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Journal of Fungi (Basel, Switzerland) Sep 2020During the course of a screening for novel biologically active secondary metabolites produced by the Sordariomycetes (Ascomycota, Fungi), the ex-type strain of was...
During the course of a screening for novel biologically active secondary metabolites produced by the Sordariomycetes (Ascomycota, Fungi), the ex-type strain of was found to produce seven novel xanthone-anthraquinone heterodimers, xanthoquinodin A11 () and xanthoquinodins B10-15 (-), together with the already known compound xanthoquinodin B4 (). The structures of the xanthoquinodins were determined by analysis of the nuclear magnetic resonance (NMR) spectroscopic and mass spectrometric data. Moreover, the absolute configurations of these metabolites were established by analysis of the H-H coupling constants, nuclear Overhauser effect spectroscopy (NOESY) correlations, and Electronic Circular Dichroism (ECD) spectroscopic data. Antifungal and antibacterial activities as well as cytotoxicity of all compounds were tested. Xanthoquinodin B11 showed fungicidal activities against [minimum inhibitory concentration (MIC) 2.1 µg/mL], (MIC 2.1 µg/mL), and (MIC 8.3 µg/mL). All the compounds - displayed anti-Gram-positive bacteria activity (MIC 0.2-8.3 µg/mL). In addition, all these eight compounds showed cytotoxicity against KB 3.1, L929, A549, SK-OV-3, PC-3, A431, and MCF-7 mammalian cell lines. The six novel compounds (-, -), together with xanthoquinodin B4, were also found in the screening of other strains belonging to , revealing the potential chemotaxonomic significance of the compound class for the genus.
PubMed: 32992954
DOI: 10.3390/jof6040188 -
3 Biotech Jul 2022The purpose of this research was to isolate microorganisms from coffee fermentation processes and screen them for their potential to improve the flavor of Arabica coffee...
The purpose of this research was to isolate microorganisms from coffee fermentation processes and screen them for their potential to improve the flavor of Arabica coffee using a new approach that included pectin degradation ability and growth in mucilage broth. All of the studied microorganisms were isolated from 38 different samples of fresh coffee cherries, coffee mucilage and coffee pulp. A total of 262 microbial isolates were obtained and subjected to screening using pectinase screening agar medium for pectinolytic organisms. The results of the pectinase production test showed that 18 yeast isolates were found to produce pectinase that could degrade the pectin present in solid media. The sugar assimilation profiles and growth of selected strains in mucilage broth were studied. Therefore, 18 isolates from the selected yeasts were subjected to molecular identification by the use of 18S rRNA gene sequencing. The diversity of the yeast isolates was studied, and they were identified as , , and sp. Moreover, isolates SWU3YWP1-3, SWU3YSK9 and INFCY1-4 were used as a seed culture for Arabica coffee fermentation. The cupping sensory scores of the control (without yeast inoculation) and those inoculated with three isolated yeast strains that were determined by Q-Arabica Graders were 73.75, 84.75, 80.25 and 75.00, respectively. Unique flavors and aromas were detected. This is the first report of screening microorganisms from the Arabica coffee fermentation process by the combination of various properties with success in improving the quality of coffee beverage.
PubMed: 35685951
DOI: 10.1007/s13205-022-03203-5 -
Frontiers in Microbiology 2023Ethanol tolerance is crucial for the oenological yeasts. Tratt, a Rosaceae plant native to China, is rich in nutritional and medicinal ingredients. In this study,...
Ethanol tolerance is crucial for the oenological yeasts. Tratt, a Rosaceae plant native to China, is rich in nutritional and medicinal ingredients. In this study, ethanol-tolerant non- yeasts were screened, and their oenological properties were further evaluated. Three ethanol-tolerant yeast strains (designated as C6, F112, and F15), which could tolerate 12% (v/v) ethanol treatment, were isolated from , and identified as , , and , respectively. The winemaking condition tolerances of these ethanol-tolerant yeast strains were similar to those of X16. However, their growth, sugar metabolic performance and sulphureted hydrogen activities, were different. The β-glucosidase production ability of strain F15 was lower than that of X16, and strains of C6 and F112 were similar to X16. Electronic sensory properties of the wines fermented using ethanol-tolerant yeasts together with showed no significant differences. However, the mixed inoculation of the ethanol-tolerant yeast strains with could regulate the volatile aroma characteristics of the fermented wine, enriching and enhancing the aroma flavor. Therefore, the selected ethanol-tolerant yeasts have the potential for application in the production of unique wine.
