-
Microbial Biotechnology Mar 2017In this work, we present the development and characterization of a strain of Pichia kudriavzevii (TY1322), with highly improved phytate-degrading capacity. The mutant...
In this work, we present the development and characterization of a strain of Pichia kudriavzevii (TY1322), with highly improved phytate-degrading capacity. The mutant strain TY1322 shows a biomass-specific phytate degradation of 1.26 mmol g h after 8 h of cultivation in a high-phosphate medium, which is about 8 times higher compared with the wild-type strain. Strain TY1322 was able to grow at low pH (pH 2), at high temperature (46°C) and in the presence of ox bile (2% w/v), indicating this strain's ability to survive passage through the gastrointestinal tract. The purified phytase showed two pH optima, at pH 3.5 and 5.5, and one temperature optimum at 55°C. The lower pH optimum of 3.5 matches the reported pH of the pig stomach, meaning that TY1322 and/or its phytase is highly suitable for use in feed production. Furthermore, P. kudriavzevii TY1322 tolerates ethanol up to 6% (v/v) and shows high osmotic stress tolerance. Owing to the phenotypic characteristics and non-genetically modified organisms nature of TY1322, this strain show great potential for future uses in (i) cereal fermentations for increased mineral bioavailability, and (ii) feed production to increase the phosphate bioavailability for monogastric animals to reduce the need for artificial phosphate fortification.
Topics: 6-Phytase; Bile; Culture Media; Drug Tolerance; Enzyme Stability; Ethanol; Gene Expression Regulation, Fungal; Hydrogen-Ion Concentration; Industrial Microbiology; Mutation; Phosphates; Pichia; Temperature
PubMed: 27790831
DOI: 10.1111/1751-7915.12427 -
Molecules (Basel, Switzerland) May 2017The potential ability of a new yeast strain, , in the synthesis of zinc oxide nanoparticles (ZnO-NPs) through a green method was explored in this study. The effect of...
The potential ability of a new yeast strain, , in the synthesis of zinc oxide nanoparticles (ZnO-NPs) through a green method was explored in this study. The effect of reaction time (12, 24 and 36 h) on the structure of the resulting ZnO nanoparticles was investigated. From the XRD and TEM results, the ZnO-NPs with a hexagonal wurtzite structure and a particle crystal size of ~10-61 nm was formed at different reaction times. Combing XRD, TEM, and PL results, it was revealed that the sample prepared at intermediate duration (24 h) has the most favorable nanosized structure with the lowest defect concentration. The biomedical properties of ZnO-NPs as free radical scavenging activity, cytotoxicity and antibacterial agents were characterized. Biosynthesized ZnO-NPs showed strong DPPH free radical scavenging and a dose dependent toxicity with non-toxic effects on Vero cells for concentrations below 190 µg/mL. Desirable bactericidal activity was shown by the ZnO-NPs on Gram-positive bacteria (, and and Gram-negative bacteria ( and ). A maximum inhibition zone of ~19 mm was observed for at a concentration of 100 µg/mL for sample prepared at 24 h The results from this study reveal that ZnO-NPs possesses potential for many medical and industrial applications.
Topics: Anti-Infective Agents; Antioxidants; Microbial Sensitivity Tests; Nanoparticles; Pichia; Zinc Oxide
PubMed: 28538674
DOI: 10.3390/molecules22060872 -
Bioinformation 2023It is of interest to isolate the probiotic yeast based on its probiotic characteristics and enzyme production. The isolate was able to withstand high acid, bile...
It is of interest to isolate the probiotic yeast based on its probiotic characteristics and enzyme production. The isolate was able to withstand high acid, bile concentration and showed a high viability. Additionally, it showed auto aggregation ability that increases with time and hydrophobicity with xylene. It was resistant to different antibiotics and showed no hemolytic activity. The isolate was also capable of producing phytase that can break down phytate. Overall, the characteristics of suggest that it could potentially have probiotic properties, and its ability to produce phytase could also make it useful in feed and animal industries.
PubMed: 37822822
DOI: 10.6026/97320630019441 -
Journal of Food Science and Technology Jul 2022Volatile organic compounds (VOCs) are important to determine the aroma and sensory perception of cocoa. Starter cultures can modulate the volatile profile of cocoa beans...
