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Natural pigments are desired for use in food products due to the long-term adverse effects of synthetic pigments on consumers, industry, and health. In the search for naturally sourced pigments, researchers explored cyanobacteria and its pigments as one of the potential bioresources. Blue-green algae produce phycobiliproteins such as Phycocyanin, Phycoerythrin, and Allophycocyanin, which can serve as natural pigments. The pigments synthesized and extracted from algal sources have vast commercial value in various industries, including cosmetics, nutraceuticals, pharmaceuticals, etc., apart from their numerous health benefits. Over the course of time, scientific research has led to multiple advancements in the production and extraction strategies of pigments from Spirulina platensis , which has led to the expansion of its applications in various sectors. This review outlines recent advances in the sources and manufacturing of Phycocyanin, with an emphasis on specific extraction and purification procedures, as well as possible applications in diagnostics, foods, cosmetics, and pharmaceutical industries. [Display omitted] • Factors affecting the growth and Stability of Phycocyanin are outlined. • Bioactivities of Phycocyanin extracted from Spirulina is reviewed. • Different extraction methods used for the extraction of PC were documented with their advantages and disadvantages. • Present review also provides an insight on biosynthesis and structure of the Phycocyanin from Phycobiliproteins. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is a burden in low- and middle-income countries, and a late diagnosis with systemic arterial hypertension (SAH) is the major complication of CKD. C-phycoerythrin (CPE) is a bioactive compound derived from Phormidium persicinum that presents anti-inflammatory and antioxidant effects in vitro and nephroprotective effects in vivo. In the current study, we determine the antihypertensive effect of CPE in a 5/6 nephrectomy-induced CKD model using twenty normotensives male Wistar rats, grouped into four groups (n = 5): sham; sham + CPE; 5/6 nephrectomy (NFx); and NFx + CPE. Treatment started a week post-surgery and continued for five weeks, with weekly hemodynamic evaluations. Following treatment, renal function, oxidative stress, and the expression of vascular dysfunction markers were assessed. The renal function analysis revealed CKD hyperfiltration, and the hemodynamic evaluation showed that SAH developed at the third week. AT1R upregulation and AT2R downregulation together with Mas1/p-Akt/p-eNOS axis were also observed. CPE treatment mitigated renal damage, preserved renal function, and prevented SAH with the modulation of the vasodilative AT1R, AT2R, and Mas1/pAKT/peNOS axis. This result reveals that CPE prevented CKD progression to SAH by avoiding oxidative stress and vascular dysfunction in the kidneys. [ABSTRACT FROM AUTHOR]

Currently, the use of synthetic pigments in foods is restricted since synthetic pigments are proven and suspected to be harmful to human health. Phycobiliproteins (PBPs), existed in phycobilisomes (PBSs) of algae, are a kind of pigment-proteins with intense color. The specific color of PBPs (red and blue) is given by the water-soluble open-chained tetrapyrrole chromophore (phycobilin) that covalently attaches to the apo-protein via thioether linkages to cysteine residues. According to the spectral characteristics of PBPs, they can be categorized as phycoerythrins (PEs), phycocyanins (PCs), allophycocyanins (APCs), and phycoerythrocyanins (PECs). PBPs can be used as natural food colorants, fluorescent substances, and bioactive ingredients in food applications owing to their color characteristics and physiological activities. This paper mainly summarizes the extraction and purification methods of the PBPs and reviews their characteristics and applications. Moreover, the use of several strategies such as additives, microencapsulation, electrospray, and cross-linking to improve the stability and bioavailability of PBPs as well as the future outlooks of PBPs as natural colorants in food commercialization are elucidated. [ABSTRACT FROM AUTHOR]

Cryptophytes are known to vary widely in coloration among species. These differences in color arise primarily from the presence of phycobiliprotein accessory pigments. There are nine defined cryptophyte phycobiliprotein (Cr‐PBP) types, named for their wavelength of maximal absorbance. Because Cr‐PBP type has traditionally been regarded as a categorical trait, there is a paucity of information about how spectral absorption characteristics of Cr‐PBPs vary among species. We investigated variability in primary and secondary peak absorbance wavelengths and full width at half max (FWHM) values of spectra of Cr‐PBPs extracted from 75 cryptophyte strains (55 species) grown under full spectrum irradiance. We show that there may be substantial differences in spectral shapes within Cr‐PBP types, with Cr‐Phycoerythrin (Cr‐PE) 545 showing the greatest variability with two, possibly three, subtypes, while Cr‐PE 566 spectra were the least variable, with only ±1 nm of variance around the mean absorbance maximum of 565 nm. We provide additional criteria for classification in cases where the wavelength of maximum absorbance alone is not definitive. Variations in spectral characteristics among strains containing the same presumed Cr‐PBP type may indicate differing chromophore composition and/or the presence of more than one Cr‐PBP in a single cryptophyte species. [ABSTRACT FROM AUTHOR]

Thermophilic cyanobacteria are prokaryotic photoautotrophic microorganisms capable of growth between 45 and 73 °C. They are typically found in hot springs where they serve as essential primary producers. Several key features make these robust photosynthetic microbes biotechnologically relevant. These are highly stable proteins and their complexes, the ability to actively transport and concentrate inorganic carbon and other nutrients, to serve as gene donors, microbial cell factories, and sources of bioactive metabolites. A thorough investigation of the recent progress in thermophilic cyanobacteria reveals a significant increase in the number of newly isolated and delineated organisms and wide application of thermophilic light-harvesting components in biohybrid devices. Yet despite these achievements, there are still deficiencies at the high-end of the biotechnological learning curve, notably in genetic engineering and gene editing. Thermostable proteins could be more widely employed, and an extensive pool of newly available genetic data could be better utilised. In this manuscript, we attempt to showcase the most important recent advances in thermophilic cyanobacterial biotechnology and provide an overview of the future direction of the field and challenges that need to be overcome before thermophilic cyanobacterial biotechnology can bridge the gap with highly advanced biotechnology of their mesophilic counterparts. Key points: • Increased interest in all aspects of thermophilic cyanobacteria in recent years • Light harvesting components remain the most biotechnologically relevant • Lack of reliable molecular biology tools hinders further development of the chassis [ABSTRACT FROM AUTHOR]

