Identification of Irpex and Rhodotorula on surveillance bronchoscopy in a pediatric lung transplant recipient: A case report and review of literature of these atypical fungal organisms.

BACKGROUND: Invasive fungal disease (IFD) is a frequent complication in pediatric lung transplant recipients, occurring in up to 12% of patients in the first year. Risk factors for infection include impaired lung defenses and intense immunosuppressive regimens. While most IFD occurs from Aspergillus, other fungal conidia are continuously inhaled, and infections with fungi on a spectrum of human pathogenicity can occur. CASE REPORT: We report a case of a 17-year-old lung transplant recipient in whom Irpex lacteus and Rhodotorula species were identified during surveillance bronchoscopy. She was asymptomatic and deemed to be colonized by Irpex lacteus and Rhodotorula species following transplant. 2 years after transplantation, she developed a fever, respiratory symptoms, abnormal lung imaging, and histological evidence of acute and chronic bronchitis on transbronchial biopsy. After developing symptoms concerning for a pulmonary infection and graft dysfunction, she was treated for a presumed IFD. Unfortunately, further diagnostic testing could not be performed at this time given her tenuous clinical status. Despite the initiation of antifungal therapy, her graft function continued to decline resulting in a second lung transplantation. CONCLUSIONS: This case raises the concern for IFD in lung transplant recipients from Irpex species. Further investigation is needed to understand the pathogenicity of this organism, reduce the incidence and mortality of IFD in lung transplant recipients, and refine the approach to diagnosis and manage the colonization and isolation of rare, atypical fungal pathogens in immunocompromised hosts.

New neuroprotective derivatives of cinnamic acid by biotransformation.

Microbial transformation is extensively utilized to generate new metabolites in bulk amounts with more specificity and improved activity. As cinnamic acid was reported to exhibit several important pharmacological properties, microbial transformation was used to obtain its new derivatives with enhanced biological activities. By manipulating the 2-stage fermentation protocol of biotransformation, five metabolites were produced from cinnamic acid. Two of them were new derivatives; N-propyl cinnamamide 2̲ and 2-methyl heptyl benzoate 3̲ produced by Alternaria alternata. The other 3 metabolites, p-hydroxy benzoic acid 4̲, cinnamyl alcohol 5̲ and methyl cinnamate 6̲, were produced by Rhodotorula rubra, Rhizopus species and Penicillium chrysogeneum, respectively. Cinnamic acid and its metabolites were evaluated for their cyclooxygenase (COX) and acetylcholinesterase (AChE) inhibitory activities. Protection against H2O2 and Aß1-42 induced-neurotoxicity in human neuroblastoma (SH-SY5Y) cells was also monitored. Metabolite 4̲ was more potent as a COX-2 inhibitor than the parent compound with an IC50 value of 1.85 ± 0.07 µM. Out of the tested compounds, only metabolite 2̲ showed AChE inhibitory activity with an IC50 value of 8.27 µM. These results were further correlated with an in silico study of the binding interactions of the active metabolites with the active sites of the studied enzymes. Metabolite 3̲ was more potent as a neuroprotective agent against H2O2 and Aß1-42 induced-neurotoxicity than catechin and epigallocatechin-3-gallate as positive controls. This study suggested the two new metabolites 2̲ and 3̲ along with metabolite 4̲ as potential leads for neurodegenerative diseases associated with cholinergic deficiency, neurotoxicity or neuroinflammation.

Carotenoids production by Rhodosporidium paludigenum yeasts: Characterization of chemical composition, antioxidant and antimicrobial properties.

The high market potential imposed by natural carotenoids has turned the scientific interest in search for new strains, capable of synthesizing a wide spectrum of these pigments. In this study, Rhodosporidium paludigenum NCYC 2663 and 2664 were investigated for carotenoids production and lipid accumulation utilizing different carbon sources (glucose, fructose, sucrose, mixture of glucose: galactose). Strain R. paludigenum 2663 produced the highest total carotenoids titer (2.21 mg/L) when cultivated on sucrose, together with 4 g/L lipids (30% w/w content) and 7 g/L exopolysaccharides. In the case of R. paludigenum 2664, glucose favored the production of 2.93 mg/L total carotenoids and 1.57 g/L lipids (31.8% w/w content). Analysis of the chemical profile during fermentation revealed that ß-carotene was the prominent carotenoid. Strain 2663 co-produced γ-carotene, torulene and torularhodin in lower amounts, whereas 2664 synthesized almost exclusively ß-carotene. The produced lipids from strain 2663 were rich in oleic acid, while the presence of linoleic acid was also detected in the lipoic fraction from strain 2664. The obtained carotenoid extracts exhibited antioxidant (IC50 0.14 mg/mL) and high antimicrobial activity, against common bacterial and fungal pathogenic strains. The results of this study are promising for the utilization of biotechnologically produced carotenoids in food applications.

