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Journal of Food Science and Technology Jun 2023Kombucha is a fermented tea with a combination of yeast and bacteria. Kombucha teas may have a variable microbiota based on geographic origin and cultural conditions....
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Kombucha is a fermented tea with a combination of yeast and bacteria. Kombucha teas may have a variable microbiota based on geographic origin and cultural conditions. The microbial flora of kombucha has been studied with culture-dependent methods. But, the improvement of the metataxonomic approach has broadened our perspective on fermented foods. In this study, a kombucha mother was procured from an artisanal supplier in Türkiye. High-throughput new-generation sequencing (16S rRNA and Internal Transcribed Spacer (ITS)) was carried out to investigate the microbial communities of kombucha after 7 days of fermentation in both liquid tea (L) and pellicle (P). Microbial counts, pH (4.42 ± 0.01 and 3.50 ± 0.02), and TA% (0.26 ± 0.02 and 0.60 ± 0.04) were also detected on the first and 7 days of fermentation. According to metataxonomic results, the dominant bacteria were (%21.13), an acetic acid-producing bacteria, and the dominant fungal genus was (64.35%) in L while sp. CE17 was the dominant bacteria (7%) and was also the dominant yeast in P. This study also revealed different species which were not common in kombucha including propionic acid and butyric acid-producing bacteria such as and , a butyrivibriocin producing bacteria. Accordingly, different yeast species were detected such as and .
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s13197-023-05725-z.
PubMed: 37187981
DOI: 10.1007/s13197-023-05725-z -
Journal of Dairy Science Oct 2022Bovine mastitis, a major infectious disease affecting milking cows, leads to reduced milk yield and quality, reduced animal welfare, and an increased need for culling....
Bovine mastitis, a major infectious disease affecting milking cows, leads to reduced milk yield and quality, reduced animal welfare, and an increased need for culling. Although its major causative agents are bacteria, yeast species and achlorophyllous algae of the Prototheca genus are well known as causative agents of bovine refractory mastitis. Nevertheless, few studies have analyzed specific yeasts and Prototheca in this context. Herein, we present survey data of yeast species and Prototheca species isolated from bulk tank milk in the Tokachi district of Japan from April 2020 through March 2021. The species of 276 isolates were determined. Yeast species accounted for 184 isolates, of which Pichia kudriavzevii was the most prevalent species. Regarding Prototheca species, only Prototheca bovis was isolated (92 isolates). Prototheca bovis and Pichia kudriavzevii were detected throughout the year and were detected repeatedly on the same farm. Kluyveromyces marxianus was the second most frequently isolated yeast species after Pichia kudriavzevii. Candida parapsilosis, the fourth most frequently isolated yeast species, was found discontinuously. Analysis of monthly data indicated that Kluyveromyces marxianus and Candida parapsilosis were mainly found during the winter and summer months, respectively. Candida akabanensis and Pichia cactophila were the third and fifth most frequently isolated yeast species, respectively. They were detected repeatedly in bulk tank milk samples from the same farms. Results obtained from bulk tank milk underscore the prevalence of these species. These study results are expected to contribute to the elucidation of problematic yeast and Prototheca species.
Topics: Animals; Cattle; Cattle Diseases; Female; Japan; Kluyveromyces; Mastitis, Bovine; Milk; Phylogeny; Pichia; Prototheca
PubMed: 35965121
DOI: 10.3168/jds.2022-21781 -
New Biotechnology Jul 2022Oleaginous yeasts offer an interesting possibility for renewable lipid production, since the single cell oil accumulated can be based on a wide range of cheap,...
