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Food Microbiology Aug 2023The color of mulberry wine is difficult to maintain since the main chromogenic substances, anthocyanins, are severely degraded during fermentation and aging. This study...
Formation of vinylphenolic pyranoanthocyanins by selected indigenous yeasts displaying high hydroxycinnamate decarboxylase activity during mulberry wine fermentation and aging.
The color of mulberry wine is difficult to maintain since the main chromogenic substances, anthocyanins, are severely degraded during fermentation and aging. This study selected Saccharomyces cerevisiae I34 and Wickerhamomyces anomalus D6, both displaying high hydroxycinnamate decarboxylase (HCDC) activity (78.49% and 78.71%), to enhance the formation of stable vinylphenolic pyranoanthocyanins (VPAs) pigments during mulberry wine fermentation. The HCDC activity of 84 different strains from eight regions in China was primarily screened via the deep well plate micro fermentation method, after which the tolerance and brewing characteristics were evaluated via simulated mulberry juice. The two selected strains and a commercial Saccharomyces cerevisiae were then inoculated individually or sequentially into the fresh mulberry juice, while the anthocyanin precursors and VPAs were identified and quantified via UHPLC-ESI/MS. The results showed that the HCDC-active strains facilitated the synthesis of stable pigments, cyanidin-3-O-glucoside-4-vinylcatechol (VPC3G), and cyanidin-3-O-rutinoside-4-vinylcatechol (VPC3R), highlighting its potential for enhancing color stability.
Topics: Anthocyanins; Wine; Saccharomyces cerevisiae; Fermentation; Morus; Carboxy-Lyases
PubMed: 37098424
DOI: 10.1016/j.fm.2023.104272 -
Food Microbiology Aug 2023Contamination of white-brined cheeses (WBCs) with yeasts is of major concern in the dairy industry. This study aimed to identify yeast contaminants and characterize...
Contamination of white-brined cheeses (WBCs) with yeasts is of major concern in the dairy industry. This study aimed to identify yeast contaminants and characterize their succession in white-brined cheese during a shelf-life of 52 weeks. White-brined cheeses added herbs (WBC1) or sundried tomatoes (WBC2) were produced at a Danish dairy and incubated at 5 °C and 10 °C. An increase in yeast counts was observed for both products within the first 12-14 weeks of incubation and stabilized afterwards varying in a range of 4.19-7.08 log CFU/g. Interestingly, higher incubation temperature, especially in WBC2, led to lower yeast counts, concurrently with higher diversity of yeast species. Observed decrease in yeast counts was, most likely, due to negative interactions between yeast species leading to growth inhibition. In total, 469 yeast isolates from WBC1 and WBC2 were genotypically classified using the (GTG)-rep-PCR technique. Out of them, 132 representative isolates were further identified by sequencing the D1/D2 domain of the 26 S rRNA gene. Predominant yeast species in WBCs were Candida zeylanoides and Debaryomyces hansenii, while Candida parapsilosis, Kazachstania bulderi, Kluyveromyces lactis, Pichia fermentans, Pichia kudriavzevii, Rhodotorula mucilaginosa, Torulaspora delbrueckii, and Wickerhamomyces anomalus were found in lower frequency. Heterogeneity of yeast species in WBC2 was generally larger compared to WBC1. This study indicated that, along with contamination levels, taxonomic heterogeneity of yeasts is an important factor influencing yeast cell counts, as well as product quality during storage.
Topics: Cheese; Yeasts; Polymerase Chain Reaction
PubMed: 37098422
DOI: 10.1016/j.fm.2023.104266 -
Animal Microbiome Apr 2023Yeasts are gaining attention as alternative ingredients in aquafeeds. However, the impact of yeast inclusion on modulation of intestinal microbiota of fish fed...
BACKGROUND
Yeasts are gaining attention as alternative ingredients in aquafeeds. However, the impact of yeast inclusion on modulation of intestinal microbiota of fish fed plant-based ingredients is limited. Thus, the present study investigates the effects of yeast and processing on composition, diversity and predicted metabolic capacity of gut microbiota of Atlantic salmon smolt fed soybean meal (SBM)-based diet. Two yeasts, Cyberlindnera jadinii (CJ) and Wickerhamomyces anomalus (WA), were produced in-house and processed by direct heat-inactivation with spray-drying (ICJ and IWA) or autolyzed at 50 °C for 16 h, followed by spray-drying (ACJ and AWA). In a 42-day feeding experiment, fish were fed one of six diets: a fishmeal (FM)-based diet, a challenging diet with 30% SBM and four other diets containing 30% SBM and 10% of each of the four yeast products (i.e., ICJ, ACJ, IWA and AWA). Microbial profiling of digesta samples was conducted using 16S rRNA gene sequencing, and the predicted metabolic capacities of gut microbiota were determined using genome-scale metabolic models.
