex I of the electron transport chain was to be present in M. pulcherrima, but absent in the others. The predicted importance of Complex I was diminished when we incorporated constraints on the amount of enzymatic protein, as this shifts the metabolism towards fermentation.
CONCLUSIONS
Our results suggest that Complex I in the electron transport chain is a key differentiator between Metschnikowia pulcherrima and the other yeasts considered. Yet, more annotations and experimental data have the potential to improve model quality in order to increase fidelity and confidence in these results. Further experiments should be conducted to confirm the in vivo effect of Complex I in M. pulcherrima and its respiratory metabolism.
Topics: Yeasts; Metschnikowia; Torulaspora; Wine; Fermentation
PubMed: 37990145
DOI: 10.1186/s12859-023-05506-7