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Frontiers in Microbiology 2023The microbiological and metabolic outcomes of good cocoa fermentation practices can be standardized and influenced through the addition of starter culture mixtures...
The microbiological and metabolic outcomes of good cocoa fermentation practices can be standardized and influenced through the addition of starter culture mixtures composed of yeast and bacterial strains. The present study performed two spontaneous and 10 starter culture-initiated (SCI) cocoa fermentation processes (CFPs) in Costa Rica with local Trinitario cocoa. The yeast strains IMDO 050523, IMDO 020003, and IMDO 060005 were used to compose starter culture mixtures in combination with the lactic acid bacterium strain IMDO 0611222 and the acetic acid bacterium strain IMDO 0506386. The microbial community and metabolite dynamics of the cocoa pulp-bean mass fermentation, the metabolite dynamics of the drying cocoa beans, and the volatile organic compound (VOC) profiles of the chocolate production were assessed. An amplicon sequence variant approach based on full-length 16S rRNA gene sequencing instead of targeting the V4 region led to a highly accurate monitoring of the starter culture strains added, in particular the IMDO 0611222 strain. The latter strain always prevailed over the background lactic acid bacteria. A similar approach, based on the internal transcribed spacer (ITS1) region of the fungal rRNA transcribed unit, was used for yeast strain monitoring. The SCI CFPs evolved faster when compared to the spontaneous ones. Moreover, the yeast strains applied did have an impact. The presence of IMDO 050523 was necessary for successful fermentation of the cocoa pulp-bean mass, which was characterized by the production of higher alcohols and esters. In contrast, the inoculation of IMDO 020003 as the sole yeast strain led to underfermentation and a poor VOC profile, mainly due to its low competitiveness. The IMDO 060005 strain tested in the present study did not contribute to a richer VOC profile. Although differences in VOCs could be revealed in the cocoa liquors, no significant effect on the final chocolates could be obtained, mainly due to a great impact of cocoa liquor processing during chocolate-making. Hence, optimization of the starter culture mixture and cocoa liquor processing seem to be of pivotal importance.
PubMed: 37621398
DOI: 10.3389/fmicb.2023.1232323 -
Oral Oncology Nov 2023Head and neck cancer (HNC) impairs patient immunity and increases susceptibility to oral fungal infections (OFIs). Effectively treating such infections requires accurate...
OBJECTIVES
Head and neck cancer (HNC) impairs patient immunity and increases susceptibility to oral fungal infections (OFIs). Effectively treating such infections requires accurate identification of the causative pathogens. This study aimed to characterize the mycobiota profile of OFIs in HNC patients undergoing radiation treatment (RT).
MATERIALS AND METHODS
A 6-year retrospective analysis of oral mucosal samples from HNC patients with a history of RT and OFIs between 2014 and 2019 was conducted using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) profiling. Samples from the Clinical Microbiology Laboratory at Karolinska University Hospital were evaluated for mycobiota diversity and species co-occurrence patterns in the ongoing-RT and post-RT groups.
RESULTS
A total of 190 oral fungi (88% Candida, 5% Pichia) were isolated from 162 HNC patients receiving RT. In the ongoing-RT group, the emergent non-albicans Candida (NAC) species; F. solani and C. jadinii, were detected for the first time. The dominant pathogens in both ongoing and post-RT groups were C. albicans, C. glabrata, P. kudriavzevii, C. parapsilosis, and C. tropicalis, as shown by Venn analysis. Network analysis revealed greater fungi diversity and multi-species co-occurrence in the ongoing-RT group. C. albicans commonly co-occurred with C. glabrata in both ongoing-RT (21%) and post-RT groups (30%).
CONCLUSION
MALDI-TOF MS identified a wide range of oral fungal species in HNC patients receiving RT. While C. albicans remains the most prevalent OFIs pathogen, multi-species co-occurrence and novel NACs were noted. Understanding the ecological interactions among these causative pathogens could significantly advance the development of effective therapeutics for treating OFIs in HNC patients.
