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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 -
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 -
International Journal of Molecular... May 2024Mycoses are one of the major causes of morbidity/mortality among immunocompromised individuals. Considering the importance of these infections, the World Health...
Mycoses are one of the major causes of morbidity/mortality among immunocompromised individuals. Considering the importance of these infections, the World Health Organization (WHO) defined a priority list of fungi for health in 2022 that include as belonging to the critical priority group and () to the medium priority group. The existence of few available antifungal drugs, their high toxicity, the acquired fungal resistance, and the appearance of new species with a broader spectrum of resistance, points out the need for searching for new antifungals, preferably with new and multiple mechanisms of action. The cyclam salt H[H(PhCH)Cyclam]Cl was previously tested against several fungi and revealed an interesting activity, with minimal inhibitory concentration (MIC) values of 8 µg/mL for and of 128 µg/mL for . The main objective of the present work was to deeply understand the mechanisms involved in its antifungal activity. The effects of the cyclam salt on yeast metabolic viability (resazurin reduction assay), yeast mitochondrial function (JC-1 probe), production of reactive oxygen species (DCFH-DA probe) and on intracellular ATP levels (luciferin/luciferase assay) were evaluated. H[H(PhCH)Cyclam]Cl induced a significant decrease in the metabolic activity of both and , an increase in Reactive Oxygen Species (ROS) production, and an impaired mitochondrial function. The latter was observed by the depolarization of the mitochondrial membrane and decrease in ATP intracellular levels, mechanisms that seems to be involved in the antifungal activity of H[H(PhCH)Cyclam]Cl. The interference of the cyclam salt with human cells revealed a CC value against HEK-293 embryonic kidney cells of 1.1 μg/mL and a HC value against human red blood cells of 0.8 μg/mL.
Topics: Antifungal Agents; Candida albicans; Humans; Reactive Oxygen Species; Candida; Microbial Sensitivity Tests; Mitochondria; Membrane Potential, Mitochondrial; Pichia
PubMed: 38791254
DOI: 10.3390/ijms25105209 -
Scientific Reports Jan 2024The timely and accurate diagnosis of candidemia, a severe bloodstream infection caused by Candida spp., remains challenging in clinical practice. Blood culture, the...
The timely and accurate diagnosis of candidemia, a severe bloodstream infection caused by Candida spp., remains challenging in clinical practice. Blood culture, the current gold standard technique, suffers from lengthy turnaround times and limited sensitivity. To address these limitations, we propose a novel approach utilizing an Electronic Nose (E-nose) combined with Time Series-based classification techniques to analyze and identify Candida spp. rapidly, using culture species of C. albicans, C.kodamaea ohmeri, C. glabrara, C. haemulonii, C. parapsilosis and C. krusei as control samples. This innovative method not only enhances diagnostic accuracy and reduces decision time for healthcare professionals in selecting appropriate treatments but also offers the potential for expanded usage and cost reduction due to the E-nose's low production costs. Our proof-of-concept experimental results, carried out with culture samples, demonstrate promising outcomes, with the Inception Time classifier achieving an impressive average accuracy of 97.46% during the test phase. This paper presents a groundbreaking advancement in the field, empowering medical practitioners with an efficient and reliable tool for early and precise identification of candidemia, ultimately leading to improved patient outcomes.
Topics: Humans; Candida; Candidemia; Artificial Intelligence; Electronic Nose; Candida parapsilosis; Pichia
PubMed: 38200060
DOI: 10.1038/s41598-023-50332-9 -
IMA Fungus Sep 2023Among molecular-based techniques for fungal identification, Sanger sequencing of the primary universal fungal DNA barcode, the internal transcribed spacer (ITS) region...
