Rapid extraction of phycobiliproteins from cultured cyanobacteria samples

Microalgae: A Promising Source of Bioactive Phycobiliproteins

Phycobiliproteins are photosynthetic light-harvesting pigments isolated from microalgae with fluorescent, colorimetric and biological properties, making them a potential commodity in the pharmaceutical, cosmetic and food industries. Hence, improving their metabolic yield is of great interest. In this regard, the present review aimed, first, to provide a detailed and thorough overview of the optimization of culture media elements, as well as various physical parameters, to improve the large-scale manufacturing of such bioactive molecules. The second section of the review offers systematic, deep and detailed data about the current main features of phycobiliproteins. In the ultimate section, the health and nutritional claims related to these bioactive pigments, explaining their noticeable potential for biotechnological uses in various fields, are examined.

Phycobiliproteins from algae: Current updates in sustainable production and applications in food and health

Phycobiliproteins are light-harvesting complexes found mainly in cyanobacteria and red algae, playing a key role in photosynthesis. They are extensively applied in food, cosmetics, and biomedical industry due to bright color, unique fluorescence characteristics and diverse physiological activities. They have received much attention in the past few decades because of their green and sustainable production, safe application, and functional diversity. This work aimed to provide a comprehensive summary of parameters affecting the whole bioprocess with a special focus on the extraction and purification, which directly determines the application of phycobiliproteins. Food grade phycobiliproteins are easy to prepare, whereas analytical grade phycobiliproteins are extremely complex and costly to produce. Most phycobiliproteins are denatured and inactivated at high temperatures, severely limiting their application. Inspired by recent advances, future perspectives are put forward, including (1) the mutagenesis and screening of algal strains for higher phycobiliprotein productivity, (2) the application of omics and genetic engineering for stronger phycobiliprotein stability, and (3) the utilization of synthetic biology and heterologous expression systems for easier phycobiliprotein isolation. This review will give a reference for exploring more phycobiliproteins for food and health application development.

Uncovering Research Trends of Phycobiliproteins Using Bibliometric Approach

Phycobiliproteins are gaining popularity as long-term, high-value natural products which can be alternatives to synthetic products. This study analyzed research trends of phycobiliproteins from 1909 to 2020 using a bibliometric approach based on the Scopus database. The current findings showed that phycobiliprotein is a burgeoning field in terms of publications outputs with "biochemistry, genetics, and molecular biology" as the most related and focused subject. The Journal of Applied Phycology was the most productive journal in publishing articles on phycobiliproteins. Although the United States of America (U.S.A.) contributed the most publications on phycobiliproteins, the Chinese Academy of Sciences (China) is the institution with the largest number of publications. The most productive author on phycobiliproteins was Glazer, Alexander N. (U.S.A.). The U.S.A. and Germany were at the forefront of international collaboration in this field. According to the keyword analysis, the most explored theme was the optimization of microalgae culture parameters and phycobiliproteins extraction methods. The bioactivity properties and extraction of phycobiliproteins were identified as future research priorities. Synechococcus and Arthrospira were the most cited genera. This study serves as an initial step in fortifying the phycobiliproteins market, which is expected to exponentially expand in the future. Moreover, further research and global collaboration are necessary to commercialize phycobiliproteins and increase the consumer acceptability of the pigments and their products.

Applying Seaweed Compounds in Cosmetics, Cosmeceuticals and Nutricosmetics

The interest in seaweeds for cosmetic, cosmeceutics, and nutricosmetics is increasing based on the demand for natural ingredients. Seaweeds offer advantages in relation to their renewable character, wide distribution, and the richness and versatility of their valuable bioactive compounds, which can be used as ingredients, as additives, and as active agents in the formulation of skin care products. Bioactive compounds, such as polyphenols, polysaccharides, proteins, peptides, amino acids, lipids, vitamins, and minerals, are responsible for the biological properties associated with seaweeds. Seaweed fractions can also offer technical features, such as thickening, gelling, emulsifying, texturizing, or moistening to develop cohesive matrices. Furthermore, the possibility of valorizing industrial waste streams and algal blooms makes them an attractive, low cost, raw and renewable material. This review presents an updated summary of the activities of different seaweed compounds and fractions based on scientific and patent literature.