PubMed: 37323890
DOI: 10.3389/fmicb.2023.1202440 -
Animal Microbiome Apr 2023Yeasts are gaining attention as alternative ingredients in aquafeeds. However, the impact of yeast inclusion on modulation of intestinal microbiota of fish fed...
BACKGROUND
Yeasts are gaining attention as alternative ingredients in aquafeeds. However, the impact of yeast inclusion on modulation of intestinal microbiota of fish fed plant-based ingredients is limited. Thus, the present study investigates the effects of yeast and processing on composition, diversity and predicted metabolic capacity of gut microbiota of Atlantic salmon smolt fed soybean meal (SBM)-based diet. Two yeasts, Cyberlindnera jadinii (CJ) and Wickerhamomyces anomalus (WA), were produced in-house and processed by direct heat-inactivation with spray-drying (ICJ and IWA) or autolyzed at 50 °C for 16 h, followed by spray-drying (ACJ and AWA). In a 42-day feeding experiment, fish were fed one of six diets: a fishmeal (FM)-based diet, a challenging diet with 30% SBM and four other diets containing 30% SBM and 10% of each of the four yeast products (i.e., ICJ, ACJ, IWA and AWA). Microbial profiling of digesta samples was conducted using 16S rRNA gene sequencing, and the predicted metabolic capacities of gut microbiota were determined using genome-scale metabolic models.
RESULTS
The microbial composition and predicted metabolic capacity of gut microbiota differed between fish fed FM diet and those fed SBM diet. The digesta of fish fed SBM diet was dominated by members of lactic acid bacteria, which was similar to microbial composition in the digesta of fish fed the inactivated yeasts (ICJ and IWA diets). Inclusion of autolyzed yeasts (ACJ and AWA diets) reduced the richness and diversity of gut microbiota in fish. The gut microbiota of fish fed ACJ diet was dominated by the genus Pediococcus and showed a predicted increase in mucin O-glycan degradation compared with the other diets. The gut microbiota of fish fed AWA diet was highly dominated by the family Bacillaceae.
CONCLUSIONS
The present study showed that dietary inclusion of FM and SBM differentially modulate the composition and predicted metabolic capacity of gut microbiota of fish. The inclusion of inactivated yeasts did not alter the modulation caused by SBM-based diet. Fish fed ACJ diet increased relative abundance of Pediococcus, and mucin O-glycan degradation pathway compared with the other diets.
PubMed: 37016467
DOI: 10.1186/s42523-023-00242-y -
Foods (Basel, Switzerland) Jun 2023Microbial and biochemical changes in the brine during the spontaneous fermentation of Gordal, Hojiblanca and Manzanilla olive cultivars processed according to the...
Microbial and biochemical changes in the brine during the spontaneous fermentation of Gordal, Hojiblanca and Manzanilla olive cultivars processed according to the natural style were monitored. The microbial composition was assessed through a metagenomic study. Sugars, ethanol, glycerol, organic acids and phenolic compounds were quantified by standard methods. In addition, the volatile profiles, contents of phenolic compounds in the olives and quality parameters of the final products were compared. Fermentation in Gordal brines was conducted by lactic acid bacteria (mainly and ) and yeasts (mainly , and ). In Hojiblanca and Manzanilla brines, halophilic Gram-negative bacteria (e.g., , and ) along with yeasts (mainly, ) were responsible for the fermentation. Higher acidity and lower pH values were reached in Gordal brines compared to Hojiblanca and Manzanilla. After 30 days of fermentation, no sugars were detected in Gordal brine, but residual amounts were found in the brines from Hojiblanca (<0.2 g/L glucose) and Manzanilla (2.9 g/L glucose and 0.2 g/L fructose). Lactic acid was the main acid product in Gordal fermentation, whereas citric acid was the predominant organic acid in the Hojiblanca and Manzanilla brines. Manzanilla brine samples showed a greater concentration of phenolic compounds than Hojiblanca and Gordal brines. After a 6-month fermentation, Gordal olives were superior compared to the Hojiblanca and Manzanilla varieties regarding product safety (lower final pH and absence of ), content of volatile compounds (richer aroma), content of bitter phenolics (lower content of oleuropein, which resulted in less perceived bitterness) and color parameters (more yellow and lighter color, indicating a higher visual appraisal). The results of the present study will contribute to a better understanding of each fermentation process and could help to promote natural-style elaborations using the above-mentioned olive cultivars.