Topics: Humans; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Retrospective Studies; Candida; Mycoses; Head and Neck Neoplasms
PubMed: 37611433
DOI: 10.1016/j.oraloncology.2023.106556 -
Food Science & Nutrition Aug 2023Soybean paste was a traditional fermented product in northeast China, mainly fermented by molds, yeast, , and lactic acid bacteria. In this study, the safety and...
Soybean paste was a traditional fermented product in northeast China, mainly fermented by molds, yeast, , and lactic acid bacteria. In this study, the safety and fermentation ability of lactic acid bacteria and yeast strains isolated from traditional soybean paste in northeast China were evaluated, and the dynamic changes of biogenic amines, aflatoxin, total acids, amino acid nitrogen, and volatile compounds were investigated during the fermentation of the traditional soybean paste. Among the tested strains, DPUL-J8 could decompose putrescine by 100%, and no biogenic amine was produced by DPUY-J8. DPUL-J8 and DPUY-J8 with strong biogenic amine degrading capacities were inoculated into the soybean paste. After 30 days of fermentation, the content of biogenic amines and aflatoxin in the fermented soybean paste declined by more than 60% and 50%, respectively. At the same time, compared with the control group without inoculation, the contents of total acid (1.29 ± 0.05 g/100 g), amino acid nitrogen (0.82 ± 0.01 g/100 g), and volatile compounds in soybean paste fermented by DPUL-J8 and DPUY-J8 were significantly increased, which had a good flavor. These results indicated that the use of DPUL-J8 and DPUY-J8 as starter cultures for soybean paste might be a good strategy to improve the safety and flavor of traditional Chinese soybean paste.
PubMed: 37576040
DOI: 10.1002/fsn3.3372 -
F1000Research 2022is a non-albicans species with a high prevalence, which causes candidaemia. Current treatment guidelines include fluconazole as a primary therapeutic option for the...
is a non-albicans species with a high prevalence, which causes candidaemia. Current treatment guidelines include fluconazole as a primary therapeutic option for the treatment of these infections; however, it is only a fungistatic against ., and both inherent and acquired resistance to fluconazole have been reported. . species is also reported as the only . which has an intrinsic resistance factor to fluconazole. Therefore, in dealing with antifungal resistance, it is necessary to develop new antifungal agents that are efficient in the treatment of fungal infections, especially those caused by . The purpose of this study was to investigate the genome of clinical isolates and correlate the resistant phenotypes with mutations in resistance genes. A total of 16 samples of from clinical samples from hospitals in Jakarta were used in the experiment. All colonies were extracted using the QIAamp DNA Mini Kit. The library was prepared using the Illumina DNA Prep Kit. The sequencing process was carried out on the Illumina MiSeq Platform using a 2x301 paired-end configuration. FASTQ raw files are available under the BioProject Accession Number PRJNA819536 and Sequence Read Archive Accession Numbers SRR18739949 and SRR18739964.
Topics: Humans; Fluconazole; Indonesia; Microbial Sensitivity Tests; Candida albicans; Whole Genome Sequencing; Faculty
PubMed: 37416067
DOI: 10.12688/f1000research.121402.2 -
Mycopathologia Dec 2023We performed a retrospective survey of non-Candida albicans candidemia in patients with cancer, including those with solid tumors and those with hematological...
We performed a retrospective survey of non-Candida albicans candidemia in patients with cancer, including those with solid tumors and those with hematological malignancies as well as transplants patients both, solid-organ transplant recipients and hematopoietic stem cell transplant recipients. The study was performed at two healthcare centers in New York City and covered the years 2018-2022. A total of 292 patients (318 isolates) were included in the study. In order of frequency, C. glabrata (38%) was the most common species recovered, followed by C. parapsilosis (19.2%), C. tropicalis (12.6%), C. krusei (10.7%), C. lusitaniae (5.7%), and C. guilliermondii (4.4%). Micafungin was the most common antifungal treatment and 18.5% of patients were on antifungal prophylaxis. The 30-day crude mortality was 40%. 4.5% of patients had more than one non-albicans species detected. In conclusion, this study represents one of the largest surveys of non-albicans species in cancer and transplant patients and provides data on the current epidemiology of these Candida species in this patient population.
