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Spirulina polysaccharides (PSP) possess significant biological properties. However, it is still a lack of investigation on the anti-colorectal cancer effect and mechanism. In this study, PSP showed significant effects on LoVo cell spheroids with an IC 50 value of 0.1943 mg/mL. The analysis of transcriptomics and metabolomics indicated the impact of PSP on LoVo spheroid cells through involvement in the two pathways of "glycine, serine, and threonine metabolism" and "ABC transporters". And, the q-PCR data further verified the pointed mechanism of PSP on colon cancer (CC) by regulating the expression levels of relevant genes in the synthesis pathways of serine and glycine in tumor cells. Furthermore, the anti-colon cancer effects of PSP were verified via other human colon cancer cell lines HCT116 and HT29 spheroids (IC 50 = 0.0646 mg/mL and 0.2213 mg/mL, respectively), and three patient-derived organoids (PDOs) with IC 50 values ranging from 3.807 to 7.788 mg/mL. In addition, this study found that a mild concentration of PSP cannot enhance the anti-tumor effect of 5-Fu. And a significant inhibition was found of PSP in 5-Fu resistance organoids. These results illustrated that PSP could be a treatment or supplement for 5-Fu resistant colorectal cancer (CRC). [ABSTRACT FROM AUTHOR]

In this study, the biosynthesis of phycocyanin β-subunit (CpcB) in Escherichia coli BL21 was investigated, and its antioxidant activity and application in anti-browning of fresh-cut apples was explored. Four genes (cpcB , cpeS , hox1 and pcyA) involved in the biosynthesis of CpcB were cloned and transformed into E. coli BL21 by constructing recombinant plasmid pETDuet-5. The positive transformant was screened by ampicillin resistance. The analysis of SDS-PAGE and zinc fluorescence spectrum showed that CpcB was successfully expressed in E. coli BL21 with a molecular weight of 21 kDa. The purified CpcB had a maximum absorption peak at 615 nm, and its maximum florescence emission wavelength was 640 nm. It exhibited a stronger ability to scavenge four free radicals than Vc. The color change in fresh-cut apples was obviously delayed by the CpcB treatment. These results suggest that CpcB may be used as a potential anti-browning agent for food preservation. [ABSTRACT FROM AUTHOR]

The physicochemical properties of alginate can affect the release profile of encapsulated bioactives, but this is poorly understood. The influence of alginate viscosity (low- A1, medium- A2 and high- A3) and molecular weight (kDa) on the release of encapsulated bioactives (seaweed and spirulina powder) was investigated in an in - vitro gastrointestinal (GSI) model. Beads encapsulated with A2 at 1% (w/v) have overall higher release of bioactives (protein, phlorotannins and antioxidants) but A3 at 0.5% (w/v) was able to release and absorb similar amount of bioactives with ~10% difference with A2. The relative release of protein, phlorotannins and antioxidant was 96%, 111% and 43% respectively from A2 in gastric digestion. In contrast, protein (165%) and phlorotannins (234%) release was highest from A3 in intestinal phase. These results establish the importance of physicochemical properties of the encapsulating matrix on water retention capacity and their interaction with bioactive material to release into the system. Unlabelled Image • Physicochemical properties of alginate affect the release of encapsulated bioactives. • The highest release of bioactives was from medium viscosity alginate (A2) encapsulation. • A3 at half the concentration of A2 released similar amount (~10% less) of bioactives. • A3 (high viscosity and molecular weight) absorbed lowest amount of water (fresh - 15.05 g and dry weight - 0.98 g). [ABSTRACT FROM AUTHOR]

Spirulina has been widely used worldwide as a food and medicinal ingredient for centuries. Polysaccharides are major bioactive constituents of Spirulina and are of interest because of their functional properties and unlimited application potential. However, the clinical translation and market industrialization of the polysaccharides from genus Spirulina (PGS) are retarded due to the lack of a further understanding of their isolation, bioactivities, structure-activity relationships (SARs), toxicity, and, most importantly, versatile applications. Herein, we provide an overview of the extraction, purification, and structural features of PGS; meanwhile, the advances in bioactivities, SARs, mechanisms of effects, and toxicity are discussed and summarized. Furthermore, the applications, potential developments, and future research directions are scrutinized and highlighted. This review may help fill the knowledge gap between theoretical insights and practical applications and guide future research and industrial application of PGS. • Extraction and purification methods of polysaccharides from the genus Spirulina (PGS) were introduced. • Structural features, bioactivities, and structure-activity relationships are summarized and discussed. • The findings on safety concerns and applications were scrutinized and highlighted. • The potential developments and future research directions were envisioned. [ABSTRACT FROM AUTHOR]

