One-step chromatographic procedure for purification of B-phycoerythrin from Porphyridium cruentum

Exploring the versatility of Porphyridium sp.: A comprehensive review of cultivation, bio-product extraction, purification, and characterization techniques

Interest in red microalgae of the Porphyridium genus has surged due to their richness in phycobiliproteins, polyunsaturated fatty acids, and sulfated polysaccharides. These biomasses and their derivatives find applications across food, feed, nutraceutical, pharmaceutical, and cosmetic industries. A deeper understanding of their properties and extraction methods is essential to optimize downstream processing. This paper comprehensively reviews Porphyridium sp., focusing on cultivation techniques, bioproduct extraction, purification, and characterization. It delves into protein, lipid, and polysaccharide extraction, considering the influence of culture conditions on biomass yield. Various methods like chromatography, electrophoresis, and membrane-based techniques for cell lysis and bioproduct recovery are explored, highlighting their pros and cons. By offering diverse insights, this review aims to inspire innovative research and industry progress in red microalgae biotechnology, contributing to sustainable solutions across sectors.

Optimised phycoerythrin extraction method from Porphyridium sp. combining imidazolium-based ionic liquids

Phycoerythrin (PE) extraction from Porphyridium sp. was studied employing ultrasound-assisted extraction combined with aqueous mixtures of two imidazolium-based ionic liquids (ILs) simultaneously, marking a significant novelty. A face-centred central composite design and response surface optimised PE yield (EPE), considering the effects of ionic liquid concentration (IL), [Emim][EtSO4]/[Bmim][EtSO4] mass ratio (E/B), biomass concentration (BM), and time (t). Improvements in EPE by 300 % and 115 % were achieved compared to a phosphate buffer solution and the freeze-thaw method, respectively. Temperature and pH effects were examined independently, leading to the determination of optimal operating conditions: BM = 10 mg mL-1, IL = 18.6 wt%, E/B = 0.78/0.22, t = 10 min, T = 35 °C, and pH = 7.5. Results indicated the potential for reusing the ILs for at least five consecutive extraction cycles, maintaining an EPE of 94.2 % compared to fresh ones. This underscores the success and innovation of the developed technology in enhancing PE extraction from Porphyridium sp.

Valuable pigments from microalgae: phycobiliproteins, primary carotenoids, and fucoxanthin

Phycobiliproteins, carotenoids and fucoxanthin are photosynthetic pigments extracted from microalgae and cyanobacteria with great potential biotechnological applications, as healthy food colorants and cosmetics. Phycocyanin possesses a brilliant blue color, with fluorescent properties making it useful as a reagent for immunological essays. The most important source of phycocyanin is the cyanobacterium Arthrospira platensis, however, recently, the Rhodophyta Galdieria sulphuraria has also been identified as such. The main obstacle to the commercialization of phycocyanin is represented by its chemical instability, strongly reducing its shelf-life. Moreover, the high level of purity needed for pharmaceutical applications requires several steps which increase both the production time and cost. Microalgae (Chlorella, Dunaliella, Nannochloropsis, Scenedesmus) produce several light harvesting carotenoids, and are able to manage with oxidative stress, due to their free radical scavenging properties, which makes them suitable for use as source of natural antioxidants. Many studies focused on the selection of the most promising strains producing valuable carotenoids and on their extraction and purification. Among carotenoids produced by marine microalgae, fucoxanthin is the most abundant, representing more than 10% of total carotenoids. Despite the abundance and diversity of fucoxanthin producing microalgae only a few species have been studied for commercial production, the most relevant being Phaeodactylum tricornutum. Due to its antioxidant activity, fucoxanthin can bring various potential benefits to the prevention and treatment of lifestyle-related diseases. In this review, we update the main results achieved in the production, extraction, purification, and commercialization of these important pigments, motivating the cultivation of microalgae as a source of natural pigments.