Volatile organic compounds (VOCs) are important to determine the aroma and sensory perception of cocoa. Starter cultures can modulate the volatile profile of cocoa beans during fermentation. This study aimed to determine the VOCs and sensory of chocolates produced using cocoa beans fermented with yeast starters ( (MH979681) (MH979675) and the mixture of the two yeasts (Mix)). The VOCs of chocolates were determined by Head-Space Solid Phase Microextraction followed by Gas Chromatography-Mass Spectrophotometry. Sensory analysis was determined by using trained panels. VOCs profiles of chocolates produced using beans fermented with HT, PK or Mix were noticeably different from Ghana and control chocolates (no starter). The addition of yeast starters during cocoa fermentation produced chocolates that were preferred by trained panels. Bitterness and astringency were the more intense flavour attributes in chocolates produced using cocoa beans added with yeast starters. The chocolate produced using cocoa beans fermented with PK was the most acidic; whereas chocolate produced using beans fermented with Mix had the sweetest taste. The addition of PK or HT is helpful in producing chocolate with a distinct flavour.
PubMed: 35734109
DOI: 10.1007/s13197-021-05292-1 -
Scientific Reports Nov 2023Second-generation bioethanol production using lignocellulosic biomass as feedstock requires a highly efficient multistress-tolerant yeast. This study aimed to develop a...
Adaptive laboratory evolution under acetic acid stress enhances the multistress tolerance and ethanol production efficiency of Pichia kudriavzevii from lignocellulosic biomass.
Second-generation bioethanol production using lignocellulosic biomass as feedstock requires a highly efficient multistress-tolerant yeast. This study aimed to develop a robust yeast strain of P. kudriavzevii via the adaptive laboratory evolution (ALE) technique. The parental strain of P. kudriavzevii was subjected to repetitive long-term cultivation in medium supplemented with a gradually increasing concentration of acetic acid, the major weak acid liberated during the lignocellulosic pretreatment process. Three evolved P. kudriavzevii strains, namely, PkAC-7, PkAC-8, and PkAC-9, obtained in this study exhibited significantly higher resistance toward multiple stressors, including heat, ethanol, osmotic stress, acetic acid, formic acid, furfural, 5-(hydroxymethyl) furfural (5-HMF), and vanillin. The fermentation efficiency of the evolved strains was also improved, yielding a higher ethanol concentration, productivity, and yield than the parental strain, using undetoxified sugarcane bagasse hydrolysate as feedstock. These findings provide evidence that ALE is a practical approach for increasing the multistress tolerance of P. kudriavzevii for stable and efficient second-generation bioethanol production from lignocellulosic biomass.
Topics: Acetic Acid; Cellulose; Ethanol; Saccharomyces cerevisiae; Biomass; Furaldehyde; Saccharum; Fermentation
PubMed: 38017261
DOI: 10.1038/s41598-023-48408-7 -
Translational Animal Science Jul 2020Growth performance, liver and spleen weight, plasma, and ceca digesta metabolites and incidences of diarrhea were investigated in growing pigs fed spent biomass of...
Growth performance, liver and spleen weight, plasma, and ceca digesta metabolites and incidences of diarrhea were investigated in growing pigs fed spent biomass of Ninety six barrows (~25 kg, 4 pigs/pen) were fed 1 of 4 experimental diets ( = 6) for 7 weeks. The diets were control, corn-, and soybean meal-based diet or control plus 2.5%, 3.75%, or 5.0% . Diets were formulated to be isocaloric and iso nitrogenous. Feed intake and body weight (BW) were recorded weekly for calculation of average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Fecal scores were taken 3 d/wk to assess incidence and severity of diarrhea. One pig/pen close to pen average was bled for plasma metabolites on days 7 and 49 and subsequently euthanized for spleen and liver weight, ileal and cecum digesta samples for concentration of short-chain fatty acids (SCFA). The concentration of crude protein, crude fat, and non-fiber carbohydrates in biomass was 36.4%, 9.6%, and 50.8% DM, respectively. Inclusion of tended ( = 0.06) to linearly reduce ADG from days 8 through 49 resulting in a trend ( = 0.06) for linear reduction in the final BW. The final BW was 79.0, 79.2, 76.8, and 75.5 kg for the 0%, 2.5%, 3.75%, and 5.0% , respectively. Diets had no effect ( > 0.10) on ADFI, G:F, spleen, and liver weight throughout the entire experiment. On day 7, there was cubic ( = 0.03) decrease and quadratic ( = 0.02) increase in plasma concentration of creatinine and urea N, respectively. However, there were no ( > 0.10) diet effects on plasma metabolites on day 49. There was a tendency ( = 0.08) for linear increase in cecum digesta concentration of acetic acid. There were no diet effects ( > 0.10) on fecal score in the first 4 wk of feeding. In conclusion, feeding yeast tended to depress growth and stimulate cecum fermentation at higher dose and had no detrimental effects on organ weights or plasma metabolites in growing pigs.