RESULTS
The microbial composition and predicted metabolic capacity of gut microbiota differed between fish fed FM diet and those fed SBM diet. The digesta of fish fed SBM diet was dominated by members of lactic acid bacteria, which was similar to microbial composition in the digesta of fish fed the inactivated yeasts (ICJ and IWA diets). Inclusion of autolyzed yeasts (ACJ and AWA diets) reduced the richness and diversity of gut microbiota in fish. The gut microbiota of fish fed ACJ diet was dominated by the genus Pediococcus and showed a predicted increase in mucin O-glycan degradation compared with the other diets. The gut microbiota of fish fed AWA diet was highly dominated by the family Bacillaceae.
CONCLUSIONS
The present study showed that dietary inclusion of FM and SBM differentially modulate the composition and predicted metabolic capacity of gut microbiota of fish. The inclusion of inactivated yeasts did not alter the modulation caused by SBM-based diet. Fish fed ACJ diet increased relative abundance of Pediococcus, and mucin O-glycan degradation pathway compared with the other diets.
PubMed: 37016467
DOI: 10.1186/s42523-023-00242-y -
International Journal of Environmental... Mar 2023The main goal of wastewater treatment is to significantly reduce organic compounds, micronutrients (nitrogen and phosphorus) and heavy metals and other contaminants...
The main goal of wastewater treatment is to significantly reduce organic compounds, micronutrients (nitrogen and phosphorus) and heavy metals and other contaminants (pathogens, pharmaceuticals and industrial chemicals). In this work, the efficiency of removing different contaminants (COD, NO, NO, NH, PO, SO, Pb, Cd) from synthetic wastewater was tested using five different yeast strains: CMGBP16 (P1), S228C (P2), CM6B70 (P3), CMGB234 (P4) and CMGB88 (P5). The results showed a removal efficiency of up to 70% of COD, 97% of nitrate, 80% of nitrite, 93% of phosphate and 70% of sulfate ions for synthetic wastewater contaminated with Pb (43 mg/L) and Cd ions (39 mg/L). In contrast, the results showed an increase in ammonium ions, especially in the presence of Pb ions. The yeast strains showed a high capacity to reduce Pb (up to 96%) and Cd (up to 40%) ions compared to the initial concentrations. In presence of a crude biosurfactant, the removal efficiency increased up to 99% for Pb and 56% for Cd simultaneously with an increase in yeast biomass of up to 11 times. The results, which were obtained in the absence of aeration and in neutral pH conditions, proved a high potential for practical applications in the biotreatment of the wastewater and the recovery of Pb and Cd ions, with a high benefit-cost ratio.
Topics: Wastewater; Saccharomyces cerevisiae; Cadmium; Biodegradation, Environmental; Lead; Metals, Heavy; Phosphates
PubMed: 36981703
DOI: 10.3390/ijerph20064795 -
Foods (Basel, Switzerland) Mar 2023Natural compounds are a suitable alternative to synthetic food preservatives due to their natural origin and health-promoting properties. In the current study,...
Natural compounds are a suitable alternative to synthetic food preservatives due to their natural origin and health-promoting properties. In the current study, phenolic-phenolic and phenolic-synthetic combinations were tested for their antibiofilm formation, anti-planktonic growth, and anti-adhesion properties against , (formerly ), , and . The phenolics were vanillin and cinnamic acid, while the synthetic preservatives were sodium benzoate, potassium sorbate, and sodium diacetate. The vanillin-cinnamic acid combination had synergistic effect in all the tested yeasts for the biofilm inhibition with a fractional inhibitory concentration index (FICI) of ≤0.19 for , 0.25 for , 0.31 for . , and 0.5 for . Most of the phenolic-synthetic combinations had indifferent interaction regarding biofilm formation. The vanillin-cinnamic acid combination also had higher activity against spoilage yeasts adhesion on the abiotic surface and planktonic growth compared to the phenolic-synthetic combinations. For the phenolic-synthetic anti-planktonic activity, synergistic interaction was present in all the vanillin-synthetic combinations in , vanillin-sodium benzoate and vanillin-potassium sorbate in , vanillin-sodium benzoate in , and cinnamic acid-sodium diacetate in . These results suggest a novel antimicrobial strategy that may broaden the antimicrobial spectrum and reduce compound toxicity against food spoilage yeasts.