Biochemical Composition and Phycoerythrin Extraction from Red Microalgae: A Comparative Study Using Green Extraction Technologies

Porphyridium spp. is a debated family that produces phycoerythrin (PE) for use in multiple industrial applications. We compared the differences in the biochemical composition and phycoerythrin yield of P. cruentum and P. purpureum by conventional and green extraction technologies. The protein content in P. cruentum was 42.90 ±1.84% w/w. The omega-3 fatty acid (FA) was highlighted by eicosapentaenoic acid (EPA, C20:5, ω-3, ~9.74 ± 0.27% FA) and arachidonic acid (ARA, C20:4, ω-6, ~18.02 ± 0.81% FA) represented the major omega-6 fatty acid. Conversely, P. purpureum demonstrated a higher lipid content (17.34 ± 1.35% w/w) and an FA profile more saturated in palmitic (C16:0, 29.01 ± 0.94% FA) and stearic acids (C18:0, 50.02 ± 1.72% FA). Maceration and freeze/thaw were the conventional methods, whereas microwave (MW) and ultrasound (US) served as green procedures for PE extraction under the factorial-design methodology. Aqueous solvents, extraction-time and power were the main factors in the statistical extraction designs based on Response-Surface Methodology (RSM). Overall, the PE extraction yield was higher (2-to 6-fold) in P. cruentum than in P. purpureum. Moreover, green technologies (US > MW) improved the PE recovery in comparison with the conventional methods for both of the microalgae. The maximum PE yield (33.85 mg/g) was obtained under optimal US conditions (15 min and buffer solvent (PBS)) for P. cruentum. Finally, we proved the biochemical differences between the red microalgae and ratified the advantages of using green extraction for PE because it reduced the processing times and costs and increased the economic and functional-applications of bioactive compounds in the industry.

The use of cyanobacterial metabolites as natural medical and biotechnological tools: review article

Cyanobacteria are photosynthetic, Gram-negative bacteria that are considered one of the most morphologically diverse groups of prokaryotes with a chief role in the global nutrient cycle as they fixed gaseous carbon dioxide and nitrogen to organic materials. Cyanobacteria have significant adaptability to survive in harsh conditions due to they have different metabolic pathways with unique compounds, effective defensive mechanisms, and wide distribution in different habitats. Besides, they are successfully used to face different challenges in several fields, including industry, aquaculture, agriculture, food, dairy products, pollution control, bioenergy, and pharmaceutics. Analysis of 680 publications revealed that nearly 1630 cyanobacterial molecules belong to different families have a wide range of applications in several fields, including cosmetology, agriculture, pharmacology (immunosuppressant, anticancer, antibacterial, antiprotozoal, antifungal, anti-inflammatory, antimalarial, anticoagulant, anti-tuberculosis, antitumor, and antiviral activities) and food industry. In this review, we nearly mentioned 92 examples of cyanobacterial molecules that are considered the most relevant effects related to anti-inflammatory, antioxidant, antimicrobial, antiviral, and anticancer activities as well as their roles that can be used in various biotechnological fields. These cyanobacterial products might be promising candidates for fighting various diseases and can be used in managing viral and microbial infections.Communicated by Ramaswamy H. Sarma.

One structure, multiple features: The phycocyanin in biotechnology

Phycocyanine (PC) is a water-soluble, non-toxic and bioactive (antioxidant, anti-inflammatory, antitumor, etc.) phycobiliprotein isolated, mainly, from cyanobacteria. Due to its several properties, PC is considered to be a rising biomolecule for Industrial exploitation, and has become an important research axis in order to promote its production, and optimize its biotechnological applications. The aim of this review article was to discuss the basic, and recent properties and applications of PC, and to bring together data on various aspects of PC stabilization, and PC nanopar-ticles formulation. In addition, an overview of the main structural characteristics and process-ses of PC extraction and purification were also discussed. The recent scientific research findings concluded that PC is a promising both functional, and bioactive additive in industry, especially, in food as a dye, in imaging as a fluorescent labeling agent, and in the phar-maceutical and nano-pharmaceutical field as a bioactive molecule and nanopar-ticles, particularly, due to it antitumor capacity. Phycocyanine is, thus, a promising bio-active molecules in pharmacological, and medical fields.

Biologically active macromolecules: Extraction strategies, therapeutic potential and biomedical perspective

Marine biome exhibits an immense essence of excellence and enriched with high-value bioactive compounds of therapeutic and biomedical value. During the past several years, an array of biologically active molecules has been extracted/isolated and purified from numerous sources of marine origin with the aid of distinct techniques and methodologies for newer applications. The growing demand for bioactive molecules with unique functionalities in various industrial divisions, such as therapeutic sectors and biomedical, has endorsed the necessity for highly suitable and standardized strategies to extract these bioactive components using a state-of-the-art and inexpensive measures. This is also because many in practice conventional extraction methodologies suffer from processing limitations and low-yield issues. Besides that, other major issues include (i) decrease efficacy, (ii) excessive energy cost, (iii) low yield, (iv) lower cost-effective ratio, (v) minimal selectivity, (vi) low activity, and (vii) stability, etc. In this context, there is an urgent need for new and robust extraction strategies. The synergies of modern extraction techniques with efficient and novel pretreatment approaches, such as the integration of enzymes, accompanied by conventional extraction processes, should be the utmost goal of current research and development studies. The typical effectivity of the extraction techniques mostly relies on these points, i.e., (i) know-how about the source nature and type, (ii) understanding the structural and compositional profile, (iii) influence of the processing factors, (iv) interplay between the extraction conditions and the end-product, (v) understanding the available functional entities, (vi) reaction chemistry of the extract bioactive compounds, and (vii) effective exploitation of the end-product in the marketplace. Marine biome, among numerous naturally occurring sources, has been appeared an immense essence of excellence to isolate an array of biologically active constituents with medicinal values and related point-of-care applications. Herein, we reviewed the salient information covering various therapeutic potential and biomedical perspectives. Following a brief introduction and marine pharmacognosy, an array of high-value biomolecules of marine origin are discussed with suitable examples. From the robust extraction strategies viewpoint, a part of the review focuses on three techniques, i.e., (1) enzyme-assisted extraction (EAE), (2) supercritical-fluid extraction (SFE), and (3) microwave-assisted extraction (MAE). Each technique is further enriched with processing and workflow environment. The later part of the review is mainly focused on the therapeutic and biomedical perspectives of under-reviewed bio-active compounds or biomolecules. The previous and latest research on the anticancer, skin curative, cardio-protective, immunomodulatory and UV-protectant potentialities of marine-derived biologically active entities have been summarized with suitable examples and related pathways illustrations. Finally, the work is wrapped-up with current research challenges, future aspects, and concluding remarks.