Algae, which are ubiquitous in ecosystems, have evolved a variety of light-harvesting complexes to better adapt to diverse habitats. Phycobilisomes/phycobiliproteins, unique to cyanobacteria, red algae, and certain cryptomonads, compensate for the lack of chlorophyll absorption, allowing algae to capture and efficiently transfer light energy in aquatic environments. With the advancement of microscopy and spectroscopy, the structure and energy transfer processes of increasingly complex phycobilisomes have been elucidated, providing us with a vivid portrait of the dynamic adaptation of their structures to the light environment in which algae thrive: 1) Cyanobacteria living on the surface of the water use short, small phycobilisomes to absorb red-orange light and reduce the damage from blue-violet light via multiple methods; 2) Large red algae inhabiting the depths of the ocean have evolved long and dense phycobilisomes containing phycoerythrin to capture the feeble blue-green light; 3) In far-red light environments such as caves, algae use special allophycocyanin cores to optimally utilize the far-red light; 4) When the environment shifts, algae can adjust the length, composition and density of their rods to better adapt; 5) By carefully designing the position of the pigments, phycobilisomes can transfer light energy to the reaction center with nearly 100% efficiency via three energy transfer processes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is a burden in low- and middle-income countries, and a late diagnosis with systemic arterial hypertension (SAH) is the major complication of CKD. C-phycoerythrin (CPE) is a bioactive compound derived from Phormidium persicinum that presents anti-inflammatory and antioxidant effects in vitro and nephroprotective effects in vivo. In the current study, we determine the antihypertensive effect of CPE in a 5/6 nephrectomy-induced CKD model using twenty normotensives male Wistar rats, grouped into four groups (n = 5): sham; sham + CPE; 5/6 nephrectomy (NFx); and NFx + CPE. Treatment started a week post-surgery and continued for five weeks, with weekly hemodynamic evaluations. Following treatment, renal function, oxidative stress, and the expression of vascular dysfunction markers were assessed. The renal function analysis revealed CKD hyperfiltration, and the hemodynamic evaluation showed that SAH developed at the third week. AT1R upregulation and AT2R downregulation together with Mas1/p-Akt/p-eNOS axis were also observed. CPE treatment mitigated renal damage, preserved renal function, and prevented SAH with the modulation of the vasodilative AT1R, AT2R, and Mas1/pAKT/peNOS axis. This result reveals that CPE prevented CKD progression to SAH by avoiding oxidative stress and vascular dysfunction in the kidneys.

Abstract Pigment is an important food additive that plays a major role in the sensory impact of food. And natural sources, healthy and non-toxic edible pigments are receiving a lot of attention. Algae is an important source of natural pigments, and contain chlorophyll, phycoerythrin, carotene, and other natural pigments. Besides staining, the pigment also has powerful physiological activities such as antioxidants, anti-inflammatory, anti-obesity, and lipid-lowering. In this paper, three pigments in seaweed were reviewed, and their main structural properties and functions are presented, filling the gap in the review of pigments with seaweed as the main object of introduction. This review provides research basis for the development of new health foods, a new direction for the use of seaweed chlorophyll in the food and pharmaceutical industries. Graphical Abstract

Cyanobacterial species such as Oscillatoria spp. pigments are essential components that enable the photosynthetic ability of this autotrophic organism. These pigments, principally chlorophylls and phycobiliproteins, are crucial for photosynthesis and give cyanobacteria their distinctive blue-green color. Exploring these pigments is crucial for unraveling the ecological and biotechnological relevance and significance. Spectrophotometric methods were used for measuring the chlorophyll-a, phycobiliprotein, and carotenoid contents of Oscillatoria species. Oscillatoria spp. displayed significantly variable (p ˂ 0.05) chlorophyll-a ranging from 12.67 ± 0.04 to 22.72 ± 0.04 µg/mL. Phycobiliprotein content (mg/g) significantly (p ˂ 0.05) varied from 87.39 ± 0.12 µg/mL to 121.42 ± 0.06. Carotenoid content also significantly ranged from 1.0 ± 0.01 µg/mL to 1.4 ± 0.01 µg/mL. Present data will contribute to the screening and characterization of Oscillatoria spp. in terms of pigment to utilize it in rigorous scientific research and diverse commercial applications.

Phycobiliproteins (PBPs) are natural water-soluble pigment proteins, which constitute light-collecting antennae, and function in algae photosynthesis, existing in cyanobacteria, red algae, and cryptomonads. They are special pigment–protein complexes in algae with a unique structure and function. According to their spectral properties, PBPs can be mainly divided into three types: allophycocyanin, phycocyanin, and PE. At present, there are two main sources of PBPs: one is natural PBPs extracted from algae and the other way is recombinant PBPs which are produced in engineered microorganisms. The covalent connection between PBP and streptavidin was realized by gene fusion. The bridge cascade reaction not only improved the sensitivity of PBP as a fluorescent probe but also saved the preparation time of the probe, which expands the application range of PBPs as fluorescent probes. In addition to its function as a light-collecting antenna in photosynthesis, PBPs also have the functions of biological detection, ion detection, and fluorescence imaging. Notably, increasing studies have designed novel PBP-based far-red fluorescent proteins, which enable the tracking of gene expression and cell fate. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Iron is one of the important micronutrients affecting algal growth due to its fundamental role in the physiological processes, including photosynthetic electron transport, respiration, and nitrogen fixation. In this study, the effect of different iron levels on growth and the production of bioactive compounds (phycoerythrin (PE), extracellular polymeric substances (EPS), and phenolic compounds (PCs)) of five cryptophyte strains were investigated. Also, the antioxidant capacity of the bioactive compounds was explored. The results showed species-specific responses to the impact of iron on growth of cryptophytes and accumulation of bioactive compounds. The growth rates of C. pyrenoidifera and Cryptomonas sp. varied significantly at different iron levels, and a reduction in the PE content was observed for several cryptophytes cultured at the highest iron level. However, no significant differences were detected in EPS content at different iron levels. Differences in PC contents of C. pyrenoidifera and Cryptomonas sp. at medium iron level were statistically significant compared with the other two treatments. The results also revealed species-specific differences in antioxidant activity at different iron levels; each studied strain followed its own pattern in response to change in iron level, and each bioactive compound had a different antioxidant activity. Overall, however, PCs demonstrated higher antioxidant activity than PE and EPS. In summary, iron has an impact on growth, bioactive compound accumulation, and antioxidant activity. However, the species-specific responses to changes in iron level should not be ignored when modifying culture conditions for optimal harvest of bioactive compounds. [ABSTRACT FROM AUTHOR]