Oleaginous yeasts offer an interesting possibility for renewable lipid production, since the single cell oil accumulated can be based on a wide range of cheap, waste-derived carbon sources. Here, several short chain carboxylic acids and sugars commonly found in these substrates were assessed as carbon sources for Apiotrichum brassicae and Pichia kudriavzevii. While both strains were able to utilize all carbon sources employed, high volumetric lipid productivities (0.4 g/Lh) and lipid contents (68%) could be reached particularly with acetic acid as carbon source. Odd-numbered volatile fatty acids led to lower productivities and lipid contents, but the lipids contained unusually high proportions of odd-numbered fatty acids (up to 80% of total fatty acids). These fatty acids are rather uncommon in nature and might offer the possibility for various high value applications. In conclusion both strains are able to utilize a wide range of substrates potentially present in waste-derived substrates. Lipid content and volumetric lipid productivity strongly depend on the carbon source, with even-numbered volatile fatty acids resulting in the highest values. For volatile fatty acids in particular, the carbon source also strongly influences the composition of the lipids produced by the yeast strains.
Topics: Basidiomycota; Biofuels; Carbon; Fatty Acids; Fatty Acids, Volatile; Pichia; Yeasts
PubMed: 35182781
DOI: 10.1016/j.nbt.2022.02.003 -
ELife Apr 2021Bacterial members of the infant gut microbiota and bacterial-derived short-chain fatty acids (SCFAs) have been shown to be protective against childhood asthma, but a...
Bacterial members of the infant gut microbiota and bacterial-derived short-chain fatty acids (SCFAs) have been shown to be protective against childhood asthma, but a role for the fungal microbiota in asthma etiology remains poorly defined. We recently reported an association between overgrowth of the yeast in the gut microbiota of Ecuadorian infants and increased asthma risk. In the present study, we replicated these findings in Canadian infants and investigated a causal association between early life gut fungal dysbiosis and later allergic airway disease (AAD). In a mouse model, we demonstrate that overgrowth of within the neonatal gut exacerbates features of type-2 and -17 inflammation during AAD later in life. We further show that growth and adherence to gut epithelial cells are altered by SCFAs. Collectively, our results underscore the potential for leveraging inter-kingdom interactions when designing putative microbiota-based asthma therapeutics.
Topics: Animals; Asthma; Bacteria; Bacterial Physiological Phenomena; Case-Control Studies; Child; Child, Preschool; Gastrointestinal Microbiome; Humans; Infant; Mice, Inbred C57BL; Pichia; Specific Pathogen-Free Organisms; Mice
PubMed: 33876729
DOI: 10.7554/eLife.67740 -
Journal of Advanced Research Jan 2020Olfactory cues have a large impact on insect behaviour and fitness consequently showing potential in pest management. Yeast released volatiles are used by insects as...
Olfactory cues have a large impact on insect behaviour and fitness consequently showing potential in pest management. Yeast released volatiles are used by insects as olfactory cues for finding feeding and oviposition sites. The yeast strain SB-16-15 was isolated from spontaneous fermentation of berries and identified as . Thirty-nine volatiles were sampled from the headspace of yeasts by solid phase micro extraction and identified by gas chromatography and mass spectrometry techniques. Ten of those volatiles elicited antennal responses of flies, one of the most serious pest of berries. In the two-choice experiments, flies preferred the mixture composed of nine synthetic compounds analogous to electroanntenographic active volatiles released by the yeasts compare to the solvent control. Female flies were significantly attracted to the mixture at the concentration 0.1 µL mL and showed no preference to the mixture at the concentration 1 µL mL versus control while males reacted positively to the synthetic blend at the concentration 1 µL mL. Herein, for the first time, behaviour modifying effect of berry related yeast volatiles was shown suggesting these semiochemicals have potential in use for monitoring flies.
PubMed: 32071775
DOI: 10.1016/j.jare.2019.08.001 -
Microorganisms Sep 2022Kveik are consortia of yeast used for farmhouse ale production in Western Norway. Yeast strains derived from these mixtures are known, for example, for their high...
