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Foods (Basel, Switzerland) Dec 2022Gliadins proteins make up around 30% of total wheat flour proteins. They are involved in many immune disorders affecting an increasing number of people who eat foods...
Gliadins proteins make up around 30% of total wheat flour proteins. They are involved in many immune disorders affecting an increasing number of people who eat foods made with wheat flour. The triggering factor is the accumulation in the gut of immunogenic peptides derived from incomplete degradation of gliadins by gastric proteases. Previous research has revealed the effectiveness of sourdough-fermentation technology or related lactic acid bacteria in reducing wheat flour allergenic proteins. However, there are no single yeast cultures for producing reduced allergenicity wheat products. This study evaluated sourdough-related yeast strains for their ability to hydrolyze gliadin proteins. All yeast strains were able to degrade gliadins and use them as carbon and nitrogen sources. The proliferation of the yeast strains depended on the gliadin addition; complete hydrolysis was observed after 24 h. The strain showing higher proteolytic activity fermented, acceptably wheat flour dough. The gliadin content of the leavened dough was reduced by 50%. Bread made from the -fermented dough showed a 78% reduction in immunogenic α-gliadins. 50% of the decrease was attributed to the proteolytic activity of the yeast cells, and the other 35% to the baking process. These results show the potential of the yeast as a starter for reducing immunogenicity wheat products.
PubMed: 36553848
DOI: 10.3390/foods11244105 -
Genes Dec 2022Ethyl acetate is an important flavor element that is a vital component of . To date, the transcription factors that can help identify the molecular mechanisms involved...
Ethyl acetate is an important flavor element that is a vital component of . To date, the transcription factors that can help identify the molecular mechanisms involved in the synthesis of ethyl acetate have not been studied. In the present study, we sequenced and assembled the strain YF1503 transcriptomes to identify transcription factors. We identified 307 transcription factors in YF1503 using high-throughput RNA sequencing. Some transcription factors, such as C2H2, bHLH, MYB, and bZIP, were up-regulated, and these might play a role in ethyl acetate synthesis. According to the trend of ethyl acetate content, heat map results and STEM, twelve genes were selected for verification of expression levels using quantitative real-time PCR. This dynamic transcriptome analysis presents fundamental information on the transcription factors and pathways that are involved in the synthesis of ethyl acetate in aroma-producing yeast. Of significant interest is the discovery of the roles of various transcription factor genes in the synthesis of ethyl acetate.
Topics: Transcription Factors; Odorants; Yeasts; Gene Expression Profiling
PubMed: 36553608
DOI: 10.3390/genes13122341 -
Cureus Nov 2022In view of the growing incidence of pathogenic yeast infection all over the world, this study was undertaken to understand its etiology and epidemiology in Assam.
CONTEXT
In view of the growing incidence of pathogenic yeast infection all over the world, this study was undertaken to understand its etiology and epidemiology in Assam.
AIMS
To characterize and study the antifungal susceptibility pattern of the pathogenic yeasts from the clinical samples.
SETTINGS AND DESIGN
The study was a hospital-based cross-sectional study.
METHODS AND MATERIAL
150 patients were enrolled in the study and from which clinical samples were collected. A total of 83 samples showing the growth of yeast in culture were included in the study. The yeasts were identified by conventional and BioMerieux ID 32C and VITEK 2. Antifungal susceptibility test was done by disk diffusion method as per Clinical and Laboratory Standards Institute (CLSI), M44-A2.
STATISTICAL ANALYSIS USED
Data was analyzed using statistical software Epi-Info 7.1.2.0 (2013; CDC, Atlanta, USA). For comparison of categorical data, the Chi-square test or Fisher exact test was used. A value of less than 0.05 was considered statistically significant.
RESULTS
The most affected population was the age group of ≤10 years (32.5%) with male preponderance (67.5%). Yeasts were mostly isolated bloodstream infections (49.3%). The major risk factor was prolonged antibiotic intake. Predominant yeast isolates were (43.4%) followed by (19.3%). Emerging yeasts like (4.8%), (2.4%), and (1.2%) were also isolated. Amphotericin B was effective against all yeast isolates. All the isolates of were resistant to all the azoles.