Production optimization of food functional factor ergothioneine in wild-type red yeast Rhodotorula mucilaginosa DL-X01.

BACKGROUND: Ergothioneine (EGT) is a high-value food functional factor that cannot be synthesized by humans and other vertebrates, and the low yield limits its application. RESULTS: In this study, the optimal fermentation temperature, fermentation time, initial pH, inoculum age, and inoculation ratio on EGT biosynthesis of Rhodotorula mucilaginosa DL-X01 were optimized. In addition, the effects of three key precursor substances - histidine, methionine, and cysteine - on fungal EGT synthesis were verified. The optimal conditions were further obtained by response surface optimization. The EGT yield of R. mucilaginosa DL-X01 under optimal fermentation conditions reached 64.48 ± 2.30 mg L-1 at shake flask fermentation level. Finally, the yield was increased to 339.08 ± 3.31 mg L-1 (intracellular) by fed-batch fermentation in a 5 L bioreactor. CONCLUSION: To the best of our knowledge, this is the highest EGT yield ever reported in non-recombinant strains. The fermentation strategy described in this study will promote the efficient biosynthesis of EGT in red yeast and its sustainable production in the food industry. © 2024 Society of Chemical Industry.

Environmental assessment of Rhodosporidium toruloides-1588 based oil production using wood hydrolysate and crude glycerol.

Rhodosporidium toruloides, an oleaginous yeast, is a potential feedstock for biodiesel production due to its ability to utilize lignocellulosic biomass-derived hydrolysate with a considerably high lipid titer of 50-70 % w/w. Hence, for the first-time environmental assessment of large-scale R. toruloides-based biodiesel production from wood hydrolysate and crude glycerol was conducted. The global warming potential was observed to be 0.67 kg CO2 eq./MJ along with terrestrial ecotoxicity of 1.37 kg 1,4-DCB eq./MJ and fossil depletion of 0.13 kg oil eq./MJ. The highest impacts for global warming (∼45 %) and fossil depletion (∼37 %) are attributed to the use of chloroform for lipid extraction while fuel consumption for transportation contributed more than 50 % to terrestrial ecotoxicity. Further, sensitivity analysis revealed that maximizing biodiesel yield by increasing lipid yield and solid loading could contribute to reduced environmental impacts. In nutshell, this investigation reveals that environmental impact varies with the type of chemical utilized.

Sustainable production of single-cell oil and protein from wastepaper hydrolysate: identification and optimization of a Rhodotorula mucilaginosa strain as a promising yeast.

This study investigated the potential of wastepaper hydrolysate as a sustainable and low-cost carbon source for single-cell oil and protein production, attending to the growing need for alternative feedstocks and waste management strategies. Wastepaper, characterized by its high carbohydrate content, was subjected to enzymatic and chemo-enzymatic treatments for carbohydrate release. The chemo-enzymatic treatment performed better, yielding 65.3 g l-1 of fermentable sugars. A total of 62 yeast strains were screened for single-cell oil accumulation, identifying Rhodotorula mucilaginosa M1K4 as the most advantageous oleaginous yeast. M1K4 lipid production was optimized in liquid culture, and its fatty acid profile was analyzed, showing a high content of industrially valuable fatty acids, particularly palmitic (28%) and oleic (51%). Batch-culture of M1K4 in a 3-l reactor demonstrated the strain's ability to utilize wastepaper hydrolysate as a carbon source, with dry cell weight, total lipid and protein production of 17.7 g l-1, 4.5 g l-1, and 2.1 g l-1, respectively. Wastepaper as a substrate provides a sustainable solution for waste management and bioproduction. This research highlights the potential of R. mucilaginosa for lipid and protein production from wastepaper hydrolysate.

Effect of laser radiation on the growth of Rhodotorula mucilaginosa isolated from rumin fluid of cows in the Nineveh, Iraq.

