Optimization of pigment production by Rhodotorula minuta URM 5197 and Rhodotorula mucilaginosa URM 7409 using yellow passion fruit peel (Passiflora edulis)

The objective of this work was to optimize the production of pigments by Rhodotorula minuta and Rhodotorula mucilaginosa through submerged fermentation, using yellow passion fruit peel (Passiflora edulis), as the only substrate. The independent variables evaluated to optimize were: yellow passion fruit peel (YPFP), in grams (g) as culture medium, pH and fermentation time, in days. The study of pigment production and its optimization was carried out using the Doehlert matrix, with fifteen experimental conditions, of which thirteen had different combinations and two repeated the central point. The fixed variables were 30ºC and 150 rpm. Data analysis was performed using the Statistica software version 10.0. The largest amount of total pigments and total carotenoids produced by R. minuta was 28±0.01 mg/L and 72.8±0.026 µg/g, respectively; while for R. mucilaginosa the production of total pigments was 37±0.002 mg/L and total carotenoids 236.8±0.013 µg/g. The optimum production point of total pigments for R. minuta was 2.3g of YPFP, pH 6.5 and 5 days and for R. mucilaginosa 2.5g of YPFP pH 6 and 5 days. In samples of total pigments, the presence of 0.29mg/L of β-carotene for R. minuta and 0.83 mg/L for R. mucilaginosa was identified. It is possible to conclude that yellow passion fruit peel can be used as a nutrient source for Rhodotorula spp growth and pigment production with total carotenoids and β-carotene in its composition.

Effect of Selected Cations and B Vitamins on the Biosynthesis of Carotenoids by Rhodotorula mucilaginosa Yeast in the Media with Agro-Industrial Wastes

In recent years, there has been an increase in the search for novel raw materials for the production of natural carotenoids. Among yeasts, Rhodotorula species have the ability to synthesize carotenoids, mainly β-carotene, torulene, and torularhodin, depending on the culture conditions. This study aimed to determine the effect of selected cations (barium, zinc, aluminum, manganese) and B vitamins (biotin, riboflavin, niacin, pantothenic acid) on the biosynthesis of carotenoids by Rhodotorula mucilaginosa MK1 and estimate the percentages of β-carotene, torulene, and torularhodin synthesized by the yeast. The cultivation was carried out in a medium containing glycerol (waste resulting from biodiesel production) as a carbon source and potato wastewater (waste resulting from potato starch production) as a nitrogen source. Carotenoid biosynthesis was stimulated by the addition of aluminum (300 mg/L) or aluminum (300 mg/L) and niacin (100 µg/L) to the medium. The number of carotenoids produced by R. mucilaginosa MK1 in the medium containing only aluminum and in the medium with aluminum and niacin was 146.7 and 180.5 µg/gd.m., respectively. This content was 101% and 147% higher compared to the content of carotenoids produced by yeast grown in the control medium (73.0 µg/gd.m.). The addition of aluminum and barium seemed to have a positive effect on the biosynthesis of torulene, and the percentage of this compound increased from 31.86% to 75.20% and 68.24%, respectively. Niacin supplementation to the medium increased the percentage of torularhodin produced by the yeast from 23.31% to 31.59–33.79%. The conducted study showed that there is a possibility of intensifying carotenoid biosynthesis by red yeast and changing the percentages of individual carotenoids fractions by adding cations or B vitamins to the medium. Further research is needed to explain the mechanism of action of niacin on the stimulation of torularhodin biosynthesis.