Pulsed electric field-assisted extraction of valuable compounds from microorganisms

Microorganisms (bacteria, yeast, and microalgae) are a promising resource for products of high value such as nutrients, pigments, and enzymes. The majority of these compounds of interest remain inside the cell, thus making it necessary to extract and purify them before use. This review presents the challenges and opportunities in the production of these compounds, the microbial structure and the location of target compounds in the cells, the different procedures proposed for improving extraction of these compounds, and pulsed electric field (PEF)-assisted extraction as alternative to these procedures. PEF is a nonthermal technology that produces a precise action on the cytoplasmic membrane improving the selective release of intracellular compounds while avoiding undesirable consequences of heating on the characteristics and purity of the extracts. PEF pretreatment with low energetic requirements allows for high extraction yields. However, PEF parameters should be tailored to each microbial cell, according to their structure, size, and other factors affecting efficiency. Furthermore, the recent discovery of the triggering effect of enzymatic activity during cell incubation after electroporation opens up the possibility of new implementations of PEF for the recovery of compounds that are bounded or assembled in structures. Similarly, PEF parameters and suspension storage conditions need to be optimized to reach the desired effect. PEF can be applied in continuous flow and is adaptable to industrial equipment, making it feasible for scale-up to large processing capacities.

Rapid Green Extractions of C-Phycocyanin from Arthrospira maxima for Functional Applications

Cyanobacteria are a rich source of bioactive compounds, mainly in the Arthospira sp., and one of the most interesting components in recent years has been C-phycocyanin (C-PC). There have been several conventional methods for their extraction, among which stand out: chemical products, freezing-thawing (FT); enzymatic, and maceration (M); which have come to be replaced by more environmentally friendly methods, such as those assisted by microwaves (MW) and high-pressure homogenization (HPH). The aim of the research was to use these two “green extraction processes” to obtain C-PC from cyanobacteria Arthrospira maxima because they improve functionality and are fast. Extractions of C-PC were studied by means of two experimental designs for MW and HPH, based on a response surface methodology (RSM) employing, firstly, a factorial design 33: power (100, 200, and 300 W), time (15, 30, and 60 s), and types of solvents (distiller water, Na-phosphate buffer and, distiller water: Na-phosphate buffer (Ph 7.0; 1:1, v/v); and secondly, two factors with different levels: Pressure (800, 1000, 1200, 1400, and 1600 bar) and, types of solvents (distilled water, Na-phosphate buffer (pH 7.0) 100 mM and, Na-phosphate buffer:water 1:1, (v/v)). Optimum C-PC content was achieved with the HPH process under Na-phosphate solvent at 1400 bar (291.9 ± 6.7 mg/g) and the MW method showed improved results using distilled water as a solvent at 100 W for 30 s (215.0 ± 5.5 mg/g). In the case of conventional methods, the freeze–thawing procedure reached better results than maceration using the buffer (225.6 ± 2.6 mg/g). This last one also did not show a significant difference between solvents (a range of 147.7–162.0 mg/g). Finally, the main advantage of using green extractions are the high C-PC yield achieved, effectively reducing both processing times, costs, and increasing the economic and functional applications of the bioactive compound.

Marine natural pigments as potential sources for therapeutic applications

In recent years, marine natural pigments have emerged as a powerful alternative in the various fields of food, cosmetic, and pharmaceutical industries because of their excellent biocompatibility, bioavailability, safety, and stability. Marine organisms are recognized as a rich source of natural pigments such as chlorophylls, carotenoids, and phycobiliproteins. Numerous studies have shown that marine natural pigments have considerable medicinal potential and promising applications in human health. In this review, we summarize the marine natural pigments as potential sources for therapeutic applications, including: antioxidant, anticancer, antiangiogenic, anti-obesity, anti-inflammatory activities, drug delivery, photothermal therapy (PTT), photodynamic therapy (PDT), photoacoustic imaging (PAI), and wound healing. Marine natural pigments will offer a better platform for future theranostic applications.