Pigment is an important food additive that plays a major role in the sensory impact of food. And natural sources, healthy and non-toxic edible pigments are receiving a lot of attention. Algae is an important source of natural pigments, and contain chlorophyll, phycoerythrin, carotene, and other natural pigments. Besides staining, the pigment also has powerful physiological activities such as antioxidants, anti-inflammatory, anti-obesity, and lipid-lowering. In this paper, three pigments in seaweed were reviewed, and their main structural properties and functions are presented, filling the gap in the review of pigments with seaweed as the main object of introduction. This review provides research basis for the development of new health foods, a new direction for the use of seaweed chlorophyll in the food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Phycoerythrin (PE) is a natural protein–pigment complex with a strong pink color, but it is sensitive to thermal and light variations. In this study, PE was extracted from Porphyra haitanensis in a yield of 0.2% (w/w). The phycoerythrin hydrolysates (PEH) (3–10 kDa) were prepared by enzymatic hydrolysis of PE with bromelain (8000 U/g) at 47 °C for 30 min, with a degree of hydrolysis (DH) of 11.57 ± 0.39% and a color degradation rate of 7.98 ± 0.39%. The physicochemical properties of PEH were evaluated. The UV and fluorescence spectra indicated that bromelain changed the microenvironment around phycoerythrobilin (PEB). The infrared spectrum revealed that the bromelain hydrolysis increased the α-helix content of PEH. The scanning electron microscope showed that bromelain destroyed the dense and smooth structure of PE, resulting in irregular porous structures. The radical scavenging activities of DPPH and ABTS of PEH were increased relative to that of PE (p < 0.05). The thermal (50–80 °C)-, UV (0.5–3 h)-, visible light irradiation (2–8 h)-, and metal ion exposing stabilities of PEH were significantly improved (p < 0.05). This study provides a potential scheme for overcoming the sensitivity of PE to thermal and light variations and facilitates PEH as a natural colorant ingredient in food and pigment applications. [ABSTRACT FROM AUTHOR]

The phycobilisome (PBS) is the major light-harvesting apparatus in cyanobacteria and red algae. It is a large multi-subunit protein complex of several megadaltons that is found on the stromal side of thylakoid membranes in orderly arrays. Chromophore lyases catalyse the thioether bond between apoproteins and phycobilins of PBSs. Depending on the species, composition, spatial assembly, and, especially, the functional tuning of different phycobiliproteins mediated by linker proteins, PBSs can absorb light between 450 and 650 nm, making them efficient and versatile light-harvesting systems. However, basic research and technological innovations are needed, not only to understand their role in photosynthesis but also to realise the potential applications of PBSs. Crucial components including phycobiliproteins, phycobilins, and lyases together make the PBS an efficient light-harvesting system, and these provide a scheme to explore the heterologous synthesis of PBS. Focusing on these topics, this review describes the essential components needed for PBS assembly, the functional basis of PBS photosynthesis, and the applications of phycobiliproteins. Moreover, key technical challenges for heterologous biosynthesis of phycobiliproteins in chassis cells are discussed. [ABSTRACT FROM AUTHOR]

Encapsulation in liposome structure can be used as a protective carrier system for bioactive compounds during processing and storage under different conditions. Phycobiliproteins (PBPs) extracted from algae with antioxidant, antimicrobial, anti-cancer and anti-inflammatory properties can be applied to produce raw materials for functional foods. Therefore, in the present study, phycobiliprotein pigment was extracted from Gracilaria algae and the amounts of pigment was investigated. Also, nanoliposomes containing PBPs coated by chitosan (0, 0.5, 1 and 1.5%) were prepared and their physicochemical properties, antioxidant and antimicrobial activity were evaluated. The mean diameter of nanoliposomes and Polydispersity index (PDI) ranged from 336.9 to 577.7 nm and 0.25 to 0.28 in nanocarriers, respectively. The highest values of nanoliposome encapsulation efficiency of PBPs (83.98%) were obtained under optimal conditions in nanoliposomes with 1.5% chitosan coating. The results showed that the antimicrobial activity of the treatments increased significantly after encapsulation in the nanoliposome. In addition, the antioxidant activity of PBPs increased significantly after nanoencapsulation in liposomes. So that the EC50 level decreased to 81.27 and 107.67 ppm in DPPH and ABTS tests in nanoliposomes with 1.5% chitosan coating, respectively. Based on the findings of this study, it can be realized that nanocoating with chitosan effectively increases its stability, antimicrobial and antioxidant properties. Therefore, in order to increase the stability of natural compounds during different processes, it is recommended.

A separation process was established to sequentially fractionate and recover three anti-inflammatory components derived from sugars, phycobiliprotein, and chlorophyll from the hot-air-dried thalli of the red alga dulse (Palmaria palmata). The developed process consisted of three steps, without the use of organic solvents. In Step I, the sugars were separated by disrupting the cell wall of the dried thalli with a polysaccharide-degrading enzyme, and a sugar-rich extract (E1) was obtained by precipitating the other components, which were simultaneously eluted by acid precipitation. In Step II, the residue suspension from Step I was digested with thermolysin to obtain phycobiliprotein-derived peptides (PPs), and a PP-rich extract (E2) was obtained by separating the other extracts using acid precipitation. In Step III, solubilized chlorophyll was obtained by heating the residue, which was acid-precipitated, neutralized, and re-dissolved to concentrate the chlorophyll-related components (Chls)-rich extract (E3). These three extracts suppressed inflammatory-cytokine secretion by lipopolysaccharide (LPS)-stimulated macrophages, confirming that the sequential procedure had no negative effects on the activities of any of the extracts. The E1, E2, and E3 were rich in sugars, PPs, and Chls, respectively, indicating that the anti-inflammatory components were effectively fractionated and recovered through the separation protocol. [ABSTRACT FROM AUTHOR]