PubMed: 37372597
DOI: 10.3390/foods12122386 -
Microbial Cell Factories Mar 2015A key pathway for ester biosynthesis in yeast is the condensation of an alcohol with acetyl-CoA by alcohol-O-acetyltransferase (AATase). This pathway is also prevalent...
BACKGROUND
A key pathway for ester biosynthesis in yeast is the condensation of an alcohol with acetyl-CoA by alcohol-O-acetyltransferase (AATase). This pathway is also prevalent in fruit, producing short and medium chain volatile esters during ripening. In this work, a series of six AATases from Saccharomyces and non-Saccharomyces yeasts as well as tomato fruit were evaluated with respect to their activity, intracellular localization, and expression in Saccharomyces cerevisiae and Escherichia coli cell hosts. The series of AATases includes Atf1 and Atf2 from S. cerevisiae, as well as AATases from S. pastorianus, Kluyveromyces lactis, Pichia anomala, and Solanum lycopersicum (tomato).
RESULTS
When expressed in S. cerevisiae, Atf1, Atf2, and an AATase from S. pastorianus localized to lipid droplets, while AATases from non-Saccharomyces yeasts and tomato fruit did not localize to intracellular membranes and were localized to the cytoplasm. All AATases studied here formed intracellular aggregates when expressed in E. coli, and western blot analysis revealed that expression levels in E. coli were upwards of 100-fold higher than in S. cerevisiae. Fermentation and whole cell lysate activity assays of the two most active AATases, Atf1 from S. cerevisiae and an AATase from tomato fruit, demonstrated that the aggregates were enzymatically active, but with highly reduced specific activity in comparison to activity in S. cerevisiae. Activity was partially recovered at lower expression levels, coinciding with smaller intracellular aggregates. In vivo and in vitro activity assays from heterologously expressed Atf1 from S. cerevisiae, which localizes to lipid droplets under homologous expression, demonstrates that its activity is not membrane dependent.
CONCLUSIONS
The results of these studies provide important information on the biochemistry of AATases under homologous and heterologous expression with two common microbial hosts for biochemical processes, S. cerevisiae and E. coli. All studied AATases formed aggregates with low enzymatic activity when expressed in E. coli and any membrane localization observed in S. cerevisiae was lost in E. coli. In addition, AATases that were found to localize to lipid droplet membranes in S. cerevisiae were found to not be membrane dependent with respect to activity.
Topics: Acetyltransferases; Blotting, Western; Escherichia coli; Fungal Proteins; Green Fluorescent Proteins; Intracellular Space; Kluyveromyces; Lipid Droplets; Solanum lycopersicum; Microscopy, Fluorescence; Pichia; Plant Proteins; Proteins; Recombinant Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Species Specificity
PubMed: 25880435
DOI: 10.1186/s12934-015-0221-9 -
Frontiers in Microbiology 2020The ascomycete yeast is a mutualistic symbiont of different insects, including diptera vectors of diseases. Although fungal symbioses have been so far poorly... (Review)
Review
The ascomycete yeast is a mutualistic symbiont of different insects, including diptera vectors of diseases. Although fungal symbioses have been so far poorly characterized, the topic is gaining attention as yeast-insect interactions can provide pivotal information on insect biology, such as their environmental adaptation or vectorial capability. We review the symbiosis between and mosquitoes, which implies nutritional and protective functions. Furthermore, we focus on antiplasmodial effects of in malaria vectors and discuss the yeast potential for the "symbiotic control" (SC) of mosquito-borne diseases (MBDs).
PubMed: 33552032
DOI: 10.3389/fmicb.2020.621605 -
Applied and Environmental Microbiology Nov 2022With industrial agriculture increasingly challenging our ecological limits, alternative food production routes such as microbial protein (MP) production are receiving...
