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International Journal of Molecular... Jan 2021The surfaces of grapes are covered by different yeast species that are important in the first stages of the fermentation process. In recent years, non- yeasts such as ,... (Review)
Review
The surfaces of grapes are covered by different yeast species that are important in the first stages of the fermentation process. In recent years, non- yeasts such as , , , and have become popular with regard to winemaking and improved wine quality. For that reason, several manufacturers started to offer commercially available strains of these non- species. stands out, mainly due to its contribution to wine aroma, glycerol, ethanol yield, and killer factor. The metabolism of the yeast allows it to increase volatile molecules such as esters and varietal thiols (aroma-active compounds), which increase the quality of specific varietal wines or neutral ones. It is considered a low- or non-fermentative yeast, so subsequent inoculation of a more fermentative yeast such as is indispensable to achieve a proper fermented alcohol. The impact of is not limited to the grape wine industry; it has also been successfully employed in beer, cider, durian, and tequila fermentation, among others, acting as a promising tool in those fermentation processes. Although no species other than is available in the regular market, several recent scientific studies show interesting improvements in some wine quality parameters such as aroma, polysaccharides, acid management, and color stability. This could motivate yeast manufacturers to develop products based on those species in the near future.
Topics: Bioengineering; Ecology; Fermentation; Food Quality; Industrial Microbiology; Pichia; Vitis; Wine
PubMed: 33530422
DOI: 10.3390/ijms22031196 -
Molecules (Basel, Switzerland) Mar 2022Pulcherrimin is a secondary metabolite of yeasts belonging to the clade, and pulcherrimin formation is responsible for the antimicrobial action of its producers....
Pulcherrimin is a secondary metabolite of yeasts belonging to the clade, and pulcherrimin formation is responsible for the antimicrobial action of its producers. Understanding the environmental function of this metabolite can provide insight into various microbial interactions and enables the efficient development of new effective bioproducts and methods. In this study, we evaluated the antimicrobial and antiadhesive action of yeast pulcherrimin, as well as its protective properties under selected stressful conditions. Classical microbiological plate methods, microscopy, and physico-chemical testing were used. The results show that pure pulcherrimin does not have antimicrobial properties, but its unique hydrophilic nature may hinder the adhesion of hydrophilic bacterial cells to abiotic surfaces. Pulcherrimin also proved to be a good cell protectant against UV-C radiation at both high and low temperatures.
Topics: Anti-Bacterial Agents; Bone Plates; Cold Temperature; Microbial Interactions; Microbiological Techniques
PubMed: 35335219
DOI: 10.3390/molecules27061855 -
Frontiers in Bioscience (Elite Edition) Jan 2023The vineyard is a great reservoir of autochthonous yeast strains whose composition is defined by different regional (edaphology, orography or climatology) and...
BACKGROUND
The vineyard is a great reservoir of autochthonous yeast strains whose composition is defined by different regional (edaphology, orography or climatology) and anthropological factors (cultivation systems or cultural practices). Most of this yeast diversity corresponds to non- strains, some of which have potential use in winemaking.
METHODS
The oenological potential of 29 different native non- strains belonging to 4 species (, , and spp.) was evaluated, using the autochthonous XG3 strain as a control. Microfermentations with pure culture of each strain were performed in duplicate and the basic parameters and major volatiles of wines were analysed following official methodology. The best strain within each species was selected using a quantification matrix including the relevant oenological characteristics.
RESULTS
The fermentative ability of non- was lower than in all cases, but with differences among species. and showed higher fermentation rates than , whereas spp. presented a low fermentative power. At chemical level all non- strains reduced the alcoholic content, the higher alcohols and the volatile acidity of wines and increased the content of glycerol, with differences among strains within a given species. and increased the total acidity of wines. The latter and spp. strains produced lactic acid, which decreased the wine pH in the case of . According to their oenological traits the best rated strains of each species were Lt93, Td315, Mf278 and Sb474. In addition, the data obtained in pure fermentations were correlated to those chemical and aromatic compounds obtained with these non- strains in sequential fermentations.
CONCLUSIONS
Autochthonous strains of non- yeast species contribute distinctive chemical characteristics to the wines. The correlations observed between wines fermented with the different non- indigenous strains in pure and sequential fermentations suggest that their contribution to wine properties remains stable regardless of must composition or winemaking techniques.
Topics: Saccharomyces cerevisiae; Vitis; Wine; Glycerol
PubMed: 36959102
DOI: 10.31083/j.fbe1501001 -
PloS One 2021Currently, one of the most important challenges is to provide sufficient and affordable food and energy for a fast-growing world population, alongside preserving natural...
