Phaffia Rhodozyma Research Articles

Characteristic of new Phaffia rhodozyma yeast strains isolated from birch slime fluxes in Poland

Three new strains of Phaffia rhodozyma yeast have recently been isolated in Poland. The aim of this study was to phenotypically characterize these strains and to compare them with the properties of the reference strain. The potential for carotenoid biosynthesis in these strains was also determined, depending on temperature, carbon, and nitrogen sources in the medium. Phaffia rhodozyma yeasts were also identified by MALDI-TOF MS. There were minor differences in cell morphology among the strains. All strains reproduced asexually by budding and formed spherical chlamydospores. No ability for sexual reproduction was observed. Physiological tests showed minor variations between the reference strain and the isolates, likely due to the geographical specificity of the habitat from which they were originally isolated. Analysis of protein spectra showed that the tested yeast isolates had seven common peaks of different intensities, with masses at 2200, 2369, 3213, 3628, 3776, 3921, and 4710 m/z. Moreover, additional strain-dependent spectra were found. The amount of synthesized carotenoids varied with the carbon and nitrogen sources used, as well as the temperature. The best producer of carotenoids was the P. rhodozyma CMIFS 102 isolate.

Effect of natural carotenoids obtained from Haematococcus pluvialis, Paracoccus carotinifaciens, and Phaffia rhodozyma on flesh pigmentation and related biochemical mechanisms in Atlantic salmon (Salmo salar L.)

The present study highlights the efficiency of natural carotenoid sources (Haematococcus pluvialis, Phaffia rhodozyma, and Paracoccus carotinifaciens) in terms of Atlantic salmon pigmentation, lipid profile, oxidation status (glutathione (GSH)/glutathione disulfide (GSSG)) ratio, and genomic stress markers (nrf2.1, keap1b1, hsp70, and h2q8 genes) during an 88-day feeding trial. As controls, fish fed synthetic astaxanthin was used. Four experimental diets with equal nutritional composition, except for the pigment source, were tested in an experimental design of 12 tanks and 372 fish (n = 3 × 31 per feed, start weight of 149 ± 27.5 g).Astaxanthin from H. pluvialis, P. rhodozyma, and P. carotinifaciens were found to be as efficient as synthetic astaxanthin in terms of visual perception, oxidation status and lipid peroxidation as there were no significant differences (p > 0.05) in a* value, GSH/GSSG ratio, or lipid profile between the different groups. Additionally, there were no significant differences in the gene expression of nrf2.1, keap1b1, or hsp70 in the NQC or the PC. Fish fed P. rhodozyma showed the most favorable results as it had the numerically highest a* and C* values and the lowest L* value. Moreover, no significant difference in total muscle astaxanthin concentration was observed between the fish fed P. rhodozyma and those fed synthetic astaxanthin. However, the fish fed synthetic astaxanthin had a significantly higher concentration of total flesh astaxanthin than those fed H. pluvialis and P. carotinifaciens.The results conclude that naturally produced astaxanthin has a significant potential in Atlantic salmon pigmentation. However, further research on slaughter-ready salmon is essential to prove the concept.

Effects of Phaffia rhodozyma on microbial community dynamics and tobacco quality during tobacco fermentation.

