Microalga Porphyridium Purpureum Research Articles

Scale-up cultivation enhanced arachidonic acid accumulation by red microalgae Porphyridium purpureum.

The present study attempts to cultivate Porphyridium purpureum under different scale-up conditions for further development and commercialization of microalgae-derived PUFAs such as ARA and EPA. Different temperatures (25, 30, and 35°C) and light intensities (70, 165, and 280μmol/m2s) were applied to the 50 L pilot-scale cultivation of P. purpureum in ASW. The cultivation under the light intensity of 280μmol/m2s at 35°C obtained biomass concentration up to 9.52g/L, total fatty acid content to 56.82mg/g, and ARA content to 22.29mg/g. While the maximum EPA content of 7.00mg/g was achieved under the light intensity of 280μmol/m2s at 25°C and the highest ratio of UFAs to TFAs of 74.66% was also obtained in this trial. Both biomass concentration and TFAs content were improved by increasing light intensity and temperature. Moreover, the ratio of ARA to EPA was enhanced by increasing cultivation temperature under the light intensity of 280μmol/m2s. In contrast with flask culture, the conversionof linoleic acid (C18:2) to ARA was enhanced in scale-up culture, leading to more ARA content. Phosphate limitation enhanced the synthesis of lipid and LPUFAs. Moreover, the biomass concentration and biosynthesis of palmitic acid were preferred by sufficient C (NaHCO3).

Erratum to: One-stage immobilization of the microalga Porphyridium purpureum using a biocompatible silica precursor and study of the fluorescence of its pigments.

The biocompatible silica precursor tetrakis(2-hydroxyethyl)orthosilicate with ethylene glycol residues was used instead of the common alcohol-containing tetraethoxysilane for the first time to prepare a biorecognition element by entrapping the marine microalga Porphyridium purpureum into a silica matrix by a one-stage sol–gel procedure at conditions (pH, ionic strength, and temperature) appropriate for living cells. We show that the microalga immobilized in this way fully maintains its viability and functionality. We furthermore show that the silica matrix had a stabilizing effect, providing microalgal survival and functionality at increased temperature. The high optical transparency of the silica matrix allowed us to study the optical properties of Porphyridium purpureum thoroughly. When irradiated by a laser, intense fluorescence of chlorophyll-a and phycoerythrin of the photosynthetic system was observed. The characteristics of this fluorescence differed notably from that observed with P. purpureum in suspension before immobilization; possible reasons for this and an underlying mechanism are discussed.

One-stage immobilization of the microalga Porphyridium purpureum using a biocompatible silica precursor and study of the fluorescence of its pigments.

The biocompatible silica precursor tetrakis(2-hydroxyethyl)orthosilicate with ethylene glycol residues was used instead of the common alcohol-containing tetraethoxysilane for the first time to prepare a biorecognition element by entrapping the marine microalga Porphyridium purpureum into a silica matrix by a one-stage sol-gel procedure at conditions (pH, ionic strength, and temperature) appropriate for living cells. We show that the microalga immobilized in this way fully maintains its viability and functionality. We furthermore show that the silica matrix had a stabilizing effect, providing microalgal survival and functionality at increased temperature. The high optical transparency of the silica matrix allowed us to study the optical properties of Porphyridium purpureum thoroughly. When irradiated by a laser, intense fluorescence of chlorophyll-a and phycoerythrin of the photosynthetic system was observed. The characteristics of this fluorescence differed notably from that observed with P.purpureum in suspension before immobilization; possible reasons for this and an underlying mechanism are discussed.

Enhancing total fatty acids and arachidonic acid production by the red microalgae Porphyridium purpureum

This study investigated the effect of aeration rate and light intensity on biomass production and total fatty acids (TFA) accumulation by Porphyridium purpureum. The red microalgae is also known to accumulate considerable amount of arachidonic acid (ARA). In artificial seawater medium, the highest yield of TFA (473.44 mg/L) was obtained with the aeration rate of 3 L/min and light intensity of 165 µmol/m2s, whilst the highest yield of ARA (115.47 mg/L) was achieved with the aeration rate of 3 L/min and light intensity of 110 µmol/m2s. It was found that higher aeration rate led to more biomass and TFA/ARA production. However, higher light intensity could contribute to biomass accumulation, but it was adverse for TFA and ARA biosynthesis. By optimizing two operating factors (i.e., light intensity and aeration rate), TFA and ARA production by P. purpureum was significantly improved. This research provides a potential alternative means for producing ARA.

Phosphate limitation promotes unsaturated fatty acids and arachidonic acid biosynthesis by microalgae Porphyridium purpureum.