Inoculation of pear flowers with Metschnikowia reukaufii and Acinetobacter nectaris enhances attraction of honeybees and hoverflies, but does not increase fruit and seed set.
Currently, one of the most important challenges is to provide sufficient and affordable food and energy for a fast-growing world population, alongside preserving natural habitats and maintaining biodiversity. About 35% of the global food production depends on animals for pollination. In recent years, an alarming worldwide decline in pollinators has been reported, putting our food production under additional pressure. Therefore, there is an urgent need to find sustainable ways to ensure this crucial ecosystem service. Recent studies have shown that floral nectar is generally colonized by microorganisms, specifically yeasts and bacteria, which may alter nectar chemistry and enhance attraction of pollinators. In this study, we investigated changes in pollinator foraging behavior and pollination success in European pear (Pyrus communis L.) cultivars 'Regal Red' and 'Sweet Sensation' (red sports of 'Doyenné de Comice') after flower inoculation with the typical nectar-inhabiting microorganisms Metschnikowia reukaufii and Acinetobacter nectaris, and a combination of both. Pollination success was monitored by measuring the number of flower visits, fruit set and seed set in two consecutive years, 2019 and 2020. Results revealed that application of a mixture of M. reukaufii and A. nectaris resulted in significantly higher visitation rates of honeybees and hoverflies. By contrast, no effects on flower visits were found when yeasts and bacteria were applied separately. Fruit set and seed set were not significantly affected by any of the inoculation treatments. The only factors affecting fruit set were initial number of flower clusters on the trees and the year. The absence of treatment effects can most likely be attributed to the fact that pollination was not a limiting factor for fruit set in our experiments. Altogether, our results show that inoculation of flowers with nectar microbes can modify pollinator foraging patterns, but did not lead to increased pollination success under the conditions tested.
Topics: Animals; Bees; Flowers; Fruit; Plant Nectar; Pollination; Pyrus
PubMed: 33886638
DOI: 10.1371/journal.pone.0250203 -
Molecules (Basel, Switzerland) Jan 2021Wine fermentation processes are driven by complex microbial systems, which comprise eukaryotic and prokaryotic microorganisms that participate in several biochemical... (Review)
Review
Wine fermentation processes are driven by complex microbial systems, which comprise eukaryotic and prokaryotic microorganisms that participate in several biochemical interactions with the must and wine chemicals and modulate the organoleptic properties of wine. Among these, yeasts play a fundamental role, since they carry out the alcoholic fermentation (AF), converting sugars to ethanol and CO together with a wide range of volatile organic compounds. The contribution of , the reference organism associated with AF, has been extensively studied. However, in the last decade, selected strains received considerable commercial and oenological interest due to their specific pro-technological aptitudes and the positive influence on sensory quality. This review aims to highlight the inter-specific variability within the heterogeneous class of non- in terms of synthesis and release of volatile organic compounds during controlled AF in wine. In particular, we reported findings on the presence of model non- organisms, including spp. and , in combination with . The evidence is discussed from both basic and applicative scientific perspective. In particular, the oenological significance in different kind of wines has been underlined.
Topics: Fermentation; Hanseniaspora; Metschnikowia; Odorants; Pichia; Saccharomycetales; Torulaspora; Volatile Organic Compounds; Wine
PubMed: 33530641
DOI: 10.3390/molecules26030644 -
Ecology and Evolution Dec 2022Host immune traits arise from both genetic and environmental sources of variation. When immune traits have a strong genetic basis, the presence and severity of disease...
Host immune traits arise from both genetic and environmental sources of variation. When immune traits have a strong genetic basis, the presence and severity of disease in a population may influence the distribution of those traits. Our study addressed how two immune-related traits (gut penetrability and the hemocyte response) are shaped by genetic and environmental sources of variation, and how the presence of a virulent disease altered the relative frequency of these traits in natural populations. hosts were sampled from five Indiana lakes between June and December 2017 before and during epidemics of their fungal pathogen, . Collected were experimentally exposed to and assayed for their gut penetrability, hemocyte response, and multi-locus genotype. Mixed-effects models were constructed to partition variance in immune traits between genetic and environmental sources. We then isolated the genetic sources to produce genotype-specific estimates of immune traits for each multi-locus genotype. Finally, we assessed the relative frequency and dynamics of genotypes during epidemics and asked whether genotypes with more robust immune responses increased in frequency during epidemics. Although genotype was an important source of variation for both gut penetrability and the hemocyte response, environmental factors (e.g., resource availability, prevalence, and co-infection) still explained a large portion of observed variation, suggesting a high degree of flexibility in immune traits. Additionally, no significant associations were detected between a genotype's immune traits and its frequency in a population. Our study highlights the power of variance partitioning in understanding the factors driving variation in traits and motivates further research on immunological flexibility and the ecological drivers of immune variation.
