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World Journal of Microbiology &... Mar 2023The aim of this study was to determine the microbial diversity and mycotoxin profile of artisanal infant flours commonly vended in public healthcare centres and retail...
The aim of this study was to determine the microbial diversity and mycotoxin profile of artisanal infant flours commonly vended in public healthcare centres and retail markets in Côte d'Ivoire. Thus, maize, millet, sorghum, soya and multigrain (mix of different cereals) flour samples collected from different localities were first, analysed for nutritional composition, then for microbial communities using high-throughput sequencing and for mycotoxins through UHPLC-MS/MS method. Firmicutes was the most abundant bacterial phylum and the dominant genera were Weissella, Staphylococcus, Pediococcus. Potential pathogenic genera such as Bacillus, Enterobacter, Acinetobacter and Burkholderia were also found. The fungal community was composed of two dominant phyla (Ascomycota and Basidiomycota) and 31 genera with > 0.1% relative abundance. In samples from public healthcare centres, Candida, Hyphopichia, Trichosporon, and Cyberlindnera were the most dominant genera according to the flour type while in samples from retail markets, they were Cyberlindnera, Clavispora, Nakaseomyces, Aureobasidium and Candida. Possible toxigenic genera Fusarium and Aspergillus were also detected. Aflatoxin B1 (AFB1), Ochractoxin (OTA), Fumonisin B1 (FB1) and B2 (FB2) were the mycotoxins found in the analysed flours. AFB1 was detected in 100% of maize (range 1.2-120.5 µg/kg; mean: 44.2 µg/kg) and 50-83.3% of millet flours (range 0.2-31.5 µg/kg; mean: 31.5 µg/kg). Its level in all maize and rice flour samples exceeded EU standard (0.1 µg/kg). For OTA and fumonisins, millet and maize flours showed the highest levels of sample exceeding the EU standard. Thus, artisanal infant flours marketed in Côte d'Ivoire, mainly maize and rice flours, although containing potentially beneficial bacteria, represent potential health risks for children.
Topics: Child; Infant; Humans; Mycotoxins; Flour; Ochratoxins; Cote d'Ivoire; Tandem Mass Spectrometry; Food Contamination; Edible Grain; Zea mays; Microbiota
PubMed: 36943491
DOI: 10.1007/s11274-023-03577-5 -
International Journal of Biological... Apr 2021The content of pullulan and melanin in 500 mutants of Aureobasidum pullulans obtained by ultraviolet mutagenesis were examined and statistically analyzed, and a strong...
The content of pullulan and melanin in 500 mutants of Aureobasidum pullulans obtained by ultraviolet mutagenesis were examined and statistically analyzed, and a strong positive correlation was found between them. The result was further confirmed by culturing wild type strain As3.3984 in different media. Then we constructed melanin-deletion mutant As-Δalb1 and pullulan-deletion mutant As-Δpul. As-Δalb1 was a melanin-free strain with the yield of pullulan decreased by 41.01%. The supplementation of melanin in the culture of As-Δalb1 increased the production of pullulan. As-Δpul synthesized neither pullulan nor melanin and recovered melanin synthesis by adding pullulan to the medium. The results suggested that high concentration- of pullulan induced morphological transformation and synthesis of melanin, and melanin promoted the synthesis of pullulan. The pullulan biosynthetic genes, upt, pgm, ugp, and pul, were down-regulated, while the negative regulatory gene of pullulan synthesis, creA, was up-regulated by melanin deficiency.
Topics: Aureobasidium; Gene Deletion; Genes, Fungal; Glucans; Melanins
PubMed: 33609584
DOI: 10.1016/j.ijbiomac.2021.02.108 -
Foods (Basel, Switzerland) May 2023We have successfully identified the transcription factor from the fungus Hit-lcy3T, which regulates melanin biosynthesis genes. Bioinformatics analysis revealed that...
