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Archives of Microbiology Mar 2024The present study focuses on investigating 60 strains of yeast isolated from the natural fermentation broth of Vitis labruscana Baily × Vitis vinifera L. These...
Recovery and characterization of β-glucosidase-producing non-Saccharomyces yeasts from the fermentation broth of Vitis labruscana Baily × Vitis vinifera L. for investigation of their fermentation characteristics.
The present study focuses on investigating 60 strains of yeast isolated from the natural fermentation broth of Vitis labruscana Baily × Vitis vinifera L. These strains underwent screening using lysine culture medium and esculin culture medium, resulting in the identification of 27 local non-Saccharomyces yeast strains exhibiting high β-glucosidase production. Subsequent analysis of their fermentation characteristics led to the selection of four superior strains (Z-6, Z-11, Z-25, and Z-58) with excellent β-glucosidase production and fermentation performance. Notably, these selected strains displayed a dark coloration on esculin medium and exhibited robust gas production during Duchenne tubules' fermentation test. Furthermore, all four non-Saccharomyces yeast strains demonstrated normal growth under specific conditions including SO mass concentration ranging from 0.1 to 0.3 g/L, temperature between 25 and 30 °C, glucose mass concentration ranging from 200 to 400 g/L, and ethanol concentration at approximately 4%. Molecular biology identification confirmed that all selected strains belonged to Pichia kudriavzevii species which holds great potential for wine production.
Topics: Vitis; Saccharomyces cerevisiae; Fermentation; beta-Glucosidase; Esculin; Yeasts; Wine; Pichia
PubMed: 38493436
DOI: 10.1007/s00203-024-03878-9 -
Journal of Bioscience and Bioengineering Jun 2024The aim of this study was to evaluate the physiology of 13 yeast strains by assessing their kinetic parameters under anaerobic conditions. They included Saccharomyces...
The aim of this study was to evaluate the physiology of 13 yeast strains by assessing their kinetic parameters under anaerobic conditions. They included Saccharomyces cerevisiae CAT-1 and 12 isolated yeasts from different regions in Brazil. The study aimed to enhance understanding of the metabolism of these strains for more effective applications. Measurements included quantification of sugars, ethanol, glycerol, and organic acids. Various kinetic parameters were analyzed, such as specific substrate utilization rate (q), maximum specific growth rate (μ), doubling time, biomass yield, product yield, maximum cell concentration, ethanol productivity (P), biomass productivity, and CO concentration. S. cerevisiae CAT-1 exhibited the highest values in glucose for μ (0.35 h), q (3.06 h), and P (0.69 gEth L h). Candida parapsilosis Recol 37 did not fully consume the substrate. In fructose, S. cerevisiae CAT-1 stood out with higher values for μ (0.25 h), q (2.24 h), and P (0.60 gEth L h). Meyerozyma guilliermondii Recol 09 and C. parapsilosis Recol 37 had prolonged fermentation times and residual substrate. In sucrose, only S. cerevisiae CAT-1, S. cerevisiae BB9, and Pichia kudriavzevii Recol 39 consumed all the substrate, displaying higher P (0.72, 0.51, and 0.44 gEth L h, respectively) compared to other carbon sources.
Topics: Fructose; Glucose; Sucrose; Fermentation; Anaerobiosis; Saccharomyces cerevisiae; Carbon; Biomass; Ethanol; Yeasts; Kinetics; Glycerol; Brazil
PubMed: 38493064
DOI: 10.1016/j.jbiosc.2024.02.003 -
European Journal of Clinical... May 2024This study investigates how surfactants affect the in-vitro anti-infective efficacy of micafungin, caspofungin, anidulafungin, and amphotericin B in treating pulmonary...
PURPOSE
This study investigates how surfactants affect the in-vitro anti-infective efficacy of micafungin, caspofungin, anidulafungin, and amphotericin B in treating pulmonary mycoses.