PubMed: 36981264
DOI: 10.3390/foods12061338 -
Frontiers in Microbiology 2023Plantaricin is a kind of bacteriocin with broad-spectrum antibacterial activity on several food pathogens and spoilage microorganisms, showing potential in...
Plantaricin is a kind of bacteriocin with broad-spectrum antibacterial activity on several food pathogens and spoilage microorganisms, showing potential in biopreservation applications. However, the low yield of plantaricin limits its industrialization. In this study, it was found that the co-culture of Y-5 and RX-8 could enhance plantaricin production. To investigate the response of RX-8 facing Y-5 and understand the mechanisms activated when increasing plantaricin yield, comparative transcriptomic and proteomic analyses of RX-8 were performed in mono-culture and co-culture. The results showed that different genes and proteins in the phosphotransferase system (PTS) were improved and enhanced the uptake of certain sugars; the key enzyme activity in glycolysis was increased with the promotion of energy production; arginine biosynthesis was downregulated to increase glutamate mechanism and then promoted plantaricin yield; and the expression of several genes/proteins related to purine metabolism was downregulated and those related to pyrimidine metabolism was upregulated. Meanwhile, the increase of plantaricin synthesis by upregulation of cluster expression under co-culture indicated that the PlnA-mediated quorum sensing (QS) system took part in the response mechanism of RX-8. However, the absence of AI-2 did not influence the inducing effect on plantaricin production. Mannose, galactose, and glutamate were critical metabolites and significantly simulate plantaricin production ( < 0.05). In summary, the findings provided new insights into the interaction between bacteriocin-inducing and bacteriocin-producing microorganisms, which may serve as a basis for further research into the detailed mechanism.
PubMed: 36910197
DOI: 10.3389/fmicb.2023.1111516 -
Frontiers in Microbiology 2023Our recent research study focused on Miang fermentation revealed that tannin-tolerant yeasts and bacteria play vital roles in the Miang production process. A high...
Our recent research study focused on Miang fermentation revealed that tannin-tolerant yeasts and bacteria play vital roles in the Miang production process. A high proportion of yeast species are associated with plants, insects, or both, and nectar is one of the unexplored sources of yeast biodiversity. Therefore, this study aimed to isolate and identify yeasts of tea flowers of var. and to investigate their tannin tolerance, which is a property essential to Miang production processes. A total of 82 yeasts were recovered from a total of 53 flower samples in Northern Thailand. It was found that two and eight yeast strains were distinct from all other known species within the genera and , respectively. These yeast strains were described as three new species, namely, , , and . The identification of these species was based on phenotypic (morphological, biochemical, and physiological characteristics) and phylogenetic analyses of a combination of the internal transcribed spacer (ITS) regions and the D1/D2 domains of the large subunit (LSU) ribosomal RNA gene. The yeast diversity in tea flowers acquired from Chiang Mai, Lampang, and Nan provinces had a positive correlation with those acquired from Phayao, Chiang Rai, and Phrae, respectively. , , and were the species uniquely found in tea flowers collected from Nan and Phrae, Chiang Mai, and Lampang provinces, respectively. Some of the tannin-tolerant and/or tannase-producing yeasts were associated with yeasts in the commercial Miang process and those found during Miang production, i.e., , , , , , , , and . In conclusion, these studies suggest that floral nectar could support the formation of yeast communities that are beneficial for Miang production.
PubMed: 36876082
DOI: 10.3389/fmicb.2023.1043430 -
Frontiers in Microbiology 2022Salami is a kind of fermented meat product with rich nutrition and unique flavor. Because it is rich in fat, it is easy to oxidize to produce bad flavor. Compared with...