We have successfully identified the transcription factor from the fungus Hit-lcy3T, which regulates melanin biosynthesis genes. Bioinformatics analysis revealed that the Cmr1 gene encodes a protein of 945 amino acids, containing two CysHis zinc finger domains and a Zn(II)Cys binuclear cluster domain located at the N-terminus of . To investigate the function of the gene, we performed gene knockout and overexpression experiments. Our results showed that is a key regulator of melanin synthesis in Hit-lcy3, and its absence caused developmental defects. Conversely, overexpression of significantly increased the number of chlamydospores in Hit-lcy3 and improved melanin production. RT-qPCR analysis further revealed that overexpression of Cmr1 enhanced the expression of several genes involved in melanin biosynthesis, including , , , and . Melanin extracted from the Hit-lcy3 was characterized using UV and IR spectroscopy. Furthermore, we assessed the antioxidant properties of Hit-lcy3 melanin and found that it possesses strong scavenging activity against DPPH, ABTS, and OH, but weaker activity against O. These findings suggest that Hit-lcy3 melanin holds promise for future development as a functional food additive.
PubMed: 37297380
DOI: 10.3390/foods12112135 -
Applied Microbiology and Biotechnology Sep 2019The fungi Aureobasidium pullulans, Mortierella humilis, Trichoderma harzianum and Phoma glomerata were used to investigate the formation of selenium- and...
The fungi Aureobasidium pullulans, Mortierella humilis, Trichoderma harzianum and Phoma glomerata were used to investigate the formation of selenium- and tellurium-containing nanoparticles during growth on selenium- and tellurium-containing media. Most organisms were able to grow on both selenium- and tellurium-containing media at concentrations of 1 mM resulting in extensive precipitation of elemental selenium and tellurium on fungal surfaces as observed by the red and black colour changes. Red or black deposits were confirmed as elemental selenium and tellurium, respectively. Selenium oxide and tellurium oxide were also found after growth of Trichoderma harzianum with 1 mM selenite and tellurite as well as the formation of elemental selenium and tellurium. The hyphal matrix provided nucleation sites for metalloid deposition with extracellular protein and extracellular polymeric substances localizing the resultant Se or Te nanoparticles. These findings are relevant to remedial treatments for selenium and tellurium and to novel approaches for selenium and tellurium biorecovery.
Topics: Biodegradation, Environmental; Fungi; Nanoparticles; Oxidation-Reduction; Selenium; Selenium Compounds; Tellurium
PubMed: 31324941
DOI: 10.1007/s00253-019-09995-6 -
Natural Product Research Jul 2023Mannans has been attracted the interest in various sectors due to its promising applications. The low toxicity of mannans allows for their use in cosmetics,...
Mannans has been attracted the interest in various sectors due to its promising applications. The low toxicity of mannans allows for their use in cosmetics, pharmaceutical, and biomedical industries. In this study, the α-D-mannan extraction conditions from by alkaline extraction were optimized using a Box-Behnken design (BBD). The effect of temperature (°C), pH and extraction time (hours) on the yield of α-mannan was investigated. The conditions that produced the highest yield (26%) were a temperature of 92 °C, extraction time of 3 h and pH 13. In addition, the α-D-mannan structure was confirmed by methylation analysis, 1D and 2D NMR spectroscopic analysis, and GC-MS.
Topics: Mannans; Temperature; Magnetic Resonance Spectroscopy
PubMed: 35086400
DOI: 10.1080/14786419.2022.2029859 -
Food Research International (Ottawa,... Nov 2023The grapevine and vinification microbiota have a strong influence on the characteristics of the produced wine. Currently we have a good understanding of the role of...
Vineyard-mediated factors are still operative in spontaneous and commercial fermentations shaping the vinification microbial community and affecting the antioxidant and anticancer properties of wines.