Optimization of production of C-phycocyanin and extracellular polymeric substances by Arthrospira sp

The key factors influencing the production of C-phycocyanin (C-PC) and extracellular polymeric substances (EPS) by photoautotrophic culture of Arthrospira sp. were optimized using Taguchi method. Six factors were varied at either three or two levels as follows: light intensity at three levels; three initial culture pHs; two species of Arthrospira; three concentrations of Zarrouk's medium; three rates of aeration of the culture with air mixed with 2% v/v carbon dioxide; and two incubation temperatures. All cultures ran for 14 days. The optimal conditions for the production of C-PC and EPS were different. For both products, the best cyanobacterium proved to be Arthrospira maxima IFRPD1183. The production of C-PC was maximized with the following conditions: a light intensity of 68 µmol photons m^-2 s^-1 (a diurnal cycle of 16-h photoperiod and 8-h dark period), an initial pH of 10, the full strength (100%) Zarrouk's culture medium, an aeration rate of 0.6 vvm (air mixed with 2% v/v CO₂) and a culture temperature of 30 °C. The concentration of Zarrouk's medium was the most important factor influencing the final concentration of C-PC. The optimal conditions for maximal production of EPS were as follows: a light intensity of 203 µmol photons m^-2 s^-1 with the earlier specified light-dark cycle; an initial pH of 9.5; a 50% strength of Zarrouk's medium; an aeration rate of 0.2 vvm (air mixed with 2% v/v CO₂); and a temperature of 35 °C. Production of C-PC and EPS in raceway ponds is discussed.

Biopolymeric agents for skin wrinkle treatment

Skin aging is caused by several factors capable of deteriorating dermal matrix and is visibly noticed in skin color and skin contour deformities. In addition to the prevention of skin aging by application of antioxidants and sunscreens, treatment of skin wrinkles with those of dermal fillers is also recommended. Dermal filler products with enhanced injectability and longer duration are being developed continuously. Biodegradable polymers such as skin elastic fibers and dermal matrix mimetic used for treatment of skin wrinkle are summarized in this article. Additionally, the importance of amino acids, enzymes, and proteins in aesthetic of skin is addressed. Thus, elective agents are proposed for the dermatologists, cosmetic formulators, and the individuals facing skin aging problems. The candidate natural peptides from marine sources are additionally presented for widening the choice of actives application for treating aging.

Biologically Active Metabolites Synthesized by Microalgae

Microalgae are microorganisms that have different morphological, physiological, and genetic traits that confer the ability to produce different biologically active metabolites. Microalgal biotechnology has become a subject of study for various fields, due to the varied bioproducts that can be obtained from these microorganisms. When microalgal cultivation processes are better understood, microalgae can become an environmentally friendly and economically viable source of compounds of interest, because production can be optimized in a controlled culture. The bioactive compounds derived from microalgae have anti-inflammatory, antimicrobial, and antioxidant activities, among others. Furthermore, these microorganisms have the ability to promote health and reduce the risk of the development of degenerative diseases. In this context, the aim of this review is to discuss bioactive metabolites produced by microalgae for possible applications in the life sciences.

Functional ingredients from microalgae

A wide variety of natural sources are under investigation to evaluate their possible use for new functional ingredient formulation. Some records attested the traditional and ancient use of wild harvested microalgae as human food but their cultivation for different purposes started about 40 years ago. The most popular species are Arthrospira (traditional name, Spirulina), Chlorella spp., Dunaliella spp. and Haematococcus spp. Microalgae provide a bewildering array of opportunities to develop healthier food products using innovative approaches and a number of different strategies. Compared to other natural sources of bioactive ingredients, microalgae have many advantages such as their huge biodiversity, the possibility to grow in arid land and with limited fresh water consumption and the flexibility of their metabolism, which could be adapted to produce specific molecules. All these factors led to very sustainable production making microalgae eligible as one of the most promising foods for the future, particularly as source of proteins, lipids and phytochemicals. In this work, a revision of the knowledge about the use of microalgae as food and as a source of functional ingredients has been performed. The most interesting results in the field are presented and commented upon, focusing on the different species of microalgae and the activity of the nutritionally relevant compounds. A summary of the health effects obtained together with pros and cons in the adoption of this natural source as functional food ingredients is also proposed.

Extraction and purification of high-value metabolites from microalgae: essential lipids, astaxanthin and phycobiliproteins

The marked trend and consumers growing interest in natural and healthy products have forced researches and industry to develop novel products with functional ingredients. Microalgae have been recognized as source of functional ingredients with positive health effects since these microorganisms produce polyunsaturated fatty acids, polysaccharides, natural pigments, essential minerals, vitamins, enzymes and bioactive peptides. For this reason, the manuscript reviews two of the main high-value metabolites which can be obtained from microalgae: pigments and essential lipids. Therefore, the extraction and purification methods for polyunsaturated fatty acids, astaxanthin, phycoerythrin and phycocyanin are described. Also, the effect that environmental growth conditions have in the production of these metabolites is described. This review summarizes the existing methods to extract and purify such metabolites in order to develop a feasible and sustainable algae industry.