Artrhospira (Spirulina) platensis produced fibrinolytic enzyme under mixotrophic conditions using corn steep liquor (CSL). The enzyme was extracted, purified by combination of two chromatographic techniques and biochemically characterized. Maximum fibrinolytic production (268.14 U mg−1) was obtained using liquid medium culture composed by 0.2% CLS after 10th day of cultivation. Fibrinolytic activity was higher when extracted by homogenization methods and was purified 32.72–fold with specific activity of 7988 U mg−1. Fibrin zymography showed an active band, indicated acts as a plasmin-like protein with molecular weight of 72 kDa. Fibrinolytic enzyme have optimum pH of 6.0, stable in the range of 6.0 to 10.0 during 24 h and optimum temperature at 40 °C with a stability below 50 °C. Fibrinolytic enzyme is a serine metalloprotease by to be enhanced by Fe2+ and inhibited by PMSF. The enzyme has higher enzymatic activity than most other fibrinolytic enzymes and is stable at temperature and pH human physiological. Overall, the fibrinolytic enzyme from A. platensis has attractive biochemical properties to potential applications in the treatment of thrombosis. • Corn steep liquor increase fibrinolytic production by A. platensis. • Homogenization is more efficient to extract fibrinolytic enzyme from A. platensis. • A fibrinolytic purified showed activity of 7988 U mg−1. • Plasmin-like protein stable at temperature and pH human physiological. [ABSTRACT FROM AUTHOR]

Following ultrasonication combined with a hot water extraction, a new type of bioactive polysaccharide, SPS-3-1, was purified from Spirulina using ultrafiltration centrifugation and gel filtration chromatography. The structure of SPS-3-1 was determined with high performance gel permeation chromatography, gas chromatography, periodate oxidation, fourier transform infrared spectroscopy, nuclear magnetic resonance, and atomic force microscopy performance. SPS-3-1 is a homogeneous β-pyran polysaccharide with 1 → 2, 1 → 3, and 1 → 4 glycosyl bonds, mainly composed of d -ribose, l -rhamnose, l -arabinose, l -foucose, and d -glucose. The molar ratio of these components is 1:0.70:1.03:2.1:6.59. The molecular weight of SPS-3-1 is 623.02 kDa. SPS-3-1 has a linear filament structure with a width of 34.132 nm and a height of 819.169 pm. We found that SPS-3-1 significantly enhanced transepithelial electrical resistance, a tight junction integrity marker, in a Caco-2 intestinal cell monolayer model. Analysis of the effect of SPS-3-1 on cell proliferation showed that SPS-3-1 inhibited the in vitro growth of Caco-2 and HepG2 cells with an IC 50 of 566.67 μg/mL and 1078.95 μg/mL, respectively. [ABSTRACT FROM AUTHOR]

This work aimed to use sodium trimetaphosphate/sodium tripolyphosphate cross-linked potato, banana, corn, cassava, and breadfruit starches as wall materials for C-phycocyanin encapsulation, characterize them and evaluate their in vivo pharmacological effects in an inflammation model. The cross-linked starches were successfully obtained, characterized, and submitted to C-phycocyanin encapsulation by freeze-drying. The characterization of cross-linked starches-C-phycocyanin composites by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, and differential scanning calorimetry demonstrated that the C-phycocyanin was encapsulated between amorphous chains of cross-linked starches. Among the five preparations, the cross-linked potato starch presented the highest phosphorous content (0.084%), substitution degree (0.004), water uptake capacity (0.88 g g−1), and C-phycocyanin encapsulation efficiency (67.58%), thus was tested in vivo. The cross-linked potato starch-C-phycocyanin prolonged the antihyperalgesic effects attributed to C-phycocyanin, evaluated by complete Freund's adjuvant (CFA) model. Starch cross-linking promoted the formation of a hydrogel network in swollen state entrapping C-phycocyanin, thus, acting as a barrier to its release to the medium and promoting long-lasting in vivo effects. The combination of chemical modification of starches followed by physical treatment presented itself as a useful tool for the development of pharmaceutical formulations. Unlabelled Image • Five starches were cross-linked using STMP/STPP reagents. • Cross-linked starches-C-phycocyanin composites were successfully obtained. • The supramolecular structures were characterized by SEM, FTIR, XRD, TG and DSC techniques. • Prolonged antihyperalgesic effects of C-phycocyanin were noticed in vivo. [ABSTRACT FROM AUTHOR]