The grapevine and vinification microbiota have a strong influence on the characteristics of the produced wine. Currently we have a good understanding of the role of vineyard-associated factors, like cultivar, vintage and terroir in shaping the grapevine microbiota. Notwithstanding, their endurance along the vinification process remains unknown. Thus, the main objective of our study was to determine how these factors influence (a) microbial succession during fermentation (i.e., bacterial and fungal) and (b) the antioxidant, antimutagenic and anticancer potential of the produced wines. These were evaluated under different vinification strategies (i.e., spontaneous V1, spontaneous with preservatives V2, commercial V3), employed at near full-scale level by local wineries, for two cultivars (Roditis and Sideritis), two terroir types, and two vintages. Cultivar and vintage were strong and persistent determinants of the vinification microbiota, unlike terroir whose effect became weaker from the vineyard, and early fermentation stages, where non-Saccharomyces yeasts, filamentous fungi (i.e., Aureobasidium, Cladosporium, Lachancea, Alternaria, Aspergillus, Torulaspora) and acetic acid bacteria (AAB) (Gluconobacter, Acetobacter, Komagataeibacter) dominated, to late fermentation stages where Saccharomyces and Oenococcus become prevalent. Besides vineyard-mediated factors, the vinification process employed was the strongest determinant of the fungal community compared to the bacterial community were effects varied per cultivar. Vintage and vinification type were the strongest determinants of the antioxidant, antimutagenic and anticancer potential of the produced wines. Further analysis identified significant positive correlations between members of the vinification microbiota like the yeasts Torulaspora debrueckii and Lachancea quebecensis with the anticancer and the antioxidant properties of wines in both cultivars. These findings could be exploited towards a microbiota-modulated vinification process to produce high-quality wines with desirable properties and enhanced regional identity.
Topics: Wine; Vitis; Antioxidants; Farms; Fermentation; Microbiota; Torulaspora; Acetic Acid
PubMed: 37803700
DOI: 10.1016/j.foodres.2023.113359 -
Microorganisms Aug 2023Airborne fungal spores constitute an important type of bioaerosol and are responsible for a number of negative effects on human health, including respiratory diseases...
Airborne fungal spores constitute an important type of bioaerosol and are responsible for a number of negative effects on human health, including respiratory diseases and allergies. We investigated the diversity and concentration of culturable airborne fungi on pedestrian bridges in Tianjin, China, using an HAS-100B air sampler. We compared the airborne fungal communities at the top central area of the selected pedestrian bridges and along the corresponding sidewalk, at ground level. A total of 228 fungal strains belonging to 96 species and 58 genera of Ascomycota (68.86%), Basidiomycota (30.26%), and Mucoromycota (0.88%) were isolated and identified using morphological and molecular analysis. was the dominant genus (20.61%), followed by (11.48%), (6.14%), (5.70%), and (4.82%). was the most frequently occurring fungal species (6.58%), followed by (5.26%), sp. (4.82%), (4.39%), and (3.95%). The recorded fungal concentration ranged from 10 to 180 CFU/m. Although there was no significant difference in the distribution and abundance of the dominant airborne fungal taxa between the two investigated bridges' sites, numerous species detected with a low percentage of abundance belonging to well-known pathogenic fungal genera, including , , , , , and , were exclusively present in one of the two sites. The relative humidity showed a stronger influence compared to the temperature on the diversity and concentration of airborne fungi in the investigated sites. Our results may provide valuable information for air quality monitoring and for assessing human health risks associated with microbial pollution.
PubMed: 37630657
DOI: 10.3390/microorganisms11082097 -
A critical review on valorization of food processing wastes and by-products for pullulan production.Journal of Food Science and Technology Aug 2023Pullulan is a commercially available exopolymer biosynthesized by supplemented with nitrogen, carbon and other vital components through submerged and solid-state... (Review)
Review
Pullulan is a commercially available exopolymer biosynthesized by supplemented with nitrogen, carbon and other vital components through submerged and solid-state fermentation. These nutrients are very expensive and it raises the cost for the production of pullulan. Hence, the need of alternative cost-effective raw materials for its production is a prerequisite. Owing to its unique physicochemical features, pullulan has various applications in the food, pharmacological, and biomedical domains. Food industrial wastes generate a considerable number of by-products which accumulates and has a negative influence on the environment. These by-products are made up of proteins, carbohydrates, and other components, can be employed as substrates for the production of pullulan. The present review briefs on the pullulan production using food processing waste and by-products and the elements that impact it. It provides an insight into versatile applications of pullulan in food industries. Various challenges and future prospects in the field of research on pullulan production have been uncovered.