Polyunsaturated fatty acids (PUFAs) are highly appreciated on their nutritive value for human health and aquaculture. P. purpureum, one of the red microalgae acknowledged as a promising accumulator of ARA, was chosen as the target algae in the present research. Effects of sodium bicarbonate (0.04-1.2g/L), temperature (25, 30 and 33°C) and phosphate (0.00-0.14g/L) on biomass yield, total fatty acids (TFA) and arachidonic acid (ARA) accumulation were investigated systemically. NaHCO3 dose of 0.8g/L and moderate temperature of 30°C were preferred. In addition, TFA and ARA production were significantly enhanced by an appropriate concentration of phosphate, and the highest TFA yield of 666.38mg/L and ARA yield of 159.74mg/L were obtained at a phosphate concentration of 0.035g/L. Interestingly, with phosphate concentration continuing to fall, UFA/TFA and ARA/EPA ratios were increased accordingly, suggesting that phosphate limitation promoted unsaturated fatty acids and arachidonic acid biosynthesis. Low concentration of phosphate may be favored to increase the enzymatic activities of ∆6-desaturase, which played a key role in catalyzing the conversion of C16:0 to C18:2, and thus the selectivity of UFA increased. Meanwhile, the increase of ARA selectivity could be attributed to ω6 pathway promotion and ∆17-desaturase activity inhibition with phosphate limitation. Phosphate limitation strategy enhanced unsaturated fatty acids and ARA biosynthesis in P. purpureum, and can be applied in commercial scale manufacturing and commercialization of ARA.

Nonlinear control of continuous cultures of Porphyridium purpureum in a photobioreactor

Advanced control strategies proved to be promising tools to improve the performances of microalgae production systems, especially in the perspective of large scale cultivation plants. This paper proposes the validation of a nonlinear control strategy with experimental results. Additionally, the on-line estimation of the biomass concentration in a photobioreactor is presented. The proposed control law maintains the biomass concentration at a targeted level. This is achieved by a state feedback linearizing control law in an inner loop, in addition to a Proportional Integral regulator with an anti-windup compensation in an outer loop. To cope with the lack of on-line biomass concentration measurements, this variable is estimated on-line by an Extended Kalman Filter, based on available on-line measurements (pH, incident light intensity and dissolved carbon dioxide concentration). Performance and robustness of the proposed control strategy are assessed through experimental results obtained with cultures of the microalgae Porphyridium purpureum in a laboratory-scale continuous photobioreactor.

A genetic and ultrastructural study of three clones of Porphyridium purpureum (Bory de Saint-Vincent, 1797) Drew et Ross, 1965 (Rhodophyta) from the marine microalgae collection of the Zhirmunsky institute of marine biology

In this paper, we present the results of a comparative genetic and ultrastructural study of three clones of the microalga Porphyridium purpureum (Rhodophyta) from the culture collection of marine microalgae of the Zhirmunsky Institute of Marine Biology. All clones, which have different geographical origins, showed a high similarity in terms of the ultramicroscopic structure and the nucleotide sequences of the nuclear ribosomal DNA genes (18S rDNA, ITS1-5.8S rDNA-ITS2, D1-D2 region of 28S rDNA). The obtained data are very helpful for the certification of two strains of P. purpureum that were isolated for the first time in the practice of Russian algological research.

Продукционные характеристики Porphyridium purpureum (Bory) Ross в условиях накопительной и квазинепрерывной культуры

Продукционные характеристики Porphyridium purpureum (Bory) Ross в условиях накопительной и квазинепрерывной культуры

Potential of fibrous adsorbents for the binding and characterization of Porphyridium purpureum bioactive polysaccharides

AbstractBACKGROUNDComplex polysaccharides are important in the pharmaceutical industry, yet, due to their large molecular weight and reduced charges, their purification is a highly demanding process that requires binding matrices with unique properties. This work demonstrates for the first time that complex polysaccharides biosynthesized by microalga Porphyridium purpureum can be adsorbed onto Q fibrous anion exchangers.RESULTSWhen the polysaccharides were characterized, the extent of sulfation was higher in native polysaccharides than in ethanol‐ or alkali‐extracts. The zeta potentials increased with increasing pH and the highest charge was observed at pH 8, while the Z‐average diameters of the polysaccharide at pH 6 were highest for alkali‐extracts. Instead of pellicular resins, Q fibrous adsorbents were used to determine Langmuir thermodynamic properties and dynamic binding capacities. The parameters included static binding capacity and dissociation constant of 13.47 ± 1.02 mg g‐1 and 0.141 ± 0.027 mg mL‐1, and 10 and 50% breakthrough capacities of 4.46 ± 0.22 and 5.51 ± 0.28 mg g‐1, respectively. The antiviral activity of the polysaccharides was demonstrated by minimizing bacteriophage lysis of Streptococcus thermophilus.CONCLUSIONThis work demonstrates that polysaccharide extraction can be optimized and the adsorption and desorption of a complex polysaccharide onto Q fibrous matrix is feasible. These parameters could be exploited for up‐scaling of polysaccharides for nutraceutical and pharmaceutical applications. © 2013 Society of Chemical Industry