Microalgal lipids biochemistry and biotechnological perspectives

In the last few years, there has been an intense interest in using microalgal lipids in food, chemical and pharmaceutical industries and cosmetology, while a noteworthy research has been performed focusing on all aspects of microalgal lipid production. This includes basic research on the pathways of solar energy conversion and on lipid biosynthesis and catabolism, and applied research dealing with the various biological and technical bottlenecks of the lipid production process. In here, we review the current knowledge in microalgal lipids with respect to their metabolism and various biotechnological applications, and we discuss potential future perspectives. The committing step in fatty acid biosynthesis is the carboxylation of acetyl-CoA to form malonyl-CoA that is then introduced in the fatty acid synthesis cycle leading to the formation of palmitic and stearic acids. Oleic acid may also be synthesized after stearic acid desaturation while further conversions of the fatty acids (i.e. desaturations, elongations) occur after their esterification with structural lipids of both plastids and the endoplasmic reticulum. The aliphatic chains are also used as building blocks for structuring storage acylglycerols via the Kennedy pathway. Current research, aiming to enhance lipogenesis in the microalgal cell, is focusing on over-expressing key-enzymes involved in the earlier steps of the pathway of fatty acid synthesis. A complementary plan would be the repression of lipid catabolism by down-regulating acylglycerol hydrolysis and/or β-oxidation. The tendency of oleaginous microalgae to synthesize, apart from lipids, significant amounts of other energy-rich compounds such as sugars, in processes competitive to lipogenesis, deserves attention since the lipid yield may be considerably increased by blocking competitive metabolic pathways. The majority of microalgal production occurs in outdoor cultivation and for this reason biotechnological applications face some difficulties. Therefore, algal production systems need to be improved and harvesting systems need to be more effective in order for their industrial applications to become more competitive and economically viable. Besides, a reduction of the production cost of microalgal lipids can be achieved by combining lipid production with other commercial applications. The combined production of bioactive products and lipids, when possible, can support the commercial viability of both processes. Hydrophobic compounds can be extracted simultaneously with lipids and then purified, while hydrophilic compounds such as proteins and sugars may be extracted from the defatted biomass. The microalgae also have applications in environmental biotechnology since they can be used for bioremediation of wastewater and to monitor environmental toxicants. Algal biomass produced during wastewater treatment may be further valorized in the biofuel manufacture. It is anticipated that the high microalgal lipid potential will force research towards finding effective ways to manipulate biochemical pathways involved in lipid biosynthesis and towards cost effective algal cultivation and harvesting systems, as well.

Quantitative analysis of extracted phycobilin pigments in cyanobacteria-an assessment of spectrophotometric and spectrofluorometric methods

Phycobilins are an important group of pigments that through complementary chromatic adaptation optimize the light-harvesting process in phytoplankton cells, exhibiting great potential as cyanobacteria species biomarkers. In their extracted form, concentrations of these water-soluble molecules are not easily determined using the chromatographic methods well suited to solvent-soluble pigments. Insights regarding the quantitative spectroscopic analysis of extracted phycobilins also remain limited. Here, we present an in-depth study of two methods that utilize the spectral properties of phycobilins in aqueous extracts. The technical work was carried out using high-purity standards of phycocyanin, phycoerythrin, and allophycocyanin. Calibration parameters for the spectrofluorometer and spectrophotometer were established. This analysis indicated the possibility of detecting pigments in concentrations ranging from 0.001 to 10 μg cm^-3. Fluorescence data revealed a reproducibility of 95 %. The differences in detection limits between the two methods enable the presence of phycobilins to be investigated and their amounts to be monitored from oligotrophic to eutrophic aquatic environments.

Sustainable production of biologically active molecules of marine based origin

The marine environment offers both economic and scientific potential which are relatively untapped from a biotechnological point of view. These environments whilst harsh are ironically fragile and dependent on a harmonious life form balance. Exploitation of natural resources by exhaustive wild harvesting has obvious negative environmental consequences. From a European industry perspective marine organisms are a largely underutilised resource. This is not due to lack of interest but due to a lack of choice the industry faces for cost competitive, sustainable and environmentally conscientious product alternatives. Knowledge of the biotechnological potential of marine organisms together with the development of sustainable systems for their cultivation, processing and utilisation are essential. In 2010, the European Commission recognised this need and funded a collaborative RTD/SME project under the Framework 7-Knowledge Based Bio-Economy (KBBE) Theme 2 Programme 'Sustainable culture of marine microorganisms, algae and/or invertebrates for high value added products'. The scope of that project entitled 'Sustainable Production of Biologically Active Molecules of Marine Based Origin' (BAMMBO) is outlined. Although the Union is a global leader in many technologies, it faces increasing competition from traditional rivals and emerging economies alike and must therefore improve its innovation performance. For this reason innovation is placed at the heart of a European Horizon 2020 Strategy wherein the challenge is to connect economic performance to eco performance. This article provides a synopsis of the research activities of the BAMMBO project as they fit within the wider scope of sustainable environmentally conscientious marine resource exploitation for high-value biomolecules.

