Porphyridium Cruentum Research Articles

Concentration and purification of Porphyridium cruentum exopolysaccharides by membrane filtration at various cross-flow velocities

Abstract Exopolysaccharides (EPS) from cell-free Porphyridium cruentum media were concentrated then purified (diafiltration) on a 0.14 μm ceramic membrane. The influence of cross-flow velocities on filtration performances was investigated. Mean permeate fluxes equal to 49.8, 68.9 and 81.9 L h−1. m−2 were obtained during the concentration at 4 bars for respectively cross-flow velocities inside the membrane lumen equal to 2.5, 3.3 and 4.2 m s−1; 49.7 L h−1. m−2 for the diafiltration at 3.3 m s−1. Permeate fluxes were correctly predicted from polysaccharide concentrations (10% deviation). Volume reduction factors higher than 7.8 were reached. Rejection rates of polysaccharides and proteins varied according to the cross-flow velocities. Thus, the EPS recovery rate or time of filtration could be modulated following the cross-flow velocity. Polysaccharides were concentrated 6.3 to 10.4 times in such a way that the final sugars concentration reached 1.74–2.26 g L−1. Rheological behavior of filtered solutions changed following the concentration progress. More than 80% (w/w) of polysaccharides were recovered while 49% and 99% of proteins and salts were removed respectively. The filtrations allowed reaching a final monosaccharide content of dry matter equal to 48.9% against 0.6% (w/w) initially.

Molecular and rheological characterization of different cell wall fractions of Porphyridium cruentum

Cell wall related polysaccharides of the red microalga Porphyridium sp. were shown to be a promising source of new sustainable thickening agents. Isolated extracellular polysaccharides (EPS) consisted of high molecular weight polymers, showing a higher intrinsic viscosity compared to several commercially used hydrocolloids. Aqueous solutions of EPS (2% w/w) were characterized by substantial viscosities and weak gel behavior. Even though the extracted water soluble cell wall polysaccharides exhibited the same monosaccharide profile as EPS (composed of galactose, glucose, xylose and glucuronic acid), a lower molecular weight and intrinsic viscosity was observed for this fraction, resulting in poor rheological properties. Therefore, it was hypothesized that the physicochemical properties were related with a different molecular structural organization of these monosaccharides and sulfate groups. The main challenge for commercialization of extracellular polysaccharides of Porphyridium sp. remains the purification of these fractions to obtain polysaccharide extracts with low protein and salt contents.

Effects of nitrogen and phosphorous stress on the formation of high value LC-PUFAs in Porphyridium cruentum.

This study systematically examined the effect of nitrogen and phosphorous stress on the formation of linoleic acid (LA), arachidonic acid (ARA), and eicosapentaenoic acid (EPA) in Porphyridium cruentum gy-h56. P. cruentum was cultivated in six different media conferring different conditions of nitrogen (N) sufficiency/deprivation and phosphorous (P) sufficiency/limitation/deprivation. Over a 16-day cultivation process, the dry-weight content, proportion of total fatty acids (TFAs), and the concentration in the medium of linoleic acid (LA) were greatly improved by a maximum of 2.5-, 1.6-, and 1.1-fold, respectively, under conditions of N or P deprivation compared with N and P sufficiency. In contrast, levels of EPA or ARA were not enhanced under N or P stress conditions. Additionally, the results showed that N deprivation weakened the impact of P deficiency on the content and proportions of LA and EPA, while P deprivation enhanced the impact of N starvation on the content and proportions of LA and EPA. The conditions of N sufficiency and P deprivation (N+P-) were the optimal conditions for the production of LA, while the optimal conditions for EPA, ARA, and TFAs production were N sufficiency and P limitation (N+P-lim). This study suggests the potential application of combining N removal from saline wastewater with the production of LA, ARA, EPA, and biodiesel.

Comparison of microalgal biomasses as functional food ingredients: Focus on the composition of cell wall related polysaccharides