Electrochemical behavior of the 316L steel type in a marine culture of microalgae (Porphyridium purpureum) under the 12/12 h photoperiod and effect of different working electrode exposure conditions on the biofilm–metal interface

The industrial crops of microalgae use processes calling upon the presence of parts of metal nature such as steel 316L type. The goal of this study is to test the electrochemical behavior of this material in a marine culture of microalgae. Porphyridium purpureum was used under a photoperiod of alternation darkness/light 12/12 h, in order to apprehend the problems of biocorrosion involved in the biofouling. The evolution of the free potential of corrosion, according to the position of the samples and for different surface roughness, observations of the surface quality under the electron microscope with sweeping were carried out. The results showed that, overall, the strain P. purpureum does not have a corrosive effect on the 316L. The free potential of corrosion lies between -0.307 and -0.005V(SCE). The adhesion of the cells seems stronger on the interface air/solid of the half-plunged sample with surface grit polished 1,000, confirmed by the presence of biofilm on the air part. The photoperiod acts on the evolution of the generated free potential of corrosion of the one 24-h period oscillation. Furthermore, the samples plunged horizontally lead to a stabilizing effect on the potential of free corrosion.

Unscented Kalman Filter state and parameter estimation in a photobioreactor for microalgae production

Microalgae have many applications such as the production of high value compounds (source of long-chain polyunsaturated fatty acids, vitamins, and pigments), in energy production (e.g. photobiological hydrogen, biofuel, methane) or in environmental remediation (especially carbon dioxide fixation and greenhouse gas emissions reduction). However, the photobioreactor microalgae process needs complex and costly hardware sensors, especially for biomass measurement. Thus, state and parameter estimation seems to be a critical issue and is studied in this paper in the case of a culture of the microalga Porphyridium purpureum. This paper is an extension of the previous work of Becerra-Celis et al. (2008) where the principal objective is to design a biomass estimator of this microalga production in a photobioreactor based on the total inorganic carbon measurement. Unscented Kalman filtering is applied to estimation of states and model parameters, producing better performances in comparison with Extented Kalman filtering. Numerical simulations in batch mode, and real-life experiments in continuous mode have been carried out. Corresponding results are given in order to highlight the performance of the proposed estimator.

Estimation of microalgal photobioreactor production based on total inorganic carbon in the medium

Microalgae biotechnology has been focusing on the use of algae in the production of high value compounds. During the last few decades, the intense research effort has been aiming at improving new controls and supervising tools as well as on a good process understanding. This requirement involves a large diversity and a better accessibility to process measurements. Probes or sensors are required to control the process. They are however relatively limited. Classical photobioreactors are usually equipped with temperature, dissolved oxygen and pH probes. These sensors actually provide very little online information on cell growth, viability, metabolic state and production. For the time being, sensors reliability cannot meet industrial bioprocessing requirements. In this context software sensors show numerous potentialities. The central axis of this work is the development of an extended Kalman filter (EKF) for the estimation of biomass concentration based on a dynamic process model in combination with total inorganic carbon measurement. A microalga Porphyridium purpureum was used as a model organism in this study. Numerical simulations and real-life experiments (batch and continuous mode) have been carried out and corresponding results are given in order to highlight the performance of the proposed estimator.

Identification of sulfoglycolipids from the alga Porphyridium purpureum by matrix‐assisted laser desorption/ionisation quadrupole ion trap time‐of‐flight mass spectrometry

Sulfoglycolipids, isolated from different phototrophic organisms, particularly plants and algae, have already been identified as bioactive compounds. In addition to their antiviral activity their influence on the immune response in mammalian cells is the focus of many studies. For the first time it has been possible to investigate purified sulfoquinovosyldiacylglycerols (SQDGs) from the microalga Porphyridium purpureum by matrix-assisted laser desorption/ionisation (MALDI) in the negative ion reflectron mode. Thereby, different solid and ionic liquid matrices have been tested to improve signal intensity during the laser ionisation. By using the MALDI Trap time-of-flight (ToF) multiple-stage (MS(n)) hybrid mass spectrometer the fatty acid compositions of the SQDGs were analysed by MS, and confirmed by MS(2) and MS(3) experiments. Thereby, hexadecanoic acid (C16:0), octadecadienoic acid (C18:2), eicosatetraenoic acid (C20:4), and eicosapentaenoic acid (C20:5) were detected in the purified fraction of SQDGs. The localisation of hexadecanoic acid (C16:0) at the sn-2 position, and unsaturated fatty acids at the sn-1 position of the SQDGs, determined by specific enzymatic hydrolysis, marks a procaryotic biosynthesis of SQDGs in the eucaryotic alga cells.