METHODS
MIC values for antifungal agents were determined against Candida krusei (now Pichia kudriavzevii) ATCC 6258, Candida albicans ATCC 90028, and 18 clinical isolates using the broth microdilution method in RPMI medium, following EUCAST recommendations. MIC assays included testing with and without Curosurf® surfactant at 1 mg/mL for C. krusei ATCC 6258 and all C. krusei isolates. Subsequent Time-kill studies in Sabouraud broth involved testing both C. albicans ATCC 90028 and C. krusei ATCC 6258 strains at concentrations equal their respective MIC values, with and without surfactant, using all four antifungals. CFU/mL were assessed at multiple time points up to 24 h. TKCs with different surfactant concentrations for C. krusei ATCC 6258 and mini-TKCs at various concentrations relative to the MIC of C. krusei isolates and the reference strain were conducted with micafungin, anidulafungin, and caspofungin.
RESULTS
MIC results showed that 1 µg/mL surfactant reduced killing of micafungin and anidulafungin against C. krusei, while caspofungin was unaffected. Amphotericin B's MIC decreased by half. TKCs demonstrated significant effects of surfactant on micafungin and anidulafungin against C. krusei, with complete abolition of anidulafungin's activity against C. albicans.
CONCLUSION
This in-vitro study highlights the concentration-dependent inhibitory effect of surfactant on antifungal activity against C. krusei and, to some extent, C. albicans, necessitating further clinical validation for invasive lung mycoses treatment.
Topics: Antifungal Agents; Microbial Sensitivity Tests; Humans; Pulmonary Surfactants; Candida albicans; Candida; Micafungin; Candidiasis; Amphotericin B; Echinocandins; Caspofungin
PubMed: 38483681
DOI: 10.1007/s10096-024-04799-7 -
Microbiology Spectrum Apr 2024Azole drugs are the main therapeutic drugs for invasive fungal infections. However, azole-resistant strains appear repeatedly in the environment, posing a major threat...
Azole drugs are the main therapeutic drugs for invasive fungal infections. However, azole-resistant strains appear repeatedly in the environment, posing a major threat to human health. Several reports have shown that mitochondria are associated with the virulence of pathogenic fungi. However, there are few studies on the mechanisms of mitochondria-mediated azoles resistance. Here, we first performed mitochondrial proteomic analysis on multiple species (, , and ) and analyzed the differentially expressed mitochondrial proteins (DEMPs) between azole-sensitive and azole-resistant species. Subsequently, we performed Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, gene ontology analysis, and protein-protein interaction network analysis of DEMPs. Our results showed that a total of 417, 165, and 25 DEMPs were identified in resistant , and , respectively. These DEMPs were enriched in ribosomal biogenesis at cytosol and mitochondria, tricarboxylic acid cycle, glycolysis, transporters, ergosterol, and cell wall mannan biosynthesis. The high activations of these cellular activities, found in and (at low scale), were mostly opposite to those observed in two fermenter species- and . Several transcription factors including Rtg3 were highly produced in resistant that experienced a complex I activation of mitochondrial electron transport chain (ETC). The reduction of mitochondrial-related activities and complex IV/V of ETC in and was companying with the reduced proteins of Tor1, Hog1, and Snf1/Snf4.IMPORTANCE spp. are common organisms that cause a variety of invasive diseases. However, spp. are resistant to azoles, which hinders antifungal therapy. Exploring the drug-resistance mechanism of pathogenic spp. will help improve the prevention and control strategy and discover new targets. Mitochondria, as an important organelle in eukaryotic cells, are closely related to a variety of cellular activities. However, the role of mitochondrial proteins in mediating azole resistance in spp. has not been elucidated. Here, we analyzed the mitochondrial proteins and signaling pathways that mediate azole resistance in spp. to provide ideas and references for solving the problem of azole resistance. Our work may offer new insights into the connection between mitochondria and azoles resistance in pathogenic fungi and highlight the potential clinical value of mitochondrial proteins in the treatment of invasive fungal infections.
Topics: Humans; Candida; Azoles; Antifungal Agents; Proteomics; Drug Resistance, Fungal; Candida albicans; Signal Transduction; Mitochondria; Invasive Fungal Infections; Mitochondrial Proteins; Microbial Sensitivity Tests
PubMed: 38442003
DOI: 10.1128/spectrum.04042-23 -
Journal of Agricultural and Food... Mar 2024Geraniol is an attractive natural monoterpene with significant industrial and commercial value in the fields of pharmaceuticals, condiments, cosmetics, and bioenergy....
