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Journal of Agricultural and Food... Apr 2020Lactic acid is a universal metabolite, as well as a growth inhibitor of ethanol producers in Baijiu fermentation. Revealing the mechanism of lactic acid tolerance is...
Lactic acid is a universal metabolite, as well as a growth inhibitor of ethanol producers in Baijiu fermentation. Revealing the mechanism of lactic acid tolerance is essential for the yield of fermented foods. Here, we employed reverse transcription-quantitative polymerase chain reaction to explore the degradation mechanism of lactic acid, based on the coculture of and . Under high lactic acid stress, decreased lactic acid from 40.00 to 35.46 g L within 24 h. Then, restored its capacity to degrade lactic acid. Finally, lactic acid decreased to 26.29 g L. Coculture significantly enhanced lactic acid consumption compared to the monoculture of (90% higher) or (209% higher). We found that lactate catabolism, H extrusion, and glycerol transport were the lactic acid tolerance pathways in yeasts. This study reveals the novel acid tolerance mechanisms of microbiota and would provide new strategies for ethanol production under acid stress.
Topics: Ethanol; Fermentation; Lactic Acid; Pichia; Saccharomyces cerevisiae; Sorghum; Wine
PubMed: 32180399
DOI: 10.1021/acs.jafc.9b08052 -
Probiotics and Antimicrobial Proteins Jun 2023Potential probiotic yeast strains isolated from fermented food need to meet safe and beneficial conditions for the host's health. The Pichia kudriavzevii YGM091 strain...
Potential probiotic yeast strains isolated from fermented food need to meet safe and beneficial conditions for the host's health. The Pichia kudriavzevii YGM091 strain isolated from fermented goat milk has outstanding probiotic characteristics, including: the high survival percentage in digestive system conditions (reaching up 247.13 ± 0.12 and 145.03 ± 0.06% at pH 3.0 and bile salt 0.5%, respectively); good tolerance to temperature, salt, phenol, ethanol; good surface properties such as high hydrophobicity percentage (> 60%), the high auto-aggregation percentage rate (66.56 ± 1.45% after 45 min of incubation) and the high co-aggregation percentage rate with pathogenic bacteria in a short time (> 40% after 2 h of incubation); biofilm forming after 24 h of incubation on abiotic surfaces; antioxidant activity reached excellent level after only 24 h of incubation (The percentage free radical scavenging and the Trolox equivalent reaching up 79.86 ± 0.70% and 92.09 ± 0.75 µg/mL after 72 h of incubation); extracellular enzymes production protease and cellulase with high activity, amylase and pectinase with moderate activity and non-lipase activity. Simultaneously, the YGM091 strain is the in vitro safety yeast: insensitive to antibiotics and fluconazole, negative for gelatinase, phospholipase, coagulase, and non-hemolysis activities. Furthermore, this strain is in vivo safety yeast with the dosages below 10 CFU/larva in the Galleria mellonella model with over 90% survival larvae and the yeast density reduced to just 10-10 CFU/larva after 72 h post-injection. Research results have demonstrated that the Pichia kudriavzevii YGM091 strain is a safe potential probiotic yeast and could become a candidate probiotic food to be used in the future.
PubMed: 37368223
DOI: 10.1007/s12602-023-10114-1 -
Journal, Genetic Engineering &... Sep 2022Fermented foods are the results of metabolic activities of various microorganisms. People have traditionally known how to culture desirable microorganisms, primarily...
BACKGROUND
Fermented foods are the results of metabolic activities of various microorganisms. People have traditionally known how to culture desirable microorganisms, primarily lactic acid bacteria, yeasts, and filamentous molds, for the manufacture of edible foods. Yeast isolated from home-made mango pickle from Hamirpur, Himachal Pradesh, was assessed for probiotic properties and their enzymatic profiling.
RESULTS
Four yeast isolates were isolated out of which P. kudriavzevii Y33 was selected on the basis of high acid tolerance as well as broadest antimicrobial activity. The selected isolate was observed to have high acid tolerance at pH 2 and show strong antimicrobial activity against all the pathogens examined. P. kudriavzevii Y33 can also withstand high bile concentration and showed high viability index, i.e., 95% at concentration of 2% of bile. The isolate was able to demonstrate high cholesterol assimilation in medium containing ox bile and taurocholate, at 88.58 and 86.83%, respectively. The autoaggregation ability of isolate increases with increasing the time of incubation and showed 87% of autoaggregation after 24 h of incubation. P. kudriavzevii Y33 exhibited resistance towards different antibiotics, found to be positive for exopolysaccharide production and showed no hemolytic activity. The isolate was observed to produce several enzymes such as β-galactosidase, protease, amylase, phytase, and lipase.