Microalgae are rich in several nutritional and health-beneficial components, showing great potential as functional food ingredients. To this extent, knowledge of the biomass composition is essential in the selection of suitable microalgae species for specific food applications. Surprisingly, although cell wall polysaccharides are generally reported to play a role in functionality, limited attention has been given to the cell wall related polysaccharides of microalgae so far. Therefore, this study aimed to characterize dry biomasses of ten microalgae species with potential as functional food ingredients, with a particular focus on the composition of cell wall related polysaccharides. The investigated species were Arthrospira platensis, Chlorella vulgaris, Diacronema lutheri, Tisochrysis lutea, Nannochloropsis sp., Odontella aurita, Phaeodactylum tricornutum, Porphyridium cruentum, Schizochytrium sp. and Tetraselmis chuii. Lipids, proteins and ash made up a large fraction of the biomasses, except for the freshwater algae C. vulgaris and A. platensis which were mainly composed of proteins and polysaccharides. Generally, low amounts of storage polysaccharides (2–8%) were observed in the investigated microalgae species, while extracellular polymeric substances were only present in P. cruentum, O. aurita, C. vulgaris and A. platensis. Cell wall polysaccharides contributed approximately 10% of the biomass and were composed of heteropolysaccharides, showing at least five different monosaccharides. Moreover, the presence of uronic acids and sulfate groups provides anionic characteristics to the cell wall related polysaccharides of several microalgae. As a result, these polysaccharides show potential to display interesting functionalities as bioactive or technological substances.

Electrochemical characterization of a Porphyridium cruentum-modified carbon paste electrode by cyclic voltammetry

ABSTRACTA carbon paste electrode was modified with red algal specie of Porphyridium cruentum and then characterization of its electrocatalytic activity was demonstrated with cyclic voltammetric studies of potassium ferricyanide (K3[Fe(CN)6]) system. Stable and fast response of modified electrode to redox couple of [Fe(CN)6]3−/[Fe(CN)6]4− was highlighted by performing experiments in comparison to bare carbon paste electrode. Fourier transform infrared spectra revealed the functional moieties of bare and modified electrode. Electrochemical surface area and surface coverage capacity were calculated for both electrodes. The effect of scan rate helped evaluate the nature of electrode process, electron transfer mechanism, and kinetic parameters (rate constant, charge transfer coefficient).

Connecting color with assembly in the fluorescent B-phycoerythrin protein complex.

Phycoerythrin is the major light-harvesting pigment protein in red algae and is nowadays widely used as a fluorescent probe in biotechnological applications such as flow cytometry and immunofluorescence microscopy. In addition, it has had substantial economic impact due to its potential as a natural food colorant. However, knowledge on the precise molecular composition of phycoerythrin is limited. Here, we use a combination of high-resolution native mass spectrometry (MS) and fluorescence spectroscopy to characterize the assembly properties of the B-phycoerythrin protein complex from Porphyridium cruentum. Our data highlight the stabilizing role of the γ subunit in the intact B-phycoerythrin protein complex. In addition, by native MS we monitor B-phycoerythrin (dis)assembly intermediates, providing insight into which species contribute to B-phycoerythrins color and the factors that give B-phycoerythrin its highly fluorescent properties. Together, the data provide significant insights into the structural properties of B-phycoerythrin which is beneficial for its use within the biotechnology industry.

Effects of nitrogen source and irradiance on Porphyridium cruentum

We determined the effects of two nitrogen sources (ammonium and nitrate) and two irradiance levels (50 and 200 μmol photons m−2 s−1) on the growth rate, cell size, proximate composition, pigment content, and photosynthesis of the unicellular red alga, Porphyridium cruentum. Irradiance significantly affects growth rate, as well as carbohydrate, protein, and phycoerythrin content. Nitrogen form significantly affects cell size, total dry weight, organic dry weight, ash content, carotene content, phycocyanin content, allophycocyanin content, maximum relative electron transport rate (rETRm), and photosynthetic efficiency (α). However, the irradiance and nitrogen source had significantly interaction with the content of lipids and chlorophyll a content, relative electron transport rate (rETR), and irradiance of saturation (Ik). These findings demonstrate that irradiance and nitrogen source influence the metabolism of P. cruentum and that the combination of these two variables induces the production of chemical products for biotechnological, aquaculture, and nutraceutical industry.

Polyunsaturated ω-3 and ω-6 fatty acids, total carotenoids and antioxidant activity of three marine microalgae extracts obtained by supercritical CO2 and subcritical n-butane

Microalgae are one of the most promising sources for new functional food products, due to their ability to synthesize polyunsaturated fatty acids, pigments and natural antioxidants (e.g. carotenoids and phenolic compounds). The aim of this study was to compare the fatty acid composition, total carotenoids and antioxidant activity of Phaeodactylum tricornutum, Nannochloropsis oculata, and Porphyridium cruentum extracts obtained from supercritical CO2 (SC-CO2) and subcritical n-butane extraction methods SC-CO2 method was selective in extract saturated fatty acids (SFAs) for all microalgae species studied. On the other hand, subcritical n-butane was shown to be an excellent and powerful method to extract polyunsaturated fatty acids (PUFAs ω3+ω6). Regarding to total carotenoids and antioxidant activity using DPPH scavenging assay a significant correlation coefficient (R2=0.80) was found among the extracts independent of the extraction method tested. This indicates that carotenoid compounds might be the major contributor to the antioxidant capacities of these microalgae.