Among molecular-based techniques for fungal identification, Sanger sequencing of the primary universal fungal DNA barcode, the internal transcribed spacer (ITS) region (ITS1, 5.8S, ITS2), is commonly used in clinical routine laboratories due to its simplicity, universality, efficacy, and affordability for fungal species identification. However, Sanger sequencing fails to identify mixed ITS sequences in the case of mixed infections. To overcome this limitation, different high-throughput sequencing technologies have been explored. The nanopore-based technology is now one of the most promising long-read sequencing technologies on the market as it has the potential to sequence the full-length ITS region in a single read. In this study, we established a workflow for species identification using the sequences of the entire ITS region generated by nanopore sequencing of both pure yeast isolates and mocked mixed species reads generated with different scenarios. The species used in this study included Candida albicans (n = 2), Candida tropicalis (n = 1), Nakaseomyces glabratus (formerly Candida glabrata) (n = 1), Trichosporon asahii (n = 2), Pichia kudriavzevii (formerly Candida krusei) (n = 1), and Cryptococcus neoformans (n = 1). Comparing various methods to generate the consensus sequence for fungal species identification, the results from this study indicate that read clustering using a modified version of the NanoCLUST pipeline is more sensitive than Canu or VSEARCH, as it classified species accurately with a lower abundance cluster of reads (3% abundance compared to 10% with VSEARCH). The modified NanoCLUST also reduced the number of classified clusters compared to VSEARCH, making the subsequent BLAST+ analysis faster. Subsampling of the datasets, which reduces the size of the datasets by approximately tenfold, did not significantly affect the identification results in terms of the identified species name, percent identity, query coverage, percentage of reads in the classified cluster, and the number of clusters. The ability of the method to distinguish mixed species within sub-populations of large datasets has the potential to aid computer analysis by reducing the required processing power. The herein presented new sequence analysis pipeline will facilitate better interpretation of fungal sequence data for species identification.
PubMed: 37674240
DOI: 10.1186/s43008-023-00125-6 -
Asian Pacific Journal of Cancer... Oct 2023Candida krusei is the cause of the fungal infection candidiasis, which has a high mortality rate. Intrinsic resistance to fluconazole can cause the failure of Krusei...
BACKGROUND
Candida krusei is the cause of the fungal infection candidiasis, which has a high mortality rate. Intrinsic resistance to fluconazole can cause the failure of Krusei candidiasis treatment. Therefore, it is necessary to find alternative drugs to eliminate the fungus. Extracts of Syzygium aromaticum and Alpinia purpurata have been proven to be alternative solutions for treating Candida krusei resistance.
OBJECTIVE
This study aims to explore the active compounds Syzygium aromaticum and Alpinia purpurata as treatments against Candida krusei through bioactivity tests, molecular modeling, and toxicity tests.
METHODS
Determination of antifungal activity with the agar well diffusion and microbroth dilution method. Molecular modeling was conducted using the following software: Marvin Sketch, LigandScout 4.4.5, AutoDock ver 4.2.6, PyMOL, LigPlus, MOE ver 2008.
RESULT
Bioactivity test results of the two natural extracts against C. krusei ATCC 6258, it was found that the S. aromaticum and A. purpurata extracts have MIC50 values of 0.031 μg/mL and 1.435x105 μg/mL. The molecular modeling found that the compounds Benzotriazole, 1-(4-methyl-3-nitrobenzoyl)-, 1,3,4-Eugenol Acetate, Stigmasta-5,22-dien-3-ol, acetate (3 beta)- and Farnesyl acetate from the two natural extracts, interacts with the active site of the enzyme lanosterol-14-α-demethylase with a binding energy of -8.91, -6.04, -13.53, and -7.15 kcal/mol. The oral acute toxicity test of S. aromaticum and A. purpurata extracts proved that the LD50 was >6000 mg/kg BW and >8000 mg/kg BW. The acute dermal toxicity test of the two extracts showed that the LD50 was >6000 mg/kg BW.
CONCLUSION
S. aromaticum and A. purpurata extracts have been proven to be alternative solutions for treating Candida krusei resistance.
Topics: Humans; Antifungal Agents; Syzygium; Alpinia; Plant Extracts; Microbial Sensitivity Tests; Candidiasis; Toxicity Tests; Acetates
PubMed: 37898844
DOI: 10.31557/APJCP.2023.24.10.3403 -
Food Chemistry: X Jun 2024Kombucha is a traditional beverage produced by a living culture known as SCOBY or "symbiotic culture of bacteria and yeast". Culture-dependent production is essential...