Carotenoids are important precursors of various aroma components in tobacco and play an important role in the sensory quality of tobacco. Phaffia rhodozyma is a species of Xanthophyllomyces capable of synthesizing a highly valuable carotenoid-astaxanthin, but has not yet been used in improving tobacco quality. The dynamic changes of microbial community and metabolites during tobacco fermentation were analyzed in combination with microbiome and metabolome, and the quality of tobacco after fermentation was evaluated by sensory scores. P. rhodozyma could grow and produce carotenoids in tobacco extract, with a maximum biomass of 6.50 g/L and a maximum carotenoid production of 36.13 mg/L at 100 g/L tobacco extract. Meanwhile, the correlation analysis combined with microbiome and metabolomics showed that P. rhodozyma was significantly positively correlated with 11 metabolites such as 6-hydroxyluteolin and quercetin. Furthermore, the contents of alcohols, ketones and esters, which were important aromatic components in fermented tobacco, reached 77.57 μg/g, 58.28 μg/g and 73.51 μg/g, increasing 37.39%, 265.39% and 266.27% compared to the control group, respectively. Therefore, the aroma and flavor, and taste scores of fermented tobacco increased by 0.5 and 1.0 points respectively. This study confirmed that P. rhodozyma fermentation could effectively improve the sensory evaluation of tobacco, and provided a novel microbial fermentation method to improve tobacco quality.

Research on the Cell Wall Breaking and Subcritical Extraction of Astaxanthin from Phaffia rhodozyma.

This study focused on developing an effective cell wall-breaking method for Phaffia rhodozyma, followed by utilizing subcritical fluid extraction to isolate, extract, and concentrate astaxanthin from the complex fermentation products of P. rhodozyma. A comprehensive comparison of seven distinct methods for disrupting cell walls, including dimethyl sulfoxide treatment, lactic acid treatment, sodium hydroxide treatment, β-glucanase enzymatic digestion, β-mannanase enzymatic digestion, and a combined enzymatic treatment involving both β-mannanase and β-glucanase was conducted. The results identified the lactic acid method as the most effective in disrupting the cell walls of P. rhodozyma. The software, Design Expert, was used in the process of extracting astaxanthin from cell lysates using a subcritical extraction method. Through fitting analysis and response surface optimization analysis by Design Expert, the optimal extraction conditions were determined as follows: an extraction temperature of 41 °C, extraction frequency of two times, and extraction time of 46 min. These parameters facilitated the efficient extraction, concentration, and enrichment of astaxanthin from P. rhodozyma, resulting in an astaxanthin concentration of 540.00 mg/L. This result can establish the foundation for its high-value applications.

Xanthophyllomyces dendrorhous Is a Safe Dietary Supplement with Potent Antioxidant Defense Enhancing Activity.

Xanthophyllomyces dendrorhous (X. dendrorhous), previously known as Phaffia rhodozyma, is a red yeast that is widely recognized as a rich source of carotenoids, particularly astaxanthin, which exhibits potent antioxidant activity and other health-promoting functions. However, there is currently a lack of research on the safety of consuming X. dendrorhous. To address this, we conducted an acute toxicity study followed by a 90-day subchronic toxicity trial to evaluate the safety of X. dendrorhous and investigate its in vivo antioxidant activity. In the acute toxicity study, Sprague-Dawley rats were administered a maximum of 12 g/kg body weight of X. dendrorhous powder by gavage and survived without any adverse effects for 14 days. In the subsequent subchronic toxicity test, the rats were randomly divided into five groups, each with free access to their diet adulterated with 0% (control), 2.5% (low), 5% (middle), 10% (high), and 20% (extreme high) X. dendrorhous powder. The rats' behavior, body weight, and food intake were monitored during the 90-day experiment. At the end of the experiment, urine, blood, and organs were collected from the rats for biochemical testing. Additionally, the antioxidant activity in rat sera was evaluated. The results of the acute toxicity test demonstrated that the LD50 of X. dendrorhous was greater than 12 g/kg body weight, indicating that the substance was not toxic. Throughout the 90-day period of subchronic toxicity, the triglyceride levels of male rats fed with 10 and 20% X. dendrorhous increased to 1.54 ± 0.17 and 1.55 ± 0.25 mmol/L (P < 0.05), respectively. This may be attributed to the elevated fat content of the diet in the high-dose and extreme high-dose groups, which was 5.5 and 2.5% higher than that in the control, respectively. Additionally, the white pulp in the spleen exhibited an increase, and the number of white blood cells in the extreme high-dose group increased by 2.41 × 109/L (P < 0.05), which may contribute to enhanced immunity. Finally, the body weight, food intake, blood and urine indexes, and histopathological examination results of the organs of the rats did not demonstrate any regular toxic effects. With the adulteration of X. dendrorhous, the activity of GSH-Px in male rats increased by 16-36.32%. The activity of GSH-Px in female rats of the extreme high-dose group increased by 14.70% (P < 0.05). The free radical scavenging ability of ABTS in male rats in the two high-dose groups exhibited an increase of 6.5 and 11.41% (P < 0.05). In contrast, the MDA content of male rats in the extreme high-dose group demonstrated a reduction of 2.73 nmol/mL (P < 0.05). These findings indicate that X. dendrorhous has no toxic effects, can be taken in high doses, and has a beneficial antioxidant effect that may enhance the body's immunity.