Salami is a kind of fermented meat product with rich nutrition and unique flavor. Because it is rich in fat, it is easy to oxidize to produce bad flavor. Compared with the way of adding artificial or natural antioxidants to reduce the degree of sausage oxidation, the antioxidant characteristics of developing the starter itself deserve more attention. In this study, firstly the antioxidant activities of 5 strains of yeast were measured , and then the mixture of yeast and Lactobacillus rhamnosus YL-1 was applied to fermented sausage model. The effect of the starter in the sausage model was investigated through physicochemical parameters, degree of fat oxidation, free fatty acid content, and though volatile flavor compound analysis, sensory evaluation and various indexes after storage were observed. Metagenomics was used to explore metabolic pathways, functional genes and key enzymes related to lipid oxidizing substances in sausage in yeast. The results showed that Wickerhamomyces anomalus Y12-3 and Y12-4 had strong tolerance to H2O2, and had higher SOD and CAT enzyme activities. The addition of yeast effectively reduced the material value of peroxidation value and active thiobarbiturate in salami. In flavor analysis, the content of flavor compounds associated with lipid oxidation, such as hexanal, heptanal, nonanal and (E)-2-decenal were significantly lower with the use of Debaryomyces hansenii Y4-1 and Y12-3. Meanwhile, the possible pathways of yeast metabolism of flavor substances related to lipid oxidation (mainly aldehydes) were discussed with the help of metagenomic techniques. According to the results of metagenomics, fatty acid degradation (ko00071) metabolic pathway was related to the degradation of aldehydes through aldehyde dehydrogenase, which was the potential key enzyme.
PubMed: 36726562
DOI: 10.3389/fmicb.2022.1113848 -
Molecules (Basel, Switzerland) Jan 2023Olive mill wastewater (OMWW) represents a by-product but also a source of biologically active compounds, and their recycling is a relevant strategy to recover income and...
Olive mill wastewater (OMWW) represents a by-product but also a source of biologically active compounds, and their recycling is a relevant strategy to recover income and to reduce environmental impact. The objective of the present study was to obtain a new functional beverage with a health-promoting effect starting from OMWW. Fresh OMWW were pre-treated through filtration and/or microfiltration and subjected to fermentation using strains belonging to , and . During fermentation, phenolic content and hydroxytyrosol were monitored. Moreover, the biological assay of microfiltered fermented OMWW was detected versus tumor cell lines and as anti-inflammatory activity. The results showed that in microfiltered OMWW, fermentation was successfully conducted, with the lowest pH values reached after 21 days. In addition, in all fermented samples, an increase in phenol and organic acid contents was detected. Particularly, in samples fermented with and in single and combined cultures, the concentration of hydroxytyrosol reached values of 925.6, 902.5 and 903.5 mg/L, respectively. Moreover, biological assays highlighted that fermentation determines an increase in the antioxidant and anti-inflammatory activity of OMWW. Lastly, an increment in the active permeability on Caco-2 cell line was also revealed. In conclusion, results of the present study confirmed that the process applied here represents an effective strategy to achieve a new functional beverage.
Topics: Humans; Wastewater; Olea; Caco-2 Cells; Phenols; Environment; Industrial Waste; Olive Oil
PubMed: 36677704
DOI: 10.3390/molecules28020646 -
International Journal of Molecular... Jan 2023Three killer toxins that were previously investigated, one excreted by Kluyveromyces wickerhamii and two by different strains of Wickerhamomyces anomalus, were produced...
Three killer toxins that were previously investigated, one excreted by Kluyveromyces wickerhamii and two by different strains of Wickerhamomyces anomalus, were produced at the pilot scale, lyophilized and characterized, and the formulates were assessed for their zymocidial effect against Brettanomyces bruxellensis spoilage yeast. A comparative analysis allowed the evaluation of the minimum inhibitory concentration (MIC) against a sensitive strain. Fungicidal and fungistatic concentrations were used to evaluate the cytocidal effect using a cytofluorimetric approach that confirmed the lethal effect of all lyophilized formulates against spoilage yeasts. Moreover, the potential killer toxins' cytotoxicity against human intestinal cells (Caco-2) were evaluated to exclude any possible negative effect on the consumers. Finally, the effective lethal effect of all three lyophilized killer toxins toward sensitive strain were tested. The results indicated that all of them acted without dangerous effects on the human epithelial cells, opening the way for their possible commercial application. In particular, D15 showed the lowest MIC and the highest activity, was evaluated also in wine, revealing a strong reduction of yeast growth and, at the same time, a control of ethyl phenols production.
Topics: Humans; Caco-2 Cells; Yeasts; Brettanomyces; Wine; Toxins, Biological; Food Microbiology
PubMed: 36674823
DOI: 10.3390/ijms24021309