Topics: Humans; Antifungal Agents; Transplant Recipients; Retrospective Studies; Microbial Sensitivity Tests; Candida; Candidemia; Candida glabrata; Candida parapsilosis; Candida tropicalis; Neoplasms
PubMed: 37365379
DOI: 10.1007/s11046-023-00765-7 -
International Journal of Food... Aug 2023The increasing demand for more flavored and complex beers encourages the investigation of novel and non-conventional yeasts with the ability to provide a combination of...
The increasing demand for more flavored and complex beers encourages the investigation of novel and non-conventional yeasts with the ability to provide a combination of bioflavoring and low ethanol yields. The present study identified 22 yeasts isolated from different brewing sources, including the fermentation by-products known as yeast sludges, and characterized a selection of strains to find the more suitable for the aforementioned aims. HPLC and GC-FID analysis of its brewing products were performed. The most promising results were obtained with the non-conventional yeasts Pichia kudriavzevii MBELGA61 and Meyerozyma guilliermondii MUS122. The former, isolated from a Belgian wheat beer sludge, was capable of growing in wort (17.0°Bx., 20 °C) with very low ethanol yields (1.19 % v/v). Besides, upon mixed fermentations with Saccharomyces cerevisiae, was suitable to produce volatile compounds such as ethyl acetate, 2-phenyl ethanol and isoamyl alcohol, with characteristic fruity notes. M. guilliermondii MUS122, isolated from a golden ale beer sludge, partially attenuated the wort with low production of ethanol and biomass. In addition, provided some fruity and floral nuances to the aroma profile of mixed fermentations with brewer's yeast. The results suggest that these strains favor the development of more fruity-flowery aroma profiles in beers. Furthermore, they are suitable for use in mixed fermentations with Saccharomyces brewer's strains, although the ethanol level did not decrease significantly.
Topics: Fermentation; Beer; Sewage; Yeasts; Saccharomyces cerevisiae; Ethanol
PubMed: 37244227
DOI: 10.1016/j.ijfoodmicro.2023.110254 -
Foods (Basel, Switzerland) May 2023Cocoa bean fermentation is carried out in different production areas following various methods. This study aimed to assess how the bacterial and fungal communities were...
Cocoa bean fermentation is carried out in different production areas following various methods. This study aimed to assess how the bacterial and fungal communities were affected by box, ground or jute fermentation methods, using high-throughput sequencing (HTS) of phylogenetic amplicons. Moreover, an evaluation of the preferable fermentation method was carried out based on the microbial dynamics observed. Box fermentation resulted in higher bacterial species diversity, while beans processed on the ground had a wider fungal community. and were observed in all three fermentation methods studied. Moreover, dominated box fermentation and abounded in ground-fermented samples. was the most important yeast in jute and box, while prevailed in the box and ground fermentation. PICRUST analysis was performed to identify potential interesting pathways. In conclusion, there were noticeable differences between the three different fermentation methods. Due to its limited microbial diversity and the presence of microorganisms that guarantee good fermentation, the box method was found to be preferable. Moreover, the present study allowed us to thoroughly explore the microbiota of differently treated cocoa beans and to better understand the technological processes useful to obtain a standardized end-product.
PubMed: 37238842
DOI: 10.3390/foods12102024 -
PLoS Pathogens May 2023The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida...