Mechanism of melatonin and sodium orthovanadate regulating astaxanthin biosynthesis in Phaffia rhodozyma

Astaxanthin is a kind of carotenoids, which has strong antioxidant activity. It is widely used in food, chemical industry, medical treatment and other fields. Our previous research confirmed that carotenoids in Phaffia rhodozyma could be influenced by melatonin (MT) and sodium orthovanadate (SOV), but their metabolic regulation mechanism of astaxanthin biosynthesis was not clear. In this study, metabolic regulation mechanism of MT and SOV was explored by metabonomics and fermentation dynamics. The results showed that adding 1.54 mM SOV at 27.03 h and 7.49 mM MT at 36 h could improve the astaxanthin cell yield by 64.67 %, from 3.54 mg/g to 5.83 mg/g. SOV promoted carbon flux into astaxanthin synthesis pathway by inhibiting its activity by binding to glutamate dehydrogenase pocket and reducing the expression of arginine, glutamine and isoleucine in amino acid pathway. The regulation of MT increased the expression of fatty acid synthase, fatty acid desaturase and acetyl-CoA carboxylase in fatty acid pathway, thus increasing the accumulation of fatty acids. Fermentation dynamic kinetics showed SOV and MT effectively weakened the growth coupling limitation of carotenoid and astaxanthin synthesis, which increased the astaxanthin content by 22.52 % and 21.32 %, respectively. This study provided a theoretical basis for regulating the production of astaxanthin in Phaffia rhodozyma.

Creation of Single Cell Protein-Producing Mutants of Phaffia Rhodozyma

Recently, there has been an increasing demand for sustainable protein sources for aquaculture. In aquaculture, sustainable protein includes sources that can be produced with a minimal environmental footprint, such as single-cell proteins, proteins from algae, insects, and by-products from the agricultural industry. Single-cell proteins that are derived from microorganisms show a sustainable alternative to traditional protein sources due to their high protein content and rapid growth. This research focuses on creating mutants of the yeast Phaffia rhodozyma to increase single-cell protein production. This yeast has significant industrial potential and biological features. The yeast Phaffia rhodozyma is already known for its unique ability to synthesize astaxanthin, so this case will focus on its ability to produce protein. In the study, we used wild strain yeast and previously obtained white mutants on inorganic nitrogen media for further random mutagenesis methods to introduce specific mutations into the genome aimed at improving their ability to biosynthesize protein. Amino acid inhibitor was used to select potential protein-producing mutants. The protein content of the biomass obtained from the experiments was analyzed in detail using BCA (Protein Assay Reagent) analysis, which confirmed their potential as a source of nutrients for aquaculture. This method is based on the reaction between bicinchoninic acid and the peptide bonds of proteins, which results in the formation of a color whose intensity is proportional to the amount of protein in the sample. The results obtained allow further research into the development of cost-effective and environmentally friendly alternatives for feed in aquaculture.

