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Frontiers in Microbiology 2019Effects of wine and dairy yeast fermentation on chemical constituents of tilapia fish head hydrolysate supplemented with glucose in an unsalted and acidic environment...
Effects of wine and dairy yeast fermentation on chemical constituents of tilapia fish head hydrolysate supplemented with glucose in an unsalted and acidic environment were investigated. Three wine yeasts ( Biodiva, Lalvin EC-1118 and Frootzen) and one dairy yeast ( NCYC1425) were employed as single starter cultures, respectively, and were compared with one soy sauce yeast ( NCYC1433). Each yeast showed different growth kinetics and fermentation performance. Compared with NCYC1433, other yeasts presented a significant higher rate of glucose consumption ( < 0.05). Besides, NCYC1425 and Frootzen produced more citric acid and succinic acid, respectively, while Lalvin EC-1118 exhibited higher pyruvic acid production. Significant lower levels of total free amino acids were observed in samples inoculated with wine yeasts relative to other yeasts ( < 0.05). Non-soy sauce yeasts produced increased various levels of esters and alcohols without traditional fish sauce unpleasant odorants, especially NCYC1425 and Frootzen. The results confirmed that non-soy sauce yeasts are suitable for fish sauce flavor compound modification and to develop a fast fermentation process for saltless fish sauce from fish head, which could increase the acceptability of fish sauce and improve the utilization of fish by-products.
PubMed: 31649641
DOI: 10.3389/fmicb.2019.02300 -
Applied Bionics and Biomechanics 2022Detection of food spoilage with simple and fast methods is an important issue in food security and safety. The present study is mainly aimed at identifying and...
Detection of food spoilage with simple and fast methods is an important issue in food security and safety. The present study is mainly aimed at identifying and quantifying four yeast species in white fresh soft cheese using an electronic nose (EN). The yeast species , , , and were used. Six concentrations of each yeast species (100, 200, 400, 600, 800, and 1000 cells/g cheese) were inoculated in 100 g of fresh soft cheese and incubated for 48 h at 25°C. The EN was used to identify and quantify different yeast species in cheese samples. It was found that EN was able to discriminate between four yeast species using principal component analysis (PCA). Moreover, EN was able to quantify in good precision three (, , and ) of the four tested yeasts presented in cheese samples using partial least squares (PLS) models. It seems that EN is a reliable tool that can be used as a fast technique to identify and quantify cheese spoilage in the cheese industry.
PubMed: 35082918
DOI: 10.1155/2022/8472661 -
Brazilian Journal of Microbiology :... Dec 2021Yeast isolates from flowers and fruits from a Brazilian forest were studied. The yeasts were identified at species and strain level by PCR-RFLP and PCR-RAPD,...
Yeast isolates from flowers and fruits from a Brazilian forest were studied. The yeasts were identified at species and strain level by PCR-RFLP and PCR-RAPD, respectively. The 46 isolated yeasts were classified into 11 different species belonging to the genera Candida, Diutina, Hanseniaspora, Meyerozyma, Pichia, Rhodotorula, and Torulaspora. A total of 20 different strains were found. In order to ascertain the probiotic potential, the resistance to gastrointestinal conditions, autoaggregation, and hydrophobicity assays were studied, along with the capacity to form biofilm. The results indicate that, although most of the strains presented better results than Saccharomyces boulardii (the only strain recognized as a probiotic yeast), four strains were the most promising, namely, Rhodotorula mucilaginosa 32, Meyerozyma caribbica 35, and Diutina rugosa 12 and 45, according to the Duncan test. Several biotechnological properties were evaluated. D. rugosa inhibited Dekkera bruxellensis. The assimilation or fermentation of seven sugars was tested, and only five of the yeasts did not show a capacity to assimilate any of the sugars under aerobic conditions. However, all strains were able to ferment at least one of the sugars under anaerobic conditions. As far as enzyme production is concerned, positive results were only found for the enzymes' amylase, pectinase, and protease. D. rugosa 42 and Hanseniaspora opuntiae 18, followed of Pichia kluyveri 26, showed high values for the production of melatonin. In conclusion, the results of this study show that several non-Saccharomyces present probiotic characteristics, and these have good potential for industrial applications in the food or biotechnology industries.
