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Microbiology Spectrum Dec 2021This study investigated the effect of Ca ascorbate on the biocontrol efficacy of Pichia kudriavzevii and the possible mechanisms. The results indicated that the...
This study investigated the effect of Ca ascorbate on the biocontrol efficacy of Pichia kudriavzevii and the possible mechanisms. The results indicated that the biocontrol activity of was significantly enhanced by 0.15 g L of Ca ascorbate, with higher growth rates of yeast cells and . The antioxidant enzyme activity in , including catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD), were improved by Ca ascorbate and reached the maximum at 96 h, 96 h, and 72 h, respectively. The expression of the antioxidant enzyme-related genes (8.55-fold) and (7.26-fold) peaked at 96 h, while (2.8-fold) peaked at 48 h, which were similar to the trends of enzyme activities. Compared with the control, 0.15 g L of Ca ascorbate and CaCl increased the activity of succinate dehydrogenase in , thereby enhancing the utilization of nutrients by yeast cells, and calcium ascorbate had the strongest effect. The expressions of , , , and were significantly higher in the Ca ascorbate treatment than the other groups, and the CaCl treatment was also significantly higher than the control. These results indicated that Ca ascorbate can effectively improve the energy metabolism and cell wall synthesis and slow down the senescence of yeast cells. In general, Ca ascorbate can improve the environmental adaptability of and thus improve the biocontrol effect, which is associated with inducing antioxidant enzymes in yeast cells and enhancing energy metabolism and nutrient utilization efficiency to increase nutrient competition with pathogens. Antagonistic yeast is a promising way to control postharvest fruit decay because of its safety and broad-spectrum resistance. However, the biocontrol efficacy of yeast is limited by environmental stress, such as oxidative stress. Therefore, the improvement of antioxidant capacity has become a research hot spot in improving the biocontrol efficacy of yeast. The induction of Ca ascorbate on the antioxidant capacity and physiological activity of yeast was studied. The results showed better induction of antioxidant enzyme and physiological activity in yeast by Ca ascorbate for better antioxidant capacity, and Ca also played a synergistic promotion effect, which improved the biocontrol efficacy. These results provide an approach for the research and application of improving the environmental adaptability and biocontrol effectiveness of yeast.
Topics: Antibiosis; Antioxidants; Ascorbic Acid; Biological Control Agents; Botrytis; Catalase; Fruit; Solanum lycopersicum; Oxidative Stress; Pichia; Plant Diseases
PubMed: 34937188
DOI: 10.1128/spectrum.01507-21 -
Journal of Biomolecular Structure &... 2022One of the major constraints limiting the use of abundantly available lignocellulosic biomass as potential feedstock for alcohol industry is the lack of C/C co-sugar...
One of the major constraints limiting the use of abundantly available lignocellulosic biomass as potential feedstock for alcohol industry is the lack of C/C co-sugar fermenting yeast. The present study explores a mutant yeast BGY1-γm as a potential strain for bioconversion of glucose/xylose sugars of green biomass into ethanol under batch fermentation. The mutant strain having higher alcohol dehydrogenase activity (11.31%) showed significantly higher ethanol concentration during co-fermentation of glucose/xylose sugars (14.2%) as compared to the native strain. Based on 99% sequence similarity of ADH encoding gene from the mutant with the gene sequences from other yeast strains, the ADH enzyme was identified as ADH-1 type. The study reveals first three-dimensional model of ADH-1 utilizing glucose/xylose sugars from BGY1-γm (ADH mutant). The refined and validated model of ADH mutant was used for molecular docking against the substrate (acetaldehyde) and product (ethanol). Molecular docking results showed that substrate and product exhibited a binding affinity of -4.55 and -4.5 kcal/mol with ADH mutant. Acetaldehyde and ethanol interacted at the active site of ADH mutant via hydrogen bonds (Ser42, His69 and Asp163) and hydrophobic interactions (Cys40, Ser42, His69, Cys95, Trp123 and Asp163) to form the stable protein-ligand complex. Molecular dynamics analysis revealed that ADH-mutant acetaldehyde and ADH-mutant ethanol complexes were more stable than ADH mutant. MMPBSA binding energy confirmed that binding of substrate and product results in the formation of a lower energy stable protein-ligand complex.Communicated by Ramaswamy H. Sarma.