Background: The fungi Rhodotorula species are widespread airborne contaminants and are thought to be natural occupants of human skin, lungs, urine, and feces. Therefore, Rhodotorula mucilaginosa, Rhodotorula minuta, and Rhodotorula glutinis are three of the most prevalent species. Aim: This study aims to isolate R. mucilaginosa from the rumen fluid of cows in the province of Mosul and to determine how laser light irradiation affects the growth and morphological traits of these Fungi. Methods: From the rumen fluid of AL-Restaki and AL-Karadi of cows, the R. mucilaginosa was isolated. Using the traditional approach and the ID-Yst card system Vitek 2. A semiconductor laser system with a power of 50 mW and a wavelength of 450 nm was used in the experiment to evaluate the light laser irradiation effects on the culture growth of R. mucilaginosa directly under two light irradiation conditions of 30 and 60 minutes. Results: According to traditional methods and the ID-Yst card system Vitek 2, R. mucilaginosa predominated 7/30 (23.3%), and these strains effectively grow on medium sabouraued dextrose agar as evidenced by the carotenoid pigments that gave their colonies a salmon-pink to coral-red. Compared with a control group where no laser was used, the impact of light laser irradiation was assessed 24 hours after the irradiation using biomass (dry weight measuring yeast cell content in suspension) and microscopic analysis using Gram stain. Microscopic examinations showed the irregular shape of the cells linked to one another. The irradiated subculture of on Sabouraued dextrose agar and incubation at 37°C for 3 days demonstrated inhibited growth in 4/7 (57.1%) isolates. In addition, there was no discernible difference vertically at p < 0.05 between the control group and the R. mucilaginosa biomass concentration under light irradiation circumstances (30 and 60 minutes). Conclusion: This study proved that R. mucilaginosa is found in the rumen fluid of cows. Also, the isolated R. mucilaginosa displayed sensitivity to laser irradiation lights, revealing the more significant topographical alterations of the cell structure that had happened, the irregular shape of the cells, and how they were connected as a result of evolution.

Transcriptome Analysis on Key Metabolic Pathways in Rhodotorula mucilaginosa Under Pb(II) Stress.

Rhodotorula mucilaginosa shows adaption to a broad range of Pb2+ stress. In this study, three key pathways, i.e., glycolysis (EMP), the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation (OXPHOS), were investigated under 0-2,500 mg · L-1 Pb stress, primarily based on biochemical analysis and RNA sequencing. R. mucilaginosa cells showed similar metabolic response to low/medium (500/1000 mg · L-1) Pb2+ stress. High (2,500 mg · L-1) Pb2+ stress exerted severe cytotoxicity to R. mucilaginosa. The downregulation of HK under low-medium Pb2+ suggested a correlation with the low hexokinase enzymatic activity in vivo. However, IDH3, regulating a key step of circulation in TCA, was upregulated to promote ATP feedstock for downstream OXPHOS. Then, through activation of complex I & IV in the electron transport chain (ETC) and ATP synthase, ATP production was finally enhanced. This mechanism enabled fungal cells to compensate for ATP consumption under low-medium Pb2+ toxicity. Hence, R. mucilaginosa tolerance to such a broad range of Pb2+ concentrations can be attributed to energy adaption. In contrast, high Pb2+ stress caused ATP deficiency. Then, the subsequent degradation of intracellular defense systems further intensified Pb toxicity. This study correlated responses of EMP, TCA, and OXPHOS pathways in R. mucilaginosa under Pb stress, hence providing new insights into the fungal resistance to heavy metal stress. IMPORTANCE Glycolysis (EMP), the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation (OXPHOS) are critical metabolism pathways for microorganisms to obtain energy during the resistance to heavy metal (HM) stress. However, these pathways at the genetic level have not been elucidated to evaluate their cytoprotective functions for Rhodotorula mucilaginosa under Pb stress. In this study, we investigated these three pathways based on biochemical analysis and RNA sequencing. Under low-medium (500-1,000 mg · L-1) Pb2+ stress, ATP production was stimulated mainly due to the upregulation of genes associated with the TCA cycle and the electron transport chain (ETC). Such an energy compensatory mechanism could allow R. mucilaginosa acclimation to a broad range of Pb2+ concentrations (up to 1000 mg · L-1). In contrast, high (2500 mg · L-1) Pb2+ stress exerted its excessive toxicity by provoking ATP deficiency and damage to intracellular resistance systems. This study provided new insights into R. mucilaginosa resistance to HM stress from the perspective of metabolism.

