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Antonie Van Leeuwenhoek Nov 2023The use of yeasts as a feed supplement for cattle can promote animal development and performance. However, for the positive results to be consistent, strains with...
The use of yeasts as a feed supplement for cattle can promote animal development and performance. However, for the positive results to be consistent, strains with probiotic properties must be selected. The objective of this study was to isolate and identify yeasts present in the bovine feces and evaluate their probiotic potential together with strains previously isolated from the rumen (preliminary study). A total of 193 isolates were studied, including 139 isolates (19 species) from fecal samples from 11 different animals (Bos taurus and Bos indicus) and 54 strains previously isolated from rumen fluid (Bos taurus). The yeast population in the feces ranged from 3.51 to 4.99 log CFU/g, with Candida pararugosa being the most abundant (isolated from the feces of six samples analysed). Isolates were selected that had negative results in the safety tests (hemolytic activity, DNAse, and gelatinase) and had percentages greater than 35 and 70% for hydrophobicity and auto-aggregation, respectively. In addition, selected isolates had percentages greater than 77.7 and 74.7% for coaggregation with pathogenic strains of Escherichia coli and Clostridium perfringens, respectively. The isolates with percentage growth at 39 °C greater than 64.6% and viability greater than 96.7% were selected for survival testing under bovine gastrointestinal conditions. After the tests, the seven best isolates were selected, belonging to the species Candida pararugosa (L60, CCMA 928 and CCMA 930) and Pichia kudriavzevii (L97, L100, CCMA904, CCMA 907). The selected isolates were exopolysaccharide producers. Based on the results of the evaluated properties, the seven selected isolates were classified as potential probiotics for cattle.
Topics: Cattle; Animals; Saccharomyces cerevisiae; Gastrointestinal Tract; Feces; Escherichia coli; Probiotics
PubMed: 37650994
DOI: 10.1007/s10482-023-01865-6 -
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 -
Journal of Agricultural and Food... Jun 2023Nontraditional yeasts prevalent in tropical agricultural fermentations such as coffee and cocoa are known to contribute to aroma profiles, yet the functional roles and...
Nontraditional yeasts prevalent in tropical agricultural fermentations such as coffee and cocoa are known to contribute to aroma profiles, yet the functional roles and interactions between the associated microbial consortia in a farm fermentation are unclear. Here, boiled green bean extract (GBE) from green coffee beans was developed as a rich screening medium to deconstruct the microbial consortia and their interactions during the fermentation of dried green coffee beans. When cultivated in coculture with on GBE, strain-specific groupings with distinct volatile organic profiles were observed for nontraditional yeasts (e.g., spp., ). Further changes are evident when constructed consortia composed of nontraditional yeast, , and var. were cultured in GBE, and a comparison with abiotically acidified GBE suggests that pH plays a major role in the influence of lactic acid bacteria (LAB) on fermentation aromas. This approach represents a tool for the development of starter culture formulations to create different flavor profiles in coffee fermentation.
Topics: Fermentation; Saccharomyces cerevisiae; Odorants; Yeasts; Cacao; Chocolate
PubMed: 37310147
DOI: 10.1021/acs.jafc.3c01357 -
Foods (Basel, Switzerland) Nov 2022Pit mud, a specific fermented soil, is an essential material for the fermentation of Chinese strong-flavour liquor. However, few studies to date have sought to...
Pit mud, a specific fermented soil, is an essential material for the fermentation of Chinese strong-flavour liquor. However, few studies to date have sought to characterize the spatial profiles of pit mud fungal communities in fermentation cellars from Chinese strong-flavour liquor distilleries. In this analysis, differences in fungal community structures and physicochemical properties in pit mud samples from different spatial positions within fermentation cellars were analyzed, revealing unique characteristic multidimensional pit mud fungal community profiles. , , , , , , , , were dominant in the pit mud samples form the upper cellar wall, whereas , , , , , , , , , were predominant in the middle cellar wall. , , , , , and are majorly present in the down cellar wall layer. , , , , , and were identified as the dominant fungi in pit mud samples from the cellar bottom. Additionally, and are present at notably high levels in all layers of pit mud samples. Moisture, pH, PO, acetic acid, humus, K, Mg, Ca, butyric acid, and caproic acid levels in these different pit mud positions exhibited a rising incremental pattern from the upper wall layer to the bottom layer, whereas lactic acid levels were significantly lower in the bottom pit mud layer relative to these other layers. Moisture, pH, and NH-N were identified as the three most significant factors associated with fungal community composition through a redundancy analysis. Overall, these findings may offer a theoretical foundation for future efforts to improve or standardize artificial pit mud.
