Search Results (19)

The aim of this study is to evaluate the effects of different types of sourdough (I to IV), developed with a specific starter culture (including Lactiplantibacillus plantarum, Levilactobacillus brevis, and Candida famata), on bread fermentation performance and shelf-life. Real-time tracking of multiple parameters (pH, dough rising, ethanol release, and total titratable acidity) was monitored by a smart fermentation oven. The impact of the different treatments on the lactic acid, acetic acid, and ethanol content of the breads were quantified by high performance liquid chromatography analysis. In addition, the bio-preservation capacity of the breads contaminated with fungi was analyzed. The results show that liquid sourdough (D3: Type 2) and backslopped sourdough (D4: Type 3) increased significantly (p < 0.05) in dough rise, dough acidification (lower pH, higher titratable acidity), production of organic acids (lactic and acetic), and presented the optimal fermentation quotient. These findings were substantiated by chemometric analysis, which successfully clustered the starters based on performance and revealed a strong positive correlation between acetic acid production and dough-rise, highlighting the superior heterofermentative profile of D3 and D4. These types of sourdough also stood out for their antifungal capacity, preventing the visible growth of Aspergillus niger and Penicillium commune for up to 10 days after inoculation. Full article

Riboflavin (vitamin B₂) is an essential micronutrient required for all living organisms. It is naturally synthesized by plants and most microorganisms, including the bacterium Bacillus subtilis, the filamentous fungus Ashbya gossypii, and the yeast Candida famata—all of which are known to be riboflavin overproducers. The choice of production organism in industrial applications depends on factors such as yield, ease of cultivation, and the availability of genetic tools. As a result, several microorganisms are commonly used, and their relative prominence can shift over time with advances in metabolic engineering and process optimization. This review presents a comparative analysis of riboflavin biosynthesis across prokaryotic and eukaryotic systems, with a particular focus on regulatory mechanisms governing flavinogenesis. Special attention is given to recent advances in metabolic engineering strategies, including the application of CRISPR/Cas9 genome editing in Bacillus subtilis and Ashbya gossypii. In yeast systems, significant improvements in riboflavin production have been achieved primarily through the manipulation of transcriptional regulators (e.g., SEF1, SFU1, TUP1) and metabolic genes. The role of other important genes (PRS3, ADE4, ZWF1, GND1, RFE1, VMA1, etc.) in riboflavin overproduction in C. famata is described. The review also explores the use of alternative, low-cost feedstocks—including lignocellulosic hydrolysates and dairy by-products—to support more sustainable and economically viable riboflavin production. Although considerable progress has been achieved in genetic optimization and bioprocess development, further work is required to fine-tune metabolic flux and maximize riboflavin synthesis, particularly under industrial conditions. This review highlights key opportunities for future research aimed at refining metabolic interventions and expanding the use of renewable substrates for environmentally sustainable riboflavin production. Full article

Manouri is a Greek whey cheese, with a Protected Denomination of Origin recognition, produced by heating the cheese whey and added milk and/or cream at high temperatures (88–90 °C) to form a coagulum. High-heat treatment results in the inactivation of any indigenous microorganisms from the raw materials. However, the high moisture, fat and pH of the cheese make it a favorable medium for the growth of any microbial contamination. The objective of this study was to investigate the application of a commercial protective culture (CPC) on the microbial profile of Manouri cheese during storage. Three treatments were prepared: S1 was the control cheese with sterile water sprayed on the surface, S2 was sprayed with a dense CPC and S3 with a diluted CPC. The experimental cheeses were covered with greaseproof paper and stored at 5 °C for 21 days. For all three treatments, the fat content and total solids showed a significant increase during storage, while protein and carbohydrates showed a significant decrease at 14 days. The application of the CPC resulted in cheeses with higher pH than the control cheese, probably due to the growth of acidifying lactic acid bacteria in the microbiota of the S2 and S3 cheeses. Manouri cheese sprayed with the CPC showed a reduction of 1.60–1.69 log CFU/g in the population of yeasts; no effect was observed on Enterobacteriaceae and Staphylococcus spp. The dominant yeast microbiota was identified as Candida zeylanoides (63.5%), Candida parapsilosis (21.1%) and Candida famata (15.4%). Although the application of the CPC was not able to control the spoilage bacteria, it showed an effective way to control the growth of yeasts in Manouri cheese. However, the presence of certain Candida spp. reveals the significance of applying good hygiene practices throughout the cheesemaking process. Full article