Rhodotorula fungemia in a patient with acute lymphoblastic leukemia / Fungemia de Rhodotorula em paciente com leucemia linfoblástica aguda / Fungemia por Rhodotorula en un paciente con leucemia linfoblástica aguda

Objectives: Rhodotorula is an environmental yeast that belongs to Basidiomycota Phylum. Rhodotorula species are ubiquitous in nature, can be found in soil and freshwater. Immunocompromised patients can develop Rhodotorulosis due to wide-ranging exposure to Rhodotorula in the hospital environment. Case Discussion: The patient was a 3-year-old male with a diagnosis of Pro B-Acute Lymphoblastic Leukemia (ALL). He was admitted to the hospital with complaints of malaise, fatigue, weight loss, and diarrhea between courses of chemotherapy. Rhodotorula was isolated from the patient's blood culture obtained during the elevation of temperature. After 14 days of amphotericin B treatment, clinical situation of the patient was improved and he was discharged. Conclusion: Rhodotorula spp. as a rare yet emerging pathogen, often presents as fever of unknown etiology resistant to antibacterial treatment and can be associated with fungemia and other severe complications.(AU)

Objetivos: Rhodotorula é uma levedura ambiental que pertence ao filo Basidiomycota. As espécies de Rhodotorula são onipresentes na natureza, podem ser encontradas no solo e na água doce. Pacientes imunocomprometidos podem desenvolver rodotorulose devido à ampla exposição a Rhodotorula no ambiente hospitalar. Descrição do caso: O paciente era uma criança de 3 anos de idade com diagnóstico de Leucemia Linfoblástica Aguda Pro B (LLA). O paciente deu entrada no hospital com queixas de mal-estar, cansaço, perda de peso e diarreia entre os ciclos de quimioterapia. A Rhodotorula foi isolada da hemocultura do paciente obtida durante a elevação da temperatura. Após 14 dias de tratamento com anfotericina B, a situação clínica do paciente melhorou e o paciente recebeu alta. Conclusão: Rhodotorula spp. como um patógeno raro, porém emergente, frequentemente se apresenta como febre de etiologia desconhecida resistente ao tratamento antibacteriano e pode estar associada a fungemia e outras complicações graves.(AU)

Objetivos: Rhodotorula es una levadura ambiental que pertenece al filo Basidiomycota. Las especies de Rhodotorula son ubicuas en la naturaleza, se pueden encontrar en el suelo y en agua dulce. Los pacientes inmunodeprimidos pueden desarrollar Rhodotorulosis debido a una amplia exposición a Rhodotorula en el entorno hospitalario. Descripción del caso: El paciente era un niño de 3 años con diagnóstico de leucemia linfoblástica aguda Pro B (LLA). El paciente ingresó en el hospital con quejas de malestar, fatiga, pérdida de peso y diarrea entre ciclos de quimioterapia. Se aisló Rhodotorula del hemocultivo del paciente que se obtuvo durante la elevación de la temperatura. Después de 14 días de tratamiento con anfotericina B, la situación clínica del paciente mejoró y fue dado de alta. Conclusión: Rhodotorula spp. como patógeno poco común pero emergente, a menudo se presenta como fiebre de etiología desconocida resistente al tratamiento antibacteriano y puede asociarse con fungemia y otras complicaciones graves.(AU)

Evaluation of anti-tumor effect of the exopolysaccharide from new cold-adapted yeast, Rhodotorula mucilaginosa sp. GUMS16 on chronic myeloid leukemia K562 cell line.

Recently, the development and application of fungal exopolysaccharides (EPS) as natural biopolymers are on the rise. The present study is based on the investigation of possible antiproliferative and antioxidant activities of EPS from the Rhodotorula mucilaginosa sp. GUMS16 on BCR-ABL positive cells (K562). The cytotoxicity, colony formation assays lactate and dehydrogenase (LDH) activity were performed to assess the possible cancer cell death. To elucidate the underlying antiproliferative mechanism of the EPS, cell cycle analysis following real-time PCR (gene expression assessment) were evaluated. The results indicated that, the EPS with an IC50 dose of 1500 µg/ml, reduced the viability of K562 cells without having toxic effects on normal cells as well as decrease in size and number of colonies in EPS-treated group (p < 0.0001). The increase of LDH was 2.75 times more than the control (p < 0.0001). Gene expression revealed up- and down-regulation of apoptotic and anti-apoptotic genes in EPS group compared with the control. Moreover, the DPPH scavenging activity of the EPS in treated cells was significantly higher than the control group (p < 0.0001). Taken together, we concluded that the EPS from GUMS16 strain is able to inhibit the growth of K562 cells besides having antioxidant activities.