Slightly Acidic Electrolyzed Water to Remove Methylobacterium mesophilicum, Rhodotorula mucilaginosa and Cladosporium cladosporioides in Households

(1) Background: Slightly acidic electrolyzed water (SAEW) is an effective and safe sterilizing solution. Its active component is hypochlorous acid (HOCl) which has been proved to exhibit a strong disinfectant activity. In this research we evaluated the effectiveness of SAEW in the removal of Methylobacterium mesophilicum, Rhodotorula mucilaginosa and Cladosporium cladosporioides, responsible for pink-colored biofilm and black mold in households. (2) Methods: Two concentrations of SAEW, 20 mg/L and 40 mg/L, were tested against M. mesophilicum, R. mucilaginosa and C. cladosporioides. In vitro experiments and mesh experiments were conducted to test the effectiveness of SAEW. (3) Results: The test results showed that 40 mg/L SAEW was effective in removing R. mucilaginosa and C. cladosporioides, with the population decreasing by approximately two orders of magnitude. For M. mesophilicum, resistance towards SAEW was observed; to obtain a 1.3 order of magnitude decrease in bacterial population, washing 5 times with 40 mg/L SAEW was necessary. Mesh experiments showed that SAEW can remove black mold; (4) Conclusions: Overall results indicated that SAEW was particularly effective for R. mucilaginosa and C. cladosporioides species commonly found in Japanese households.

Draft Genome Sequence of Rhodotorula mucilaginosa from an Adult Patient in Qatar

Rhodotorula mucilaginosa is an opportunistic fungal pathogen of public health importance. We present the draft genome sequence of an isolate (Rhodo3571) cultured from an immunocompetent patient. The isolate is similar to other R. mucilaginosa genomes in the NCBI database. Presented here are the genome assembly and its comparison to other reference genomes.

Operating Mode Effect on Lipids Production from Rhodotorula mucilaginosa: Modelling and Simulation Trends

A sustainable alternative for fossil fuels substitution is the production of biodiesel from natural lipids. Mainly, such oil used is in the form of triglycerides and is characterized by being potentially renewable, non-toxic, and biodegradable, thus making it a sustainable product. For producing such biofuel, yeast oil is one of the most viable and currently known options, obtaining theoretically optimal results. In this article, kinetic parameters from the oleaginous yeast Rhodotorula mucilaginosa will simulate lipid accumulation capacity based on different bioreactor operating modes. Likewise, The Matlab software is used to simulate batch and continuous operating modes to establish comparisons between the productions obtained and their respective yields. The results obtained for the batch mode were: 14 g/L for the growth of biomass and an estimate of 0.22 g/g for lipid production. Likewise, for the continuous mode, its results were: 19 g/L for biomass growth and a value of 0.30 g/g in lipid production. The simulated results in continuous mode would demonstrate the effectiveness of its implementation since a more significant lipid accumulation is reached.

Effects of Rhodotorula mucilaginosa on the Immune Function and Gut Microbiota of Mice

As a dominant species among marine yeasts, Rhodotorula benthica accounts for ~50% of all marine yeasts. Rhodotorula is rich in a variety of bioactive substances and commonly used in the production of carotenoids by microbial fermentation and is worth developing. Therefore, the present study used a strain of Rhodotorula mucilaginosa isolated from the coastal waters of the South China Sea as the target yeast to investigate its impact on the immune function and gut microbiota of mice. A total of 200 mice were randomly divided into gavage groups and control group and garaged for 30 consecutive days at different concentration. Samples were collected on day 15 and day 30 of gavage administration. The results showed that R. mucilaginosa ZTHY2 could increase the thymus and spleen indices of mice, and its effect on the thymus index was more significant after long-term gavage administration. Short-term (15 days) gavage administration of R. mucilaginosa suspension enhanced delayed hypersensitivity in mice, increased serum IgG, IgA, and IL-2. Long-term (30 days) gavage administration of R. mucilaginosa suspension significantly enhanced the phagocytosis of macrophages in mice and significantly increased serum TNF-α and INF-γ. R. mucilaginosa ZTHY2 altered the structure of the gut microbiota of mice at the phylum and genus levels, leading to an increased relative abundance of Firmicutes and Lactobacillus and a decreased relative abundance of Bacteroidetes. This strain increased the beneficial intestinal bacteria and reduced the harmful intestinal bacteria in mice. This study provides experimental evidence and lays the foundation for the future development and application of this strain as a microecological source of carotenoids.