Background: This study aimed to determine, at the phenotypic and molecular levels, resistance and virulence markers in Candida spp. isolated from community-acquired infections in Bucharest outpatients during 2021, and to demonstrate the efficiency of alternative solutions against them based on silver nanoparticles (AgNPs). Methods: A total of 62 Candida spp. strains were isolated from dermatomycoses and identified using chromogenic culture media and MALDI-TOF MS, and then investigated for their antimicrobial resistance and virulence markers (VMs), as well as for metabolic enzymes using enzymatic tests for the expression of soluble virulence factors, their biofilm formation and adherence capacity on HeLa cells, and PCR assays for the detection of virulence markers and the antimicrobial activity of alternative solutions based on AgNPs. Results: Of the total of 62 strains, 45.16% were Candida parapsilosis; 29.03% Candida albicans; 9.67% Candida guilliermondii; 3.22% Candida lusitaniae, Candia pararugosa, and Candida tropicalis; and 1.66% Candida kefyr, Candida famata, Candida haemulonii, and Candida metapsilosis. Aesculin hydrolysis, caseinase, and amylase production were detected in the analyzed strains. The strains exhibited different indices of adherence to HeLa cells and were positive in decreasing frequency order for the LIP1, HWP1, and ALS1,3 genes (C. tropicalis/C. albicans). An inhibitory effect on microbial growth, adherence capacity, and on the production of virulence factors was obtained using AgNPs. Conclusions: The obtained results in C. albicans and Candida non-albicans circulating in Bucharest outpatients were characterized by moderate-to-high potential to produce VMs, necessitating epidemiological surveillance measures to minimize the chances of severe invasive infections. Full article

Cymbopogon citratus is commonly used in folk medicine for the treatment of nervous and gastrointestinal disturbances and other medical issues because of its potent antioxidant capacity. The current study evaluated the anti-candida effects of silver nanoparticles (AgNPs) synthesized from an aqueous extract of C. citratus against different Candida spp. The aqueous extract was prepared from the fresh leaves of C. citratus. The silver nanoparticles (AgNPs) were prepared and validated by UV spectroscopy, Fourier-transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), and zeta size analysis. C. albicans, C. krusei, C. parapsilosis, C. tropicalis, C. famata, C. rhodotorula, and C. glabrata were used in the antifungal assay. Microscopical imaging were used to investigate the different morphological changes induced by treatment. FTIR spectrum confirmed the existence of various functional groups of biomolecules capping the nanoparticles. The average particle size of synthesized AgNPs was 100.6 nm by zeta-sizer and 0.012 to 0.059 mm by TEM. In the antifungal assay, AgNPs aggregates induced significant inhibition of the growth of all species (p < 0.05) compared to the control and the biofilm maturation in C. famata and C. albicans. These considerable antifungal activities might lead to the development of appropriate alternative remedy for the treatment of fungal infections. Full article