Nitrogen Starvation Impacts the Photosynthetic Performance of Porphyridium cruentum as Revealed by Chlorophyll a Fluorescence

Nitrogen is one of the most important nutrients needed for plants and algae to survive, and the photosynthetic ability of algae is related to nitrogen abundance. Red algae are unique photosynthetic eukaryotic organisms in the evolution of algae, as they contain phycobilisomes (PBSs) on their thylakoid membranes. In this report, the in vivo chlorophyll (Chl) a fluorescence kinetics of nitrogen-starved Porphyridium cruentum were analyzed to determine the effects of nitrogen deficiency on photosynthetic performance using a multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer. Due to nitrogen starvation, the photochemical efficiency of PSII and the activity of PSII reaction centers (RCs) decreased, and photoinhibition of PSII occurred. The water-splitting system on the donor side of PSII was seriously impacted by nitrogen deficiency, leading to the inactivation of the oxygen-evolving complex (OEC) and decreased light energy conversion efficiency. In nitrogen-starved cells, a higher proportion of energy was used for photochemical reactions, and thermal dissipation was reduced, as shown by qP and qN. The ability of nitrogen-starved cells to tolerate and resist high photon flux densities was weakened. Our results showed that the photosynthetic performance of P. cruentum was severely impacted by nitrogen deficiency.

Microalgal biomass as a (multi)functional ingredient in food products: Rheological properties of microalgal suspensions as affected by mechanical and thermal processing

Microalgae show great potential for use as novel ingredients in food products, as they are rich in several nutritional and health-beneficial components. However, addition of total microalgal biomass might alter the structural properties of the food system. Therefore, information is required about their rheological characteristics towards selection of microalgae species for specific food products. This study comprises the rheological characterization of seven commercially available microalgae species in aqueous suspensions, before and after mechanical and thermal processing. Substantial differences in rheological properties were observed between the investigated microalgal suspensions. Among the untreated suspensions, Porphyridium cruentum, Chlorella vulgaris and Odontella aurita showed the largest structural properties and could be described as weak gels. All suspensions showed shear-thinning flow behavior at the examined concentration of 8% w/w, except for Nannochloropsis species. Shear-thinning behavior was also observed for the separated serum phase of P. cruentum, which might be attributed to the presence of sulfated exopolysaccharides. During processing, rheological properties were significantly altered. High pressure homogenization was used as a mechanical treatment, followed by a pasteurization or sterilization process. Whereas suspensions of Arthrospira platensis and C. vulgaris showed an increased storage modulus and viscosity after processing, the opposite was observed for P. cruentum and O. aurita. No clear effect of processing was observed for suspensions of Nannochloropsis sp., Schizochytrium sp. and Phaeodactylum tricornutum. Investigation of the microstructure revealed differences in degree of cell disruption by high pressure homogenization, with Nannochloropsis sp. being the most resistant. Subsequent thermal processing resulted in aggregation of released cell material and/or intact cells. In conclusion, the obtained results provide the scientific knowledge base for the selection of microalgae species towards food applications. Whereas some microalgae species hardly affect the structural properties of the food product, other microalgae species show large potential for use as a structuring agent in food applications.

Potency of Endo-Exopolysaccharide from Porphyridium cruentum (S.F.Gray) Nägeli as Antioxidant (DPPH) and Biological Toxicity (BSLT)