A Chitosan-Based Flocculation Method for Efficient Recovery of High-Purity B-Phycoerythrin from a Low Concentration of Phycobilin in Wastewater

Increasing the yield and purity of B-phycoerythrin (B-PE) can improve the economic state of microalgae industrial processing. One method of cost reduction involves the recovery of remaining B-PE from wastewater. In this study, we developed a chitosan (CS)-based flocculation technique for the efficient recovery of B-PE from a low concentration of phycobilin in wastewater. We investigated the effects of the molecular weight of chitosan, B-PE/CS mass ratio, and solution pH on the flocculation efficiency of CS and the effects of phosphate buffer concentration and pH on the recovery rate of B-PE. The maximum flocculation efficiency of CS, recovery rate, and purity index of B-PE were 97.19% ± 0.59%, 72.07% ± 1.37%, and 3.20 ± 0.025 (drug grade), respectively. The structural stability and activity of B-PE were maintained during the recovery process. Economic evaluation revealed that our CS-based flocculation method is more economical than the ammonium sulfate precipitation method is. Furthermore, the bridging effect and electrostatic interaction play important roles in B-PE/CS complex flocculation process. Hence, our study provides an efficient and economical method to recover high-purity B-PE from a low concentration of phycobilin in wastewater, which promoted the application of B-PE as a natural pigment protein in food and chemical applications.

A novel antioxidant protein of non-phycobiliprotein family derived from marine red alga Porphyra haitanensis

BACKGROUND

Oxidation has been reported as the one of the deterioration reactions of proteins in aquatic products. Searching for new bioactive substances from marine algae has been one of the main areas in food science and additives.

RESULTS

In this study, a novel protein from the red alga Porphyra haitanensis was determined after ammonium sulfate precipitation and gel filtration chromatography. It closely corresponded to the antioxidant activity and was identified as an uncharacterized protein with a molecular mass of 43 kDa, designated Ph43. Bioinformatic analysis revealed that Ph43 is a novel protein of non-phycobiliprotein family with putative chordin domains and rich in α-helical conformation. Recombinant protein (rPh43) was expressed in Escherichia coli as a Hig-tagged protein using a pET-22b vector system and purified by affinity high-performance liquid chromatography. Spectroscopy analysis revealed that there were no structural differences between rPh43 and natural recovered Ph43. Moreover, rPh43 showed equal/higher antioxidant activity compared with Ph43. rPh43 has the potential for application as a natural antioxidant for food stabilization.

CONCLUSION

Our results identified a novel antioxidant protein with molecular mass of 43 kDa derived from Porphyra haitanensis that belongs to the non-phycobiliprotein family. © 2023 Society of Chemical Industry.

Promising Biomolecules with High Antioxidant Capacity Derived from Cryptophyte Algae Grown under Different Light Conditions

The accumulation and production of biochemical compounds in microalgae are influenced by available light quality and algal species-specific features. In this study, four freshwater cryptophyte strains (Cryptomonas ozolinii, C. pyrenoidifera, C. curvata, and C. sp. (CPCC 336)) and one marine strain (Rhodomonas salina) were cultivated under white (control), blue, and green (experimental conditions) lights. Species-specific responses to light quality were detected, i.e., the color of light significantly affected cryptophyte biomass productivity and biochemical compositions, but the optimal light for the highest chemical composition with high antioxidant capacity was different for each algal strain. Overall, the highest phycoerythrin (PE) content (345 mg g−1 dry weight; DW) was reached by C. pyrenoidifera under green light. The highest phenolic (PC) contents (74, 69, and 66 mg g−1 DW) were detected in C. curvata under control conditions, in C. pyrenoidifera under green light, and in C. ozolinii under blue light, respectively. The highest exopolysaccharide (EPS) content (452 mg g−1 DW) was found in C. curvata under the control light. In terms of antioxidant activity, the biochemical compounds from the studied cryptophytes were highly active, with IC50 -values < 50 µg mL−1. Thus, in comparison to well-known commercial microalgal species, cryptophytes could be considered a possible candidate for producing beneficial biochemical compounds.