PubMed: 36429136
DOI: 10.3390/foods11223544 -
Journal of Advanced Pharmaceutical... 2022Pomegranate peels (PGPs) are known to have the potential as antibacterial not only from their nutrient content but also the microflora. The activities might be caused by...
Pomegranate peels (PGPs) are known to have the potential as antibacterial not only from their nutrient content but also the microflora. The activities might be caused by the existence of indigenous yeast that can be utilized to inhibit the growth of pathogenic bacteria. This study aims to identify antibacterial and antioxidant activity of indigenous yeast isolated from PGP. The research was conducted by experimental methods and followed by descriptive analysis. The study was done by the isolation of indigenous yeast from PGPs, which was identified using the rRNA sequence analysis of internal transcribed spacer (ITS) region with the primers of ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') and then compared with Basic Local Alignment Search Tools (BLAST) algorithm toward the GenBank. Antibacterial activities of indigenous yeast were tested with agar plug diffusion and time kill test toward and . The yeast identification obtained two isolates similar to CBS 314 and two isolates of ATCC 6258 which have antibacterial activity against and . PGP D4 have best antimicrobial activities with a strong activity against (±9 mm) and medium activity against (±3.1 mm).
PubMed: 35223442
DOI: 10.4103/japtr.japtr_86_21 -
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 -
Acta Tropica Jul 2022Reptiles have become popular exotic pets and in some parts of the world, they are used as important source of food, medicines, and materials. Synanthropic lizards are...
Reptiles have become popular exotic pets and in some parts of the world, they are used as important source of food, medicines, and materials. Synanthropic lizards are recognized as reservoirs of viruses, bacteria, and parasites but their role in dissemination of zoonotic pathogenic yeasts in the environment was never investigated. Therefore, fecal samples (n=177) from Podarcis siculus (Italian wall lizard), Chalcides ocellatus (Ocellated skink) and Tarentola mauritanica (Moorish gecko) were collected and yeasts were isolated and identified biochemically and molecularly by sequencing the rDNA internal transcribed spacer region (ITS). The phylogenetical relationship of isolated yeast species and their antifungal susceptibility profiles to ten antifungal agents were also assessed. Sixty samples (n=60/177; 33.9%) scored positive for yeasts, with the highest occurrence in C. ocellatus (n=11/17; 64.7%) and the highest variety of species in P. siculus (n=11/12; 91.6%). A total of 364 isolates belonging to Candida, Trichosporon, Saccharomyces and Geotrichum genera were molecularly identified. In particular, Candida albicans (n=160; 44%) followed by Trichosporon coremiiforme (n=44; 12.1%), Pichia kudriavzevii (n=32; 8.8%) and Trichosporon asahii (n=28; 7.7%) were the most frequently isolated species. The phylogenetic tree grouped all representative sequence types within the clade including Candida spp. strains from different geographical areas and from animal species, including human. All tested strains showed high susceptibility to the assayed antifungal drugs. This study suggests the role of lizards as reservoirs and spreaders of zoonotic pathogenic yeasts in the environment. The absence of resistance phenomena in the isolated yeasts might reflect an environment free of azole antifungal pollution or chemicals, suggesting the usefulness of these animals as bio indicators of environment quality.
Topics: Animals; Antifungal Agents; Candida; Lizards; Microbial Sensitivity Tests; Phylogeny; Yeasts
PubMed: 35443196
DOI: 10.1016/j.actatropica.2022.106472 -
Foods (Basel, Switzerland) Dec 2020Biocontrol is one of the most promising alternatives to synthetic fungicides for food preservation. , and section are the most concerning pathogens for grape...