Energy metabolism analysis of exogenous glutamate on promoting co-accumulation of astaxanthin yield and biomass in Phaffia rhodozyma D3

Effective metabolic regulators play an essential role in regulating astaxanthin biosynthesis in Phaffia rhodozyma. In this study, it was found that 5 mM glutamate increased the astaxanthin yield and biomass of P. rhodozyma D3 to 22.34 mg/L and 6.12 g/L, which were 1.22 and 1.33 times higher than the control group, respectively. Meanwhile, glucose uptake was increased and the level of reactive oxygen species (ROS) was reduced with 5 mM glutamate. To further explore the interrelationship between glutamate and astaxanthin synthesis, the energy metabolism of P. rhodozyma D3 with and without glutamate was analysed. Glutamate promoted the Embden-Meyerhof-Parnas pathway (EMP) metabolic flux, modulated the tricarboxylic acid (TCA) cycle and the pentose phosphate pathway (PPP), activated the ornithine cycle and purine metabolism, and provided more ATP and NADPH for astaxanthin accumulation. This study clarified the possible mechanism by which glutamate promoted astaxanthin accumulation in P. rhodozyma.

Effects of Three Sources of Astaxanthin on the Growth, Coloration, and Antioxidant Capacity of Rainbow Trout (Oncorhynchus mykiss) during Long-Term Feeding

Astaxanthin is an important pigment for the rainbow trout Oncorhynchus mykiss. This study was conducted to investigate the effects of different sources of dietary astaxanthin on the growth, coloration, and antioxidant capacity of the commercial-sized O. mykiss during long-term feeding. Haematococcus pluvialis (HP), yeast Phaffia rhodozyma (PR), and synthetic astaxanthin (SA) were added to the basic feed (no astaxanthin, NA) to prepare the isonitrogenous and isolipidic experimental diets; the actual astaxanthin content values in the diets were 31.25, 32.96, and 31.50 mg/kg, respectively. Eighteen hundred O. mykiss, averaging 670 ± 20 g, were randomly divided into four groups and then fed with the experimental diet for four months. Dietary supplementation of P. rhodozyma and synthetic astaxanthin had no significant effects on the growth and tissue indexes of O. mykiss. In contrast, dietary supplementation with astaxanthin from H. pluvialis significantly increased the weight gain rate after four months of feeding. The fillet lightness of O. mykiss in the PR and SA was statistically lower than that in the NA and HP; the redness and astaxanthin content of fillet in the HP, PR, and SA groups were statistically higher than those in the NA. The total antioxidant capacity of the liver and serum in the HP was statistically higher than that in other diet groups, and a higher liver total superoxide dismutase activity was detected in the HP compared with the PR. Dietary supplementation of astaxanthin significantly increased the glutathione peroxidase activity in the liver and serum, and the highest serum glutathione peroxidase activity was detected in the HP, while dietary astaxanthin significantly decreased the malondialdehyde content in the liver and serum. Dietary supplementation of PR significantly increased the fillet ash content, while the highest fillet total lipid content was detected in the HP. Dietary astaxanthin significantly improved fillet redness and antioxidant capacity, among which H. pluvialis astaxanthin has greater effects on improving weight gain, antioxidant capacity, and fillet total lipid content.

Biotechnological potential of red yeast isolated from birch forests in Poland

ObjectivesThis study aimed to isolate red yeast from sap, bark and slime exudates collected from Polish birch forests and then assessment of their biotechnological potential.Results24 strains of red yeast were isolated from the bark, sap and spring slime fluxes of birch (Betula pendula). Strains belonging to Rhodotorula mucilaginosa (6), Rhodosporidiobolus colostri (4), Cystrofilobasidium capitaum (3), Phaffia rhodozyma (3) and Cystobasidium psychroaquaticum (3) were dominant. The highest efficiency of carotenoid biosynthesis (5.04 mg L−1) was obtained by R. mucilaginosa CMIFS 004, while lipids were most efficiently produced by two strains of P. rhodozyma (5.40 and 5.33 g L−1). The highest amount of exopolysaccharides (3.75 g L−1) was produced by the R. glutinis CMIFS 103. Eleven strains showed lipolytic activity, nine amylolytic activity, and only two proteolytic activity. The presence of biosurfactants was not found. The growth of most species of pathogenic moulds was best inhibited by Rhodotorula yeasts.ConclusionSilver birch is a good natural source for the isolation of new strains of red yeast with wide biotechnological potential.