Thermophilic cyanobacteria are cosmopolitan and abundant in the thermal environment. Their light-harvesting complexes, phycobilisomes (PBS), are highly important in photosynthesis. To date, there is limited information on the PBS composition of thermophilic cyanobacteria whose habitats are challenging for survival. Herein, genome-based methods were used to investigate the molecular components of PBS in 19 well-described thermophilic cyanobacteria. These cyanobacteria are from the genera Leptolyngbya, Leptothermofonsia, Ocullathermofonsia, Thermoleptolyngbya, Trichothermofonsia, Synechococcus, Thermostichus, and Thermosynechococcus. According to the phycobiliprotein (PBP) composition of the rods, two pigment types are observed in these thermophiles. The amino acid sequence analysis of different PBP subunits suggests several highly conserved cysteine residues in these thermophiles. Certain amino acid contents in the PBP of thermophiles are significantly higher than their mesophilic counterparts, highlighting the potential roles of specific substitutions of amino acid in the adaptive thermostability of light-harvesting complexes in thermophilic cyanobacteria. Genes encoding PBS linker polypeptides vary among the thermophiles. Intriguingly, motifs in linker apcE indicate a photoacclimation of a far-red light by Leptolyngbya JSC-1, Leptothermofonsia E412, and Ocullathermofonsia A174. The composition pattern of phycobilin lyases is consistent among the thermophiles, except for Thermostichus strains that have extra homologs of cpcE, cpcF, and cpcT. In addition, phylogenetic analyses of genes coding for PBPs, linkers, and lyases suggest extensive genetic diversity among these thermophiles, which is further discussed with the domain analyses. Moreover, comparative genomic analysis suggests different genomic distributions of PBS-related genes among the thermophiles, indicating probably various regulations of expression. In summary, the comparative analysis elucidates distinct molecular components and organization of PBS in thermophilic cyanobacteria. These results provide insights into the PBS components of thermophilic cyanobacteria and fundamental knowledge for future research regarding structures, functions, and photosynthetic improvement. [ABSTRACT FROM AUTHOR]

In addition to their membrane‐bound chlorophyll a/c light‐harvesting antenna, the cryptophyte algae have evolved a unique phycobiliprotein antenna system located in the thylakoid lumen. The basic unit of this antenna consists of two copies of an αβ protomer where the α and β subunits scaffold different combinations of a limited number of linear tetrapyrrole chromophores. While the β subunit is highly conserved, encoded by a single plastid gene, the nuclear‐encoded α subunits have evolved diversified multigene families. It is still unclear how this sequence diversity results in the spectral diversity of the mature proteins. By careful examination of three newly determined crystal structures in comparison with three previously obtained, we show how the α subunit amino acid sequences control chromophore conformations and hence spectral properties even when the chromophores are identical. Previously we have shown that α subunits control the quaternary structure of the mature αβ.αβ complex (either open or closed), however, each species appeared to only harbor a single quaternary form. Here we show that species of the Hemiselmis genus contain expressed α subunit genes that encode both distinct quaternary structures. Finally, we have discovered a common single‐copy gene (expressed into protein) consisting of tandem copies of a small α subunit that could potentially scaffold pairs of light harvesting units. Together, our results show how the diversity of the multigene α subunit family produces a range of mature cryptophyte antenna proteins with differing spectral properties, and the potential for minor forms that could contribute to acclimation to varying light regimes. PDB Code(s): 7T7U, 7T8S and 7T89; [ABSTRACT FROM AUTHOR]

Phycobiliprotein is a kind of natural pigment active protein, which exists widely in all kinds of seaweed. It is an important part of seaweed photosynthesis. Phycobiliproteins often exist on the thylakoid membrane in the form of phycobilisomes. Phycobiliproteins have specific light absorption peak and fluorescence emission peak. Phycobiliproteins have various biological activities such as anti-oxidation, anti-tumor, anti-radiation, and immune-enhancing. High purity phycobiliproteins have high economic values. In recent years, many new research progresses have been made in the extraction and purification process and application development. To provide with a systematic and detailed information about those features of phycobiliproteins, this article reviews a relatively comprehensive analysis on the extraction source, structural composition, extraction, purification process and the application of phycobiliprotein in the fields of food, cosmetics and medicine, which provides reference for the further development and utilization of phycobiliprotein.

Crude enzymes produced by a marine bacterium Pseudoalteromonas sp. JS4-1 were used to hydrolyze phycobiliprotein. Enzymatic productions showed good performance on DPPH radical and hydroxyl radical scavenging activities (45.14 ± 0.43% and 65.11 ± 2.64%, respectively), especially small peptides with MWCO <3 kDa. Small peptides were fractioned to four fractions using size-exclusion chromatography and the second fraction (F2) had the highest activity in hydroxyl radical scavenging ability (62.61 ± 5.80%). The fraction F1 and F2 both exhibited good antioxidant activities in oxidative stress models in HUVECs and HaCaT cells. Among them, F2 could upregulate the activities of SOD and GSH-Px and reduce the lipid peroxidation degree to scavenge the ROS to protect Caenorhabditis elegans under adversity. Then, 25 peptides total were identified from F2 by LC-MS/MS, and the peptide with the new sequence of INSSDVQGKY as the most significant component was synthetized and the ORAC assay and cellular ROS scavenging assay both illustrated its excellent antioxidant property. [ABSTRACT FROM AUTHOR]

Phycobiliprotein (PB), which is produced by cyanobacteria, has potential applications as a valuable pharmaceutical product. In this study, PB was separated by using a nonwoven-fabric membrane (Rx-1) that contained quaternary amino groups. PB was extracted from a Nostoc commune, which is a type of microalga, by disrupting the cell walls by a freeze–thaw method. Two types of biomolecules, namely PB and other biomolecules X, were identified by gel permeation chromatography. Permeation of the PB-containing solution through Rx-1 increased the purity of the PB in the filtrate from 0.25 to 0.45. The adsorption constant (Kp) and maximum adsorbed amount of each protein on Rx-1 (qmax) were determined by fitting the experimental data to a mathematical model. The obtained values for Kp and qmax were used to simulate scaled-up treatment of a PB-containing solution. Permeation of a PB-containing solution (3.0 L at 1.2 × 10−3 m³/h) through Rx-1 (volume of scale-up membrane, 8.0 × 10−4 m³) enabled PB separation for 26 h. Further PB purification could be achieved by using the Rx-1 membrane in combination with precipitation with ammonium sulfate solution and an ultrafiltration membrane. [ABSTRACT FROM AUTHOR]

This study is focused on the effect of phycobiliprotein extraction of Gracilaria on the quality of common carp burgers, and the application of nanoliposomes containing pigment in the improvement of its antimicrobial and antioxidant activity of burgers during refrigerated storage in 18 days. Burgers were incorporated with phycobiliprotein and liposomal phycobiliprotein (2.5% and 5% w/w), and their chemical and microbial changes in terms of pH, peroxide value (PV), thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), total viable counts (TVC), psychrotrophic bacterial counts (PTC), and sensory characteristics were evaluated. Results presented a nanoliposome size of about 515.5 nm with capable encapsulation efficiency (83.98%). Our results showed non-encapsulated phycobiliprotein could delay the deterioration of common carp burgers, as a reduction in PV, TBA, and TVB-N, TVC, and PTC values in burgers treated with free and nano encapsulated phycobiliprotein. Moreover, the potential of phycobiliprotein was improved when it was encapsulated into chitosan coated liposomes. Burgers treated with 5% nanoliposomes displayed the lowest amount of lipid oxidation and microbial deterioration in comparison to others during storage. According to chemical, microbial and sensory evaluation, the shelf life of common carp burgers was increased in samples treated with encapsulated phycobiliprotein at 2.5% and 5%, as compared to the control (p ≤ 0.05).