With industrial agriculture increasingly challenging our ecological limits, alternative food production routes such as microbial protein (MP) production are receiving renewed interest. Among the multiple substrates so far evaluated for MP production, renewable bioethanol (EtOH) is still underexplored. Therefore, the present study investigated the cultivation of five microorganisms (2 bacteria, 3 yeasts) under carbon (C), nitrogen (N), and dual C-N-limiting conditions (molar C/N ratios of 5, 60, and 20, respectively) to evaluate the production (specific growth rate, protein and biomass yield, production cost) as well as the nutritional characteristics (protein and carbohydrate content, amino acid [AA] profile) of MP production from bioethanol. Under C-limiting conditions, all the selected microorganisms showed a favorable AA profile for human nutrition (average AA score of 1.5 or higher), with a negative correlation between protein content and growth rate. Maximal biomass yields were achieved under conditions where no extracellular acetate was produced. Cyberlindnera saturnus and Wickerhamomyces anomalus displayed remarkably high biomass yields (0.40 to 0.82 g cell dry weight [CDW]/g EtOH), which was reflected in the lowest estimated biomass production costs when cultivated with a C/N ratio of 20. Finally, when the production cost was evaluated on a protein basis, Corynebacterium glutamicum grown under C-limiting conditions showed the most promising economic outlook. The global protein demand is rapidly increasing at rates that cannot be sustained, with projections showing 78% increased global protein needs by 2050 (361 compared to 202 million ton/year in 2017). In the absence of dedicated mitigation strategies, the environmental effects of our current food production system (relying on agriculture) are expected to surpass the planetary boundaries-the safe operating space for humanity-by 2050. Here, we illustrate the potential of bioethanol-renewable ethanol produced from side streams-as a main resource for the production of microbial protein, a radically different food production strategy in comparison to traditional agriculture, with the potential to be more sustainable. This study unravels the kinetic, productive, and nutritional potential for microbial protein production from bioethanol using the bacteria Methylorubrum extorquens and Corynebacterium glutamicum and the yeasts Cyberlindnera saturnus, and Metschnikowia pulcherrima, setting the scene for microbial protein production from renewable ethanol.
Topics: Humans; Nitrogen; Carbon; Biomass; Ethanol; Yeasts; Fermentation; Biofuels
PubMed: 36286523
DOI: 10.1128/aem.01188-22 -
Scientific Reports Sep 2021Symbiotic fungi of wood-inhabiting insects are often considered to aid wood digestion of host insects when the associated fungi can assimilate wood-associated...
Symbiotic fungi of wood-inhabiting insects are often considered to aid wood digestion of host insects when the associated fungi can assimilate wood-associated indigestible materials. In most cases, however, the components of wood that are utilized by fungal symbionts remain poorly understood. The lizard beetle Doubledaya bucculenta (Coleoptera, Erotylidae, Languriinae) farms the symbiotic yeast Wickerhamomyces anomalus inside the cavity of host bamboo internodes, which serves as food for larvae. To determine the carbon sources of the internodes serving as nutritional substrates for W. anomalus, we used ion exchange chromatography measurements to analyze free and structural sugar compositions in fresh pith (FP), yeast-cultured pith (YP), and larva-reared pith (LP) of internodes. Glucose and fructose were the major free sugars in FP and markedly decreased in YP and LP. For structural sugars, no sugar significantly decreased in YP or LP compared with FP. Carbon assimilation tests showed that W. anomalus assimilated glucose, mannose, fructose, and sucrose strongly, xylose and cellobiose moderately, and xylan weakly. Elemental analysis revealed that the compositions of carbon, hydrogen, and nitrogen were not significantly different among tissue types. These results suggest that W. anomalus does not consume bamboo-associated indigestible sugars but most free sugars, mainly glucose and fructose, in the pith. Our findings suggest that a symbiont's abilities may not always benefit its host in nature.
Topics: Animals; Carbon; Coleoptera; Female; Larva; Oviposition; Saccharomycetales; Sasa; Symbiosis
PubMed: 34584161
DOI: 10.1038/s41598-021-98733-y -
Foods (Basel, Switzerland) Sep 2023Microbial inoculation in moromi fermentation has a great influence on the physicochemical and flavour properties of soy sauces. This work investigated the effect of...
Microbial inoculation in moromi fermentation has a great influence on the physicochemical and flavour properties of soy sauces. This work investigated the effect of inoculating and on the flavour formation of early-stage moromi (30 days) fermented at a lower temperature (22 °C) by determining their physicochemical and aroma changes. The results showed that single yeast or LAB inoculation increased the production of amino nitrogen, lactic acid and acetic acid, as well as free amino acids and key flavour components. Particularly, the sequential inoculation of and produced more free amino acids and aromatic compounds, and there might be synergistic effects between these two strains. More characteristic soy sauce flavour compounds, such as benzaldehyde, HEMF, guaiacol and methyl maltol were detected in the sequentially inoculated moromi, and this sample showed higher scores in savoury, roasted and caramel intensities. These results confirmed that sequential inoculation of and could be a choice for the future production of moromi with good flavour and quality under a lower temperature.
PubMed: 37761218
DOI: 10.3390/foods12183509