Chitosan film, Spirulina sp. film and its blend were developed as biosorbents to remove Cr6+ and Pb2+ ions from aqueous solutions. The kinetic study and the pH effect on biosorption efficiency were evaluated to comprehend the interactions between the ions and biosorbents. The characterization analyses pointed out that occurred interaction between both biomaterials, which resulted in structural alterations through the blend. The Spirulina sp. film exhibited the highest biosorption capacities for Cr6+ (43.2 mg g−1) and Pb2+ (35.6 mg g−1) ions, however, its physical integrity was not kept in acid medium. The blend film showed results slightly lower (35.8 mg g−1 for Cr6+ and 31.6 mg g−1 for Pb2+), but its physical integrity remained intact in all assays. Chitosan film presented the lower biosorption capacities (15.4 mg g−1 for Cr6+ and 20.9 mg g−1 for Pb2+). Elovich and pseudo–second order models were the most suitable to express the kinetic behaviors for Cr6+ and Pb2+, respectively. Therefore, chitosan/ Spirulina sp. blend could be a green alternative for Cr6+ and Pb2+ removal, because this biosorbent showed high biosorption capacity obtained from Spirulina sp. and great physical integrity obtained of chitosan. • Chitosan film, Spirulina sp. film and its blend were successfully developed. • Spirulina sp. film showed the highest biosorption capacities for Cr6+ and Pb2+ ions, but no integrity at acid pH. • Chitosan improved the mechanical properties of the blend film. • Blend film stood out due to its high biosorption capacity and physical integrity. • Electrostatic interactions were the main mechanism regarding biosorption process. [ABSTRACT FROM AUTHOR]

The sulfated polysaccharides of red microalgae have attracted increasing attention in recent years due to their unique rheological and bioactivities. Todate, most studies are devoted to the polysaccharide of the marine species Porphyridium sp., with limited information about that of the brackish water- Dixoniella grisea and the freshwater- Porphyridium aerugineum. We therefore conducted a comparative study of the two less explored sulfated polysaccharides, emphasizing their similarities and differences in composition, physical properties and biocompatibility. Both polysaccharides were found to be composed of 6–8 monosaccharides, predominantly xylose. Sulfur content was 0.8% for P. aerugineum and 1.6% for D. grisea. Solutions of both polysaccharides were highly viscous and exhibited shear thinning and weak gel behavior. Both were found to be stable in an alkaline environment, whereas in an acidic environment the viscosity of the polysaccharide of the brackish water species increased while that of the freshwater species decreased. Both exhibited a similar morphology, having a porous fibrous structure with a rough amorphous surface. By complementing previous studies on the Porphyridium sp. polysaccharide, we have established a sound basis for elucidating the structure/function relationships that in turn, will promote the development of innovative applications for the biotech industries for pharmaceutics, food and drug-delivery. [ABSTRACT FROM AUTHOR]

Abstract This objective of this work was to monitor the EPS production during the growth of Spirulina sp. LEB-18, evaluate the productivity and to characterize the exopolymers obtained on pilot-scale under outdoor conditions. The production of crude EPS occurred in all phases of biomass growth and was approximately ten folds higher than that biomass concentration of Spirulina sp. LEB-18 at the end cultivation, demonstrating the importance of the use of supernatant after harvesting of Spirulina to obtain high value bioproducts. The EPS extracted by Spirulina sp. LEB-18 are typically heteropolymers with one high molecular weight fraction (polysaccharides) with potential to be utilized as an alternative bioflocculant and another fraction of lower molecular mass (proteins). The presence of uronic acids, pyruvates and acyl groups of carbohydrates or carboxylic groups of amino acids in protein moiety is the main responsible for overall negative charge of EPS, which is also of biotechnological importance. Moreover, due to the pseudoplastic behavior of the solutions and high thermal stability, the obtained EPS can be widely applied in several industrial sectors, thus determining its technological and market potentiality. Highlights • Monitoring the EPS production during the growth of Spirulina sp. LEB-18 • Characterization of EPS obtained on pilot-scale under outdoor conditions • Production heteropolymers with high molecular weight fraction (polysaccharides) • Production heteropolymers with fraction of lower molecular mass (proteins) [ABSTRACT FROM AUTHOR]