Topics: Biotechnology; Ecosystem; Fermentation; Fruit; Probiotics; Random Amplified Polymorphic DNA Technique; Sugars; Yeasts
PubMed: 34595728
DOI: 10.1007/s42770-021-00541-z -
Microbiological Research Apr 2021A diversity of yeasts and lactic bacteria were isolated from the feces of ring-tailed coaties bred in captivity and related to the production of "misha coffee"....
Isolation of microorganisms from the feces of ring-tailed coati related to the production of "misha coffee" in the central forest of Peru and evaluation of some features of technological importance.
A diversity of yeasts and lactic bacteria were isolated from the feces of ring-tailed coaties bred in captivity and related to the production of "misha coffee". Isolation of yeasts was carried out using oxytetracycline-glucose-yeast extract agar containing 100 mg/L oxytetracycline and, lactic bacteria using de Man-Rogosa and Sharpe agar containing 20 mg/L of vancomicin. Then, isolates were biochemically analysed using API strips (ID 32C for yeasts and 50CHL for lactic bacteria) followed by 16S and 26S rRNA gene sequencing. Among the yeasts, Debaryomyces hansenii, Pichia kluyveri, Pichia kudriavzevii, and Candida sorboxilosa were the most frequent, whereas Weissella cibaria, Weissella paramesenteroides, Enterococcus thailandicus and Enterococcus faecalis were the most important lactic bacteria. Cultivation of the isolated yeasts under agitated conditions, showed that Pichia kluyveri LBFT.Lev3 (0.15 ± 0.01 h) and Pichia kudriavzevii LBTF.Lev7 (0.14 ± 0.01 h) had higher specific growth rates than Debaryomyces hansenii LBFT.Lev9 (0.09 ± 0.01 h), whereas cultivation of lactic bacteria under static fashion showed that Weisella paramesenteroides LBTF.Bal2 (0.16 ± 0.01 h) and Weisella cibaria LBTF.Bal3 (0.18 ± 0.01 h) had better growth than Enterococcus thailandicus LBTF.Bal1 (0.1 ± 0.015 h) and Enterococcus faecalis LBTF.Bal7 (0.14 ± 0.01 h). Additionally, evaluation of pectinolytic activity revealed that Pichia kudriavzevii LBTF.Lev7 and Debaryomyces hansenii LBFT.Lev9 were able to use pectin as carbon source for their growth. On the other hand, W. cibaria LBTF.Bal3, E. thailandicus LBTF.Bal1 and W. paramesenteroides LBTF.Bal2 showed inhibitory activity against S. mutans ATCC 35668, B. subtilis subsp. spizizenii ATCC 6633 and Staph. epidermidis ATCC 14990. Results of this study are useful for the search of potential application of the isolated yeasts and lactic bacteria in coffee and other food fermentations.
Topics: Animals; Bacteria; Coffee; Feces; Food Microbiology; Forests; Peru; Procyonidae; Yeasts
PubMed: 33418399
DOI: 10.1016/j.micres.2020.126670 -
Food Chemistry Oct 2020In the present work we aimed to demonstrate the influence of inoculum starter in support high quality fermentation. Cocoa fermentations were performed in wooden boxes...
In the present work we aimed to demonstrate the influence of inoculum starter in support high quality fermentation. Cocoa fermentations were performed in wooden boxes and eight yeasts strains were used in separated fermentations of fine cocoa, type Scavina, as starter inoculum. Temperature, pH, titirable acidity, reducing sugar and free amino acids were evaluated during or after fermentation. The influence of starters yeasts on the decrease of acidity, sugar concentration and free amino acids was significant. The strains Candida parapsilosis, Torulaspora delbrueckii and Pichia kluyveri showed greater changes in the reducing sugar and free amino acids in fermented cocoa beans. These results indicate the ability of yeast used as inoculum starter to modify the end condition and further enhance the quality of fine cocoa beans.