<p>Sources of antioxidants are abundant in nature, one of which is derived from microalgae. Microalgae species that have potentially to be developed as a producer of antioxidant compounds is <em>Porphyridium cruentum</em><em> </em>(S.F.Gray) Nägeli. <em>P. cruentum</em> is a red microalga (Rhodophyceae) and has been known as polysaccharides producer (exopolysaccharide and endopolysaccharide) and as an antioxidant. This study aims to determine antioxidant activity of the extracts and biological toxicity of endo- and exopolysaccharide <em>P. cruentum</em>. The antioxidant activity use reduction method of free radicals (DPPH), whereas toxicity uses Brine Shrimp Lethality Test. (BSLT). The result shows that there is an antioxidant activity with IC<sub>50</sub> value of 50.586 5 mg · kg<sup>–1</sup> (exopolysaccharide) and 145.998 8 mg · kg<sup>–1</sup> (endopolysaccharide). In addition, the result indicates the toxic nature of the <em>Artemia salina</em> Leach. with LC<sub>50</sub> values of 513.175 1 mg · kg<sup>–1</sup> (exopolysaccharide) and 521.823 3 mg · kg<sup>–1</sup> (endopolysaccharide). Therefore, endo- and exopolysaccharide produced by <em>P. cruentum</em> suitable to be used as an alternative source of natural antioxidants and potential for further developed as antitumor drugs.</p><div><p class="Els-keywords"><strong>Keywords:</strong><em> </em>antioxidant, biological toxixity, endo-exopolysaccharide, <em>Porphyridium cruentum</em> (S.F.Gray) Nägeli.</p></div>

Enhanced production of fatty acids in three strains of microalgae using a combination of nitrogen starvation and chemical inhibitors of carbohydrate synthesis

Microalgae are attracting much attention as superior biodiesel producers. In particular, under stressful conditions, they accumulate organic compounds consisting entirely of carbon and hydrogen. The aim of this work was to increase intracellular fatty acid content in Dunaliella tertiolecta (Chlorophyceae), Nannochloropsis oculata (Eustigmatophyceae), and Porphyridium cruentum (Rhodophyceae) using a combination of nitrogen starvation and chemical inhibitors of carbohydrate biosynthesis. These microalgae were subjected to nitrogen starvation and their physiological changes were then observed over time. In D. tertiolecta, no significant change in total fatty acid content was detected on day 3.5 relative to the initial total fatty acid content (day 0), while total carbohydrate content dramatically increased as the nitrogen starvation period was extended. In N. oculata, total fatty acid content rapidly increased, reaching up to nearly 40% of the DCW at day 3.5. However, total carbohydrate content exhibited a gradual reduction throughout the experiment. In P. cruentum, total carbohydrate content increased up to 43% of DCW on day 3.5 and total fatty acid content increased slightly under nitrogen depletion. These data suggest that different eukaryotic microalgae use different storage products under stressful conditions. Among the three strains, D. tertiolecta showed decreased total carbohydrate content and enhanced total fatty acid content following inhibition of carbohydrate synthesis by dichlorophenyl dimethylurea and cyclohexane diamine tetra acetic acid. The results demonstrate the possibility of furthering our understanding of the fatty acid and carbohydrate biosynthesis metabolic network that responds to environmental changes in microalgae.

Feasibility of attached cultivation for polysaccharides production by Porphyridium cruentum.

Porphyridium cruentum is one of the most valued microalgae species able to produce both pigments and exopolysaccharides. Conventional liquid suspended cultivation in ponds and photobioreactors show its disadvantages in lower cultivation efficiency and higher stirring power consumption due to the high viscosity of the medium by the accumulation of polysaccharides. In this work, a new method of culture (called attached cultivation) based on the growth of microalgae using a supporting surface was successfully applied to the cultivation of P. cruentum and the effect of the main influential parameters on its growth rate and polysaccharides production has been investigated. Higher values of these factors resulted in a faster growth rate and, in particular, optimum values of 6.98gm-2 for initial biomass density, 100µmolm-2s-1 for light intensity, continuous illumination, 2.0% for CO2 concentration, and 0.1vv-1min-1 for aeration rate produced the best polysaccharide production of 42% dry weight. The nutrition profile of P. cruentum obtained in attached and suspended cultivations was similar. Overall these results demonstrate that the attached cultivation is a promising technique which greatly improves the growth rate of P. cruentum as well as its production of polysaccharides and, therefore, it is worth enhancing to be exploited for commercial application.

Economic analysis of pilot-scale production of B-phycoerythrin.

β-Phycoerythrin is a color protein with several applications, from food coloring to molecular labeling. Depending on the application, different purity is required, affecting production cost and price. Different production and purification strategies for B-phycoerythrin have been developed, the most studied are based on the production using Porphyridium cruentum and purified using chromatographic techniques or aqueous two-phase systems. The use of the latter can result in a less expensive and intensive recovery of the protein, but there is lack of a proper economic analysis to study the effect of using aqueous two-phase systems in a scaled-up process. This study analyzed the production of B-Phycoerythrin using real data obtained during the scale-up of a bioprocess using specialized software (BioSolve, Biopharm Services, UK). First, a sensitivity analysis was performed to identify critical parameters for the production cost, then a Monte Carlo analysis to emulate real processes by adding uncertainty to the identified parameters. Next, the bioprocess was analyzed to determine its financial attractiveness and possible optimization strategies were tested and discussed. Results show that aqueous two-phase systems retain their advantages of low cost and intensive recovery (54.56%); the costs of production per gram calculated (before titer optimization: US$15,709 and after optimization: US$2,374) allowed to obtain profit (in the range of US$millions in a 10-year period) for a potential company taking this production method by comparing the production cost against commercial prices. The bioprocess analyzed is a promising and profitable method for the generation of a highly purified B-phycoerythrin. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1472-1479, 2016.