Abstract This study focused on evaluating whether the injection of CO 2 , which is associated with the use of thermoelectric fly ashes and a reduced supply of nitrogen, affects the production of intracellular carbohydrates from Spirulina. For this purpose, the addition of 0.25 g L−1 of NaNO 3 , along with a 10% (v v−1) of CO 2 injection, a flow rate of 0.3 vvm for 1 or 5 min, as well as 0, 120 and 160 ppm of fly ashes, was studied. The assays with 120 ppm of fly ashes presented the best kinetic parameters and CO 2 biofixation rate, regardless of the CO 2 injection time. Meanwhile, the experiments with 120 and 160 ppm of fly ash and CO 2 injection for 1 min presented 63.3 and 61.0% (w w−1) of carbohydrates, respectively. Thus, this study represents an important strategy to increase the accumulation of carbohydrates in Spirulina , with potential application in the production of bioethanol. Highlights • Spirulina reached up to 63.3% (w w−1) of carbohydrates using 120 ppm of fly ashes; • 0.3 vvm of CO 2 injected for 1 min resulted in a higher carbohydrate content; • Addition of 120 ppm of fly ashes increased the biomass concentration; • This biomass has high potential for bioethanol production. [ABSTRACT FROM AUTHOR]

Phycocyanin is a pigment of intense blue color, constituting the biomass of microalga such as Spirulina . This pigment is sensitive to pH and this instability results in color change. Thus, phycocyanin fading may become interesting for application in intelligent packaging. The objective of the study was to develop PLA/PEO ultrafine fibers containing phycocyanin to be used as pH indicators membranes for food packaging. The ultrafine fibers were formed by electrospinning process. The average diameter of 1318 nm was obtained for PLA/PEO ultrafine fibers with 2% (w·v −1 ) of phycocyanin and 921 nm for those developed with 3% (w·v −1 ) of the dye. PLA/PEO ultrafine fibers with 3% (w·v −1 ) of the phycocyanin presented the best responses regarding the perception of color change (ΔE). With the highest thickness (68.7 μm) of the ultrafine fibers developed from 3% (w·v −1 ) of phycocyanin, the ΔE value found was 18.85 to the variation of pH 3 to 4 and for variation from pH 5 to 6 the value of ΔE was 18.66. Thus, the use of PLA/PEO ultrafine fibers containing phycocyanin as pH indicator is an innovative application for intelligent packaging, since the color of pigment changes depending on pH variation. [ABSTRACT FROM AUTHOR]

In this study, the suppressive effects of peptides P1 (LDAVNR) and P2 (MMLDF) from enzymatic hydrolysate of Spirulina maxima on mast cell degranulation was elucidated. It was revealed that P1 and P2 exhibited significant inhibition on cell degranulation via decreasing β-hexosaminidase release at concentration of 200 μM. Moreover, the inhibitory effects of P1 and P2 on expression and production of interleukin (IL)-13 were evidenced. Furthermore, peptide treatment caused a remarkable inhibition on the phosphorylation of Akt and mitogen-activated protein kinases (MAPKs) including ERK, p38, and JNK. Notably, the inhibitory activity of P1 on cell degranulation was found due to blockade of FcεRI receptor. Meanwhile, the inhibitory activity of P2 was involved in alleviation of intracellular reactive oxygen species (ROS) production. Collectively, peptides P1 and P2 from S. maxima were suggested to be promising inhibitors of mast cell degranulation, contributing to the development of bioactive ingredients for amelioration of allergic diseases. [ABSTRACT FROM AUTHOR]