Background: Artemisia sieberi (mugwort) is a member of the daisy family Asteraceae and is widely propagated in Saudi Arabia. A. sieberi has historical medical importance in traditional societies. The current study aimed to assess the antibacterial and antifungal characteristics of the aqueous and ethanolic extracts of A. sieberi. In addition, the study investigated the effect of silver nanoparticles (AgNPs) synthesized from the A. sieberi extract. Methods: The ethanolic and aqueous extracts and AgNPs were prepared from the shoots of A. sieberi. The characteristics of AgNPs were assessed by UV–visible spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The antibacterial experiments were performed against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. The fungal species used were Candida parapsilosis, Candida krusei, Candida famata, Candida rhodotorula, and Candida albicans. The antibacterial and antifungal characteristics were evaluated by measuring the diameter of growing organisms in Petri dishes treated with different concentrations of either extracts or AgNPs compared to the untreated controls. Furthermore, TEM imaging was used to investigate any ultrastructure changes in the microbes treated with crude extracts and AgNO₃. Results: The ethanolic and aqueous extracts significantly decreased the growth of E. coli, S. aureus, and B. subtilis (p < 0.001), while P. aeruginosa was not affected. Unlike crude extracts, AgNPs had more substantial antibacterial effects against all species. In addition, the mycelial growth of C. famata was reduced by the treatment of both extracts. C. krusei mycelial growth was decreased by the aqueous extract, while the growth of C. parapsilosis was affected by the ethanolic extract and AgNPs (p < 0.001). None of the treatments affected the growth of C. albicans or C. rhodotorula. TEM analysis showed cellular ultrastructure changes in the treated S. aureus and C. famata compared to the control. Conclusion: The biosynthesized AgNPs and extracts of A. sieberi have a potential antimicrobial characteristic against pathogenic bacterial and fungal strains and nullified resistance behavior. Full article

The use of yeasts as starter cultures was boosted with the emergence of large-scale fermentations in the 20th century. Since then, Saccharomyces cerevisiae has been the most common and widely used microorganism in the food industry. However, Candida species have also been used as an adjuvant in cheese production or as starters for coffee, cocoa, vegetable, meat, beer, and wine fermentations. A thorough screening of candidate Candida is sometimes performed to obtain the best performing strains to enhance specific features. Some commonly selected species include C. pulcherrima (teleomorph Metschnikowia pulcherrima) (wine), C. parapsilosis (teleomorph Monilia parapsilosis) (coffee), C. famata (teleomorph Debaryomyces hansenii) (cheese), and C. zeylanoides (teleomorph Kurtzmaniella zeylanoides) and C. norvegensis (teleomorph Pichia norvegensis) (cocoa). These species are associated with the production of key metabolites (food aroma formation) and different enzymes. However, safety-associated selection criteria are often neglected. It is widely known that some Candida species are opportunistic human pathogens, with important clinical relevance. Here, the physiology and metabolism of Candida species are addressed, initially emphasizing their clinical aspects and potential pathogenicity. Then, Candida species used in food fermentations and their functional roles are reported. We recommended that Candida not be used as food cultures if safety assessments are not performed. Some safety features are highlighted to help researchers choose methods and selection criteria. Full article

Atypical Candida spp. infections are rising, mostly due to the increasing numbers of immunocompromised patients. The most common Candida spp. is still Candida albicans; however, in the last decades, there has been an increase in non-Candida albicans Candida species infections (e.g., Candida glabrata, Candida parapsilosis, and Candida tropicalis). Furthermore, in the last 10 years, the reports on uncommon yeasts, such as Candida lusitaniae, Candida intermedia, or Candida norvegensis, have also worryingly increased. This review summarizes the information, mostly related to the last decade, regarding the infections, diagnosis, treatment, and resistance of these uncommon Candida species. In general, there has been an increase in the number of articles associated with the incidence of these species. Additionally, in several cases, there was a suggestive antifungal resistance, particularly with azoles, which is troublesome for therapeutic success. Full article

The enological potential of two previously characterized indigenous yeast isolates, Hanseniaspora uvarum S-2 and Candida famata WB-1, in pure and sequential inoculation with commercial yeast Saccharomyces cerevisiae QA23 were analyzed in industrial-scale vinification of the grape variety Tamjanika. Their contribution to the quality and aroma profile was investigated by quantifying volatile compounds and wine sensory evaluation. Both yeast isolates were able to complete alcoholic fermentation, to reduce ethanol concentration up to 1.06% v/v (in monoculture) in comparation to S. cerevisiae QA23, and to enhance aroma and sensory profile. Based on calculated odor activity values (OAV), p-cymene, ethyl hexanoate, ethyl octanoate, and ethyl decanoate were the major aroma volatile compounds in all Tamjanika wine samples. Analyzed yeast strains significantly affected relative contribution of volatile compounds and can be considered responsible for the differences and uniqueness of the obtained wine samples. Besides confirmation of good enological and fermentative characteristics, selected isolates can be characterized as high ester-producing strains with potential to enhance the floral and fruity aromas of wine. The present study represents a further step toward the use of indigenous yeast isolates at industrial-scale fermentation in order to ensure the regional signature of Tamjanika wine. Full article