Purification and Concentration of C-Phycocyanin from Spirulina platensis Using Aqueous Two-Phase System

In this article, the partitioning behavior of C-phycocyanin (C-PC) in aqueous two-phase systems (ATPS) with different component was investigated to evaluate the applicability of ATPS for extracting high purity of C-PC without chromatography. Under the optimized conditions (pH = 6; PEG-2000, 16 %, w/w; potassium sodium tartrate 21 %, w/w), a maximum purity of 5.01 was achieved after the whole separation process and the yield of the C-PC was 76.94 %.

Heart health peptides from macroalgae and their potential use in functional foods

Macroalgae have for centuries been consumed whole among the East Asian populations of China, Korea, and Japan. Due to the environment in which they grow, macroalgae produce unique and interesting biologically active compounds. Protein can account for up to 47% of the dry weight of macroalgae depending on species and time of cultivation and harvest. Peptides derived from marcoalgae are proven to have hypotensive effects in the human circulatory system. Hypertension is one of the major, yet controllable, risk factors in cardiovascular disease (CVD). CVD is the main cause of death in Europe, accounting for over 4.3 million deaths each year. In the United States it affects one in three individuals. Hypotensive peptides derived from marine and other sources have already been incorporated into functional foods such as beverages and soups. The purpose of this review is to highlight the potential of heart health peptides from macroalgae and to discuss the feasibility of expanding the variety of foods these peptides may be used in.

Purified c-phycoerythrin: safety studies in rats and protective role against permanganate-mediated fibroblast-DNA damage

We have evaluated in vitro cytotoxicity of cyanobacterial phycoerythrin (C-PE) on three human cell lines by cell proliferation and neutral red uptake assays. No toxic effects of C-PE were observed to any of the cell lines tested. The protective role of purified C-PE to potassium permanganate-mediated human fibroblast-DNA damage was assessed by comet assay at 0 (control), 10 and 20 microg C-PE ml(-1) doses in pre-, simultaneous and post-mutagen exposure conditions. Significant DNA damage was detected only in post-mutagen exposure conditions. Our findings confirmed that the C-PE is non-toxic and provides protection against permanganate-mediated DNA damage. The preliminary acute (2000 mg C-PE kg(-1) body weight, b.w.) and 90 day sub-chronic (0, 5, 15 and 25 mg C-PE kg(-1) b.w./day) oral toxicity studies of purified C-PE in male albino rats showed no mortality or treatment-related major clinical signs, and all the doses of C-PE were well tolerated. The no observed adverse effect level and no observed effect level were found to be 15 and 5 mg C-PE kg(-1) b.w./day respectively.

Perspectives on microalgal CO₂-emission mitigation systems--a review

The problem of climate change arising mainly from CO₂ emission is currently a critical environmental issue. Biofixation using microalgae has recently become an attractive approach to CO₂ capture and recycling with additional benefits of downstream utilization and applications of the resulting microalgal biomass. This review summarizes the history and strategies of microalgal mitigation of CO₂ emissions, photobioreactor systems used to cultivate microalgae for CO₂ fixation, current microalgae harvesting methods, as well as applications of valuable by-products. It is of importance to select appropriate microalgal species to achieve an efficient and economically feasible CO₂-emission mitigation process. The desired microalgae species should have a high growth rate, high CO₂ fixation ability, low contamination risk, low operation cost, be easy to harvest and rich in valuable components in their biomass.

A novel method of single step hydrophobic interaction chromatography for the purification of phycocyanin from Phormidium fragile and its characterization for antioxidant property

Phycocyanin--a major phycobiliprotein constitutively produced by many cyanobacteria--holds several promising applications in diagnostics, biomedical research, and therapeutics. This paper discusses a novel rapid method for the purification of cyanobacterial phycocyanin (C-PC) from Phormidium fragile using hydrophobic interaction chromatography. The protein was extracted and concentrated by grinding under liquid nitrogen and ammonium sulfate fractionation. C-PC was purified by single step hydrophobic interaction chromatography. Purified phycocyanin showed absorbance maximum (lambda(max)) at 624 nm. The criterion of purity (R) achieved was 4.52. Phycocyanin to phycoerythrin and phycocyanin to allophycocyanin purity ratio were 3.85 and 7.49, respectively. The purified protein showed a pI of 5.2 and has two subunits with molecular mass of 19 and 20 kDa each, corresponding to its highly reported alpha and beta subunits. The subunits of phycocyanin were confirmed by their bilin fluorescence using zinc assisted fluorescence enhancement technique. Intact C-PC was of 125 kDa as determined by HPLC, suggested the (alphabeta)(3) subunit assembly. Results obtained by this method in terms of purity, recovery, process time, simplicity, and efficacy are much better than previous methodologies. Purified phycocyanin was further scrutinized for its antioxidant capacity and judged against five non-enzymatic antioxidants by FRAP assay.