Objective: Effects of phycobiliprotein and phycocyanin from artifically raised Nostoc sphaeroides Kützing on the growth of tumor in S180 tumor-bearing mice and its mechanism. Methods: The in vivo antitumor activity of phycobiliprotein and phycocyanin from Nostoc sphaeroides Kützing was evaluated by examining the tumor volume of S180 tumor-bearing mice, mouse organ indices and tumor tissue section observation, and its mechanism of action was initially studied. Results: The results of in vivo antitumor effect showed that the tumor inhibition rates of phycobiliprotein 12.5, 25 and 50 mg/kg dose groups were 11.19%, 20.14% and 37.65%, respectively, against mouse sarcoma S180. The tumor inhibition rates of phycocyanin 12.5, 25 and 50 mg/kg dose groups were 19.74%, 35.00% and 52.06%, respectively, against mouse sarcoma S180. Phycocyanin significantly promoted the expression of oncoprotein P53 and pro-apoptotic protein Bax, and inhibited the expression of apoptosis suppressor protein Bcl2. Conclusion: Phycocyanin high dose group significantly reduced the proliferation of S180 sarcoma cells. Phycocyanin low and medium doses and phycocyanin high doses also had some inhibitory effects. Phycobiliprotein and phycocyanin from artifically raised Nostoc sphaeroides Kützing have better in vivo antitumor activity.

This study investigated the production of antioxidant peptides from Porphyra yezoensis through fermentation with three strains of microorganisms: Lactiplantibacillus plantarum L13, Bacillus amyloliquefaciens MMB-02, and Saccharomyces cerevisiae A8. The crude peptides were extracted by aqueous acid precipitation and purified by Sephadex G-25 gel column to produce highly active antioxidant components with molecular weight of <4000 Da. The LC-MS/MS result revealed that the fermentation group contained more hydrophobic amino acids and oligopeptides, which were mainly originated from phycobiliproteins and algal blue proteins. Finally, the antioxidant activity of Porphyra yezoensis was determined with DPPH· and ABTS· scavenging rates of 54.87% and 57.39%, respectively. The ferric ion-reducing power (FRAP) and enzyme activities of SOD and CAT were significantly higher than those of the control group. This study provides a scientific foundation for the deep processing of striped seaweed and contributes to the theoretical understanding of synthetic antioxidant substitutes. • Synergistic fermentation of P. yezoensis by 3 microbial strains were studied. • Antioxidant peptides were produced from mixed fermented Porphyra yezoensis. • Peptides were mainly hydrophobic amino acids with low molecular weight. • Extracted crude peptides were purified to produce highly active antioxidants. • Antioxidants from microbial co-fermentation can be a viable synthetic alternative. [ABSTRACT FROM AUTHOR]

The rising global population has decreased available land, demanding food security. In reaction, sustainable sources like aquatic foods, or "blue foods," derived from freshwater and marine ecosystems, arise from high-quality protein. Algae, a key blue food protein, is pivotal in meeting the food industry's needs. Algae are divided into two categories based on cellular structure: macroalgae, also known as seaweeds, which are large aquatic plants, and microalgae, which are tiny eukaryotic organisms. Both macro and microalgae are nutrient-dense, offering essential amino acids and bioactive compounds, making them a promising solution for the growing demand for sustainable protein sources. Algae proteins, with their remarkable functional properties such as solubility, emulsification, foaming, gelation, and coloring, can be produced sustainably without competing for agricultural land. Research has explored incorporating algae biomass into food products like cookies, bread, yogurt, snacks, and soups to boost protein content. This review delves into the origins, varieties, physical and techno-functional characteristics, and uses of macro and microalgae proteins in food, while also addressing the benefits and drawbacks of algae proteins. • Algal proteins are a sustainable and nutrient rich source of proteins. • Techno-functional properties of algal proteins make them an excellent ingredient. • Algal proteins are underutilized due to their high cost and limited awareness. • Functional food trends have initiated the integration of such proteins into a variety of products. [ABSTRACT FROM AUTHOR]

Phycobiliproteins (PBPs) are natural water-soluble pigment proteins, which constitute light-collecting antennae, and function in algae photosynthesis, existing in cyanobacteria, red algae, and cryptomonads. They are special pigment–protein complexes in algae with a unique structure and function. According to their spectral properties, PBPs can be mainly divided into three types: allophycocyanin, phycocyanin, and PE. At present, there are two main sources of PBPs: one is natural PBPs extracted from algae and the other way is recombinant PBPs which are produced in engineered microorganisms. The covalent connection between PBP and streptavidin was realized by gene fusion. The bridge cascade reaction not only improved the sensitivity of PBP as a fluorescent probe but also saved the preparation time of the probe, which expands the application range of PBPs as fluorescent probes. In addition to its function as a light-collecting antenna in photosynthesis, PBPs also have the functions of biological detection, ion detection, and fluorescence imaging. Notably, increasing studies have designed novel PBP-based far-red fluorescent proteins, which enable the tracking of gene expression and cell fate.

The chromophore bound to the 84th amino acid in the -subunit ( 84), the chromophore bound to the 82nd amino acid in the -subunit ( 82), and the chromophore bound to the 153th amino acid in the -subunit ( 153) are depicted using blue stick, purple spacefill, and black stick representations, respectively. Based on the structural data obtained by Ma et al. [[11]], the absorption wavelength of each 82 chromophore in the PC hexamer located next to the top of core B was calculated using quantum chemical treatment, including the electric effect from its surrounding phycocyanin proteins and two linker proteins. Conclusions According to the quantum chemical calculations of this research, the 82 chromophore in the N2 chain, which is the closest of those in the phycocyanin (PC) hexamer to the core, is significantly redshifted by L SB RC sb 1, indicating that it is the energy sink of the rod. The hexameric structure modulates the optical absorption wavelength of the outside chromophore and effectively transfers the light energy absorbed at the outer chromophore to the inner chromophores [[23]]. [Extracted from the article]