Topics: Saccharomyces cerevisiae; Ethanol; Alcohol Dehydrogenase; Xylose; Molecular Docking Simulation; Ligands; Acetaldehyde; Glucose; Fermentation
PubMed: 34424128
DOI: 10.1080/07391102.2021.1967196 -
Food Chemistry: X Jun 2023Mixed fermentation using saccharomyces cerevisiae and non- has become one of the main research strategies to improve wine aroma. Hence, this study applied the mixed...
Mixed fermentation using saccharomyces cerevisiae and non- has become one of the main research strategies to improve wine aroma. Hence, this study applied the mixed fermentation technique using and to brew Cabernet Sauvignon wine and to investigate the effects of inoculation timing and inoculation ratio on the polyphenolics, antioxidant activity and aroma of the resulting wine. The results showed that mixed fermentation significantly improved the amounts of flavan-3-ols. In particular, S1:5 had the highest amounts of (-)-catechin and procyanidin B1 (73.23 mg/L and 46.59 mg/L), while S1:10 had the highest (-)-epicatechin content (57.95 mg/L). Meanwhile, S1:10 showed the strongest FRAP, CUPRAC and ABTS + activities (31.46 %, 25.38 % and 13.87 % higher than that of CK, respectively). In addition, mixed fermentation also increased the amounts of phenylethanol, isoamyl alcohol and ethyl esters, which enhanced the rose-like and fruity flavor of wine. This work used a friendly non- alongside appropriate inoculation strategies to provide an alternative approach for improved wine aroma and phenolic profile.
PubMed: 37131849
DOI: 10.1016/j.fochx.2023.100685 -
World Journal of Microbiology &... Sep 2023Esters were identified as the primary volatile flavor compounds in Chinese Baijiu, exerting a significant influence on its quality and aroma. This study focused on the...
Esters were identified as the primary volatile flavor compounds in Chinese Baijiu, exerting a significant influence on its quality and aroma. This study focused on the yeast strain Pichia kudriavzevii, renowned for its high capacity to produce esters. Whole genome sequences were annotated and analyzed using the GO, KEGG, KOG, CAZy, and Pfam databases to determine the genetic basis underly the enhanced ester production capacity. Results showed that P. kudriavzevii gene function was concentrated in biosynthetic capacity, metabolic capacity, amino acid translocation capacity, glycoside hydrolysis capacity and transfer capacity. Additionally, acyltransferase and kinase were predicted as active sites contributing to P. kudriavzevii high ester production. We further compared the volatile composition differences between P. kudriavzevii and Saccharomyces cerevisiae through Headspace solid-phase microextraction-gas Chromatography-mass spectrometry (HS-SPME-GC-MS), revealing P. kudriavzevii produced 3.5 times more esters than S. cerevisiae. Overall, our findings suggest that P. kudriavzevii had potential applications in the Baijiu brewing industry.
Topics: Saccharomyces cerevisiae; Pichia; Amino Acids; Esters
PubMed: 37713136
DOI: 10.1007/s11274-023-03743-9 -
Microorganisms May 2024Because data on the fungal gut community structure of African children are scarce, we aimed to describe it by reanalysing rRNA ITS1 and ITS2 metabarcoding data from a...
Because data on the fungal gut community structure of African children are scarce, we aimed to describe it by reanalysing rRNA ITS1 and ITS2 metabarcoding data from a study designed to assess the influence of microbiota in malaria susceptibility in Malian children from the Dogon country. More specifically, we aimed to establish the core gut mycobiome and compare the gut fungal community structure of breastfed children, aged 0-2 years, with other age groups. Briefly, DNA was extracted from 296 children's stool samples. Both rRNA ITS1 and ITS2 genomic barcodes were amplified and subjected to Illumina MiSeq sequencing. The ITS2 barcode generated 1,975,320 reads and 532 operational taxonomic units (OTUs), while the ITS1 barcode generated 647,816 reads and 532 OTUs. The alpha diversity was significantly higher by using the ITS1 compared to the ITS2 barcode ( < 0.05); but, regardless of the ITS barcode, we found no significant difference between breastfed children, aged 0-2 years, compared to the other age groups. The core gut mycobiome of the Malian children included , , , , and section , which were present in at least 50% of the 296 children. Further studies in other African countries are warranted to reach a global view of African children's core gut mycobiome.