CONCLUSIONS
The study reflects that there is a growing incidence of emerging yeast infections and efforts are to be made for their identification and antifungal susceptibility testing for the initiation of appropriate therapy.
PubMed: 36532931
DOI: 10.7759/cureus.31512 -
Frontiers in Microbiology 2022As a C13-norisoprenoid aroma substance, β-damascenone is a highly important aromatic compound and an active constituent. The purpose of this study was to investigate...
As a C13-norisoprenoid aroma substance, β-damascenone is a highly important aromatic compound and an active constituent. The purpose of this study was to investigate the change law of β-damascenone during the light-flavor brewing process, and screen the indigenous microbial strains that produce this compound and optimize fermentation parameters for improving β-damascenone production using a statistical approach. In this project, YWB-1 exhibited the highest producing activity of β-damascenone. Fermentation conditions were optimized for β-damascenone production using a one-factor-at-a-time (OFAT) approach. A Plackett-Burman design was subsequently adopted to assess the effects of initial pH, incubation temperature, inoculum size, fermentation period, and original Brix degree. Analysis of variance (ANOVA) showed that the correlation coefficient ( ) of the executive model was 0.9795, and this value was significant ( < 0.05). Three significant variables were optimized at three different coded levels using a Box-Behnken design (BBD) of response surface methodology (RSM). Here, 7.25 μg/L β-damascenone was obtained under the following optimum conditions: initial pH of 3.31, original Brix degree of 10.53%, and fermentation period of 52.13 h. The yield was increased 3.02-fold compared with that obtained under unoptimized conditions. This information is conducive to the control of flavor production by regulating variable parameters in fermentation.
PubMed: 36523831
DOI: 10.3389/fmicb.2022.1067671 -
Foods (Basel, Switzerland) Nov 2022Ethanol stress to yeast is well recognized and exists widely during the brewing process of alcohol products. is an important ester-producing yeast in the brewing...
Ethanol stress to yeast is well recognized and exists widely during the brewing process of alcohol products. is an important ester-producing yeast in the brewing process of Chinese and other alcohol products. Therefore, it is of great significance for the alcohol products brewing industry to explore the effects of ethanol stress on the growth metabolism of . In this study, the effects of ethanol stress on the growth, esters production ability, cell membrane integrity and reactive oxygen species (ROS) metabolism of NCU003 were studied. Our results showed that ethanol stress could inhibit the growth, reduce the ability of non-ethyl ester compounds production and destroy the cell morphology of NCU003. The results also showed that 9% ethanol stress produced excessive ROS and then increased the activities of antioxidant enzymes (superoxide dismutase, catalase, aseorbateperoxidase and glutathione reductase) compared to the control group. However, these increased antioxidant enzyme activities could not prevent the damage caused by ROS to NCU003. Of note, correlation results indicated that high content of ROS could promote the accumulation of malondialdehyde content, resulting in destruction of the integrity of the cell membrane and leading to the leakage of intracellular nutrients (soluble sugar and protein) and electrolytes. These results indicated that the growth and the non-ethyl ester compounds production ability of could be inhibited under ethanol stress by accumulating excessive ROS and the destruction of cell membrane integrity in .
PubMed: 36429336
DOI: 10.3390/foods11223744 -
Foods (Basel, Switzerland) Nov 2022The co-fermentation of Saccharomyces cerevisiae and ester-producing yeasts is considered to be an effective way to improve the flavor and quality of fruit wine. In this...