PubMed: 37273573
DOI: 10.1007/s13197-022-05490-5 -
Yeast (Chichester, England) Sep 2020Epiphytic yeasts were isolated from different cultivars of apples and lemons and identified by a combination of PCR-RFLP of 5.8S rRNA region and sequencing of D1/D2...
Biocontrol ability and action mechanisms of Aureobasidium pullulans GE17 and Meyerozyma guilliermondii KL3 against Penicillium digitatum DSM2750 and Penicillium expansum DSM62841 causing postharvest diseases.
Epiphytic yeasts were isolated from different cultivars of apples and lemons and identified by a combination of PCR-RFLP of 5.8S rRNA region and sequencing of D1/D2 domain of the 26S rRNA gene. Among 69 isolates, Aureobasidium pullulans GE17 and Meyerozyma guilliermondii KL3 strains showed the greatest antagonistic activity against two significant apple and lemon postharvest pathogens, Penicillium expansum DSM62841 (blue mold) and Penicillium digitatum DSM2750 (green mold), after preliminary screening. Yeasts were applied as single and mixed cultures with two different cell concentrations of 10 and 10 cells/ml in the present study. It was determined that antagonistic activity of two yeast strains studied emerged with a combination of several mechanisms of action including competition for space and nutrients, production of volatile organic compounds (VOCs), secretion of extracellular lytic enzymes and inhibition of fungal spore germination. The highest inhibition of mycelial growth on P. expansum DSM62841 and P. digitatum DSM2750 (83.4% and 74.7%, respectively) was achieved by utilization of single culture of A. pullulans GE17. Otherwise, the application of mixed culture at the ratio of 10 cells/ml inhibited spore germination of both pathogens from 86% to 95%. Results of this study suggest that an increase in yeast cell concentrations positively affected their biocontrol activity against blue and green molds. According to the results, employing single culture of M. guilliermondii KL3 did not exhibit effective antagonistic activity against blue and green molds. However, utilization of A. pullulans GE17 alone and mixed culture showed succesfull controlling against both P. expansum DSM62841 and P. digitatum DSM2750.
Topics: Antibiosis; Aureobasidium; Biological Control Agents; Citrus; Fruit; Malus; Penicillium; Saccharomycetales; Spores, Fungal
PubMed: 32452099
DOI: 10.1002/yea.3501 -
FEMS Microbiology Letters Oct 2022Microbes produce and respond to a range of structurally and functionally diverse volatiles. Many microbial volatiles have antimicrobial properties. Since volatiles can...
Microbes produce and respond to a range of structurally and functionally diverse volatiles. Many microbial volatiles have antimicrobial properties. Since volatiles can diffuse through complex 3D systems like spider nests, they are promising pathogen protection for social arthropods. Here, we analyzed the volatilomes of five nest microbiome members of the Namibian, social spider Stegodyphus dumicola, namely the bacteria Massilia sp. IC2-278, Massilia sp. IC2-477, Sphingomonas sp. IC-11, Streptomyces sp. IC-207, and the fungus Aureobasidium sp. CE_32, and tested their antimicrobial activity against two putative spider pathogens, namely Bacillus thuringiensis and Purpureocillium lilacinum. Most nest microbiome members released volatilomes with antibacterial and/or antifungal activities under in vitro conditions. The analysis of their volatilomes using GC/Q-TOF revealed that they include numerous antimicrobial volatiles. We tested the antimicrobial activity of five pure volatile compounds found in the volatilomes and revealed that all of them were antibacterial and/or antifungal. We could not identify the same antimicrobial volatiles as in a previous in situ study, but our results indicate that social spider-associated microorganisms as a source of antimicrobial volatiles are important for pathogen inhibition. Additionally, we showed the influence of the volatilomes on the antibiotic sensitivity of B. thuringiensis offering novel approaches to counter antibiotic resistance.
Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Antifungal Agents; Microbiota; Spiders; Streptomyces
PubMed: 36073497
DOI: 10.1093/femsle/fnac088