CONCLUSIONS
The results of the current study revealed that P. kudriavzevii Y33 has various beneficial qualities that suggest it could be used as probiotics. Enzymes produced by yeast isolate help in improving flavor and mineral availability in the fermented products.
PubMed: 36083419
DOI: 10.1186/s43141-022-00416-2 -
Food Chemistry: X Oct 2023Microbial activity during spontaneous fermentation in alcoholic beverages have driven in developing the chemical and aromatic characteristic of products but not clear in...
Microbial activity during spontaneous fermentation in alcoholic beverages have driven in developing the chemical and aromatic characteristic of products but not clear in apricot wines. We have characterised the composition of fungal communities and volatile metabolites in apricot wine spontaneous fermentation among two Shaanxi regions. Results showed that , , and , were the dominant fungi in apricot wine fermentation. A total of 80 volatiles including esters, alcohols, acids and terpenes were detected from two apricot wines. Their correlations suggested that apricot wine aroma was mainly affected by , rather than we commonly considered. Furthermore, reinforced inoculation of LQD20 has exhibited the commendable potential in enhancing sensory qualities. The results of this study provide fundamental information of the indigenous microbiota in microbial dynamic during apricot wine fermentation, which would be helpful in exploiting the strains with potential for industrial use as starter cultures.
PubMed: 37780311
DOI: 10.1016/j.fochx.2023.100862 -
Journal of Fungi (Basel, Switzerland) Dec 2021Improving the comprehensive utilization of sugars in lignocellulosic biomass is a major challenge for enhancing the economic viability of lignocellulose biorefinement. A...
Improving the comprehensive utilization of sugars in lignocellulosic biomass is a major challenge for enhancing the economic viability of lignocellulose biorefinement. A robust yeast N-X showed excellent performance in ethanol production under high temperature and low pH conditions and was engineered for ᴅ-xylonate production without xylitol generation. The recombinant strain N-X/S1 was employed for sequential production of ᴅ-xylonate and ethanol from ᴅ-xylose, feeding on ᴅ-glucose without pH control in a two-stage strategy of aerobic and shifting micro-aerobic fermentation. Acid-pretreated corncob without detoxification and filtration was used for ᴅ-xylonate production, then simultaneous saccharification and ethanol fermentation was performed with cellulase added at pH 4.0 and at 40 °C. By this strategy, 33.5 g/L ᴅ-xylonate and 20.8 g/L ethanol were produced at yields of 1.10 g/g ᴅ-xylose and 84.3% of theoretical value, respectively. We propose a promising approach for the sequential production of ᴅ-xylonate and ethanol from non-detoxified corncob using a single microorganism.
PubMed: 34947020
DOI: 10.3390/jof7121038 -
Archives of Microbiology Sep 2021Soil yeasts exhibit an array of beneficial effects to plants viz., plant growth promotion, phosphate solubilization, nitrogen and sulphur oxidation, etc. Yeasts remain...
Soil yeasts exhibit an array of beneficial effects to plants viz., plant growth promotion, phosphate solubilization, nitrogen and sulphur oxidation, etc. Yeasts remain as poorly investigated group of microorganisms that represent an abundant and dependable source of bioactive/chemically novel compounds and potential bioinoculants. Hence this study holds the key concept of assessing the performance of soil yeasts with potential plant growth promoting ability in soil quality improvement. Sixteen soil yeast isolates with plant growth promoting traits were assessed for biofilm forming potential and five potential soil yeast isolates were selected and identified through molecular technique. Soil incubation study was performed with these isolates to assess their impact on soil physical, chemical and biological properties. Due to inoculation of soil yeasts, notable changes were observed in soil physical, chemical and biological properties. Among the soil yeast isolates, Pichia kudriavzevii gave better results in soil incubation study.
Topics: Pichia; Soil; Soil Microbiology
PubMed: 34165623
DOI: 10.1007/s00203-021-02447-8 -
Digestive Diseases and Sciences Jan 2022Although intestinal fungi are known to interact with the immune system, the relationship between intestinal fungi and childhood celiac disease (CeD), an immune-mediated...
BACKGROUND
Although intestinal fungi are known to interact with the immune system, the relationship between intestinal fungi and childhood celiac disease (CeD), an immune-mediated condition, has rarely been reported.
AIMS
The aim of this study was to describe gut fungal profiles in a cohort of children with new-onset CeD.
METHODS
Mucosal and fecal samples were collected from children with CeD and controls and subjected to metagenomics analysis of fungal microbiota communities. DNA libraries were sequenced using Illumina HiSeq platform 2 × 150 bp. Bioinformatic analysis was performed to quantify the relative abundance of fungi. Shannon alpha diversity metrics and beta diversity principal coordinate (PCo) analyses were calculated, and DESeq tests were performed between celiac and non-celiac groups.
