Yeast carotenoids: production and activity as antimicrobial biomolecule.

Carotenoids are a large group of organic, pigmented, isoprenoid-type compounds that play biological activities in plants and microorganisms (yeasts, bacteria, and microalgae). Literature reported it as vitamin A precursors and antioxidant activity. Carotenoids also can act as antimicrobial agents and few reports showed quantitative measurements of Minimal Inhibitory Concentrations against different pathogens. In this sense, some carotenoids were added to medical-surgical materials. The demand for scale-up of different naturally obtained carotenoids has increased due to the concern about the detrimental health effects caused by synthetic molecules and antimicrobial resistance. In this review, we reported the variability in pigment production and culture conditions, extraction methods used in laboratory, and we discussed the antimicrobial activity carried out by these molecules and the promising acting as new molecules to be scaled-up to industry.

Biotechnological Production of Carotenoids Using Low Cost-Substrates Is Influenced by Cultivation Parameters: A Review.

Carotenoids are natural lipophilic pigments mainly found in plants, but also found in some animals and can be synthesized by fungi, some bacteria, algae, and aphids. These pigments are used in food industries as natural replacements for artificial colors. Carotenoids are also known for their benefits to human health as antioxidants and some compounds have provitamin A activity. The production of carotenoids by biotechnological approaches might exceed yields obtained by extraction from plants or chemical synthesis. Many microorganisms are carotenoid producers; however, not all are industrially feasible. Therefore, in this review, we provide an overview regarding fungi that are potentially interesting to industry because of their capacity to produce carotenoids in response to stresses on the cultivation medium, focusing on low-cost substrates.

The suppression of torulene and torularhodin treatment on the growth of PC-3 xenograft prostate tumors.

Torulene and torularhodin are two of the principal carotenoids in Sporidiobolus pararoseus and have a similar structure to that of lycopene. The present study was to elucidate the anti-cancer activity of torulene and torularhodin in vivo with lycopene as a control. Nude mice were orally supplemented every day with a low or high dose [9 or 18 mg/kg body weight (BW)] of lycopene, torularhodin or torulene. Two weeks after the supplementation, mice were injected once with hormone-independent prostatic carcinoma PC-3 cells. When the tumor of the control group load exceeded 200 mm(3), mice were killed and the study was terminated. Compared with the controls, high-carotenoid supplementation lowered the mean number of tumors from 248.13 ± 28.74 to 50.83 ± 7.63, 70.34 ± 6.77, and 60.53 ± 6.78 mm(3) (P < 0.05, n = 8) by, respectively. Histological examination showed tumor degeneration, apoptosis and necrosis presented at the end of the experiment. Quantitative polymerase chain reaction and immunohistochemistry results showed Bcl-2 expression of the control group was higher than that of the carotenoid-treated group while the expression of Bax was lower than the carotenoid-treated group. High-carotenoid supplementation also increased the mRNA expressions of caspase-3, 8 and 9 in tumor tissues. These results show that both torulene and torularhodin supplementation inhibit the growth of prostate cancer in nude mice and suggest that such an action is associated the apoptosis of tumor cells.

Rhodotorula glutinis-potential source of lipids, carotenoids, and enzymes for use in industries.

Rhodotorula glutinis is capable of synthesizing numerous valuable compounds with a wide industrial usage. Biomass of this yeast constitutes sources of microbiological oils, and the whole pool of fatty acids is dominated by oleic, linoleic, and palmitic acid. Due to its composition, the lipids may be useful as a source for the production of the so-called third-generation biodiesel. These yeasts are also capable of synthesizing carotenoids such as ß-carotene, torulene, and torularhodin. Due to their health-promoting characteristics, carotenoids are commonly used in the cosmetic, pharmaceutical, and food industries. They are also used as additives in fodders for livestock, fish, and crustaceans. A significant characteristic of R. glutinis is its capability to produce numerous enzymes, in particular, phenylalanine ammonia lyase (PAL). This enzyme is used in the food industry in the production of L-phenylalanine that constitutes the substrate for the synthesis of aspartame-a sweetener commonly used in the food industry.

Diversity of Red Yeasts in Various Regions and Environments of Poland and Biotechnological Potential of the Isolated Strains.