The enhancement of astaxanthin production in Phaffia rhodozyma through a synergistic melatonin treatment and zinc finger transcription factor gene overexpression.

Astaxanthin has multiple physiological functions and is applied widely. The yeast Phaffia rhodozyma is an ideal source of microbial astaxanthin. However, the stress conditions beneficial for astaxanthin synthesis often inhibit cell growth, leading to low productivity of astaxanthin in this yeast. In this study, 1 mg/L melatonin (MT) could increase the biomass, astaxanthin content, and yield in P. rhodozyma by 21.9, 93.9, and 139.1%, reaching 6.9 g/L, 0.3 mg/g DCW, and 2.2 mg/L, respectively. An RNA-seq-based transcriptomic analysis showed that MT could disturb the transcriptomic profile of P. rhodozyma cell. Furthermore, differentially expressed gene (DEG) analysis show that the genes induced or inhibited significantly by MT were mainly involved in astaxanthin synthesis, metabolite metabolism, substrate transportation, anti-stress, signal transduction, and transcription factor. A mechanism of MT regulating astaxanthin synthesis was proposed in this study. The mechanism is that MT entering the cell interacts with components of various signaling pathways or directly regulates their transcription levels. The altered signals are then transmitted to the transcription factors, which can regulate the expressions of a series of downstream genes as the DEGs. A zinc finger transcription factor gene (ZFTF), one of the most upregulated DEGs, induced by MT was selected to be overexpressed in P. rhodozyma. It was found that the biomass and astaxanthin synthesis of the transformant were further increased compared with those in MT-treatment condition. Combining MT-treatment and ZFTF overexpression in P. rhodozyma, the biomass, astaxanthin content, and yield were 8.6 g/L, 0.6 mg/g DCW, and 4.8 mg/L and increased by 52.1, 233.3, and 399.7% than those in the WT strain under MT-free condition. In this study, the synthesis and regulation theory of astaxanthin is deepened, and an efficient dual strategy for industrial production of microbial astaxanthin is proposed.

Magnetic field and a bio-based solvent as greener alternatives in Phaffia rhodozyma cultivation: insights into astaxanthin and antioxidant activity thermal degradation

This study aimed to evaluate magnetic fields (MF) and a bio-based solvent as greener alternatives for processing natural astaxanthin from Phaffia rhodozyma biomass. To improve carotenoid production, MF was evaluated using a central composite design (CCD), which demonstrated effectiveness by increasing astaxanthin production by 24.8% and productivity by 78.9% by comparison with the control in validated models. In the context of solid-liquid extraction, an environmental assessment of astaxanthin recovery identified ethanol (EtOH) as a promising and sustainable alternative, with an 89% recovery yield during processing. Furthermore, the study inspired an assessment of the stability of carotenogenic extracts at various temperatures throughout time, providing useful information about antioxidant activity and color parameters during storage. This study is one of the first to incorporate insights into the use of MF application and a bio-based solvent as greener alternatives for processing natural astaxanthin from P. rhodozyma biomass.