The phycobilisomes attached to the outer side of the thylakoid membrane absorb and transmit light energy in cyanobacteria and red algae. They consist of phycobiliproteins and linker polypeptides. LCM involved in the attachment of the phycobilisomes to the membrane is called core–membrane linker polypeptide. This study aimed to clone the apcE gene encoding the core–membrane linker polypeptide ApcE from Arthrospira platensis FACHB314. Then, the apcE gene was expressed with phycocyanobilin synthesis–related elements in Escherichia coli. The fluorescence emission spectra showed that purified ApcE was fluorescing (λmax = 670 nm), indicating that ApcE could bind with phycocyanobilin in low yield in an autocatalytic reaction. The Cys201, Cys419, Cys616, and Cys644 of the polypeptide were mutated to investigate the binding sites of ApcE with phycocyanobilin. The fluorescence peak of mutant strain E.coli HPApcE201 almost did not exist, implying that Cys201was the binding site of ApcE. The ApcE and allophycocyanin (APC) or phycocyanins (PC) were co-expressed in E. coli separately to investigate the role of ApcE in the fluorescence activity of phycobiliproteins. The mass spectrometry results showed that high–molecular weight protein polymers of ApcE and APC or of ApcE and PC might exist. The fluorescence emission spectra showed that the characteristic fluorescence peak of APC and PC was higher and the wavelength range of fluorescence peak was larger with ApcE expression. [ABSTRACT FROM AUTHOR]

Antiretroviral therapy is the single existing therapy for patients infected with HIV; however, it has drawbacks in terms of toxicity and resistance. Thus, there is a continuous need to explore safe and efficacious anti-retroviral agents. C-Phycocyanin (C-PC) is a phycobiliprotein, which has been known for various biological properties; however, its effect on HIV-1 replication needs revelation. This study aimed to identify the inhibitory effects of C-PC on HIV-1 using in vitro and in silico approaches and to assess its role in the generation of mitochondrial reactive oxygen species (ROS) during HIV-1 infection. In vitro anti-HIV-1 activity of C-PC was assessed on TZM-bl cells through luciferase gene assay against four different clades of HIV-1 strains in a dose-dependent manner. Results were confirmed in PBMCs, using the HIV-1 p24 antigen assay. Strong associations between C-PC and HIV-1 proteins were observed through in silico molecular simulation-based interactions, and the in vitro mechanistic study confirmed its target by inhibition of reverse transcriptase and protease enzymes. Additionally, the generation of mitochondrial ROS was detected by the MitoSOX and DCF-DA probe through confocal microscopy. Furthermore, our results confirmed that C-PC treatment notably subdued the fluorescence in the presence of the virus, thus reduction of ROS and the activation of caspase-3/7 in HIV-1-infected cells. Overall, our study suggests C-PC as a potent and broad in vitro antiviral and antioxidant agent against HIV-1 infection. [ABSTRACT FROM AUTHOR]

In manufacturing industries that use seaweeds containing high moisture as raw materials, the volume reduction of seaweeds is a basic requirement for their efficient storage, transport, and processing. In this study, fresh red algae, dulse Palmaria palmata was hot air–dried at 30 and 60 °C with or without pre-freezing for 1 week, and anti-inflammatory components, phycobiliprotein (P) and chlorophyll a-related compounds (C) were extracted together using water from the dried thalli. The water extractability of each was diminished by pre-freezing and markedly impaired by hot-air drying of the raw dulse. In contrast, the anti-inflammatory activity of thermolysin digested P and C mixtures, which was evaluated using lipopolysaccharide-stimulated murine macrophages, persisted despite exposure of the raw materials to the freezing and hot-air-drying processes. In addition, the deterioration in the extractability of P caused by hot-air drying was recovered by the enzymatic degradation of the cell wall hardened by drying, and the water extract showed strong anti-inflammatory activity. These results indicated that hot-air–dried dulse can be used as an anti-inflammatory material by utilizing the appropriate physicochemical procedure for restoring the extractability of the anti-inflammatory components, and enzymatic algal cell degradation is one such practical countermeasure. [ABSTRACT FROM AUTHOR]

Encapsulation in liposome structure can be used as a protective carrier system for bioactive compounds during processing and storage under different conditions. Phycobiliproteins (PBPs) extracted from algae with antioxidant, antimicrobial, anti-cancer and anti-inflammatory properties can be applied to produce raw materials for functional foods. Therefore, in the present study, phycobiliprotein pigment was extracted from Gracilaria algae and the amounts of pigment was investigated. Also, nanoliposomes containing PBPs coated by chitosan (0, 0.5, 1 and 1.5%) were prepared and their physicochemical properties, antioxidant and antimicrobial activity were evaluated. The mean diameter of nanoliposomes and Polydispersity index (PDI) ranged from 336.9 to 577.7 nm and 0.25 to 0.28 in nanocarriers, respectively. The highest values of nanoliposome encapsulation efficiency of PBPs (83.98%) were obtained under optimal conditions in nanoliposomes with 1.5% chitosan coating. The results showed that the antimicrobial activity of the treatments increased significantly after encapsulation in the nanoliposome. In addition, the antioxidant activity of PBPs increased significantly after nanoencapsulation in liposomes. So that the EC50 level decreased to 81.27 and 107.67 ppm in DPPH and ABTS tests in nanoliposomes with 1.5% chitosan coating, respectively. Based on the findings of this study, it can be realized that nanocoating with chitosan effectively increases its stability, antimicrobial and antioxidant properties. Therefore, in order to increase the stability of natural compounds during different processes, it is recommended. [ABSTRACT FROM AUTHOR]

Almost all of the current hair dye products today contain synthetic chemicals which may cause allergic reactions in some users. Phycocyanin (PC), a non-toxic cyanobacterial pigment, has been used in the food and cosmetics sectors. There are however, been a few reports on the application of phycocyanin as a hair colorant. This study aimed to assess the biological qualities of phycocyanin for use in natural hair dye product. Phycocyanin was tested for use against anti skin-pathogen (Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 14990, Methicillin-resistant Staphylococcus aureus (MRSA) DMST 20625, Propionibacterium acnes DMST 14916, Candida albicans DMST 21424, and Malassezia furfur M21), cytotoxicity of human immortalized keratinocyte (HaCaT) cells and tested for color fastness when used as a shampoo wash. According to the findings, Arthrospira (Spirulina) platensis phycocyanin has not shown the potential for use against anti-skin pathogenic microorganisms. While testing phycocyanin at the maximum doses of 2.5 mg/mL, the cytotoxicity test revealed that it is not hazardous to HaCaT cells. Bleached hair was dyed with a mixture of phycocyanin, natural developers, and mordants. A chroma meter was used to monitor color changes after shampoo washing. The findings revealed that phycocyanin has dyeability potential. 50% of the dyed hair color remained after 5 shampoo washes. The stability and color degradation of phycocyanin in hair dye powder formulation demonstrated good physical stability along with four cycles of heating/cooling. As a result, we can see that this pigment has the potential to be used as an active ingredient in natural hair dyes.