PubMed: 38792756
DOI: 10.3390/microorganisms12050926 -
Environmental Science and Pollution... Jan 2023(S)-1-(1-naphthyl) ethanol (SNE) is a chiral drug intermediate for the production of mevinic acid analog, a potent cholesterol agent. It acts as an HMG-CoA reductase...
(S)-1-(1-naphthyl) ethanol (SNE) is a chiral drug intermediate for the production of mevinic acid analog, a potent cholesterol agent. It acts as an HMG-CoA reductase inhibitor and is hence used in the synthesis of statins. Statins are lipid-lowering drugs used to lower cholesterol in the body. In our present study, we carried out whole-cell bioreduction of 1-Acetonaphthone to enantiopure SNE using selected microorganisms acquired by soil acclimation technique. The microorganism which exhibited higher bioreduction activity was determined using high-performance liquid chromatography (HPLC), and it was identified as Pichia kudriavzevii by ITS primer sequencing. After optimizing the parameters, Pichia sp. produced SNE with good conversion (75%), yield (67%), and excellent enantiomeric excess (100%). The microbial enzyme showed higher activity at 24-h-old supernatant. The crude and partially purified enzyme exhibited a specific activity of 51.13 U/mL and 62.72 U/mL, respectively, with a 1.22 purification fold.
Topics: Hydroxymethylglutaryl-CoA Reductase Inhibitors; Ethanol; Cholesterol
PubMed: 35819672
DOI: 10.1007/s11356-022-21749-y -
Frontiers in Microbiology 2021and were used as starter cultures to conduct inoculated wet fermentations of coffee beans, and their growth, metabolic activities and impact on the flavor, aroma and...
and were used as starter cultures to conduct inoculated wet fermentations of coffee beans, and their growth, metabolic activities and impact on the flavor, aroma and overall sensory quality of coffee were compared with spontaneous fermentation (control). and dominated the fermentations, growing to maximum populations of about 10.0 log CFU/ml compared with 8.0 log CFU/ml in the spontaneous fermentation. The dominance of the inoculated yeasts led to faster and more complete utilization of sugars in the mucilage, with resultant production of 2-3 fold higher concentrations of metabolites such as glycerol, alcohols, aldehydes, esters, and organic acids in the fermented green beans. Cup tests showed coffee produced from the inoculated fermentations, especially with , received higher scores for flavor, aroma and acidity than the control. The findings of this study confirmed the crucial role of yeasts in the wet fermentation of coffee beans and their contribution to high quality coffee, and demonstrated the potential and as starter cultures in the process.
PubMed: 34421873
DOI: 10.3389/fmicb.2021.713969 -
Biotechnology For Biofuels Nov 2021High-temperature bioethanol production benefits from yeast thermotolerance. Salt stress could induce obvious cross-protection against heat stress of Pichia kudriavzevii,...
Salt stress improves thermotolerance and high-temperature bioethanol production of multi-stress-tolerant Pichia kudriavzevii by stimulating intracellular metabolism and inhibiting oxidative damage.
BACKGROUND
High-temperature bioethanol production benefits from yeast thermotolerance. Salt stress could induce obvious cross-protection against heat stress of Pichia kudriavzevii, contributing to the improvement of its thermotolerance and bioethanol fermentation. However, the underlying mechanisms of the cross-protection remain poorly understood.