A simple method for extracting C-phycocyanin from Spirulina platensis using Klebsiella pneumoniae

C-phycocyanin (C-PC) was extracted from fresh Spirulina platensis by deploying a species of non-pathogenic nitrogen-fixing bacteria, namely, Klebsiella pneumoniae. The algal slurry was neither washed nor centrifuged; the bacterial culture was poured into the slurry, the vessel sealed, and crude C-PC extracted after about 24 h. The extraction was clean and efficient, and the purity and concentration of C-PC proved to be of adequate quality.

Large-scale recovery of C-phycocyanin from Spirulina platensis using expanded bed adsorption chromatography

C-phycocyanin was purified on a large scale by a combination of expanded bed adsorption, anion-exchange chromatography and hydroxyapatite chromatography from inferior Spirulina platensis that cannot be used for human consumption. First, phycobiliproteins were extracted by a simple, scaleable method and then were recovered by Phenyl-Sepharose chromatography in an expanded bed column. The purity (the A(620)/A(280) ratio) of C-phycocyanin isolated with STREAMLINE column was up to 2.87, and the yield was as high as 31 mg/g of dried S. platensis. After the first step, we used conventional anion-exchange chromatography for the purification steps, with a yield of 7.7 mg/g of dried S. platensis at a purity greater than 3.2 and with an A(620)/A(650) index higher than 5.0. The fractions from anion-exchange chromatography with a level of purity that did not conform to the above standard were subjected to hydroxyapatite chromatography, with a C-PC yield of 4.45 mg/g of dried S. platensis with a purity greater than 3.2. The protein from both purification methods showed one absolute absorption peak at 620 nm and a fluorescence maximum at 650 nm, which is consistent with the typical spectrum of C-phycocyanin. SDS-PAGE gave two bands corresponding to 21 and 18 kDa. In-gel digestion and LC-ESI-MS showed that the protein is C-phycocyanin.

Commercial applications of microalgae

The first use of microalgae by humans dates back 2000 years to the Chinese, who used Nostoc to survive during famine. However, microalgal biotechnology only really began to develop in the middle of the last century. Nowadays, there are numerous commercial applications of microalgae. For example, (i) microalgae can be used to enhance the nutritional value of food and animal feed owing to their chemical composition, (ii) they play a crucial role in aquaculture and (iii) they can be incorporated into cosmetics. Moreover, they are cultivated as a source of highly valuable molecules. For example, polyunsaturated fatty acid oils are added to infant formulas and nutritional supplements and pigments are important as natural dyes. Stable isotope biochemicals help in structural determination and metabolic studies. Future research should focus on the improvement of production systems and the genetic modification of strains. Microalgal products would in that way become even more diversified and economically competitive.

Capillary electrophoresis-mass spectrometry ofSpirulina platensis proteins obtained by pressurized liquid extraction

In this work, the usefulness of CE-MS to monitor and optimize the pressurized liquid extraction (PLE) of proteins from Spirulina platensis microalga is demonstrated. Crude and purified PLE extracts from microalga were analyzed by CE-MS. It was observed that the use of purification protocols of phycobiliproteins (namely, ultrafiltration or precipitation-dialysis-freeze drying) resulted in better CE resolution and MS signals, demonstrating that sample matrix plays an important role in CE-MS of proteins in real samples. Ultrafiltration was found less laborious and much faster than precipitation-dialysis-freeze drying (1 vs. 48 h). Direct analysis of crude extracts was demonstrated to be also possible by CE-MS, providing less-quality information but enough to characterize PLE extracts in a much faster way. Therefore, the latter protocol was selected to monitor and optimize the extraction process of phycobiliproteins from S. platensis. To do that, different extraction conditions were tested, including time, temperature and pressure of extraction, nature of pressurized liquid, distribution of microalga inside the extraction cell, type of packing, etc. It is demonstrated that the combined use of PLE and CE-MS allows the attainment of extracts rich in phycobiliproteins in short extraction times (namely, yields of 20% can be obtained in less than 2 h under the optimum PLE process in an automatic way). To our knowledge, this work shows for the first time the usefulness of CE-MS for monitoring and optimizing a PLE process.