Phycoerythrin (PE) is a natural protein–pigment complex with a strong pink color, but it is sensitive to thermal and light variations. In this study, PE was extracted from Porphyra haitanensis in a yield of 0.2% (w/w). The phycoerythrin hydrolysates (PEH) (3–10 kDa) were prepared by enzymatic hydrolysis of PE with bromelain (8000 U/g) at 47 °C for 30 min, with a degree of hydrolysis (DH) of 11.57 ± 0.39% and a color degradation rate of 7.98 ± 0.39%. The physicochemical properties of PEH were evaluated. The UV and fluorescence spectra indicated that bromelain changed the microenvironment around phycoerythrobilin (PEB). The infrared spectrum revealed that the bromelain hydrolysis increased the α-helix content of PEH. The scanning electron microscope showed that bromelain destroyed the dense and smooth structure of PE, resulting in irregular porous structures. The radical scavenging activities of DPPH and ABTS of PEH were increased relative to that of PE (p < 0.05). The thermal (50–80 °C)-, UV (0.5–3 h)-, visible light irradiation (2–8 h)-, and metal ion exposing stabilities of PEH were significantly improved (p < 0.05). This study provides a potential scheme for overcoming the sensitivity of PE to thermal and light variations and facilitates PEH as a natural colorant ingredient in food and pigment applications.

Depending upon their growth responses to high and low irradiance, respectively, thermophilic Synechococcus sp. isolates from microbial mats associated with the effluent channels of Mushroom Spring, an alkaline siliceous hot spring in Yellowstone National Park, can be described as either high-light (HL) or low-light (LL) ecotypes. Strains isolated from the bottom of the photic zone grow more rapidly at low irradiance compared to strains isolated from the uppermost layer of the mat, which conversely grow better at high irradiance. The LL-ecotypes develop far-red absorbance and fluorescence emission features after growth in LL. These isolates have a unique gene cluster that encodes a putative cyanobacteriochrome denoted LcyA, a putative sensor histidine kinase; an allophycocyanin (FRL-AP; ApcD4-ApcB3) that absorbs far-red light; and a putative chlorophyll a-binding protein, denoted IsiX, which is homologous to IsiA. The emergence of FRL absorbance in LL-adapted cells of Synechococcus sp. strain A1463 was analyzed in cultures responding to differences in light intensity. The far-red absorbance phenotype arises from expression of a novel antenna complex containing the FRL-AP, ApcD4-ApcB3, which is produced when cells were grown at very low irradiance. Additionally, the two GAF domains of LcyA were shown to bind phycocyanobilin and a [4Fe-4S] cluster, respectively. These ligands potentially enable this photoreceptor to respond to a variety of environmental factors including irradiance, redox potential, and/or oxygen concentration. The products of the gene clusters specific to LL-ecotypes likely facilitate growth in low-light environments through a process called Low-Light Photoacclimation. [ABSTRACT FROM AUTHOR]

Cyanobacteria have attracted the attention of researchers because of their promising role as primary and secondary metabolites in functional food and drug design. Due to an ever-increasing awareness of health and the use of natural products to avoid the onset of many chronic and lifestyle metabolic diseases, the global demand for the use of natural drugs and food additives has increased in the last few decades. There are several reports about the highly valuable cyanobacterial products such as carotenoids, vitamins, minerals, polysaccharides, and phycobiliproteins showing antioxidant, anti-cancerous, anti-inflammatory, hypoglycemic, and antimicrobial properties. Recently, it has been shown that allophycocyanin increases longevity and reduces the paralysis effect at least in Caenorhabditis elegans. Additionally, other pigments such as phycoerythrin and phycocyanin show antioxidative properties. Because of their high solubility in water and zero side effects, some of the cyanobacterial tetrapyrrole derivatives, i.e., pigments, facilitate an innovative and alternative way for the beverage and food industries in place of synthetic coloring agents at the commercial level. Thus, not only are the tetrapyrrole derivatives essential constituents for the synthesis of most of the basic physiological biomolecules, such as hemoglobin, chlorophyll, and cobalamin, but also have the potential to be used for the synthesis of synthetic compounds used in the pharmaceutical and nutraceutical industries. In the present review, we focused on the different aspects of tetrapyrrole rings in the drug design and food industries and addressed its remaining limitations to be used as natural nutrient supplements and therapeutic agents. [ABSTRACT FROM AUTHOR]

Phycobiliproteins (PBPs) are colored and water-soluble biliproteins found in cyanobacteria, rhodophytes, cryptomonads and cyanelles. They are divided into three main types: allophycocyanin, phycocyanin and phycoerythrin, according to their spectral properties. There are two methods for PBPs preparation. One is the extraction and purification of native PBPs from Cyanobacteria, Cryptophyta and Rhodophyta, and the other way is the production of recombinant PBPs by heterologous hosts. Apart from their function as light-harvesting antenna in photosynthesis, PBPs can be used as food colorants, nutraceuticals and fluorescent probes in immunofluorescence analysis. An increasing number of reports have revealed their pharmaceutical potentials such as antioxidant, anti-tumor, anti-inflammatory and antidiabetic effects. The advances in PBP biogenesis make it feasible to construct novel PBPs with various activities and produce recombinant PBPs by heterologous hosts at low cost. In this review, we present a critical overview on the productions, characterization and pharmaceutical potentials of PBPs, and discuss the key issues and future perspectives on the exploration of these valuable proteins. [ABSTRACT FROM AUTHOR]

Phycocyanin, a natural blue phycobiliprotein extracted from cyanobacteria, recently focused the interest of food industry as promising pigment and antioxidant. Eco-extraction of phycocyanin via ultrasound using five glycerol-based NaDES was described here. Response surface methodology (RSM) and artificial neural network (ANN) were adapted for the generation of predictive models to simulate and optimize phycocyanin extraction. Input parameters were extraction time (15–60 min), temperature (25–50 °C) and water addition (20–60%). Two original glycerol-based NaDES, glycerol:glucose:betaine (4:1:1) and glycerol:glucose:proline (4:1:1), displayed the highest phycocyanin recovery, combined with high free radical scavenging activity. Additionally, a stabilizing effect of NaDES on phycocyanin was highlighted after accelerated ageing. Optimized extraction protocol developed here allowed then the extraction, pre-formulation and stabilization of phycocyanin in one step, opening the way to a sustainable formulation of this bioactive pigment for food industry. [ABSTRACT FROM AUTHOR]