Due to the growing demand for natural carotenoids, researchers have been searching for strains that are capable of efficient synthesis of these compounds. This study tested 114 red yeast strains collected from various natural environments and food specimens in Poland. The strains were isolated by their ability to produce red or yellow pigments in rich nutrient media. According to potential industrial significance of the carotenoids, both their total production and share of individual carotenoids (ß-carotene, γ-carotene, torulene, and torularhodin) were analyzed. The total content of carotenoid pigments in the yeast dry matter ranged from 13.88 to 406.50 µg/g, and the percentages of individual carotenoids highly varied among the strains. Most of the yeast isolates synthesized torulene at the highest amount. Among the studied strains, isolates with a total carotenoid content in biomass greater than 200 µg/g and those containing more than 60% torularhodin were selected for identification (48 strains). The identified strains belonged to six genera: Rhodotorula, Sporidiobolus, Sporobolomyces, Buckleyzyma, Cystofilobasidium, and Erythrobasidium. The largest number of isolates belonged to Rhodotorula babjevae (18), Rhodotorula mucilaginosa (7), Sporidiobolus pararoseus (4), and Rhodotorula glutinis (4).

Statistical optimisation of cell growth and carotenoid production by rhodotorula mucilaginosa.

Sequential statistical methods were used to maximise carotenoid production by a strain of Rhodotorula mucilaginosa, isolated from the Brazilian ecosystem. Initially, a factorial 2(5-1) experimental design was used, and the variables were pH and the levels of glucose, yeast extract, MgSO4.7H2O and KH2PO4. The nitrogen source (yeast extract) was the most important variable in enhancing carotenoid production; MgSO4.7H2O and KH2PO4 had a negative influence. The initial pH had no significant effect on carotenoid and cell productions. We further investigated the effects of glucose and yeast extract effects, using a second-order central composite design (CCD) to optimise carotenoid production, which was adequately approximated with a full quadratic equation obtained from a two-factor-2-level design. The analysis of quadratic surfaces showed that after 5 days of cultivation at 25 °C, the maximum carotenoid concentration (745 µg l(-1)) was obtained with 15 g l(-1) of yeast extract and 20 g l(-1) of glucose. The maximum carotenoid production (152 µg g(-1)) was obtained with 5 g l(-1) yeast extract and 10 g l(-1) glucose. Carotenoid formation was more sensitive to changes in yeast extract concentration than to changes in glucose concentration. Maximum cell production was achieved with 15-17 g l(-1) of yeast extract and 15-20 g l(-1) of glucose.

Transcriptomic and metabolomic analysis reveals the potential mechanisms underlying the improvement of ß-carotene and torulene production in Rhodosporidiobolus colostri under low temperature treatment.

Carotenoids are a group of versatile isoprenoid pigments widely utilized in the food, pharmaceutical and cosmetic industries. Rhodosporidiobolus colostri is a cold-adapted yeast that has piqued interest as a natural source of microbial carotenoids, including ß-carotene, torulene and torularhodin. Here, the effect of low temperature on carotenoid production in R. colostri was investigated. The results indicated that the total carotenoid production was significantly increased at the low temperature (16 ℃) treatment (29.016 mg/L) as compared to control (25 ℃) (17.147 mg/L) after 5 days of cultivation. Among them, the increase in ß-carotene and torulene serve as the main contributors to the improvement in total carotenoid production. Integrative analyses of the transcriptome and metabolome suggested that the up-regulation of the terpenoid backbone biosynthesis pathway and the down-regulation of the TCA cycle flux allow more acetyl-CoA to be diverted to carotenogenesis, which might be the reason for the increased production of ß-carotene and torulene in R. colostri under low temperature treatment. Our results presented herein should not only provide an effective strategy for increasing total carotenoids production in R. colostri, but lay the molecular groundwork to further facilitate genetic engineering to enhance the yield of certain carotenoids.

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.

Lipid and carotenoid production by the Rhodosporidium toruloides mutant in cane molasses.

Cane molasses is beneficial for lipid and carotenoid production in microalgae. We made a survey for the lipid and carotenoid production profile of R. toruloides M18 (MT) with various concentrations of molasses under nitrogen-deficited conditions. The production of α-linolenate and torularhodin from MT were 1.22- and 14.68-fold higher than those of the wild-type strain. We observed that molasses at concentrations of 35 g/L and 70 g/L represented a cheap and environmentally friendly strategy for producing lipids and carotenoids. Transcriptome and WGCNA analysis demonstrated that the genes relevant to the lipid and carotenoid production, including MYB, bHLH, Δ-4 desaturase, Δ-12 desaturase and FA2H, were significantly highly expressed. The results indicated that molasses could represent an inexpensive means for achieving high lipids and carotenoids production in R. toruloides.