Harvesting and Separation Technique of Porphyridium cruentum Polysaccharide Using Ultrafiltration Membrane

Red microalga Porphyridium cruentum secreting polysaccharides into its medium culture. Harvesting<br />and separation of polysaccharide of P. cruentum usually use centrifugation and in large scale needs high<br />cost. The use of ultrafiltration membrane can be one of the alternatives for harvesting and separation of<br />P. cruentum polysaccharide. This study aimed to determine the characteristic of membrane and permeat<br />from harvesting and separation of P. cruentum polysaccharide using ultrafiltration. Research consisted of<br />four stages : membrane characterization, cultivation of P. cruentum, harvesting using 0.05 μm ultrafiltration<br />membrane, and polysaccharide separation using 0.01 μm ultrafiltration membrane. Characterization of<br />membrane permeability and internal resistance on ultrafiltration 0.05 μm dan 0.01 μm were 137.32 L/m2hbar<br />and 62.38 L/m2hbar and 0.01 barm2h/L and 0.02 barm2h/L, respectively. Harvesting using ultrafiltration 0.05<br />μm produced flux 131.37-94.75 L/m2h, biomass rejection 96% and permeate with OD (Optical Density) (0.01<br />± 0.00), viscosity (2.4 ± 0.17 cp), pH (8 ± 0.00), and salinity (42.37 ± 0.11 ‰). Separation of polysaccharide<br />using ultrafiltration 0.05 μm produced flux 58.11-51.53 L/m2h and permeate with viscosity (2.2 ± 0.30 cp),<br />pH (7.8 ± 0.01), and salinity (38.73 ± 0.05 ‰). Ultrafiltration process decreased OD, viscosity, and salinity<br />of permeate.

Harvesting and Separation Technique of Porphyridium cruentum Polysaccharide Using Ultrafiltration Membrane

Red microalga Porphyridium cruentum secreting polysaccharides into its medium culture. Harvesting<br />and separation of polysaccharide of P. cruentum usually use centrifugation and in large scale needs high<br />cost. The use of ultrafiltration membrane can be one of the alternatives for harvesting and separation of<br />P. cruentum polysaccharide. This study aimed to determine the characteristic of membrane and permeat<br />from harvesting and separation of P. cruentum polysaccharide using ultrafiltration. Research consisted of<br />four stages : membrane characterization, cultivation of P. cruentum, harvesting using 0.05 μm ultrafiltration<br />membrane, and polysaccharide separation using 0.01 μm ultrafiltration membrane. Characterization of<br />membrane permeability and internal resistance on ultrafiltration 0.05 μm dan 0.01 μm were 137.32 L/m2hbar<br />and 62.38 L/m2hbar and 0.01 barm2h/L and 0.02 barm2h/L, respectively. Harvesting using ultrafiltration 0.05<br />μm produced flux 131.37-94.75 L/m2h, biomass rejection 96% and permeate with OD (Optical Density) (0.01<br />± 0.00), viscosity (2.4 ± 0.17 cp), pH (8 ± 0.00), and salinity (42.37 ± 0.11 ‰). Separation of polysaccharide<br />using ultrafiltration 0.05 μm produced flux 58.11-51.53 L/m2h and permeate with viscosity (2.2 ± 0.30 cp),<br />pH (7.8 ± 0.01), and salinity (38.73 ± 0.05 ‰). Ultrafiltration process decreased OD, viscosity, and salinity<br />of permeate.<br /><br />

Supramolecular architecture of photosynthetic membrane in red algae in response to nitrogen starvation