Modelling of growth and product formation of Porphyridium purpureum

In this contribution experimental data and simulations of growth and product formation of the unicellular microalgae Porphyridium purpureum are presented. A mathematical model has been developed for a better understanding of growth and product formation in production plants. The model has been refined with the results of several cultivations in a new photobioreactor designed especially for the study of microalgal kinetics under highly defined illumination conditions. In this photobioreactor light is generated by an external light source and then distributed by means of optical fibres into an internal draft tube which also serves as irradiation element. All cultivations were performed in turbidostate mode. The influence of different light intensity changes, including stepwise change and light–dark cycles in the range from millisecond to second, has been investigated and the results were integrated into the mathematical model. The structured mathematical model consists of three levels: metabolic flux, control of macromolecules and the reactor level. A new linear optimization approach has been realized, enabling the model to describe even very different cultivation conditions. Output variables are among others the commercially interesting macromolecules of the microalgae, e.g. polysaccharides, pigments and polyunsaturated fatty acids. Thus, reliable predictions of the specific production rates of these products are possible for the production in a larger scale.

Modelling of Growth and Product Formation of Porphyridium purpureum Under Defined Conditions

Abstract In this contribution both experimental data and simulations of growth rate and product formation of the microalgae Porphyridium purpureum are presented. The mathematical model has been developed for a better understanding of the processes in production plants. This is achieved by the usage of a scale-down reactor concept, on one hand, and, on the other hand, by the inclusion of the dynamic metabolic behaviour of the different macro-molecules under changing conditions. The mathematical simulation model has been refined with the results of several cultivations that have been carried out in a new photo-bioreactor, which allows for the study of microalgal kinetics under defined illumination conditions

An isotopic labeling method for determining production of volatile organohalogens by marine microalgae

An isotopic method has been developed to establish the biological production of volatile organohalogens. The marine microalgae Porphyridium purpureum and Dunaliella tertiolecta were grown in seawater medium containing NaH13CO3, and volatile organohalogens were extracted and analyzed by gas chromatography-mass spectrometry (GC-MS). Isotopically labeled methyl halides were formed in each microalgal culture, and the 13CHCl3 found in the P. purpureum culture confirmed the production of chloroform reported by Scarratt and Moore (Limnol. Oceanogr. 1999. 44: 703–707). No incorporation of 13C into dichloromethane was observed, even though slightly increased CH2Cl2 concentrations were detected in both algal cultures at the end of the incubation period.

Production of chlorinated hydrocarbons and methyl iodide by the red microalga Porphyridium purpureum

Two experiments were performed using axenic batch cultures of the red microalga Porphyridium purpureum. The cultures were grown in sealed 5‐liter glass vessels under a high‐purity artificial atmosphere and analyzed for the production of several halocarbons, including chloroform (CHCl3), methylene chloride (CH2 Cl2), methyl iodide (CH3l), trichloroethylene (C2 HCl3), and tetrachloroethylene (C2Cl4). Two cultures and a control were used in each experiment. The first experiment followed the system for 17 d at low light intensity (20 μmol quanta m−2 s−1), while the second was comprised of 7 d at low light followed by 24 h at high light intensity (800 umol quanta m−2 s−1). In both experiments, only chloroform and methyl iodide were produced in measurable quantities. This is the first report of chloroform production in a microalgal species. The chlorophyll a (Chl a) normalized production rate of chloroform in the various cultures ranged between 1.3 × 10−7 and 7.8 × 10−7 mol (g Chl a)−1 d−1 (15–93 μg [g Chl a]−1 d−1). Chloroform production peaked during the logarithmic growth phase. Methyl iodide production ranged between 2.0 × 10−7 and 1.2 × 10−6 mol (g Chl a)−1 d−1 (28‐170 μg [g Chl a]−1 d−1). Exposure of the cultures to high irradiance (800 μmol quanta m−2 s−1) did not stimulate the production of any of the compounds. In contrast to an earlier published account involving this species of algae, the production of tri and tetrachloroethylene was not detected in any of the cultures under either low or high irradiance.