The co-fermentation of Saccharomyces cerevisiae and ester-producing yeasts is considered to be an effective way to improve the flavor and quality of fruit wine. In this study, three kinds of ester-producing yeasts (Candida glabrata NCUF308.1, Pichia anomala NCUF306.1, and Wickerhamomyces anomalus NCUF307.1) and S. cerevisiae NCUF309.2 were used to simulate blueberry wine co-fermentation at different ratios. The results showed that, compared with S. cerevisiae NCUF309.2 fermentation (S), the population of S. cerevisiae NCUF309.2 in co-fermentation samples decreased to varying degrees, and the content of ethanol also decreased. The results also showed that the co-fermentation of C. glabrata NCUF308.1 and S. cerevisiae NCUF309.2 at the ratio of 1:1 (CS1), co-fermentation of P. anomala NCUF306.1 and S. cerevisiae NCUF309.2 at the ratio of 5:1 (PS5), and co-fermentation of W. anomalus NCUF307.1 and S. cerevisiae NCUF309.2 at the ratio of 5:1 (WS5) could significantly increase the content of ester compounds (p < 0.05), which was 3.29, 4.75, and 3.04 times that of the S sample, respectively. Among them, the sample of CS1 was characterized by phenethyl acetate and isoamyl acetate, while the samples of CS5 and PS5 were characterized by propyl octanoate and ethyl decanoate, and the sample of WS5 was characterized by 3-methylbutyl hexanoate. However, the contents of odor active compounds were higher in the CS1 sample. Therefore, the samples of CS1 had the potential to create the distinctive flavor of blueberry wine.
PubMed: 36429247
DOI: 10.3390/foods11223655 -
BMC Microbiology Nov 2022Wickerhamomyces anomalus (W. anomalus) is a kind of non-Saccharomyces yeast that has a variety of unique physiological characteristics and metabolic features and is...
BACKGROUND
Wickerhamomyces anomalus (W. anomalus) is a kind of non-Saccharomyces yeast that has a variety of unique physiological characteristics and metabolic features and is widely used in many fields, such as food preservation, biomass energy, and aquaculture feed protein production. However, the mechanism of W. anomalus response to ethanol stress is still unclear, which greatly limits its application in the production of ethanol beverages and ethanol fuels. Therefore, we checked the effects of ethanol stress on the morphology, the growth, and differentially expressed genes (DEGs) and metabolites (DEMs) of W. anomalus.
RESULTS
High concentrations of ethanol (9% ethanol and 12% ethanol) remarkably inhibited the growth of W. anomalus. Energy metabolism, amino acid metabolism, fatty acids metabolism, and nucleic acid metabolism were significantly influenced when exposing to 9% ethanol and 12% ethanolstress, which maybe universal for W. anomalus to response to different concentrations of ethanol stressl Furthermore, extracellular addition of aspartate, glutamate, and arginine significantly abated ethanol damage and improved the survival rate of W. anomalus.
CONCLUSIONS
The results obtained in this study provide insights into the mechanisms involved in W. anomalus response to ethanol stress. Therefore, new strategies can be realized to improve the ethanol tolerance of W. anomalus through metabolic engineering.
Topics: Ethanol; Transcriptome; Saccharomycetales; Yeasts
PubMed: 36380285
DOI: 10.1186/s12866-022-02691-y -
Molecules (Basel, Switzerland) Oct 2022The excessive use of fossil sources for the generation of electrical energy and the increase in different organic wastes have caused great damage to the environment;...
The excessive use of fossil sources for the generation of electrical energy and the increase in different organic wastes have caused great damage to the environment; these problems have promoted new ways of generating electricity in an eco-friendly manner using organic waste. In this sense, this research uses single-chamber microbial fuel cells with zinc and copper as electrodes and pineapple waste as fuel (substrate). Current and voltage peaks of 4.95667 ± 0.54775 mA and 0.99 ± 0.03 V were generated on days 16 and 20, respectively, with the substrate operating at an acid pH of 5.21 ± 0.18 and an electrical conductivity of 145.16 ± 9.86 mS/cm at two degrees Brix. Thus, it was also found that the internal resistance of the cells was 865.845 ± 4.726 Ω, and a maximum power density of 513.99 ± 6.54 mW/m was generated at a current density of 6.123 A/m, and the final FTIR spectrum showed a clear decrease in the initial transmittance peaks. Finally, from the biofilm formed on the anodic electrode, it was possible to molecularly identify the yeast with 99.82% accuracy. In this way, this research provides a method that companies exporting and importing this fruit may use to generate electrical energy from its waste.
Topics: Bioelectric Energy Sources; Ananas; Electricity; Electrodes; Biofilms; Wastewater
PubMed: 36364216
DOI: 10.3390/molecules27217389 -
World Journal of Microbiology &... Nov 2022Yeast mannoproteins are proposed as a paraprobiotics with antimicrobial and prebiotic properties. They can be used as biopreservatives in food and in diseases therapies....