PubMed: 32904991
DOI: 10.1093/tas/txaa152 -
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 -
Frontiers in Microbiology 2022To explore the potential application of non- yeasts screened from Baijiu fermentation environment in winemaking, the effect of four Baijiu non- yeasts (two and two )...
To explore the potential application of non- yeasts screened from Baijiu fermentation environment in winemaking, the effect of four Baijiu non- yeasts (two and two ) sequentially fermented with on the physicochemical parameters and volatile compounds of wine was analyzed. The results indicated that there was no obvious antagonism between and or in sequential fermentations, and all strains could be detected at the end of alcoholic fermentation. Compare with pure fermentation, sequential fermentations significantly reduced higher alcohols, fatty acids, and ethyl esters and increased acetate esters; sequential fermentations reduced the contents of C6 alcohols, total higher alcohols, fatty acids, and ethyl esters and significantly increased the contents of acetate esters (especially ethyl acetate and 3-methylbutyl acetate). Sequential fermentation of Baijiu non- yeast and improved the flavor and quality of wine due to the higher ester content and lower concentration of higher alcohols and fatty acids, non- yeasts selected from Baijiu fermentation environment have potential applications in winemaking, which could provide a new strategy to improve wine flavor and quality.
PubMed: 35711782
DOI: 10.3389/fmicb.2022.902597 -
Microorganisms Apr 2023There is an expanding market for beer of different flavors. This study aimed to prepare a craft Belgian-style pale ale with a non- yeast. 4A was used as a sole starter...
There is an expanding market for beer of different flavors. This study aimed to prepare a craft Belgian-style pale ale with a non- yeast. 4A was used as a sole starter culture, and malted barley as the only substrate. The ingredients and brewing process were carefully monitored to ensure the quality and innocuousness of the beverage. During fermentation, the yeast consumed 89.7% of total sugars and produced 13.8% / of ethanol. The product was fermented and then aged for 8 days, adjusted to 5% / alcohol, and analyzed. There were no traces of mycotoxins, lead, arsenic, methanol, or microbiological contamination that would compromise consumer health. According to the physicochemical analysis, the final ethanol concentration (5.2% /) and other characteristics complied with national and international guidelines. The ethyl acetate and isoamyl alcohol present are known to confer sweet and fruity flavors. The sensory test defined the beverage as refreshing and as having an apple and pear flavor, a banana aroma, and a good level of bitterness. The judges preferred it over a commercial reference sample of Belgian-style pale ale made from . Hence, 4A has the potential for use in the beer industry.
PubMed: 37110400
DOI: 10.3390/microorganisms11040977 -
PLoS Pathogens Jul 2018We investigated genomic diversity of a yeast species that is both an opportunistic pathogen and an important industrial yeast. Under the name Candida krusei, it is...
We investigated genomic diversity of a yeast species that is both an opportunistic pathogen and an important industrial yeast. Under the name Candida krusei, it is responsible for about 2% of yeast infections caused by Candida species in humans. Bloodstream infections with C. krusei are problematic because most isolates are fluconazole-resistant. Under the names Pichia kudriavzevii, Issatchenkia orientalis and Candida glycerinogenes, the same yeast, including genetically modified strains, is used for industrial-scale production of glycerol and succinate. It is also used to make some fermented foods. Here, we sequenced the type strains of C. krusei (CBS573T) and P. kudriavzevii (CBS5147T), as well as 30 other clinical and environmental isolates. Our results show conclusively that they are the same species, with collinear genomes 99.6% identical in DNA sequence. Phylogenetic analysis of SNPs does not segregate clinical and environmental isolates into separate clades, suggesting that C. krusei infections are frequently acquired from the environment. Reduced resistance of strains to fluconazole correlates with the presence of one gene instead of two at the ABC11-ABC1 tandem locus. Most isolates are diploid, but one-quarter are triploid. Loss of heterozygosity is common, including at the mating-type locus. Our PacBio/Illumina assembly of the 10.8 Mb CBS573T genome is resolved into 5 complete chromosomes, and was annotated using RNAseq support. Each of the 5 centromeres is a 35 kb gene desert containing a large inverted repeat. This species is a member of the genus Pichia and family Pichiaceae (the methylotrophic yeasts clade), and so is only distantly related to other pathogenic Candida species.
Topics: Candida; Metagenomics; Phylogeny; Pichia
PubMed: 30024981
DOI: 10.1371/journal.ppat.1007138