Topics: Amino Acids; Cacao; Candida parapsilosis; Chocolate; Fermentation; Food Microbiology; Hydrogen-Ion Concentration; Pichia; Seeds; Temperature; Torulaspora; Yeasts
PubMed: 32464557
DOI: 10.1016/j.foodchem.2020.127110 -
BMC Infectious Diseases Jan 2018Opportunistic infections due to Candida species occur frequently in cancer patients because of their inherent immunosuppression. The aim of the present study was to...
BACKGROUND
Opportunistic infections due to Candida species occur frequently in cancer patients because of their inherent immunosuppression. The aim of the present study was to investigate the epidemiology of yeast species from the oral cavity of patients during treatment for oncological and haematological malignancies.
METHODS
MALDI-TOF was performed to identify yeasts isolated from the oral cavity of 350 cancer patients. Moreover, antifungal susceptibility testing was performed in according to CLSI guidelines (M27-A3).
RESULTS
Among 162 yeasts and yeast-like fungi isolated from the oral cavity of cancer patients, Candida albicans was the most common species (50.6%), followed by Candida glabrata (24.7%), Pichia kudriavzevii (Candida krusei (9.9%)), Candida tropicalis (4.3%), Candida dubliniensis (3.7%), Kluyveromyces marxianus (Candida kefyr (3.7%)) and Candida parapsilosis (1%). In addition, uncommon yeast species i.e., Saprochaete capitata, Saccharomyces cerevisiae, Clavispora lusitaniae (C. lusitaniae) and Pichia kluyveri (C. eremophila) were recovered from oral lesions. Oral colonization by C. albicans, non-albicans Candida species and uncommon yeasts were as follow; 55%, 44% and 1%, whereas oral infection due to C. albicans was 33.3%, non-albicans Candida species 60.6%, and uncommon yeasts 6.1%. Poor oral hygiene and xerostomia were identified as independent risk factors associated with oral yeast colonization. The overall resistance to fluconazole was 11.7% (19/162). Low MIC values were observed for anidulafungin for all Candida and uncommon yeast species.
CONCLUSIONS
This current study provides insight into the prevalence and susceptibility profiles of Candida species, including emerging Candida species and uncommon yeasts, isolated from the oral cavity of Iranian cancer patients. The incidence of oral candidiasis was higher amongst patients with hematological malignancies. The majority of oral infections were caused by non-albicans Candida species which were often more resistant to anti-fungal agents. Our findings suggest that anidulafungin should be used as antifungal of choice for prophylaxis in clinically high-risk patients with documented oral colonization or infection.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antifungal Agents; Candida; Candidiasis, Oral; Female; Fluconazole; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Mouth; Neoplasms; Pichia; Prevalence; Risk Factors; Saccharomycetales; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Xerostomia; Young Adult
PubMed: 29310582
DOI: 10.1186/s12879-017-2916-5 -
Applied and Environmental Microbiology Mar 1992Representative strains (n = 61) of the yeast Pichia kluyveri from across the United States were studied for their ability to kill 71 other strains (representing 25...
Representative strains (n = 61) of the yeast Pichia kluyveri from across the United States were studied for their ability to kill 71 other strains (representing 25 species) of yeast. This survey showed killing activity in 69% of the P. kluyveri strains tested. More extensive analysis of killer activity of 197 P. kluyveri strains against strains of five tester species showed comparable activity (67% of strains tested). This activity was shown to be equally variable within localities, within regions, and across the continent. The genetic basis of the variability was ascertained by tetrad analysis and is most likely due to alleles segregating at three epistatic loci. Evidence for the idea that killer toxins have a role in excluding other yeasts from particular habitats is discussed.
Topics: Crosses, Genetic; Genetics, Population; Genotype; Models, Genetic; Mycotoxins; Phenotype; Pichia; United States
PubMed: 1575502
DOI: 10.1128/aem.58.3.990-997.1992 -
Foods (Basel, Switzerland) Jun 2021In this study, Vidal grape must was fermented using commercial F33 in pure culture as a control and in mixed culture with five indigenous non- yeast strains ( QTX22,...