Is the carotenoid production from Phaffia rhodozyma yeast genuinely sustainable? a comprehensive analysis of biocompatibility, environmental assessment, and techno-economic constraints

Microorganisms, such as yeasts, filamentous fungi, bacteria, and microalgae, have gained significant attention due to their potential in producing commercially valuable natural carotenoids. In recent years, Phaffia rhodozyma yeasts have emerged as intriguing non-conventional sources of carotenoids, particularly astaxanthin and β-carotene. However, the shift from academic exploration to effective industrial implementation has been challenging to achieve. This study aims to bridge this gap by assessing various scenarios for carotenoid production and recovery. It explores the use of ionic liquids (ILs) and bio-based solvents (ethanol) to ensure safe extraction. The evaluation includes a comprehensive analysis involving Life Cycle Assessment (LCA), biocompatibility assessment, and Techno-Economic Analysis (TEA) of two integrated technologies that utilize choline-based ILs and ethanol (EtOH) for astaxanthin (+β-carotene) recovery from P. rhodozyma cells. This work evaluates the potential sustainability of integrating these alternative solvents within a yeast-based bioeconomy.

Two at once: simultaneous increased production of astaxanthin and mycosporines in a single batch culture using a Phaffia rhodozyma mutant strain.

Phaffia rhodozyma is a basidiomycetous yeast characterized by its production of the carotenoid pigment astaxanthin, which holds high commercial value for its significance in aquaculture, cosmetics and as nutraceutics, and the UV-B-absorbing compound mycosporine-glutaminol-glucoside (MGG), which is of great biotechnological relevance for its incorporation into natural sunscreens. However, the industrial exploitation has been limited to the production of astaxanthin in small quantities. On the other hand, the accumulation of MGG in P. rhodozyma was recently reported and could add value to the simultaneous production of both metabolites. In this work, we obtain a mutant strain that overproduces both compounds, furthermore we determined how the accumulation of each is affected by the carbon-to-nitrogen ratio and six biotic and abiotic factors. The mutant obtained produces 159% more astaxanthin (470.1μgg-1) and 220% more MGG (57.9mgg-1) than the parental strain (295.8μgg-1 and 26.2mgg-1 respectively). Furthermore, we establish that the carotenoids accumulate during the exponential growth phase while MGG accumulates during the stationary phase. The carbon-to-nitrogen ratio affects each metabolite differently, high ratios favoring carotenoid accumulation while low ratios favoring MGG accumulation. Finally, the accumulation of both metabolites is stimulated only by photosynthetically active radiation and low concentrations of hydrogen peroxide. The mutant strain obtained is the first hyper-productive mutant capable of accumulating high concentrations of MGG and astaxanthin described to date. The characterization of how both compounds accumulate during growth and the factors that stimulate their accumulation, are the first steps toward the future commercial exploitation of strains for the simultaneous production of two biotechnologically important metabolites.

The use of droplet-based microfluidic technologies for accelerated selection of Yarrowia lipolytica and Phaffia rhodozyma yeast mutants.

Microorganisms are widely used for the industrial production of various valuable products, such as pharmaceuticals, food and beverages, biofuels, enzymes, amino acids, vaccines, etc. Research is constantly carried out to improve their properties, mainly to increase their productivity and efficiency and reduce the cost of the processes. The selection of microorganisms with improved qualities takes a lot of time and resources (both human and material); therefore, this process itself needs optimization. In the last two decades, microfluidics technology appeared in bioengineering, which allows for manipulating small particles (from tens of microns to nanometre scale) in the flow of liquid in microchannels. The technology is based on small-volume objects (microdroplets from nano to femtolitres), which are manipulated using a microchip. The chip is made of an optically transparent inert to liquid medium material and contains a series of channels of small size (<1 mm) of certain geometry. Based on the physical and chemical properties of microparticles (like size, weight, optical density, dielectric constant, etc.), they are separated using microsensors. The idea of accelerated selection of microorganisms is the application of microfluidic technologies to separate mutants with improved qualities after mutagenesis. This article discusses the possible application and practical implementation of microfluidic separation of mutants, including yeasts like Yarrowia lipolytica and Phaffia rhodozyma after chemical mutagenesis will be discussed.

Advances in microbial astaxanthin production.