Riboflavin or vitamin B2 is a water-soluble vitamin and a precursor of flavin coenzymes, flavin mononucleotide, and flavin adenine dinucleotide, which play a key role as enzyme cofactors in energy metabolism. Candida famata yeast is a promising producer of riboflavin, as it belongs to the group of so-called flavinogenic yeasts, capable of riboflavin oversynthesis under conditions of iron starvation. The role of the particular structural genes in the limitation of riboflavin oversynthesis is not known. To study the impact of overexpression of the structural genes of riboflavin synthesis on riboflavin production, a set of plasmids containing genes RIB1, RIB6, and RIB7 in different combinations was constructed. The transformants of the wild-type strain of C. famata, as well as riboflavin overproducer, were obtained, and the synthesis of riboflavin was studied. It was found that overexpression of RIB1 and RIB6 genes coding for enzymes GTP cyclohydrolase II and 3,4-dihydroxy-2-butanone-4-phosphate synthase, which catalase the initial steps of riboflavin synthesis, elevated riboflavin production by 13–28% relative to the parental riboflavin-overproducing strains. Full article

The oenological potential of native strains of Metschnikowia pulcherrima B-5 and Candida famata WB-1, isolated from blackberries, was investigated in pure and sequential fermentation of Chardonnay grape with commercial Saccharomyces cerevisiae QA23. The effect of pre-fermentative cold maceration was also analysed. The fermentations were performed in the pilot-scale trials and the profile of volatile compounds and their sensory characteristics were determined. The application of C. famata WB-1 and M. pulcherrima B-5 reduced the volatile acidity and increased total polyphenols of the wines, compared to the control samples. Higher alcohols and esters were dominant, while fatty acids and aldehydes and ketones were also detected. Esters had the greatest contribution to sensory characteristics, especially the development of floral and fruity aromas. Most esters were present in lower concentrations in sequential fermentations compared to the pure fermentations with M. pulcherrima B-5 or C. famata WB-1. Pre-fermentative maceration positively affected both the aroma and the sensory profile. The best sensory score was determined for wines produced using C. famata WB-1 in the fermentations without pre-fermentative maceration, and the sequential fermentation of M. pulcherrima B-5 with maceration. Native strains of M. pulcherrima B-5 and C. famata WB-1 have shown great potential for the enhancement of the aromatic and sensory profile of Chardonnay wine. Full article

The essential oils of three specimens of Myrcia multiflora (A, B and C) and Eugenia florida were extracted by hydrodistillation, and the chemical compositions from the essential oils were identified by gas chromatography and flame ionization detection (CG/MS and CG-FID). The fungicide potential of the EOs against five fungicide yeasts was assessed: Candida albicans INCQS-40175, C. tropicalis ATCC 6258, C. famata ATCC 62894, C. krusei ATCC 13803 and C. auris IEC-01. The essential oil of the specimen Myrcia multiflora (A) was characterized by the major compounds: α-bulnesene (26.79%), pogostol (21.27%) and δ-amorphene (6.76%). The essential oil of the specimen M. multiflora (B) was rich in (E)-nerolidol (44.4%), (E)-γ-bisabolene (10.64%) and (E,E)-α-farnesene (8.19%), while (E)-nerolidol (92.21%) was the majority of the specimen M. multiflora (C). The sesquiterpenes seline-3,11-dien-6-α-ol (12.93%), eremoligenol (11%) and γ-elemene (10.70%) characterized the chemical profile of the EOs of E. florida. The fungal species were sensitive to the essential oil of M. multiflora (B) (9–11 mm), and the lowest inhibitory concentration (0.07%) was observed in the essential oil of M. multiflora (A) against the yeasts of C. famata. Fungicidal action was observed in the essential oils of M. multiflora (A) against C. famata, with an MIC of 0.78 µL/mL and 3.12 µL/mL; C. albicans, with an MFC of 50 µL/mL and M. multiflora (C) against C. albicans; and C. krusei, with a MFC of 50 µL/mL. Full article