RESULTS
Salt stress showed obvious cross-protection for thermotolerance and high-temperature ethanol production of P. kudriavzevii observed by biomass, cell morphology and bioethanol production capacity. The biomass and ethanol production of P. kudriavzevii at 45 °C were, respectively, improved by 2.6 and 3.9 times by 300 mmol/L NaCl. Metabolic network map showed that salt stress obviously improved the key enzymes and intermediates in carbohydrate metabolism, contributing to the synthesis of bioethanol, ATP, amino acids, nucleotides, and unsaturated fatty acids, as well as subsequent intracellular metabolisms. The increasing trehalose, glycerol, HSPs, and ergosterol helped maintain the normal function of cell components. Heat stress induced serious oxidative stress that the ROS-positive cell rate and dead cell rate, respectively, rose from 0.5% and 2.4% to 28.2% and 69.2%, with the incubation temperature increasing from 30 to 45 °C. The heat-induced ROS outburst, oxidative damage, and cell death were obviously inhibited by salt stress, especially the dead cell rate which fell to only 20.3% at 300 mmol/L NaCl. The inhibiting oxidative damage mainly resulted from the abundant synthesis of GSH and GST, which, respectively, increased by 4.8 and 76.1 times after addition of 300 mmol/L NaCl. The improved bioethanol production was not only due to the improved thermotolerance, but resulted from the up-regulated alcohol dehydrogenases and down-regulated aldehyde dehydrogenases by salt stress.
CONCLUSION
The results provide a first insight into the mechanisms of the improved thermotolerance and high-temperature bioethanol production of P. kudriavzevii by salt stress, and provide important information to construct genetic engineering yeasts for high-temperature bioethanol production.
PubMed: 34823567
DOI: 10.1186/s13068-021-02071-0 -
Letters in Applied Microbiology Jun 2024Yeasts are unicellular eukaryotic microorganisms extensively employed in various applications, notably as an alternative source of protein in feeds, owing to their...
Yeasts are unicellular eukaryotic microorganisms extensively employed in various applications, notably as an alternative source of protein in feeds, owing to their nutritional benefits. Despite their potential, marine and mangrove yeast species used in the aquaculture industry have received little attention in the Philippines. Pichia kudriavzevii (A2B R1 ISO 3), sourced from bark samples, was selected and mass-produced due to its high protein content and amino acid profile. The dried biomass of P. kudriavzevii was incorporated into the diets of Nile tilapia (Oreochromis niloticus) juveniles at varying inclusion levels (0, 1, 2, and 4 g/kg diet) and its effect on their growth performance, body composition, and liver and intestinal morphology was assessed after 40 days of feeding. The groups that received P. kudriavzevii at a concentration of 2 g/kg diet exhibited higher final body weight, percent weight gain, and specific growth rate in comparison to the other treatment groups. Whole body proximate composition did not vary among the dietary groups. Intestinal and liver histopathology also indicated no abnormalities. These findings suggest the potential of ascomycetous P. kudriavzevii as a beneficial feed additive in Nile tilapia diets, warranting further investigation into its long-term effects and broader applications in fish culture.
Topics: Animals; Animal Feed; Cichlids; Pichia; Aquaculture; Diet; Liver; Intestines; Dietary Supplements; Philippines
PubMed: 38906842
DOI: 10.1093/lambio/ovae057 -
Biotechnology For Biofuels 2020Although bioethanol production has been gaining worldwide attention as an alternative to fossil fuel, ethanol productivities and yields are still limited due to the...
BACKGROUND
Although bioethanol production has been gaining worldwide attention as an alternative to fossil fuel, ethanol productivities and yields are still limited due to the susceptibility of fermentation microorganisms to various stress and inhibitory substances. There is therefore an unmet need to search for multi-stress-tolerant organisms to improve ethanol productivity and reduce production cost, particularly when lignocellulosic hydrolysates are used as the feedstock.
RESULTS
Here, we have characterized a previously isolated LC375240 strain which is thermotolerant to high temperatures of 37 °C and 42 °C. More excitingly, growth and ethanol productivity of this strain exhibit strong tolerance to multiple stresses such as acetic acid, furfural, formic acid, HO and high concentration of ethanol at 42 °C. In addition, simple immobilization of LC375240 on corncobs resulted to a more stable and higher efficient ethanol production for successive four cycles of repeated batch fermentation at 42 °C.
CONCLUSION
The feature of being thermotolerant and multi-stress-tolerant is unique to LC375240 and makes it a good candidate for second-generation bioethanol fermentation as well as for investigating the molecular basis underlying the robust stress tolerance. Immobilization of LC375240 on corncobs is another option for cheap and high ethanol productivity.
PubMed: 32477425
DOI: 10.1186/s13068-020-01729-5