Phycoerythrin: a pink pigment from red sources (rhodophyta) for a greener biorefining approach to food applications

Phycoerythrin (PE) is a photosensitive red pigment from phycobiliprotein family predominantly present in the red algae. The concentration of PE depends on photon flux density (PFD) and the quality of light absorbed by the algae tissue. This necessitates robust techniques to extract PE from the embedded cell-wall matrix of the algal frond. Similarly, PE is sensitive to various factors which influence its stability and purity of PE. The PE is extracted from Red algae through different extraction techniques. This review explores an integrative approach of fractionating PE for the scaling-up process and commercialization. The mechanism for stabilizing PE pigment in food was critically evaluated for further retaining this pigment within the food system. The challenges and possibilities of employing efficient extraction for industrial adoption are meticulously estimated. The techniques involved in the sustainable way of extracting PE pigments improved at a laboratory scale in the past decade. Although, the complexity of industrial-scale biorefining was found to be a bottleneck. The extraction of PE using benign chemicals would be safe for food applications to promote health benefits. The precise selection of encapsulation technique with enhanced sensitivity and selectivity of the membrane would bring better stability of PE in the food matrix.

Biodegradable Solvents: A Promising Tool to Recover Proteins from Microalgae

The world will face a significant protein demand in the next few decades, and due to the environmental concerns linked to animal protein, new sustainable protein sources must be found. In this regard, microalgae stand as an outstanding high-quality protein source. However, different steps are needed to separate the proteins from the microalgae biomass and other biocompounds. The protein recovery from the disrupted biomass is usually the bottleneck of the process, and it typically employs organic solvents or harsh conditions, which are both detrimental to protein stability and planet health. Different techniques and methods are applied for protein recovery from various matrices, such as precipitation, filtration, chromatography, electrophoresis, and solvent extraction. Those methods will be reviewed in this work, discussing their advantages, drawbacks, and applicability to the microalgae biorefinery process. Special attention will be paid to solvent extraction performed with ionic liquids (ILs) and deep eutectic solvents (DESs), which stand as promising solvents to perform efficient protein separations with reduced environmental costs compared to classical alternatives. Finally, several solvent recovery options will be analyzed to reuse the solvent employed and isolate the proteins from the solvent phase.

A Novel Three-Step Extraction Strategy for High-Value Products from Red Algae Porphyridium purpureum

The microalga Porphyridium accumulates high-value compounds such as phycoerythrin, polyunsaturated fatty acids, and polysaccharides, and thus, the extraction of these compounds could significantly expand the value of Porphyridium biomass. In the present study, a novel fractional extraction strategy based on the characteristics of these compounds was established using cold water, 95% ethanol, and hot water. The yield of phycoerythrin, lipids, and polysaccharides was 63.3, 74.3, and 75.2%, respectively. The phycoerythrin exhibited excellent fluorescence characteristics but had low purity. The crude lipid was dark with poor fluidity. Digalactosyldiacylglycerol and sulphoquinovosyldiacylglycerol containing C20:5 and C20:4 were the most abundant glycerolipids, while glucose, xylose, and galactose constituted the intracellular polysaccharides that had covalently bound to proteins (8.01%), uronic acid (4.13%), and sulfate (8.31%). Compared with polysaccharides and crude lipids, crude phycoerythrin showed the best antioxidant activity. Overall, the three-step fractional extraction process was feasible for Porphyridium; however, further purification is necessary for downstream applications.

Microalgae Biomolecules: Extraction, Separation and Purification Methods

Several microalgae species have been exploited due to their great biotechnological potential for the production of a range of biomolecules that can be applied in a large variety of industrial sectors. However, the major challenge of biotechnological processes is to make them economically viable, through the production of commercially valuable compounds. Most of these compounds are accumulated inside the cells, requiring efficient technologies for their extraction, recovery and purification. Recent improvements approaching physicochemical treatments (e.g., supercritical fluid extraction, ultrasound-assisted extraction, pulsed electric fields, among others) and processes without solvents are seeking to establish sustainable and scalable technologies to obtain target products from microalgae with high efficiency and purity. This article reviews the currently available approaches reported in literature, highlighting some examples covering recent granted patents for the microalgae’s components extraction, recovery and purification, at small and large scales, in accordance with the worldwide trend of transition to bio-based products.