This work explores astaxanthin (AXT), a valuable xanthophyll ketocarotenoid pigment with significant health benefits and diverse applications across various industries. It discusses the prevalence of synthetic AXT, and the development of natural-based alternatives derived from microorganisms such as microalgae, bacteria, and yeast. The chapter examines the potential of microbial AXT production, highlighting the advantages and challenges associated with natural AXT. Key microorganisms like Haematococcus pluvialis, Paracoccus carotinifaciens, and Phaffia rhodozyma are emphasized for their role in commercially producing this valuable ketocarotenoid. The narrative covers the complexities and opportunities in microbial AXT production, from cell structure implications to downstream processing strategies. Additionally, the chapter addresses current applications, commercialization trends, and market dynamics of natural microbial AXT, emphasizing the importance of cost-effective production, regulatory compliance, and technological advancements to reduce the market cost of the final product. As demand for natural microbial-based AXT rises, this chapter envisions a future where research, innovation, and collaboration drive sustainable and competitive microbial AXT production, fostering growth in this dynamic market.

Comprehensive metabolomics and transcriptomics analyses investigating the regulatory effects of different sources of dietary astaxanthin on the antioxidant and immune functions of commercial-sized rainbow trout.

Astaxanthin is an important aquatic feed additive that enhances the antioxidant capacity, and immune function of rainbow trout (Oncorhynchus mykiss); however, very limited information is available on its underlying molecular mechanisms. Haematococcus pluvialis powder, Phaffia rhodozyma powder, and synthetic astaxanthin were added to the commercial feed (no astaxanthin, NA) to prepare three experimental feeds, referred to as the HPA, PRA, and SA groups, respectively, and their actual astaxanthin contents were 31.25, 32.96, and 31.50 mg.kg-1, respectively. A 16-week feeding trial was conducted on the O. mykiss with an initial body weight of 669.88 ± 36.22g. Serum and head kidney samples from commercial-sized O. mykiss were collected for metabolomics and transcriptomics analysis, respectively. Metabolomics analysis of the serum revealed a total of 85 differential metabolites between the astaxanthin-supplemented group and the control group. These metabolites were involved in more than 30 metabolic pathways, such as glycerophospholipid metabolism, fatty acid biosynthesis, linoleic acid metabolism, and arginine and proline metabolism. It is speculated that different sources of dietary astaxanthin may regulate antioxidant capacity and immunity mainly by affecting lipid metabolism and amino acid metabolism. Transcriptomic analysis of the head kidney revealed that the differentially expressed genes between the astaxanthin-supplemented group and the control group, such as integrin beta-1 (ITGB1), alpha-2-macroglobulin (A2M), diamine acetyltransferase 1 (SAT1), CCAAT/enhancer-binding protein beta (CEBPB) and DNA damage-inducible protein 45 alpha (GADD45A), which are involved in cell adhesion molecules, the FoxO signaling pathway, phagosomes, and arginine and proline metabolism and play regulatory roles in different stages of the antioxidant and immune response of O. mykiss.

Synthetic astaxanthin has better effects than natural astaxanthins on growth performance, body color and n-3 PUFA deposition in black tiger prawn (Penaeus monodon)