Yeast mannoproteins are proposed as a paraprobiotics with antimicrobial and prebiotic properties. They can be used as biopreservatives in food and in diseases therapies. The knowledge about the specificity and/or capability of their influence on the growth of different microorganism is limited. The study determined the effect of mannoprotein preparations of Saccharomyces cerevisiae (S. cerevisiae) ATCC 7090 and nonconventional yeast origin [Metschnikowia reukaufii (M. reukaufii) WLP 4650 and Wickerhamomyces anomalus (W. anomalus) CCY 38-1-13] on the growth of selected bacteria of the genera: Lactobacilllus, Limosilatobacillus, Limosilatobacillus, Bifidobacterium, Staphylococcus, Enterococcus, Pseudomonas, Escherichia, Proteus and Salmonella. The degree of stimulation or growth inhibition of tested bacteria depended on the type and dose of the mannoprotein and the bacterial strain. The addition of the tested preparations in the entire range of applied concentrations had a positive effect especially on the growth of Lactobacillus arabinosus ATCC 8014 and Bifidobacterium animalis subsp. lactis B12. Mannoproteins isolated from S. cerevisiae limited the growth of the Escherichia coli (E. coli) ATCC 25922, Pseudomonas aureoginosa (P. aureoginosa) ATCC 27853, Proteus mirabilis ATCC 35659 and Salmonella Enteritidis ATCC 13076 to the greatest extent, while preparations of M. reukaufii and W. anomalus origin most effectively limited the growth of Staphylococcus aureus strains, E. coli and P. aureoginosa. The growth of Enterococcus faecalis was stimulated by the presence of all studied preparations in most of the concentrations used. Further research will determine how the purification process of studied mannoproteins or oligosaccharide fractions, its structure and composition influence on the growth of selected bacteria and what is the mechanism of its activity.
Topics: Saccharomyces cerevisiae; Escherichia coli; Phylogeny; Anti-Infective Agents; Anti-Bacterial Agents; Bacteria; Microbial Sensitivity Tests
PubMed: 36319710
DOI: 10.1007/s11274-022-03448-5 -
Frontiers in Bioengineering and... 2022Advanced generation biofuels have potential for replacing fossil fuels as society moves forward into a net-zero carbon future. Marine biomass is a promising source of...
Advanced generation biofuels have potential for replacing fossil fuels as society moves forward into a net-zero carbon future. Marine biomass is a promising source of fermentable sugars for fermentative bioethanol production; however the medium derived from seaweed hydrolysis contains various inhibitors, such as salts that affected ethanol fermentation efficiency. In this study the stress tolerance of a marine yeast, M15 was characterised. Specific growth rate analysis results showed that M15 could tolerate up to 600 g/L glucose, 150 g/L xylose and 250 g/L ethanol, respectively. Using simulated concentrated seaweed hydrolysates, M15's bioethanol production potential using macroalgae derived feedstocks was assessed, in which 5.8, 45.0, and 19.9 g/L ethanol was produced from brown (), green () and red seaweed () based media. The fermentation of actual hydrolysate harvested from United Kingdom shores resulted in a relatively low ethanol concentration (15.5 g/L) due to challenges that arose from concentrating the seaweed hydrolysate. However, fed-batch fermentation using simulated concentrated green seaweed hydrolysate achieved a concentration of 73 g/L ethanol in fermentations using both seawater and reverse osmosis water. Further fermentations conducted with an adaptive strain M15-500A showed improved bioethanol production of 92.7 g/L ethanol from 200 g/L glucose and reduced lag time from 93 h to 24 h in fermentation with an initial glucose concentration of 500 g/L. The results indicated that strains M15 and M15-500A have great potential for industrial bioethanol production using marine biomass derived feedstocks. It also suggested that if a concentrated high sugar content seaweed hydrolysate could be obtained, the bioethanol concentration could achieve 90 g/L or above, exceeding the minimum industrial production threshold.
PubMed: 36312543
DOI: 10.3389/fbioe.2022.1028185