Kveik are consortia of yeast used for farmhouse ale production in Western Norway. Yeast strains derived from these mixtures are known, for example, for their high fermentation rate, thermotolerance, lack of phenolic off flavor production (POF-) and strong flocculation phenotype. In this study, we used five single cell yeast isolates from different Kveik yeasts, analyzed their fermentation and flavor production, and compared it with a typical yeast used in distilleries using 20 °C and 28 °C as the fermentation temperatures. One of the isolates, Kveik No 3, showed an impairment of maltotriose utilization and thus a reduced ethanol yield. Kveik fermentations for spirit production often harbor bacteria for flavor enrichment. We sought to improve Kveik fermentations with non-conventional yeasts (NCY). To this end we co-fermented Kveik isolates with and using 5:1 ratios (Kveik vs. NCY) at 20 °C. The combinations of Kveik No 1 with and Kveik No 1 with showed substantially increased amounts of specific volatile aroma compounds that were previously identified in the NCYs. Our results indicate that Kveik isolates appear to be suitable for co-fermentations with certain NCY to enhance beer or spirit fermentations, increasing the potential of these yeasts for beverage productions.
PubMed: 36296198
DOI: 10.3390/microorganisms10101922 -
Microorganisms May 2022The aim of this study was to reveal the sites of yeast contamination in dairy production and perform taxonomic characterization of potential yeast spoilers in cheese...
The aim of this study was to reveal the sites of yeast contamination in dairy production and perform taxonomic characterization of potential yeast spoilers in cheese making. Occurrence of spoilage yeasts was followed throughout the manufacture of white-brined cheese at a Danish dairy, including the areas of milk pasteurization, curd processing, and packaging (26 sites in total). Spoilage yeasts were isolated from whey, old cheese curd, and air samples in viable counts of 1.48-6.27 log CFU/mL, 5.44 log CFU/g, and 1.02 log CFU/m, respectively. Yeast isolates were genotypically classified using (GTG)-PCR fingerprinting and identified by sequencing of the D1/D2 region of the 26S rRNA gene. The largest yeast heterogeneity was found in old curd collected under the turning machine of molds, where 11 different yeast species were identified. The most frequently isolated yeast species were , , and . The less abundant yeast species included , , , , , , , , , and . The awareness on occurrence and taxonomy of spoilage yeasts in cheese production will contribute to a knowledge-based control of contaminating yeasts and quality management of cheese at the dairies.
PubMed: 35744597
DOI: 10.3390/microorganisms10061079 -
Food Microbiology Sep 2022White colony-forming yeasts (WCFYs) have been reported to form a white colony on the surface of kimchi, resulting in the deterioration of kimchi sensory quality....
White colony-forming yeasts (WCFYs) have been reported to form a white colony on the surface of kimchi, resulting in the deterioration of kimchi sensory quality. However, toxicity of WCFY has rarely been studied. Thus, to evaluate the safety of WCFY (i.e., Kazachstania servazzii, Candia sake, and Pichia kudriavzevii), we conducted cell and animal experiments as well as genomic analysis. In vitro studies indicated that WCFY did not induce cytotoxic responses such as lactate dehydrogenase release, excessive oxidative stress, and mitochondrial damage at concentrations of up to 2.5 × 10 CFU/mL in human intestinal and liver cells. In animal studies using rats (single-dose and 14-day repeated-dose oral toxicity studies), WCFY did not induce death, clinical signs of toxicity, histological alterations of the liver, or increases in the expression of pro-inflammatory cytokines nor cytochrome P450-2E1 in liver tissue at concentrations of up to 5 × 10 CFU/head/day. Genomic analysis revealed that P. kudriavzevii did not harbor genes related to toxicity and antimicrobial resistance. Taken together, our data suggest that exposure to WCFY through kimchi intake did not induce toxic response in the Caco-2, HepG2, and Sprague-Dawley rats. The current work provides evidence for the safety of accidental major WCFY ingestion via kimchi.
Topics: Animals; Caco-2 Cells; Fermented Foods; Genomics; Humans; Rats; Rats, Sprague-Dawley; Yeasts
PubMed: 35690449
DOI: 10.1016/j.fm.2022.104057 -
Indian Journal of Microbiology Dec 2020The search for promising yeasts that surpass the fermentative capacity of commercial strains, such as CAT-1, is of great importance for industrial ethanol processes in...