Carotenoids and lipid production from Rhodosporidium toruloides cultured in tea waste hydrolysate.

BACKGROUND: In this study, renewable tea waste hydrolysate was used as a sole carbon source for carotenoids and lipid production. A novel Rhodosporidium toruloides mutant strain, RM18, was isolated through atmospheric and room-temperature plasma mutagenesis and continuous domestication in tea waste hydrolysate from R. toruloides ACCC20341. RESULTS: RM18 produced a larger biomass and more carotenoids and α-linolenic acid compared with the control strain cultured in tea waste hydrolysate. The highest yields of torularhodin (481.92 µg/g DCW) and torulene (501 µg/g DCW) from RM18 cultured in tea waste hydrolysate were 12.86- and 1.5-fold higher, respectively, than that of the control strain. In addition, α-linolenic acid production from RM18 in TWH accounted for 5.5% of total lipids, which was 1.58 times more than that of the control strain. Transcriptomic profiling indicated that enhanced central metabolism and terpene biosynthesis led to improved carotenoids production, whereas aromatic amino acid synthesis and DNA damage checkpoint and sensing were probably relevant to tea waste hydrolysate tolerance. CONCLUSION: Tea waste is suitable for the hydrolysis of microbial cell culture mediums. The R. toruloides mutant RM18 showed considerable carotenoids and lipid production cultured in tea waste hydrolysate, which makes it viable for industrial applications.

Optimization of carotenoids production by Rhodotorula mucilaginosa (MTCC-1403) using agro-industrial waste in bioreactor: A statistical approach.

Bio-colorants are preferred over synthetic colors as bio-colorants not only impart characteristic color to the food also contain harmless bio-active antioxidant nutrients. The present study was undertaken to investigate the potential of agro-industrial waste (Onion peels, potato skin, mung bean husk and pea pods) for carotenoid production from Rhodotorula mucilaginosa. After screening of appropriate carbon, nitrogen sources from agro-industrial waste, the fermentation conditions (pH, temperature, agitation) were optimized using Response Surface Methodology and optimum conditions were pH 6.1, temperature 25.8 ᴼC and agitation 119.6 rpm. Further, to evaluate the effect of aeration on carotenoids synthesis, fermentation was carried out in 3 L bio-reactor under optimum conditions with an air input of 1.0 vvm. Aeration causes elevation of more than 100 µg carotenoids per g of dry biomass. LC-MS of extracted pigment confirmed the presence of some other carotenoids along with ß-carotene. The major carotenoid compounds were found from the investigation were torularhodin, ß-carotene, and torulene.

Salt stress increases carotenoid production of Sporidiobolus pararoseus NGR via torulene biosynthetic pathway.

Carotenoids represent a diverse class of aliphatic C40 molecules with a variety of applications in the food and pharmaceutical industries. Sporidiobolus pararoseus NGR produces various carotenoids, including torulene, torularhodin and ß-carotene. Salt stress significantly increases the torulene accumulation of S. pararoseus NGR. However, little is known, about the molecular mechanisms underlying the increased torulene biosynthesis. In this work, we investigated the effects of NaCl treatment on the contents of carotenoids (both qualitatively and quantitatively) and transcriptome. A total of 12.3 Gb of clean bases were generated in six cDNA libraries. These bases were de novo assembled into 9,533 unigenes with an average length of 1,654 nt and N50 of 2,371 nt. Transcriptome analysis revealed that of 3,849 differential expressed genes (DEGs) in response to salt stress, 2,019 were up-regulated, and 1,830 were down-regulated. Among these DEGs, we identified three carotenogenic genes crtE, crtYB, and crtI. In addition, fourteen candidate genes were predicted to participate in the conversion from torulene to torularhodin. Our findings should provide insights into the mechanisms of carotenoid biosynthesis and salt-tolerance of S. pararoseus NGR.

Increased torulene accumulation in red yeast Sporidiobolus pararoseus NGR as stress response to high salt conditions.

Carotenoids represent a class of molecules valuable for food, chemical and pharmaceutical industries. As a microbial carotenoid, torulene possesses potential health-promoting effects in human. However, few studies have been conducted to investigate optimal condition for its large-scale commercial production to date. Sporidiobolus pararoseus NGR, a pigmented yeast, was shown previously to accumulate considerable amounts of torulene, ß-carotene, and torularhodin. In this study, the effect of salt stress on the production of carotenoids in S. pararoseus NGR was investigated. After 5days of cultivation, the total amount of carotenoids was significantly higher in 0.75M (3.952mg/L) and 1M (2.89mg/L) NaCl treatments than control (1.636mg/L), respectively. Among them, the increase in torulene accumulation is the main contributor to the improvement in total amount of carotenoids under 0.75 and 1M NaCl treatments. Together, our results should advance the development of metabolic engineering for the commercial production of torulene.