Biocontrol is one of the most promising alternatives to synthetic fungicides for food preservation. , and section are the most concerning pathogens for grape development. However, frequently, other species, such as in this study, are predominant in spoiled bunches. In this work, 54 native yeasts from vineyards were screened by direct confrontation in potato dextrose agar plates as antagonists against . Isolates of , , and were selected for their antagonist activity in vitro, plus isolates of , and were used as negative controls. However, in vivo, confrontations in wounded grapes showed disagreement with direct confrontation in vitro. , , , and significantly reduced the incidence of on grapes. Nevertheless, , and themselves spoiled the wounded grapes. Inhibitions were associated with different mechanisms such as the production of volatile organic compounds (VOCs), lytic enzymes, biofilm formation, and competition for nutrients. The isolates of L18 (a producer of antifungal VOCs which completely inhibited the incidence of ) and L29 (with pectinase, chitinase and β-glucanase activity and biofilm formation which reduced 70% of the incidence of ) are proposed as suitable biocontrol agents against .
PubMed: 33327475
DOI: 10.3390/foods9121864 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Mar 2024The utilization of industrial microorganisms for the conversion of lignocellulose into high value-added chemicals is an essential pathway towards achieving carbon...
The utilization of industrial microorganisms for the conversion of lignocellulose into high value-added chemicals is an essential pathway towards achieving carbon neutrality and promoting sustainable bioeconomy. However, the pretreated lignocellulase hydrolysate often contains various sugars, salts, phenols/aldehydes and other substances, which requires microorganisms to possess strong tolerance for direct fermentation. This study aims to investigate the tolerance of to substrate, salt, and high temperature shock, in order to validate its potential for utilizing the enzymatic hydrolysate of in seawater for fermentation. The experimental results showed that the adaptively domesticated . exhibited tolerance to glucose at a concentration of 200 g/L and became a hypertonic strain. When seawater was used instead of freshwater without sterilization, the yield of glycerol in fermentation was 109% higher than that in freshwater with sterilization. Moreover, the combined thermal shock at 32 hours of fermentation and addition of 10 NaSO at 48 hours resulted in a yield of glycerol to glucose 0.37 g/g, which was 225% higher than the control group. By fermenting the enzymatic hydrolysate of . pretreated in seawater, the total conversion rate of glucose into glycerol and ethanol reached 0.45 g/g. This study indicates that hypertonic . exhibits remarkable adaptability to substrate, salt, and temperature. It not only can directly utilize complex lignocellulosic hydrolysates, but also exhibits strong tolerance to them. Therefore, it provides a potential candidate strain for the production of bio-based chemicals using lignocellulosic processes.
Topics: Glycerol; Pichia; Fermentation; Glucose; Xylose
PubMed: 38545986
DOI: 10.13345/j.cjb.230432 -
Molecules (Basel, Switzerland) Jan 2021This study aimed to identify the volatile compounds in the fermented and dried cocoa beans conducted with three distinct inoculants of yeast species due to their high...
This study aimed to identify the volatile compounds in the fermented and dried cocoa beans conducted with three distinct inoculants of yeast species due to their high fermentative capacity: , , the mixture in equal proportions 1:1 of both species, and a control fermentation (with no inoculum application). Three starter cultures of yeasts, previously isolated and identified in cocoa fermentation in the municipality of Tomé-Açu, Pará state, Brazil. The seeds with pulp were removed manually and placed in wooden boxes for the fermentation process that lasted from 6 to 7 days. On the last day of fermentation, the almonds were packaged properly and placed to dry (36 °C), followed by preparation for the analysis of volatile compounds by GC-MS technique. In addition to the control fermentation, a high capacity for the formation of desirable compounds in chocolate by the inoculants with was observed, which was confirmed through multivariate analyses, classifying these almonds with the highest content of aldehydes, esters, ketones and alcohols and low concentration of off-flavours. We conclude that the addition of mixed culture starter can be an excellent alternative for cocoa producers, suggesting obtaining cocoa beans with desirable characteristics for chocolate production, as well as creating a product identity for the producing region.
Topics: Cacao; Chocolate; Fermentation; Food Industry; Pichia; Saccharomyces cerevisiae; Seeds; Volatile Organic Compounds
PubMed: 33440885
DOI: 10.3390/molecules26020344