PubMed: 36545366
DOI: 10.1002/ece3.9640 -
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 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Aug 2021Biodiesel is an alternative fuel to addressing the energy shortage problem. Microbial lipids have attracted widespread attention as one of the potential feed-stocks for... (Review)
Review
Biodiesel is an alternative fuel to addressing the energy shortage problem. Microbial lipids have attracted widespread attention as one of the potential feed-stocks for cost-effective and efficient biodiesel production. However, the large-scale production of microbial lipids is hampered by the complexity and the high cost of aseptic culturing approach. Metschnikowia pulcherrima is an oleaginous yeast with strong environmental adaptability. It is capable of utilizing a wide spectrum of substrates, and can be cultured under non-sterile conditions. Therefore, this yeast has great potential to replace the traditional oleaginous microorganisms, particularly in the area of recycling wastewater and solid waste for the production of biodiesel. Based on the analysis of lipid production and application conditions of M. pulcherrima, this review summarized the unique advantages of M. pulcherrima and the key factors affecting lipids production. We further discussed the feasibility of cultivating M. pulcherrima on various organic wastes under non-sterile conditions for lipids production. Moreover, we analyzed the challenges associated with M. pulcherrima's in the yield and mechanism for lipids production, and proposed perspectives for how to achieve efficient biodiesel production using this yeast.
Topics: Biofuels; Candida; Lipids; Metschnikowia; Yeasts
PubMed: 34472293
DOI: 10.13345/j.cjb.200599 -
Emerging biotechnologies and non-thermal technologies for winemaking in a context of global warming.Frontiers in Microbiology 2023In the current situation, wine areas are affected by several problems in a context of global warming: asymmetric maturities, pH increasing, high alcohol degree and flat... (Review)
Review
In the current situation, wine areas are affected by several problems in a context of global warming: asymmetric maturities, pH increasing, high alcohol degree and flat wines with low freshness and poor aroma profile. The use of emerging biotechnologies allows to control or manage such problems. Emerging non- as are very useful for controlling pH by the formation of stable lactic acid from sugars with a slight concomitant alcohol reduction. Lower pH improves freshness increasing simultaneously microbiological stability. The use of spp. (specially and ) or promotes a better aroma complexity and improves wine sensory profile by the expression of a more complex metabolic pattern and the release of extracellular enzymes. Some of them are also compatible or synergic with the acidification by , and is an interesting biotool for reductive winemaking and bioprotection. The use of bioprotection is a powerful tool in this context, allowing oxidation control by oxygen depletion, the inhibition of some wild microorganisms, improving the implantation of some starters and limiting SO. This can be complemented with the use of reductive yeast derivatives with high contents of reducing peptides and relevant compounds such as glutathione that also are interesting to reduce SO. Finally, the use of emerging non-thermal technologies as Ultra High-Pressure Homogenization (UHPH) and Pulsed Light (PL) increases wine stability by microbial control and inactivation of oxidative enzymes, improving the implantation of emerging non- and lowering SO additions. GRAPHICAL ABSTRACT.
PubMed: 37869658
DOI: 10.3389/fmicb.2023.1273940 -
Current Biology : CB Jul 2020While sequencing and characterizing the mitochondrial genomes of 71 strains from the yeast genus Metschnikowia [1] (close cousin to the model species Candida albicans),...
While sequencing and characterizing the mitochondrial genomes of 71 strains from the yeast genus Metschnikowia [1] (close cousin to the model species Candida albicans), we uncovered one of the most extreme examples of mitochondrial genome architectural diversity observed to date. These Metschnikowia mitochondrial DNAs (mtDNAs) capture nearly the entire known gene-size and intron-content range for cox1 and cob across all eukaryotic life and show remarkable differences in structure and noncoding content. This genomic variation can be seen both among species and between strains of the same species, raising the question: why are Metschnikowia mitogenomes so malleable?
Topics: DNA, Mitochondrial; Electron Transport Complex IV; Genetic Variation; Genome, Fungal; Introns; Metschnikowia; Mitochondria; Saccharomyces cerevisiae Proteins
PubMed: 32693070
DOI: 10.1016/j.cub.2020.05.075