Torulene and torularhodin, protects human prostate stromal cells from hydrogen peroxide-induced oxidative stress damage through the regulation of Bcl-2/Bax mediated apoptosis.

The current study was designed to elucidate the cytoprotective effects and possible mechanisms of torulene and torularhodin on hydrogen peroxide (H2O2)-induced oxidative stress damage in human prostate stromal cells (WPMY-1). After treated with H2O2, a notable decrease was appeared in cell viability, yet the decrease was attenuated when cells were pretreated with torulene and torularhodin (0.5-10 µM) as evaluated by WST-1 assay. Pretreatment with these two carotenoids significantly attenuated H2O2-induced apoptosis in WPMY-1 cells through the inhibition of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) overproduction, as well as the activation of the activities in catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Finally, pretreatment of cells with carotenoids resulted in the regulation of the mRNA and protein expression of Bcl-2 and Bax in H2O2-exposed prostate stromal cells. The present results indicate that both torulene and torularhodin can protect human prostate stromal cells from oxidative stress damage via Bcl-2/Bax mediated apoptosis.

Carotenoid Biosynthesis in Fusarium.

Many fungi of the genus Fusarium stand out for the complexity of their secondary metabolism. Individual species may differ in their metabolic capacities, but they usually share the ability to synthesize carotenoids, a family of hydrophobic terpenoid pigments widely distributed in nature. Early studies on carotenoid biosynthesis in Fusariumaquaeductuum have been recently extended in Fusarium fujikuroi and Fusarium oxysporum, well-known biotechnological and phytopathogenic models, respectively. The major Fusarium carotenoid is neurosporaxanthin, a carboxylic xanthophyll synthesized from geranylgeranyl pyrophosphate through the activity of four enzymes, encoded by the genes carRA, carB, carT and carD. These fungi produce also minor amounts of ß-carotene, which may be cleaved by the CarX oxygenase to produce retinal, the rhodopsin's chromophore. The genes needed to produce retinal are organized in a gene cluster with a rhodopsin gene, while other carotenoid genes are not linked. In the investigated Fusarium species, the synthesis of carotenoids is induced by light through the transcriptional induction of the structural genes. In some species, deep-pigmented mutants with up-regulated expression of these genes are affected in the regulatory gene carS. The molecular mechanisms underlying the control by light and by the CarS protein are currently under investigation.

Producción de carotenoides en levaduras nativas aisladas de sistemas acuáticos en Cali, Colombia / Carotenoids production in wild yeasts isolated from aquatic systems in Cali, Colombia

Introducción: Los carotenoides son fuente importante de actividades biológicas funcionales, tales como antioxidantes o antimicrobianas, además de tener gran impacto a nivel industrial, ya sea en cosmética o suplementación animal en acuacultura. Se han reportado varias moléculas novedosas a partir de aislamientos en Latinoamérica, principalmente en la Patagonia, Argentina. Sin embargo, no hay reportes en Colombia que evalúen la producción de carotenoides en levaduras nativas pigmentadas. Objetivo: Se evaluó la capacidad de producción de carotenoides en levaduras nativas aisladas de lagos, ríos y aguas residuales de la ciudad de Cali, Colombia. Materiales y métodos: Se caracterizaron 30 levaduras provenientes de dos colecciones. De estas se obtuvo su biomasa, rendimiento de carotenoides totales y producción de ß-caroteno. Las cepas promisorias fueron identificadas secuenciando la región ITS1-5.8S-ITS2. Resultados: El mayor rendimiento en la extracción de pigmentos se obtuvo para las cepas P11A (84,36 ± 5,24 µg/g) y Rhodotorula paludigena CS13 (56,26 ± 7,08 µg/g), mientras que las concentraciones más altas de ß-caroteno fueron 10,2 µg/mL (R. paludigena CS13) y 9,7 µg/mL (R. mucilaginosa/alborubescens P10A). La cinética de crecimiento y producción de pigmentos durante cinco días fue óptima para la cepa P11A, ya que hubo un aumento en el rendimiento de carotenoides totales 10 veces mayor (48 h: 109,62 µg/g, 120 h: 1403,10 µg/g). Conclusiones: En este estudio se encontró que levaduras aisladas de sistemas acuáticos son promisorias para la producción de pigmentos carotenoides (incluyendo ß-caroteno), siendo su extracción y caracterización viable para futuros estudios biotecnológicos.