RESULTS
Overall more abundant taxa in samples of children with CeD included Tricholomataceae, Saccharomycetaceae, Saccharomycetes Saccharomyces cerevisiae, and Candida, whereas less abundant taxa included Pichiaceae, Pichia kudriavzevii, Pneumocystis, and Pneumocystis jirovecii. Alpha diversity between CeD and control individuals did not differ significantly, and beta diversity PCo analysis showed overlap of samples from CeD and controls for both fecal or mucosal samples; however, there was a clear separation between mucosal and fecal overall samples CONCLUSIONS: We report fungal dysbiosis in children with CeD, suggesting a possible role in the pathogenesis of CeD. Further larger, controlled, prospective and longitudinal studies are needed to verify the results of this study and clarify the functional role of fungi in CeD.
Topics: Celiac Disease; Child; Dysbiosis; Feces; Female; Fungi; Humans; Intestinal Mucosa; Male; Metagenomics; Microbiological Phenomena; Mycobiome; Saudi Arabia
PubMed: 33723701
DOI: 10.1007/s10620-021-06823-8 -
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 -
Microbial Biotechnology May 2021The unconventional yeast Pichia kudriavzevii is renowned for its ability to survive at low pH and has been exploited for the industrial production of various organic...
The unconventional yeast Pichia kudriavzevii is renowned for its ability to survive at low pH and has been exploited for the industrial production of various organic acids, especially succinic acid (SA). However, P. kudriavzevii can also utilize the di- and tricarboxylate intermediates of the Krebs cycle as the sole carbon sources for cell growth, which may adversely affect the extracellular accumulation of SA. Because the carboxylic acid transport machinery of P. kudriavzevii remains poorly understood, here, we focused on studying its SA transportation process from the perspective of mining and characterization of dicarboxylate transporters in a newly isolated acid-tolerant P. kudriavzevii strain CY902. Through genome sequencing and transcriptome analysis, two JEN family carboxylate transporters (PkJEN2-1 and PkJEN2-2) were found to be involved in SA transport. Substrate specificity analysis revealed that both PkJEN proteins are active dicarboxylate transporters, that can effectively import succinate, fumarate and L-malate into the cell. In addition, PkJEN2-1 can transport α-ketoglutarate, while PkJEN2-2 cannot. Since PkJEN2-1 shows higher transcript abundance than PkJEN2-2, its role in dicarboxylate transport is more important than PkJEN2-2. In addition, PKJEN2-2 is also responsible for the uptake of citrate. To our best knowledge, this is the first study to show that a JEN2 subfamily transporter is involved in tricarboxylate transport in yeast. A combination of model-based structure analysis and rational mutagenesis further proved that amino acid residues 392-403 of the tenth transmembrane span (TMS-X) of PkJEN2-2 play an important role in determining the specificity of the tricarboxylate substrate. Moreover, these two PkJEN transporters only exhibited inward transport activity for SA, and simultaneous inactivation of both PkJEN transporters reduced the SA influx, resulting in enhanced extracellular accumulation of SA in the late stage of fermentation. This work provides useful information on the mechanism of di-/tricarboxylic acid utilization in P. kudriavzevii, which will help improve the organic acid production performance of this microbial chassis.
Topics: Membrane Transport Proteins; Pichia; Saccharomyces cerevisiae; Succinates; Succinic Acid
PubMed: 33629807
DOI: 10.1111/1751-7915.13781 -
Food Science and Biotechnology Apr 2021Co-fermentation using yeast ( and ) and the bacteria () as starters isolated from spontaneous sourdough was conducted for the brewing of glucuronic acid (GlcA)-enriched...
Co-fermentation using yeast ( and ) and the bacteria () as starters isolated from spontaneous sourdough was conducted for the brewing of glucuronic acid (GlcA)-enriched apple cider. The concentration of GlcA in the apple cider co-fermented for 14 d with commercial and was 37.7 ± 1.7 mg/mL while a concentration of 62.8 ± 3.1 mg/mL was recorded for fermentation with and , which was higher than the corresponding single yeast fermentation. The co-fermented apple cider revealed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 171.67 ± 0.79 µg trolox equivalents (TE)/mL using and , compared to the control (143.89 ± 7.07 µg TE/mL) just using . Thus, the co-fermentation of and and and provided a new strategy for the development of GlcA-enriched apple cider with enhanced antioxidant capacity.
PubMed: 33936847
DOI: 10.1007/s10068-021-00883-2