Geraniol is an attractive natural monoterpene with significant industrial and commercial value in the fields of pharmaceuticals, condiments, cosmetics, and bioenergy. The biosynthesis of monoterpenes suffers from the availability of key intermediates and enzyme-to-substrate accessibility. Here, we addressed these challenges in by a plasma membrane-anchoring strategy and achieved sustainable biosynthesis of geraniol using bagasse hydrolysate as substrate. On this basis, a remarkable 2.4-fold improvement in geraniol titer was achieved by combining spatial and temporal modulation strategies. In addition, enhanced geraniol transport and modulation of membrane lipid-associated metabolism effectively promoted the exocytosis of toxic monoterpenes, significantly improved the resistance of the engineered strain to monoterpenes and improved the growth of the strains, resulting in geraniol yield up to 1207.4 mg L at shake flask level. Finally, 1835.2 mg L geraniol was obtained in a 5 L bioreactor using undetoxified bagasse hydrolysate. Overall, our study has provided valuable insights into the plasma membrane engineering of for the sustainable and green production of valuable compounds.
Topics: Acyclic Monoterpenes; Metabolic Engineering; Monoterpenes; Pichia
PubMed: 38408332
DOI: 10.1021/acs.jafc.3c09651 -
ACS Synthetic Biology Mar 2024is an industrial yeast with excellent multistress resistance. However, due to the diploid genome and the lack of meiosis and screening markers, its molecular genetic...
is an industrial yeast with excellent multistress resistance. However, due to the diploid genome and the lack of meiosis and screening markers, its molecular genetic operation is limited. Here, a gene editing system using the toxin-antitoxin pair from the type II toxin-antitoxin system in as a screening marker was constructed. The RelBE complex can specifically and effectively regulate cell growth and arrest through a conditionally controlled toxin RelE switch, thereby achieving the selection of positive recombinants. The constructed editing system achieved precise gene deletion, replacement, insertion, and gene episomal expression in . Compared with the traditional amino acid deficiency complementation editing system, this editing system produced higher biomass and the gene deletion efficiency was increased by 3.5 times. Using this system, the production of 2-phenylethanol by was increased by 11.5-13.5% through metabolic engineering and tolerance engineering strategies. These results suggest that the stable gene editing system based on toxin-antitoxin pairs can be used for gene editing of to modify metabolic pathways and promote industrial applications. Therefore, the constructed gene editing system is expected to provide a promising strategy for polyploid industrial microorganisms lacking gene manipulation methods.
Topics: Gene Editing; Antitoxins; Bacterial Toxins; Phenylethyl Alcohol; Escherichia coli; Pichia
PubMed: 38365187
DOI: 10.1021/acssynbio.3c00640 -
Medical Mycology Jan 2024Candida krusei also known as Pichia kudriavzevii is a potentially multidrug-resistant yeast because it is intrinsically resistant to fluconazole and develops acquired...
Candida krusei also known as Pichia kudriavzevii is a potentially multidrug-resistant yeast because it is intrinsically resistant to fluconazole and develops acquired resistance to echinocandins and polyenes. Here, we aim to provide a better understanding of the epidemiology and transmission modes of C. krusei infections by comparing invasive bloodstream (n = 35) and non-invasive vaginal (n = 20) C. krusei isolates. The genetic relatedness of the isolates was assessed using a newly described short tandem repeat (STR) analysis and their sensitivity to eight antifungal compounds was evaluated by antifungal susceptibility testing using the CLSI microbroth dilution method. All C. krusei isolates revealed unique STR genotypes, indicating the absence of clonal transmission in the study group. Furthermore, no drug-resistant or non-wild-type isolates were identified. Our findings demonstrated high resolution of STR genotyping for the detection and simultaneous genetic analysis of multiple C. krusei strains in clinical samples and excellent in vitro activity of common antifungal agents against invasive strains.
Topics: Female; Animals; Antifungal Agents; Turkey; Candida; Drug Resistance, Fungal; Molecular Typing; Microbial Sensitivity Tests; Pichia
PubMed: 38289726
DOI: 10.1093/mmy/myae005 -
Food Science & Nutrition Jan 2024Iron deficiency anemia is highly prevalent in developing countries due to the consumption of cereal-based foods rich in phytate that chelates minerals such as iron and...