The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida species. Its cell wall, a dynamic organelle that is the first point of interaction between pathogen and host, is relatively understudied, and its wall proteome remains unidentified to date. Here, we present an integrated study of the cell wall in P. kudriavzevii. Our comparative genomic studies and experimental data indicate that the general structure of the cell wall in P. kudriavzevii is similar to Saccharomyces cerevisiae and C. albicans and is comprised of β-1,3-glucan, β-1,6-glucan, chitin, and mannoproteins. However, some pronounced differences with C. albicans walls were observed, for instance, higher mannan and protein levels and altered protein mannosylation patterns. Further, despite absence of proteins with high sequence similarity to Candida adhesins, protein structure modeling identified eleven proteins related to flocculins/adhesins in S. cerevisiae or C. albicans. To obtain a proteomic comparison of biofilm and planktonic cells, P. kudriavzevii cells were grown to exponential phase and in static 24-h cultures. Interestingly, the 24-h static cultures of P. kudriavzevii yielded formation of floating biofilm (flor) rather than adherence to polystyrene at the bottom. The proteomic analysis of both conditions identified a total of 33 cell wall proteins. In line with a possible role in flor formation, increased abundance of flocculins, in particular Flo110, was observed in the floating biofilm compared to exponential cells. This study is the first to provide a detailed description of the cell wall in P. kudriavzevii including its cell wall proteome, and paves the way for further investigations on the importance of flor formation and flocculins in the pathogenesis of P. kudriavzevii.
Topics: Saccharomyces cerevisiae; Proteome; Proteomics; Candida albicans; Candida; Biofilms; Genomics; Cell Wall
PubMed: 37196016
DOI: 10.1371/journal.ppat.1011158 -
Journal of Food Science and Technology Jun 2023Kombucha is a fermented tea with a combination of yeast and bacteria. Kombucha teas may have a variable microbiota based on geographic origin and cultural conditions....
UNLABELLED
Kombucha is a fermented tea with a combination of yeast and bacteria. Kombucha teas may have a variable microbiota based on geographic origin and cultural conditions. The microbial flora of kombucha has been studied with culture-dependent methods. But, the improvement of the metataxonomic approach has broadened our perspective on fermented foods. In this study, a kombucha mother was procured from an artisanal supplier in Türkiye. High-throughput new-generation sequencing (16S rRNA and Internal Transcribed Spacer (ITS)) was carried out to investigate the microbial communities of kombucha after 7 days of fermentation in both liquid tea (L) and pellicle (P). Microbial counts, pH (4.42 ± 0.01 and 3.50 ± 0.02), and TA% (0.26 ± 0.02 and 0.60 ± 0.04) were also detected on the first and 7 days of fermentation. According to metataxonomic results, the dominant bacteria were (%21.13), an acetic acid-producing bacteria, and the dominant fungal genus was (64.35%) in L while sp. CE17 was the dominant bacteria (7%) and was also the dominant yeast in P. This study also revealed different species which were not common in kombucha including propionic acid and butyric acid-producing bacteria such as and , a butyrivibriocin producing bacteria. Accordingly, different yeast species were detected such as and .
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s13197-023-05725-z.
PubMed: 37187981
DOI: 10.1007/s13197-023-05725-z -
Food Chemistry: X Jun 2023Mixed fermentation using saccharomyces cerevisiae and non- has become one of the main research strategies to improve wine aroma. Hence, this study applied the mixed...
Mixed fermentation using saccharomyces cerevisiae and non- has become one of the main research strategies to improve wine aroma. Hence, this study applied the mixed fermentation technique using and to brew Cabernet Sauvignon wine and to investigate the effects of inoculation timing and inoculation ratio on the polyphenolics, antioxidant activity and aroma of the resulting wine. The results showed that mixed fermentation significantly improved the amounts of flavan-3-ols. In particular, S1:5 had the highest amounts of (-)-catechin and procyanidin B1 (73.23 mg/L and 46.59 mg/L), while S1:10 had the highest (-)-epicatechin content (57.95 mg/L). Meanwhile, S1:10 showed the strongest FRAP, CUPRAC and ABTS + activities (31.46 %, 25.38 % and 13.87 % higher than that of CK, respectively). In addition, mixed fermentation also increased the amounts of phenylethanol, isoamyl alcohol and ethyl esters, which enhanced the rose-like and fruity flavor of wine. This work used a friendly non- alongside appropriate inoculation strategies to provide an alternative approach for improved wine aroma and phenolic profile.
PubMed: 37131849
DOI: 10.1016/j.fochx.2023.100685