The search for promising yeasts that surpass the fermentative capacity of commercial strains, such as CAT-1, is of great importance for industrial ethanol processes in the world. Two yeasts, BB2 and BB9, were evaluated in comparison to the industrial yeast CAT-1. The objective was to evaluate the performance profile of the three studied strains in terms of growth, substrate consumption, and metabolite formation, aiming to determine their behaviour in different media and pH conditions. The results showed that under cultivation conditions simulating the medium used in the industrial process (must at 22° Brix at pH 3.0) the highest ethanol productivity was 0.41 g L h for CAT-1, compared to 0.11 g L h and 0.16 g L h for and BB2, respectively. CAT-1 produced three times more ethanol in must at pH 3.0 (28.30 g L) and in mineral medium at pH 3.0 (29.17 g L) and 5.0 (30.70 g L) when compared to the value obtained in sugarcane must pH 3.0 (9.89 g L). It was concluded that CAT-1 was not limited by the variation in pH in the mineral medium due to its nutritional composition, guaranteeing better performance of the yeast even in the presence of stressors. Only CAT-1 expressed he constitutive invertase enzyme, which is responsible for hydrolysing the sucrose contained in the must.
PubMed: 33087999
DOI: 10.1007/s12088-020-00891-6 -
Microbiology Spectrum Dec 2022In recent decades, the incidence of infections has increased in immunocompromised patients. This multicenter study aimed to evaluate antifungal activities of 8...
In recent decades, the incidence of infections has increased in immunocompromised patients. This multicenter study aimed to evaluate antifungal activities of 8 antifungal agents against the species isolated from 10 university hospitals in Iran. During the period from Dec 2019 to Dec 2021, species were collected from clinical samples of patients. The isolates were identified by PCR restriction fragment length polymorphism and sequencing methods. The antifungal susceptibility tests of each isolate to eight antifungal agents were performed according to the microdilution CLSI M27, M59, and M60 standard methods. A total of 598 strains were isolated from clinical samples. The most commonly isolated species was C. albicans, followed by C. glabrata, C. parapsilosis, Debaryomyces hansenii (Candida famata), C. tropicalis, (Candida krusei), C. orthopsilosis, Meyerozyma guilliermondii (Candida guilliermondii), Kluyveromyces marxianus (Candida kefyr), and Clavispora lusitaniae (Candida lusitaniae). MIC values in all species were as follows: 0.25 μg/mL for caspofungin and voriconazole; 0.5 μg/mL for amphotericin B and isavuconazole; 2 μg/mL for itraconazole, luliconazole, and posaconazole; and 16 μg/mL for fluconazole. Although 30/285 C. albicans, 15/31 3/12 , 67/125 C. glabrata, 5/15 , 6/60 C. parapsilosis, and 5/23 C. tropicalis isolates were multiazole resistant with resistance to 2 to 4 azoles, pan-azole resistance was not observed. According to our data, Candida albicans and C. glabrata were the most frequent species isolated from clinical samples in Iran. Caspofungin and voriconazole, with lower MIC values, are the most effective than other antifungal agents for the treatment of infections in this region. species cause severe invasive infections of the heart, brain, eyes, bones, and other parts of the body. Knowledge of regional distributions of causative agents and their antifungal susceptibility patterns can help to monitor resistance to antifungal agents of various species and support local and national surveillance programs. In the present study, C. albicans and C. glabrata were the most frequently isolated species from clinical samples in Iran. Increasing rates of non- isolates from the Iranian population should be looked at as alarming due to various levels of intrinsic MIC values or resistance to various antifungal drugs. Caspofungin and voriconazole are recommended over fluconazole for the treatment of infections in the study region. However, amphotericin B and isavuconazole are also active against the most common species isolated from patients. Pan azole-resistant species were not observed in the present study.
Topics: Humans; Amphotericin B; Antifungal Agents; Azoles; Candida; Candida albicans; Candida glabrata; Candidiasis; Caspofungin; Drug Resistance, Fungal; Fluconazole; Iran; Microbial Sensitivity Tests; Tertiary Care Centers; Voriconazole
PubMed: 36445122
DOI: 10.1128/spectrum.02453-22