Iron deficiency anemia is highly prevalent in developing countries due to the consumption of cereal-based foods rich in phytate that chelates minerals such as iron and zinc making them unavailable for absorption by humans. The aim of the present study was to degrade phytic acid in composite flour (wheat/cassava/sorghum) bread by the addition of phytase-producing yeasts in the baking process to achieve a phytate-to-iron molar ratio <1 and a phytate-to-zinc molar ratio <15, ratios needed to achieve an enhanced absorption by humans. The high-phytase (HP)-producing yeasts were two (YD80 and BY80) that have been genetically modified by a directed mutagenesis strategy, and TY13 isolated from a Tanzanian lactic fermented maize gruel () and selected as naturally HP yeast. To further improve the phytase production by the yeasts, four different brands of phytase-promoting yeast extracts were added in the baking process. In addition, two yeast varieties were preincubated for 1 h at 30°C to initiate phytase biosynthesis. The phytate content was measured by high-performance ion chromatography (HPIC) and the mineral content by ion chromatography (HPIC). The results showed that all three HP yeasts improved the phytate degradation compared with the composite bread with no added HP yeast. The composite bread with preincubated BY80 or TY13 plus Bacto yeast extract resulted in the lowest phytate content (0.08 μmol/g), which means a 99% reduction compared with the phytate content in the composite flour. With added yeast extracts from three of the four yeast extract brands in the baking process, all composite breads had a phytate reduction after 2-h fermentation corresponding to a phytate: iron molar ratio between 1.0 and 0.3 and a phytate: zinc molar ratio <3 suggesting a much-enhanced bioavailability of these minerals.
PubMed: 38268898
DOI: 10.1002/fsn3.3754 -
Journal of Applied Microbiology Feb 2024To assess the capability of Pichia kudriavzevii strains isolated from wine, cider, and natural environments in North Patagonia to produce ciders with reduced malic acid...
AIMS
To assess the capability of Pichia kudriavzevii strains isolated from wine, cider, and natural environments in North Patagonia to produce ciders with reduced malic acid levels.
METHODS AND RESULTS
Fermentation kinetics and malic acid consumption were assessed in synthetic media and in regional acidic apple musts. All P. kudriavzevii strains degraded malic acid and grew in synthetic media with malic acid as the sole carbon source. Among these strains, those isolated from cider exhibited higher fermentative capacity, mainly due to increased fructose utilization; however, a low capacity to consume sucrose present in the must was also observed for all strains. The NPCC1651 cider strain stood out for its malic acid consumption ability in high-malic acid Granny Smith apple must. Additionally, this strain produced high levels of glycerol as well as acceptable levels of acetic acid. On the other hand, Saccharomyces cerevisiae ÑIF8 reference strain isolated from Patagonian wine completely consumed reducing sugars and sucrose and showed an important capacity for malic acid consumption in apple must fermentations.
CONCLUSIONS
Pichia kudriavzevii NPCC1651 strain isolated from cider evidenced interesting features for the consumption of malic acid and fructose in ciders.
Topics: Malus; Fructose; Wine; Saccharomyces cerevisiae; Fermentation; Acetic Acid; Sucrose; Malates; Pichia
PubMed: 38268424
DOI: 10.1093/jambio/lxae019 -
International Journal of Infectious... Mar 2024Candida krusei disseminated infection is a rare complication of protracted neutropenia. Herein, we report a case of a 31-year-old male with relapsed acute myeloid...
Candida krusei disseminated infection is a rare complication of protracted neutropenia. Herein, we report a case of a 31-year-old male with relapsed acute myeloid leukemia who developed Candida krusei fungemia with cutaneous, ocular, splenic, renal, bone marrow and osseous involvement leading to severe hypercalcemia, treated with parenteral antifungals followed by oral ibrexafungerp.
Topics: Male; Humans; Adult; Hypercalcemia; Candidiasis; Antifungal Agents; Fungemia; Pichia
PubMed: 38266977
DOI: 10.1016/j.ijid.2024.01.012