Kombucha is a traditional beverage produced by a living culture known as SCOBY or "symbiotic culture of bacteria and yeast". Culture-dependent production is essential for stable kombucha fermentation. The aim of this study was to design a microbial community and to determine the effect of that community on the flavor and chemical properties of kombucha. The fermentations were carried out using combinations of selected species including and , which were previously isolated from kombucha. The effects of monocultures and cocultures on fermentation were investigated. The highest acetic acid producer was , which has strong antioxidant properties. In the monoculture and coculture fermentations, aldehydes, acids, and esters were generally observed at the end of fermentation. This study confirms that microbiota reconstruction is a viable approach for achieving the production of kombucha with increased bioactive constituents and consumer acceptance.
PubMed: 38808165
DOI: 10.1016/j.fochx.2024.101469 -
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 -
Annales de Biologie Clinique Feb 2024Vulvovaginal candidiasis (VVC) alongside with antifungal resistance are becoming a major clinical problem in recent years. A prospective study aimed to evaluate the...
Vulvovaginal candidiasis (VVC) alongside with antifungal resistance are becoming a major clinical problem in recent years. A prospective study aimed to evaluate the diversity of yeast strains associated with VVC in Tebessa city (northeastern Algeria) and investigate their susceptibility patterns. Over two months, yeasts were isolated on chromogenic medium from twenty-nine non-pregnant women with symptomatic VVC. The isolates were characterized with MALDI-TOF MS and antifungal susceptibility testing was performed for nine antifungal drugs using SensititreTM YeastOneTM YO10. Twenty-nine non-duplicate yeasts were recovered and the mass spectrometry profiles showed reliable scores of which four genera and five different species were identified. Candida albicans accounted for 65.5 % (n = 19) of the total number of isolates, followed by C. glabrata with 20.7% (n = 6). For the remaining non-albicans Candida (NCA) species, Kluyveromyces marxianus with 6.9% (n = 2), Pichia kudriavzevii and Saccharomyces cerevisiae with one isolate each. The antifungal susceptibilities showed wild type MICs of C. albicans to amphotericin B, azoles and echinocandins. In addition, four C. albicans isolates were resistant to flucytosine. For C. glabrata isolates, 100% non-WT phenotype was found for both posaconazole and itraconazole. For the very first time, the obtained outcomes bring out new data concerning the epidemiology of yeasts causing VVC in Algeria and their antimicrobial susceptibility profiles.
Topics: Female; Humans; Candidiasis, Vulvovaginal; Antifungal Agents; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Prospective Studies; Algeria; Candida; Candida albicans; Microbial Sensitivity Tests
PubMed: 38189374
DOI: 10.1684/abc.2023.1852 -
Food Microbiology Aug 2024Defined starter cultures, containing selected microbes could reduce the complexity of natural starter, are beneficial for controllable food fermentations. However, there...
Defined starter cultures, containing selected microbes could reduce the complexity of natural starter, are beneficial for controllable food fermentations. However, there are challenges in identifying key microbiota and constructing synthetic microbiota for traditional food fermentations. Here, we aimed to develop a defined starter culture for reproducible profile of flavour compounds, using Chinese Xiaoqu Baijiu fermentation as a case. We classified all microbes into 4 modules using weighted correlation network analysis. Module 3 presented significant correlations with flavour compounds (P < 0.05) and the highest gene abundance related with flavour compound production. 13 dominant species in module 3 were selected for mixed culture fermentation, and each species was individually deleted to analyse the effect on flavour compound production. Ten species, presenting significant effects (P < 0.05) on flavour compound production, were selected for developing the starter culture, including Rhizopus oryzae, Rhizopus microsporus, Saccharomyces cerevisiae, Pichia kudriavzevii, Wickerhamomyces anomalus, Lactobacillus acetotolerans, Levilactobacillus brevis, Weissella paramesenteroides, Pediococcus acidilactici, and Leuconostoc pseudomesenteroides. After optimising the structure of the starter culture, the profile similarity of flavour compounds produced by the starter culture reached 81.88% with that by the natural starter. This work indicated feasibility of reproducible profile of flavour compounds with defined starter culture for food fermentations.
Topics: Fermentation; Microbiota; Saccharomyces cerevisiae; China
PubMed: 38637092
DOI: 10.1016/j.fm.2024.104533