Sequential aqueous two-phase system for simultaneous purification of cyanobacterial phycobiliproteins

A logical framework was used for designing a top-down strategy for cyanobacterial phycobiliprotein purification. The purification scheme is based on the non-chromatographic technique, known as aqueous two-phase system. The scheme was optimized at every stage to enhance the recovery yield with the highest purity. We tested this strategy on four cyanobacteria, two containing only phycocyanin and allophycocyanin (Arthrospira platensis AICB49, Synechocystis sp. AICB51) and two that have an extra phycobiliprotein, namely phycoerythrin (Fremyella sp. UTEX481, Coelomoron pussilum AICB1012). The results showed that the recovery efficiency of the phycobiliproteins is strongly influenced by the phycobilisome composition. For the first two strains the recovery yield of both phycocyanin and allophycocyanin was >80%, with an analytical purity grade for phycocyanin (>4.2) and a reactive purity grade for allophycocyanin (>2.9). The recovery yield of phycoerythrin was lower but compensating with an increase in purity, 5.2 for Fremyella and 4.5 for C. pussilum.

The Potential of Algal Biotechnology to Produce Antiviral Compounds and Biopharmaceuticals

The emergence of the Coronavirus Disease 2019 (COVID-19) caused by the SARS-CoV-2 virus has led to an unprecedented pandemic, which demands urgent development of antiviral drugs and antibodies; as well as prophylactic approaches, namely vaccines. Algae biotechnology has much to offer in this scenario given the diversity of such organisms, which are a valuable source of antiviral and anti-inflammatory compounds that can also be used to produce vaccines and antibodies. Antivirals with possible activity against SARS-CoV-2 are summarized, based on previously reported activity against Coronaviruses or other enveloped or respiratory viruses. Moreover, the potential of algae-derived anti-inflammatory compounds to treat severe cases of COVID-19 is contemplated. The scenario of producing biopharmaceuticals in recombinant algae is presented and the cases of algae-made vaccines targeting viral diseases is highlighted as valuable references for the development of anti-SARS-CoV-2 vaccines. Successful cases in the production of functional antibodies are described. Perspectives on how specific algae species and genetic engineering techniques can be applied for the production of anti-viral compounds antibodies and vaccines against SARS-CoV-2 are provided.

Algae as potential feedstock for the production of biofuels and value-added products: Opportunities and challenges

The current review explores the potential application of algal biomass for the production of biofuels and bio-based products. The variety of processes and pathways through which bio-valorization of algal biomass can be performed are described in this review. Various lipid extraction techniques from algal biomass along with transesterification reactions for biodiesel production are briefly discussed. Processes such as the pretreatment and saccharification of algal biomass, fermentation, gasification, pyrolysis, hydrothermal liquefaction, and anaerobic digestion for the production of biohydrogen, bio-oils, biomethane, biochar (BC), and various bio-based products are reviewed in detail. The biorefinery model and its collaborative approach with various processes are highlighted for the production of eco-friendly, sustainable, and cost-effective biofuels and value-added products. The authors also discuss opportunities and challenges related to bio-valorization of algal biomass and use their own perspective regarding the processes involved in production and the feasibility to make algal research a reality for the production of biofuels and bio-based products in a sustainable manner.

Advances in the production of bioactive substances from marine unicellular microalgae Porphyridium spp

Porphyridium spp. are a group of unicellular marine microalgae belonging to the Rhodophyta, which evolved over one billion years and are a source of a variety of natural active components. They can naturally and efficiently accumulate phycobilin, sulfated polysaccharides, polyunsaturated fatty acids and other bioactive substances. At present, numerous attempts have been made to explore the species Porphyridium spp., whereas mainly focused on cultivation methods, metabolism regulation and the function and application of bioactive products. There is a lack of systematic summary of the existing research conclusions. In this paper, we summarized the representative results related to culture and metabolism, analyzed and discussed the existing bottleneck restrictions for their large scale application, and proposed the potential industrial development and research direction in the future. This paper is expected to provide reference and thread for research and application of Porphyridium spp..