Cocoa bean fermentation is an important process in the manufacturing of cocoa products. It involves microbes, such as lactic acid bacteria, yeast, and acetic acid bacteria. The presence of mold in cocoa bean fermentation is undesired, as it reduces the quality and may produce mycotoxins, which can cause poisoning and death. Aspergillus niger is a fungus that produces ochratoxin A, which is often found in dried agricultural products such as seeds and cereals. In this study, we applied indigenous Candida famata HY-37, Lactobacillus plantarum HL-15, and Acetobacter spp. HA-37 as starter cultures for cocoa bean fermentation. We found that the use of L. plantarum HL-15 individually or in combination Candida famata HY-37, Lactobacillus plantarum HL-15, and Acetobacter spp. HA-37 as a starter for cocoa bean fermentation can inhibit the growth of A. niger YAC-9 and the synthesis of ochratoxin A during fermentation and drying. With biological methods that use indigenous Lactobacillus plantarum HL-15 individually or in combination with Candida famata HY-37 and Acetobacter spp. HA-37, we successfully inhibited contamination by ochratoxin-A-producing fungi. Thus, the three indigenous microbes should be used in cocoa bean fermentation to inhibit the growth of fungi that produce mycotoxins and thus improve the quality. Full article

The fermentative potential of native Candida famata isolates from wild and cultivated blackberries was evaluated for potential application in Prokupac grape must fermentation. 5 isolates, out of a total 22 isolated yeasts, were identified as C. famata. After the initial screening of fermentative performances, microfermentation was performed in a sterile grape must. Produced samples were analyzed using the HPLC technique. All isolates showed an ability to grow at lower temperatures, good tolerance to 7% ethanol and 300 ppm of SO₂. C. famata isolates WB-1, WB-2 and W-5 had similar fermentation performance, but WB-1 isolate was chosen for validation at a laboratory-scale level according to a pleasant, fruity aroma, highest fermentative vigor and power, good organic acid profile and the highest level of ethanol and glycerol produced in micro-vinification experiments. Good enological performance of selected C. famata WB-1 isolate is confirmed by higher level of glycerol, lower level of ethanol and acetic acid in wine samples produced in pure and sequential fermentation, when compared to the control sample. Throughout the selection of C. famata yeasts with good enological potential, this work gives a contribution in the area of precision enology, aiming to find a perfect match between non-exploited yeasts and “autochthonous” grape cultivar Prokupac. Full article

Candidemia is an important cause of morbidity and mortality especially in immunocompromised and hospitalized patients. We retrospectively collected data of candidemia cases that occurred in the seven Hematology-Oncology Departments/Units of Greece and the Stem Cell Transplant Unit between 2015 and 2019. In total, 19 episodes of candidemia in 19 patients were recorded. The majority of the patients (78.9%) had at least one risk factor for candidemia. The most frequent risk factors associated with candidemia observed in our patients were prolonged duration of hospitalization (30 days, range 1–141), presence of a central venous catheter at diagnosis of candidemia (73.7%) and antibiotics use during the last two weeks (84.2%). Candida parapsilosis was the most common species isolated accounting for 42.1%, followed by C. albicans (26.3%) and C. famata (15.8%). Nearly all of the patients (84.2%) received antifungal monotherapy with liposomal amphotericin B or echinocandins. The central venous catheter was removed in 78.6% of patients and the median time between the first positive blood culture and catheter removal was 3 days (range 1–9). Mortality at 28 days was 26.3%. In conclusion, a predominance of non-albicans species was observed in our study in conformity with the global trend. Full article