Asymptomatic Fungemia Due to Rhodotorula spp. Caused by a Subcutaneously Implanted Central Venous Port Catheter.

A 66-year-old man was admitted to our hospital for gastrointestinal perforation. He had a history of surgery and chemotherapy for colorectal cancer and had a subcutaneously implanted central venous port catheter. After surgery for gastrointestinal tract perforation, he developed an intra-abdominal abscess, which was treated with broad-spectrum antimicrobial agents and improved. Following this improvement, Rhodotorula spp. was detected in a blood culture and at the catheter tip. He was asymptomatic despite having fungemia. His condition improved after the removal of the catheter and the administration of antifungal drugs. Fungemia due to Rhodotorula spp. is rare, and asymptomatic fungemia is even rarer.

Agroindustrial byproduct-based media in the production of microbial oil rich in oleic acid and carotenoids.

This study focuses on the potential of Rhodotorula mucilaginosa CCT 7688 in simultaneous production of lipids and carotenoids in agroindustrial byproduct-based media and specially aims at establishing a process condition that guarantees high concentrations of both bioproducts, i.e., a carotenoid-rich microbial oil with potential economic value and health benefits attributed to carotenoids and fatty acids. Four different combinations of cultivation modes (batch and fed-batch) and alternative substrates (crude glycerol, sugarcane molasses and corn steep liquor) were tested. The M2-B assay, which comprises the use of an agroindustrial byproduct-based medium without any supplementation (70 g L-1 sugarcane molasses and 3.4 g L-1 corn steep liquor) and batch mode, was selected as the most promising one to produce both compounds. Total carotenoid production and total lipid content were 1794.2 µg L-1 and 43.2% (w/w), respectively, after 144 h of cultivation. The fatty acid profile showed predominance of oleic acid (69.9%) and palmitic acid (23.2%). Thus, R. mucilaginosa CCT 7688 may be used in simultaneous production of lipids and carotenoids successfully; its fatty acid profile is similar to that found in olive oil. Both compounds are economically interesting and have great possibility of future commercial applications.

Antarctic Strain of Rhodotorula mucilaginosa UFMGCB 18,377 Attenuates Mucositis Induced by 5-Fluorouracil in Mice.

Mucositis is one of the most strenuous side effects caused by chemotherapy drugs, such as 5-fluorouracil (5-FU), during the treatment of several types of cancers. The disease is so prevalent and aggressive that many patients cannot resist such symptoms. However, despite its frequency and clinical significance, there is no effective treatment to prevent or treat mucositis. Thus, the use of probiotics as an adjuvant for the treatment has gained prominence. In the present study, we evaluated the effectiveness of oral administration of the Antarctic strain of Rhodotorula mucilaginosa UFMGCB 18,377 as an alternative to minimize side effects of 5-FU-induced mucositis in mice. Body weight, food consumption, stool consistency, and presence of blood in the feces were assessed daily in mice orally treated or not with the yeast and submitted or not to experimental mucositis. Blood, bones, and intestinal tissues and fluid were used to determine intestinal permeability and immunological, microbiological, and histopathological parameters. Treatment with R. mucilaginosa UFMGCB 18,377 was able to decrease clinical signs of the disease, such as reduction of food intake and body weight loss, and also decreased the number of intestinal enterobacteria and intestinal length shortening. Additionally, treatment was able to decrease the levels of MPO and EPO activities and inflammatory infiltrates, as well as the histopathological lesions characteristic of mucositis in the jejunum and ileum. Results of the present study showed that the oral administration of R. mucilaginosa UFMGCB 18,377 protected mice against mucositis induced by 5-FU.

Metabolomics reveals the mechanism of Antarctic yeast Rhodotorula mucliaginosa AN5 to cope with cadmium stress.