In the search for a better and brighter future, the use of natural luminescent renewable materials as substitutes for synthetic ones in the energy field is of prime importance. The incorporation of natural pigments (e.g., xanthophylls and phycobiliproteins) is a fundamental step in a broad spectrum of applications that are presently marred by their limited stability. The incorporation of bio-based luminescent molecules into solid matrices allows the fabrication of thin films, which may dramatically increase the range of applications, including sustainable photovoltaic systems, such as luminescent solar concentrators or downshifting layers. In this work, we incorporated R-phycoerythrin (R-PE), C-phycocyanin (C-PC), and fucoxanthin (FX) into poly(vinyl alcohol) (PVA) and studied their optical properties. It was found that the emission and excitation spectra of the phycobiliproteins and FX were not modified by incorporation into the PVA matrix. Moreover, in the case of FX, the emission quantum yield (η) values also remained unaltered after incorporation, showing the suitability of the PVA as a host matrix. A preliminary photostability study was performed by exposing the solid samples to continuous AM1.5G solar radiation, which evidenced the potential of these materials for future photovoltaics. [ABSTRACT FROM AUTHOR]

Light-emitting diodes (LED) can be utilized as tailorable artificial light sources for the cultivation of cyanobacteria such as Arthrospira platensis (AP). To study the influence of different LED light colors on phototrophic growth and biomass composition, AP was cultured in closed bioreactors and exposed to red, green, blue, or white LED lights. The illumination with red LED light resulted in the highest cell growth and highest cell densities compared to all other light sources (order of cell densities: red > white > green > blue LED light). In contrast, the highest phycocyanin concentrations were found when AP was cultured under blue LED light (e.g., order of concentrations: blue > white > red > green LED light). LED-blue light stimulated the accumulation of nitrogen compounds in the form of phycobiliproteins at the expense of cell growth. The results of the study revealed that exposure to different LED light colors can improve the quality and quantity of the biomass gained in AP cultures. [ABSTRACT FROM AUTHOR]

Arthrospira platensis proteins are considered as viable ingredients for functional foods with nutraceutical properties and health-promoting effects. In this study, we used five different proteases including pepsin, trypsin, alcalase, papain, and bromelain to hydrolyze A. platensis phycobiliprotein. LC–MS/MS (liquid chromatography-tandem mass spectrometry) was used to determine the composition of the hydrolysates with thousands of bioactive peptides. Based on peptide sequencing, a candidate list of 1,333 bioactive peptides was constructed for the first time for which bioinformatics tools were used to assess the properties of the bioactive peptides. The inhibitory activity of dipeptidyl peptidase IV (DPP-IV) and angiotensin-converting enzyme (ACE), as well as the antioxidant activity of five phycobiliprotein hydrolysates (PBPHs), were verified in vitro. The IC50 values of PBPH-pepsin, PBPH-trypsin, PBPH-alcalase, PBPH-papain, and PBPH-bromelain for DPP-IV inhibited activity were determined to be 4.059, 5.603, 5.257, 3.819, and 4.195 mg mL−1, respectively. All the above five PBPHs were also seen to significantly inhibit ACE activity (P < 0.0001) in the range of 0.1–1.0 mg mL−1. The activity of five PBPHs fraction was found for the 2-azino-bis (3-ethylbenzothiazoline6-sulfonic acid) diammonium salt (ABTS) assay (the highest was 1.37 mM Trolox equivalent of 30 mg mL−1 of PBPH-trypsin), 1,1diphenyl-2-picrylhydrazyl (DPPH) assay (the highest was 204.67 µM Trolox equivalent of 10 mg mL−1 of PBPH-pepsin), and Fe2+ chelating ability (the highest was 639.73 µM FeSO4 equivalent of 10 mg mL−1 of PBPH-trypsin). This study indicated that it was feasible to utilize A. platensis phycobiliprotein as a source of bioactive peptides which may be used as functional food and/or nutritional supplements for human health. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Cyanobacteria have attracted the attention of researchers because of their promising role as primary and secondary metabolites in functional food and drug design. Due to an ever-increasing awareness of health and the use of natural products to avoid the onset of many chronic and lifestyle metabolic diseases, the global demand for the use of natural drugs and food additives has increased in the last few decades. There are several reports about the highly valuable cyanobacterial products such as carotenoids, vitamins, minerals, polysaccharides, and phycobiliproteins showing antioxidant, anti-cancerous, anti-inflammatory, hypoglycemic, and antimicrobial properties. Recently, it has been shown that allophycocyanin increases longevity and reduces the paralysis effect at least in Caenorhabditis elegans. Additionally, other pigments such as phycoerythrin and phycocyanin show antioxidative properties. Because of their high solubility in water and zero side effects, some of the cyanobacterial tetrapyrrole derivatives, i.e., pigments, facilitate an innovative and alternative way for the beverage and food industries in place of synthetic coloring agents at the commercial level. Thus, not only are the tetrapyrrole derivatives essential constituents for the synthesis of most of the basic physiological biomolecules, such as hemoglobin, chlorophyll, and cobalamin, but also have the potential to be used for the synthesis of synthetic compounds used in the pharmaceutical and nutraceutical industries. In the present review, we focused on the different aspects of tetrapyrrole rings in the drug design and food industries and addressed its remaining limitations to be used as natural nutrient supplements and therapeutic agents.

A separation process was established to sequentially fractionate and recover three anti-inflammatory components derived from sugars, phycobiliprotein, and chlorophyll from the hot-air-dried thalli of the red alga dulse (Palmaria palmata). The developed process consisted of three steps, without the use of organic solvents. In Step I, the sugars were separated by disrupting the cell wall of the dried thalli with a polysaccharide-degrading enzyme, and a sugar-rich extract (E1) was obtained by precipitating the other components, which were simultaneously eluted by acid precipitation. In Step II, the residue suspension from Step I was digested with thermolysin to obtain phycobiliprotein-derived peptides (PPs), and a PP-rich extract (E2) was obtained by separating the other extracts using acid precipitation. In Step III, solubilized chlorophyll was obtained by heating the residue, which was acid-precipitated, neutralized, and re-dissolved to concentrate the chlorophyll-related components (Chls)-rich extract (E3). These three extracts suppressed inflammatory-cytokine secretion by lipopolysaccharide (LPS)-stimulated macrophages, confirming that the sequential procedure had no negative effects on the activities of any of the extracts. The E1, E2, and E3 were rich in sugars, PPs, and Chls, respectively, indicating that the anti-inflammatory components were effectively fractionated and recovered through the separation protocol.