Introduction: Carotenoids are an important source of biological activities, such as antioxidant or antimicrobial. Also, carotenoids impact the cosmetic or food supplement industry, mainly in aquaculture. Several reports in Latin America showed novel molecules, mainly in isolated strains in Patagonia, Argentina. However, in Colombia, there are not reports about carotenoid production from pigmented wild yeasts. Objective: We assessed the carotenoid production ability in wild yeasts isolated from lakes, wastewater and rivers located in Cali, Colombia. Materials and methods: 30 yeasts were selected from two collections, each of them was characterized by the biomass, yield of total carotenoids and ß-carotene production. Promisor strains were identified with sequence analysis of ITS1-5.8S-ITS2 region. The highest yield in pigment extraction was obtained by strains P11A (84,36 ± 5,24 µg/g) and Rhodotorula paludigena CS13 (56,26 ± 7,08 µg/g), while higher concentrations of ß-carotene were 10,2 µg/mL (R. paludigena CS13) and 9,7 µg/mL (R. mucilaginosa/alborubescens P10A). The kinetics of growth and pigment production for five days was optimal for the P11A strain, where we found an increasing 10-fold higher (48 h: 109,62 µg/g, 120 h: 1403,10 µg/g). Conclusions: We suggest that yeasts isolated from aquatic systems are promising for the production of carotenoid pigments (including ß-carotene), making their extraction and characterization viable for future biotechnological studies.

Statistical optimisation of cell growth and carotenoid production by Rhodotorula mucilaginosa

Sequential statistical methods were used to maximise carotenoid production by a strain of Rhodotorula mucilaginosa, isolated from the Brazilian ecosystem. Initially, a factorial 2(5-1) experimental design was used, and the variables were pH and the levels of glucose, yeast extract, MgSO4.7H2O and KH2PO4. The nitrogen source (yeast extract) was the most important variable in enhancing carotenoid production; MgSO4.7H2O and KH2PO4 had a negative influence. The initial pH had no significant effect on carotenoid and cell productions. We further investigated the effects of glucose and yeast extract effects, using a second-order central composite design (CCD) to optimise carotenoid production, which was adequately approximated with a full quadratic equation obtained from a two-factor-2-level design. The analysis of quadratic surfaces showed that after 5 days of cultivation at 25ºC, the maximum carotenoid concentration (745 µg l-1) was obtained with 15 g l-1 of yeast extract and 20 g l-1 of glucose. The maximum carotenoid production (152 µg g-1) was obtained with 5 g l-1 yeast extract and 10 g l-1 glucose. Carotenoid formation was more sensitive to changes in yeast extract concentration than to changes in glucose concentration. Maximum cell production was achieved with 15-17 g l-1 of yeast extract and 15-20 g l-1 of glucose.

Statistical optimisation of cell growth and carotenoid production by Rhodotorula mucilaginosa

Sequential statistical methods were used to maximise carotenoid production by a strain of Rhodotorula mucilaginosa, isolated from the Brazilian ecosystem. Initially, a factorial 2(5-1) experimental design was used, and the variables were pH and the levels of glucose, yeast extract, MgSO4.7H2O and KH2PO4. The nitrogen source (yeast extract) was the most important variable in enhancing carotenoid production; MgSO4.7H2O and KH2PO4 had a negative influence. The initial pH had no significant effect on carotenoid and cell productions. We further investigated the effects of glucose and yeast extract effects, using a second-order central composite design (CCD) to optimise carotenoid production, which was adequately approximated with a full quadratic equation obtained from a two-factor-2-level design. The analysis of quadratic surfaces showed that after 5 days of cultivation at 25ºC, the maximum carotenoid concentration (745 µg l-1) was obtained with 15 g l-1 of yeast extract and 20 g l-1 of glucose. The maximum carotenoid production (152 µg g-1) was obtained with 5 g l-1 yeast extract and 10 g l-1 glucose. Carotenoid formation was more sensitive to changes in yeast extract concentration than to changes in glucose concentration. Maximum cell production was achieved with 15-17 g l-1 of yeast extract and 15-20 g l-1 of glucose.