Heavy metal pollution in Antarctica has far exceeded expectations. Antarctic yeast is widely present in polar marine environment. The mechanisms of metabolomics effect of heavy metal on polar yeast have not been reported previously. In this study, gas chromatography-mass spectrometry (GC-MS) wascarried out to performed the metabolite profiling analysis of Antarctic sea-ice yeast Rhodotorula mucilaginosa AN5 exposed to different cadmium (Cd) stresses of 5 mM (HM5), 10 mM (HM10) and 20 mM (HM20), respectively. Metabolic profile analysis showed that the composition and contents of cellular metabolites have been altered by cadmium. 93 different metabolites were identified altogether, among which 23, 58 and 81 different metabolites were found in HM5, HM10 and HM20 group respectively. MetaboAnalyst analysis showed that in HM5, HM10 and HM20 groups, 12, 24 and 31 metabolic pathways were involved in the stress of cadmium to R. mucilaginosa, respectively. By contrasting with Kyoto Encyclopedia of Genes and Genomes database, we discovered that exposure of yeast AN5 to Cd stress resulted in profound biochemical changes including amino acids, organic acids and saccharides. These results will supply a nonnegligible basis of studying the adaptive resistance mechanism of Antarctic yeast Rhodotorula mucilaginosa to heavy metal.

Avaliação da interação entre leveduras isoladas de kombucha e bactérias probióticas / Evaluation of the interaction between isolated kombucha yeasts and probiotic bacteria

Um dos maiores desafios no desenvolvimento de produtos probióticos é entender como os microrganismos interagem entre si e com o hospedeiro. Quando falamos em alimentos fermentados tradicionais, este obstáculo aumenta porque a matriz alimentar já possui um microbioma intrínseco. No entanto, também é conhecido que muitos microrganismos podem interagir e cooperar para sobreviver quando condições de estresse são encontradas. Assim, o objetivo deste trabalho foi isolar leveduras de quatro diferentes kombuchas em distintos momentos fermentativos e verificar a influência que leveduras isoladas de kombucha têm na manutenção da viabilidade da bactéria probiótica Bifidobacterium animalis subsp. lactis HN019 em condições de aerobiose. Meyerozyma guilliermondii, Candida albicans, Rhodotorula mucilaginosa e Pichia membranifaciens foram leveduras encontradas nas kombuchas, das quais as duas últimas favoreceram a manutenção da alta viabilidade de HN019 em cocultura por 14 dias. Observou-se a viabilidade da bactéria acima de 9 log ao longo de todo o experimento, o que não foi observado em monocultura. Ademais, utilizou-se de análise de autoagregação, hidrofobicidade, atividade enzimática de proteases e fosfolipases das leveuras para analisar seu potencial patogênico. Observou-se que R. mucilaginosa demonstrou características semelhantes à Saccharomyces cerevisiae subsp. boulardii, e sua interação benéfica com HN019 reforça a possibilidade de que esta levedura seja uma chave para a inserção da bactéria em uma kombucha probiótica. Análises metabólicas foram realizadas e encontrou-se uma vasta diversidade de dipeptídeos, principalmente os compostos de prolina, durante a cocultura da bactéria com as leveduras. Tais dipeptídeos apresentam importantes mecanismos de ação no controle biológico e quorum sensing de bactérias e leveduras, e supostamente regulam a manutenção das relações mutualísticas entre ambos microrganismo

One of the biggest challenges in the development of probiotic products is to understand how microorganisms interact with each other and with the host. When we talk about traditional fermented foods, this obstacle increases because the food matrix already has an intrinsic microbiome. However, it is also known that many microorganisms can interact and cooperate to survive when stressful situations are encountered. Thus, the objective of this work was to isolate yeasts from four different kombuchas at different fermentation times and to verify the influence that yeasts isolated from kombucha have on maintaining the viability of the probiotic bacterium Bifidobacterium animalis subsp. lactis HN019 under aerobic conditions. Meyerozyma guilliermondii, Candida albicans, Rhodotorula mucilaginosa and Pichia membranifaciens were yeasts found in kombuchas, of which the last two favored the maintenance of HN019 high viability in co-culture for 14 days. Bacteria viability above 9 log was observed throughout the experiment, which was not observed in monoculture. In addition, analysis of autoaggregation, hydrophobicity, enzyme activity of proteases and phospholipases of yeasts was used to analyze their pathogenic potential. It was observed that R. mucilaginosa demonstrated characteristics similar to Saccharomyces cerevisiae subsp. boulardii, and its beneficial interaction with HN019 reinforces the possibility that this yeast is a key to the insertion of the bacterium in a probiotic kombucha. Metabolic analysis were performed and a wide diversity of dipeptides, mainly proline-based, was found during the co-culture of the bacteria with the yeasts. Such dipeptides have important mechanisms of action in the biological control and quorum sensing of bacteria and yeast, and supposedly regulate the maintenance of mutualistic relationships between both microorganism

Rhodotorula toruloides: an ideal microbial cell factory to produce oleochemicals, carotenoids, and other products.