The availability of nitrogen is one of the most important determinants that can limit the growth of photosynthetic organisms including plants and algae; however, direct observations on the supramolecular architecture of photosynthetic membranes in response to nitrogen stress are still lacking. Red algae are an important evolutionary group of algae which contain phycobilisomes (PBSs) on their thylakoid membranes, as do cyanobacteria. PBSs function not only as light-harvesting antennae but also as nitrogen storage. In this report, alterations of the supramolecular architecture of thylakoid membranes from red alga Porphyridium cruentum during nitrogen starvation were characterized. The morphology of the intact thylakoid membrane was observed to be round vesicles. Thylakoid membranes were reduced in content and PBSs were degraded during nitrogen starvation. The size and density of PBSs were both found to be reduced. PBS size decreased by less than one-half after 20days of nitrogen starvation, but their hemispherical morphology was retained. The density of PBSs on thylakoid membranes was more seriously affected as time proceeded. Upon re-addition of nitrogen led to increasing of PBSs on thylakoid membranes. This work reports the first direct observation on alterations in the supramolecular architecture of thylakoid membranes from a photosynthetic organism in response to nitrogen stress.

Recovery of nutrients from swine wastewater using ultrafiltration: Applications for microalgae cultivation in photobioreactors

The large-scale production of microalgae poses a number of challenges, including a costly fertilizer demand. While wastewater provides a concentrated source of nutrients, the presence of biological contaminants and the expense of heat treatment are challenging for large-scale production. The goal of this study was to use ultrafiltration to purify wastewater for use in the cultivation of microalgae. Swine waste was filtered, and the resulting permeate was utilized in a Porphyridium cruentum culture. Fluxes remained relatively constant during operation, and the complete rejection of bacteria was observed. The permeate contained high concentrations of total nitrogen (695.6mgL−1) and total phosphorus (69.1mgL−1). Higher biomass productivity and lipid contents were observed in the microalgae cultivated in the waste medium compared to that of a control medium. This suggests that, by using ultrafiltration as an alternative to heat treatment, agricultural wastewaters could be utilized as a nutrient source for microalgae.

Chemical Characterization of Six Microalgae with Potential Utility for Food Application

AbstractMicroalgae contain high levels of proteins, carbohydrates, and lipids, and have found a useful application in enhancing the nutritional value of foods. These organisms can also synthesize long‐chain fatty acids in the form of triacylglycerols, such as α‐linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linolenic acid (LA), γ‐linolenic acid (GLA) and arachidonic acid (AA). The aim of this study was to determine the chemical composition and measure protein, carbohydrates, fibers, lipids as well as the fatty acids composition of six microalgae species with potential application in the food industry. Two freshwater species, Chlorella vulgaris and Spirulina platensis, and four marine species, Nannochloropsis oculata, Nannochloropsis gaditana, Porphyridium cruentum, and Phaeodactylum tricornutum, were used in the experiments. Intracellular protein was the most prominent algal component (42.8–35.4 %), followed by carbohydrate + fiber (32.3–28.6 %), and lipids (15.6–5.3 %). N. gaditana is rich in saturated fatty acids, mainly palmitic acid (5.1 g/100 g), while the cells of S. platensis and C. vulgaris algae are abundant in GLA (1.9 g/100 g) and ALA (2.8 g/100 g) acids, respectively. P. cruentum differs from other algae, because it contains a large amount of AA (3.7 g/100 g). The marine microorganisms N. oculata and P. tricornutum are also a source of essential long‐chain polyunsaturated fatty acids (LC‐PUFA‐ɷ3), mainly composed of EPA and DHA. Our results suggest that the freshwater species C. vulgaris and S. platensis are attractive nutritional supplements because of their low fiber and high protein/carbohydrate contents, while the marine species P. tricornutum and N. oculata can enrich foods with LC‐PUFA‐ω3, because of their favorable ω3/ω6 ratio.

A novel vortex flow reactor for the purification of B-phycoerythrin from Porphyridium cruentum

The purification of B-phycoerythrin from a concentrated extract of disrupted Porphyridium cruentum cells was carried out using a new vortex flow reactor design for protein purification. The reactor behaved as an expanded bed in the laminar vortices flow regime where the Streamline DEAE resin was expanded by the axial flow and stabilized by the vortex flow. After the broth culture was centrifuged and resuspended in the adsorption buffer, the concentrated extract of disrupted cells was directly loaded into the vortex flow reactor. The purification of B-phycoerythrin was carried out in two steps: adsorption in the expanded bed and elution from the settled bed. 142.0mg of B-phycoerythrin was eluted representing a total recovery yield of 86.6%. Prior to B-phycoerythrin purification, the protein adsorption of the vortex flow reactor was characterized through hydrodynamic studies and a dynamic capacity measurement using a standard protein.