In this study, Vidal grape must was fermented using commercial F33 in pure culture as a control and in mixed culture with five indigenous non- yeast strains ( QTX22, YC30, HSP14, YC12, and QTX15) through simultaneous fermentation in a 1:1 ratio. Simultaneous fermentation inhibited the growth of F33 and delayed the time to reach the maximum biomass. Compared with pure fermentation, the contents of polyphenols, acetic esters, ethyl esters, other esters, and terpenes were increased by QTX15, YC30, and HSP14 through simultaneous fermentation. YC30 produced the highest total aroma activity and the most abundant aroma substances of all the wine samples. The odor activity values of 1 C13-norisoprenoid, 3 terpenes, 6 acetic esters, and 10 ethyl esters improved significantly, and three lactones (δ-decalactone, γ-nonalactone, and γ-decalactone) related to coconut and creamy flavor were only found in this wine. Moreover, this sample showed obvious "floral" and "fruity" note odor due to having the highest amount of ethyl ester aromatic substances and cinnamene, linalool, citronellol, β-damascenone, isoamyl ethanoate, benzylcarbinyl acetate, isobutyl acetate, etc. We suggest that simultaneous fermentation of YC30 with might represent a novel strategy for the future production of Vidal icewine.
PubMed: 34206678
DOI: 10.3390/foods10071452 -
Foods (Basel, Switzerland) Feb 2019Microbial spoilage causes food losses in the food industry and as such, the use of synthetic chemical preservatives is still required. The current study proposes the use...
Microbial spoilage causes food losses in the food industry and as such, the use of synthetic chemical preservatives is still required. The current study proposes the use of agro-waste, i.e., grape pomace extracts (GPE), as production medium for biopreservation compounds. Production kinetics, subsequent to optimization using response surface methodology (RSM) for biopreservation compounds production was studied for three yeasts using GPE broth as a fermentation medium. The results showed that the highest volumetric zone of inhibition (VZI) was 1.24 L contaminated solidified media (CSM) per mL biopreservation compounds used (BCU) when Y1117 was inoculated in a pH 3-diluted GPE broth (150 g L) incubated at 25 °C for 24 h. Similar conditions were applied for Y1125 and Y1164, albeit under slightly elongated fermentation periods (up to 28 h), prior to the attainment of a maximum VZI of only 0.72 and 0.76 L CSM mL ACU, respectively. The potential biopreservation compounds produced were identified to be isoamyl acetate, isoamyl alcohol, 2-phenyl ethylacetate and 2-phenyl ethanol.
PubMed: 30717320
DOI: 10.3390/foods8020051 -
Journal, Genetic Engineering &... Jun 2020Probiotic strains are incorporated into food substrates to contribute to fermentation process. The technological suitability of such strains to improve the flavor and...
BACKGROUND
Probiotic strains are incorporated into food substrates to contribute to fermentation process. The technological suitability of such strains to improve the flavor and nutritional value of fermented food is strain-specific. Potentially probiotic yeasts isolated from Nigerian traditional fermented foods were assessed for production of volatile compounds by gas chromatography-mass spectrophotometry. Phytases were characterized for activity and stability at different pH (3-8) and temperatures (25-50 °C).
RESULTS
A total of 45 volatiles compounds were identified from intracellular cell-free extracts of Pichia kluyveri LKC17, Issatchenkia orientalis OSL11, P. kudriavzevii OG32, P. kudriavzevii ROM11, and Candida tropicalis BOM21. They include alcohols (14), carbonyls (13), esters (10), and organic acids (8). Phenylethyl alcohol was the highest higher-alcohol in Issatchenkia orientalis OSL11 (27.51 %). The largest proportion of esters was detected in P. kudriavzevii OG32 (17.38 %). Pichia kudriavzevii OG32 and C. tropicalis BOM21 showed vigorous gowth in minimal medium supplemented with sodium phytate (2 g L). Extracellular phytases from P. kudriavzevii OG32 and Candida tropicalis BOM2 showed optimal activiy at pH 4.6 (104.28 U) and pH 3.6 (81.43 U) respectively.
CONCLUSIONS
Results obtained revealed species- and strain-specific potentials of the yeast strains to improve flavor and mineral bioavailability of fermented food products. Therefore, the application of these yeasts as starter cultures during food fermentation process is a very promising method to enhance the flavor profile and enhance mineral bioavailability in indigenous cereal-based fermented food products.
PubMed: 32507932
DOI: 10.1186/s43141-020-00031-z