Requirement of clean energy sources urges us to find substitutes for fossil fuels. Microorganisms provide an option to produce feedstock for biofuel production by utilizing inexpensive, renewable biomass. Rhodotorula toruloides (Rhodosporidium toruloides), a non-conventional oleaginous yeast, can accumulate intracellular lipids (single cell oil, SCO) more than 70% of its cell dry weight. At present, the SCO-based biodiesel is not a price-competitive fuel to the petroleum diesel. Many efforts are made to cut the cost of SCO by strengthening the performance of genetically modified R. toruloides strains and by valorization of low-cost biomass, including crude glycerol, lignocellulosic hydrolysates, food and agro waste, wastewater, and volatile fatty acids. Besides, optimization of fermentation and SCO recovery processes are carefully studied as well. Recently, new R. toruloides strains are developed via metabolic engineering and synthetic biology methods to produce value-added chemicals, such as sesquiterpenes, fatty acid esters, fatty alcohols, carotenoids, and building block chemicals. This review summarizes recent advances in the main aspects of R. toruloides studies, namely, construction of strains with new traits, valorization of low-cost biomass, process detection and optimization, and product recovery. In general, R. toruloides is a promising microbial cell factory for production of biochemicals.

Transcriptomic and Metabolomic Analyses Provide Insights into the Enhancement of Torulene and Torularhodin Production in Rhodotorula glutinis ZHK under Moderate Salt Conditions.

Carotenoids are a group of tetraterpene pigments widely used in the food, pharmaceutical, and cosmetic industries. Torulene, torularhodin, and ß-carotene, three principal carotenoids synthesized by Rhodotorula glutinis ZHK, possess strong health-promoting properties such as antioxidant, provitamin A, and antitumor. Here, the effect of different salt conditions on carotenoids production of R. glutinisZHK was investigated. The results showed that the total carotenoids were significantly enhanced in 0.5 M (3.91 mg/L) and 0.75 M (5.41 mg/L) NaCl treatments than that in 1.0 M (0.35 mg/L) and control (1.42 mg/L) after 120 h of cultivation. Of which, the increase in torulene and torularhodin production acts as the main contributor to the enhancement of total carotenoids. Transcriptome profiling revealed that salt stress efficiently promotes the gene expression of crtI, which could explain the molecular mechanisms of the enhanced torulene and torularhodin production under salt stress. Further experiments indicated that torulene and torularhodin play an important role in quenching excrescent reactive oxygen species induced by salt stress. Together, the present study reports an effective strategy for simultaneously improving torulene and torularhodin production in R. glutinis ZHK.

Effect of Rhodotorula mucilaginosa on patulin degradation and toxicity of degradation products.

Rhodotorula mucilaginosa is an antagonistic yeast for which our research team has recently reported interesting biocontrol activities against blue mould decay of apples and a strong ability to decrease the patulin concentration in vivo. However, the possible mechanisms of patulin degradation by R. mucilaginosa and the toxicity of patulin degradation products remain unclear. In this study, the effect of R. mucilaginosa on patulin degradation and toxicity of degradation products were investigated, the results showed that viable cells of R. mucilaginosa are essential to patulin degradation. Also, R. mucilaginosa eliminated patulin without adsorbing it through its cell wall. The extracellular metabolites of R. mucilaginosa stimulated by patulin showed little degradation activity for patulin. Cycloheximide addition into the medium significantly decreased the patulin degradation capacity of R. mucilaginosa cells. The main patulin degradation product by R. mucilaginosa was ascladiol, which was proved non-toxic to human hepatoma (HepG2) cells at 0.625-10 g/mL. Furthermore, toxicological analysis using a confocal laser scanning microscope revealed that the degradation product induced cellular apoptosis to a lesser extent than patulin itself. This result offers an innovative method to detoxify patulin and limit the risks of patulin in fruits and vegetables using R. mucilaginosa.