Characterization of proteins fromSpirulina platensis microalga using capillary electrophoresis-ion trap-mass spectrometry and capillary electrophoresis-time of flight-mass spectrometry

In this work, a new capillary electrophoresis-mass spectrometry (CE-MS) procedure is developed to analyze proteins in Spirulina platensis microalgae. It is demonstrated that a fine optimization of several separation parameters is essential in order to achieve suitable CE-MS analysis of these proteins in natural extracts from microalgae. Namely, optimization of the composition of the separation buffer, electrospray conditions, and washing routine between runs are required in order to obtain reliable and reproducible CE-MS analyses of the main proteins found in this microalga (namely, allophycocyanin-alpha chain, allophycocyanin-beta, c-phycocyanin-alpha, and c-phycocyanin-beta). The relative molecular mass of these biopolymers is determined using two different MS instruments coupled to CE, i.e., CE-ion trap-MS and CE-time of flight-MS (CE-TOF-MS). A comparison between the results obtained with both instruments is carried out. The high resolution of the TOF-MS enables the distinction of small modifications in proteins and, thus, a more accurate mass determination. Interestingly, molecular mass values obtained by both CE-MS procedures agree very well while these experimental values are only in partial agreement with those theoretically expected (i.e., genetically derived masses). Some protein modifications due to amino acids exchange induced by nucleotide codon mutations are proposed to explain this difference.

Analysis of natural antioxidants by capillary electromigration methods

In this work, an exhaustive survey of capillary electromigration methods used to analyze natural antioxidants is presented together with some discussion of the use of these substances use as functional foods. This review provides an updated and exhaustive overview of the separation and identification by capillary electrophoresis of natural compounds with antioxidant activity found in natural matrices and/or foods. The compounds concerned are catechins, isoflavones, anthocyanins, phenolic acids, vitamins, as well as other less common natural substances that have shown antioxidant activity.

One-step chromatography method for efficient separation and purification of R-phycoerythrin from Polysiphonia urceolata

Phycoerythrins have been widely used in food, cosmetics, immunodiagnostics and analytical reagents. An efficient one-step chromatography method for purification of R-phycoerythrins from Polysiphonia urceolata was described in this paper. Pure R-phycoerythrin was obtained with an absorbance ratio A(565)/A(280) of 5.6 and a high recovery yield of 67.33% using a DEAE-Sepharose Fast Flow chromatography with a gradient elution of pH, alternative to common gradient elution of ionic strength. The absorption spectrum of R-phycoerythrin was characterized with three absorbance maxima at 565, 539 and 498 nm, respectively and the fluorescence emission spectrum at room temperature was measured to be 580 nm. The results of native-PAGE, and SDS-PAGE showed no contamination by other proteins in the phycoerythrin solution, which suggests an efficient method for the separation and purification of R-phycoerythrins from Polysiphonia urceolata.

Analysis of cyanobacterial pigments and proteins by electrophoretic and chromatographic methods

Cyanobacteria are a diverse and ubiquitous group of prokaryotes with several unifying features. Amongst these is the macromolecular structure known as the phycobilisome, which is composed of water-soluble phycobiliproteins covalently bound by linker peptides or proteins in a configuration designed to optimize energy transfer to the photosynthetic reaction center of the organism. Phycobiliproteins are highly fluorescent by virtue of their covalently bound, linear tetrapyrrole chromophores known as bilins. Analysis of these prosthetic pigments, along with other non-water soluble pigments, such as the chlorophylls and carotenoids, can provide insight into microbial diversity. The effects of environmental growth conditions and stresses can also be probed by measuring pigment and protein concentrations. This review will focus, therefore, on applications of various chromatographic and electrophoretic methods for the analysis of cyanobacterial pigment and protein constituents. Although the greatest emphasis will be placed on the measurement of bilins and phycobiliproteins, this review will also consider other pigments and proteins important to cyanobacterial growth and survival, such as chlorophyll a, carotenoids, ectoenzymes, linker and membrane proteins, and extracellular proteins.

Coupling of Solid-Phase Microextraction and Capillary Isoelectric Focusing with Laser-Induced Fluorescence Whole Column Imaging Detection for Protein Analysis

A coupling method of solid-phase microextraction (SPME) and capillary isoelectric focusing (CIEF) with laser-induced fluorescence (LIF) whole column imaging detection (WCID) was developed for the analysis of proteins. Unlike other liquid-phase separation methods and conventional CIEF, proteins are focused into stationary bands within a pH gradient in CIEF-WCID. Thus, CIEF-WCID is the most compatible liquid-phase separation method for coupling with SPME, which can effectively resolve the problems associated with the slow desorption kinetics of SPME in a liquid phase. By combining SPME and CIEF-WCID, the desorption time can be as long as necessary, allowing complete desorption without any band broadening and analyte carryover. By using this method, R-phycoerythrin in water can be extracted by SPME in 10 min, and subsequently analyzed by CIEF-LIF-WCID within 20 min, providing a limit of detection of 3.5 x 10(-12) M (S/N = 3). The feasibility of the SPME-CIEF-LIF-WCID method was demonstrated by extracting and analyzing extracellular phycoerythrins in cultured cyanobacteria samples. Extracellular phycoerythrins at the nanomolar level were extracted and analyzed in 30 min, while avoiding the interference of the cyanobacteria cells.