Astaxanthin is an efficient nutrition strategy to relieve oxidative stress and enhance crustacean body color. Because of technological and economic benefits, synthetic astaxanthin is favored by the aquatic feed industry. However, whether synthetic astaxanthin can achieve the effects of natural astaxanthin needs further investigation. Here, we evaluated the effects of synthetic astaxanthin and natural astaxanthin (dietary supplementation with Haematococcus pluvialis and Phaffia rhodozyma) on the growth performance, body color, fatty acid composition and antioxidant capacity of black tiger prawn (Penaeus monodon). Compared with the control group (no astaxanthin supplementation), only synthetic astaxanthin significantly increased the weight gain rate (WG) and specific growth rate (SGR), together with the elevation of feed efficiency ratio (FER). All three types of astaxanthin enhanced body color by increasing astaxanthin deposition. The highest value of (a*) in the carapace and muscle occurred in the synthetic astaxanthin group. Synthetic astaxanthin significantly increased the n-3 polyunsaturated fatty acid (n-3 PUFA) contents in muscle. As expected, different sources of astaxanthin inhibited glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) activities in the hemolymph and decreased the contents of reduced glutathione (GSH) and malondialdehyde (MDA) in the hepatopancreas. Correspondingly, the structure of hepatopancreas was enhanced by astaxanthin. In addition, three types of astaxanthin almost indistinguishably enhanced the ability of shrimps to resist stress caused by transportation simulation. In conclusion, these results indicate that dietary synthetic astaxanthin has a better effect than natural astaxanthin on growth promotion, body color enhancement and n-3 PUFA deposition in muscle of black tiger prawn. Hence, synthetic astaxanthin is a suitable feed additive to promote the healthy and sustainable development of the shrimp industry.

Sustainable approach to recover β-carotene and astaxanthin from Phaffia rhodozyma grown in a stirred-tank bioreactor under the influence of magnetic fields

This study aimed to produce carotenoids by Phaffia rhodozyma in a stirred-tank bioreactor under the influence of magnetic fields (MF) and to evaluate a sustainable approach to recover them from the yeast biomass. MF application proved to be effective in increasing 8.6 and 22.9 % of β-carotene and astaxanthin production, respectively. Regarding solid–liquid extraction (SLE), the ability of aqueous and ethanolic solutions of protic ionic liquids (PILs) was determined. β-carotene and astaxanthin recovery yields increased with the anion alkyl chain length hydrophobicity. [Pro][Oct]:EtOH (50 % v v-1) was selected as the effective solvent. Moreover, it led to improvement in carotenoid stability at different storage temperatures over time in comparison with the control. This study is one of the first to describe an effective and sustainable approach to move carotenoid production from shake flasks to a bioreactor under the influence of MF and recover carotenoids from P. rhodozyma biomass.

Salicylic acid treatment and overexpression of a novel polyamine transporter gene for astaxanthin production in Phaffia rhodozyma.

Phaffia rhodozyma represents an excellent microbial resource for astaxanthin production. However, the yeast's low astaxanthin productivity poses challenges in scaling up industrial production. Although P. rhodozyma originates from plant material, and phytohormones have demonstrated their effectiveness in stimulating microbial production, there has been limited research on the effects and mechanisms of phytohormones on astaxanthin biosynthesis in P. rhodozyma. In this study, the addition of exogenous salicylic acid (SA) at a concentration as low as 0.5mg/L significantly enhanced biomass, astaxanthin content, and yield by 20.8%, 95.8% and 135.3% in P. rhodozyma, respectively. Moreover, transcriptomic analysis showed that SA had discernible impact on the gene expression profile of P. rhodozyma cells. Differentially expressed genes (DEGs) in P. rhodozyma cells between the SA-treated and SA-free groups were identified. These genes played crucial roles in various aspects of astaxanthin and its competitive metabolites synthesis, material supply, biomolecule metabolite and transportation, anti-stress response, and global signal transductions. This study proposes a regulatory mechanism for astaxanthin synthesis induced by SA, encompassing the perception and transduction of SA signal, transcription factor-mediated gene expression regulation, and cellular stress responses to SA. Notably, the polyamine transporter gene (PT), identified as an upregulated DEG, was overexpressed in P. rhodozyma to obtain the transformant Prh-PT-006. The biomass, astaxanthin content and yield in this engineered strain could reach 6.6g/L, 0.35mg/g DCW and 2.3mg/L, 24.5%, 143.1% and 199.0% higher than the wild strain at the SA-free condition, respectively. These findings provide valuable insights into potential targets for genetic engineering aimed at achieving high astaxanthin yields, and such advancements hold promise for expediting the industrialization of microbial astaxanthin production.