Bio-hydrolysis of used soybean oil: environmental-friendly technology using microbial consortium.

In this work, strains of Bacillus subtilis were inoculated in consortium with Rhodotorula mucilaginosa into spent soy oil as aiming to biological treatment and low-cost reuse. The microorganisms were previously isolated and selected for the lipolytic capacity of the alperujo residue generated during the processing of olive oil. For fermentation, bioassays containing Rhodotorula mucilaginosa isolated from alperujo and Candida rugosa CCMA 00371, both co-inoculated with Bacillus subtilis CCMA 0085 in medium containing (% w/v) 0.075 glucose and 0.375 (NH4)3 PO4 in 75 mL of water and 75 mL of spent soy oil. Despite the low biomass productivity, it has favorable characteristics to be used in animal feed supplementation. Spent soy oil was used as a carbon source proven by Bartha respirometer. The strains of R. mucilaginosa UFLA RAS 144 and B. subtilis CCMA 0085 are promising inoculants for oil degradation and can be applied in a waste treatment system.

[A Rare Yeast: Cases of Rhodotorula mucilaginosa Infection Followed Up in a Tertiary University Hospital]. / Nadir Etken Bir Maya: Üçüncü Basamak Üniversite Hastanesinde Izlenen Rhodotorula mucilaginosa Enfeksiyonu Olgulari.

Rhodotorula species are yeasts that are common in the environment,but are not frequently encountered as an infectious agent in humans. Rhodotorula mucilaginosa, Rhodotorula glutinis and Rhodotorula minuta are the species that cause disease in humans. Although its isolation from mucosa is doubtful in terms of the presence of true infection, it is more frequently encountered in daily practice due to the increasing number of invasive procedures, immune system deficiencies caused by immunosuppressive drugs and diseases. R.mucilaginosa growth isolated from various clinical samples between 2000 and 2018 in a tertiary university hospital was presented in this case report. The first case was an 82-year-old man with chronic lung disease, hypertension, congestive heart failure and acute leukemia causing severe immunosuppression. Use of broad spectrum antibiotics, history of immunosuppressive therapy, presence of jugular catheter were the risk factors in this patient. R.mucilaginosa was isolated from blood culture while the patient was receiving fluconazole treatment for Candida albicans grown in urine culture and the patient died before starting the treatment. The second case was a 34-year-old female patient with congenital heart disease. Discharge was observed at the intracardiac defibrillator site of the patient, a temporary pacemaker was inserted, and she used broad spectrum antibiotics for a long time. When the yeast growth was reported in the blood culture, caspofungin treatment was initiated. Although the treatment was switched to amphotericin B lipid complex after the culture result was reported as R.mucilaginosa, the patient died after 12 hours. The third case was a 70-year-old woman with hypertension, dementia, diabetes mellitus and rheumatoid arthritis admitted to the intensive care unit due to cerebrovascular accident. She received different immunosuppressive treatments and had invasive procedures. R.mucilaginosa was isolated from the blood culture taken from the patient's catheter, and there was no growth in the blood culture obtained from the peripheral vein. Anidulafungin was started empirically, which was changed to amphotericin B lipid complex after the identification of the yeast. The patient died for various reasons 10 days after the antifungal treatment was stopped. Our last case was a 55-year-old woman with metastatic ovarian cancer and secondary ascites. Broad-spectrum multiple antibiotics were used and invasive procedures were performed. R.mucilaginosa and C.albicans were isolated from the urine of the patient who had a urinary catheter. No growth was detected from urine after changing the urinary catheter. Therefore, growths were evaluated as colonization, and fluconazole was administered for C.albicans due to the high risk of invasive infection. The patient was lost for different reasons. The development and diversity of the treatment methods lead to the emergence of some opportunistic infectious agents that were not observed previously. Rhodotorula species are one of the rare agents that have increased over the years. Rhodotorula species should be considered as the cause of an infection if no clinical response is obtained after echinocandin and/or fluconazole treatment in patients with long-term immunosuppression and invasive procedures. Data on clinical pictures, treatment responses, follow-up and treatment results of this rare yeast are still limited. This case series was presented to draw attention to the risk factors related to R.mucilaginosa infection/colonization, clinical characteristics of the patients, follow-up results and treatment options and to contribute to the literature.