Polymer nanofibers produced by electrospinning are promising for use in food packaging because of their nanometric diameter, which provides a barrier to external conditions above the possible incorporation of the active compounds. The microalga Spirulina sp. LEB 18 synthesizes bioproducts, such as polyhydroxybutyrate (PHB), which is biodegradable and has similar mechanical and thermal properties to polymers of petrochemical origin. Moreover, phenolic compounds of microalgae have antibacterial, antifungal, and antioxidant activities, which is a differential for the development of packaging. The objective of the study was to develop a nanomaterial with antibacterial action from bioproducts of microalgal origin. PHB nanofibers containing phenolic compounds presented average diameter of 810 ± 85 nm exhibited hydrophobicity, which gave protection to the food relative to the moisture outside the package. These nanofibers showed inhibition of the growth of Staphylococcus aureus ATCC 25923 with a zone of 7.5 ± 0.4 mm. Thermal and mechanical properties have confirmed the potential applicability of this material as food packaging. This new nanomaterial combines a packaging function to protect products and to be biodegradable with the antibacterial activity that prevents the proliferation of microorganisms and ensures the quality and preservation of food. [ABSTRACT FROM AUTHOR]

The interactive effects of light intensity and NaCl concentration were investigated for Spirulina two-step cultivation process using Full Factorial Design. In the experiment interval, light intensity had no effect while the NaCl concentration had significant effect on the enhancement of extracellular polymeric substances (EPS) production. Interestingly, results revealed a significant negative interaction between light and NaCl concentration indicating that high NaCl concentration (40 gL −1 ) and low light intensity (10 μmol photons m −2 s −1 ) enhanced the EPS production. Under these conditions, EPS production reached a maximum of 1.02 g g −1 of biomass (dry weight), which is 1.67-folds greater than EPS content under optimal growth conditions (10 μmol photons m −2 s −1 , 1 g L −1 , 30 °C). Desalting and deproteinezation steps of EPS were efficient to obtain polysaccharides (PS) with high carbohydrate (67.3 ± 1.1%), low soluble proteins (5.14 ± 0.32%), ash (5.85 ± 0.71%) and sulfate (2.42 ± 0.12%) contents. Rheological studies of PS at different concentrations (1%, 2.5% and 5%) revealed that the viscosity of the solution increased with the increase of PS concentration. In addition, PS exhibited a non Newtonian shear-thinning nature, a predominant gel-like behavior and a good resistance to consecutive heating-cooling cycles. The adopted process could be, then, a promising and economic strategy to enhance EPS production and extract polysaccharides with interesting rheological properties. [ABSTRACT FROM AUTHOR]

Active food packaging films based on crab chitosan and Spirulina extract (SE) were developed. The effects of the SE incorporation at different levels on physical (color, opacity water vapor and oxygen permeability) and mechanical (tensile strength and elongation at break) properties of chitosan films were investigated. FTIR was carried out to observe the potential modifications of the chitosan films when incorporated with SE. The obtained results suggested that incorporation of SE into chitosan films improved mechanical and barrier properties. The antioxidant activity of the chitosan/SE films was characterized by means of three different analytical assays (DPPH, FRAP and FIC). Crab chitosan edible films containing SE showed higher antioxidant activity, regardless concentrations and methods assayed. Furthermore, the antioxidant activity occurred in a concentration-dependent manner. The agar disc diffusion method was used to determine the antibacterial activities of chitosan edible films against Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Listeria monocytogenes , Salmonella typhimurium , Bacillus subtilis and Bacillus cereus . The chitosan/SE films were more effective ( p < 0.05) against five of the seven tested bacteria. The obtained crab chitosan edible films incorporated with SE showed great potential to be used for active food packaging due to its excellent antioxidant and antibacterial activities. [ABSTRACT FROM AUTHOR]

The present study was designed to determine the effects of phycocyanin (PC) on Human ovarian cancer SKOV-3 cells and the underlying molecular mechanisms of action. The inhibitory effects of PC on the cell proliferation were detected by MTT assay. The IC 50 values of PC were 182.0 μM and 133.6 μM for 24 h and 48 h exposure, respectively. PC induced apoptosis in SKOV-3 cells was observed by electron microscopy and flow cytometry. The apoptosis rate was increased from 1.6% to 19.8% after PC exposure. The fluorescence intensity of ROS and the activities of Caspase-3, Caspase-8, and Caspase-9 were increased. Differentiated expression protein spots were selected and identified using proteomic techniques. There were 698 ± 73 and 683 ± 79 protein spots resolved in untreated and PC-treated cells, respectively. Forty five differential protein spots were analyzed by MALDI-TOF-MS, including mtSSB, PSME3, and nucleolin. The mRNA expression profiles determined by RT-PCR were consistent with that of the two-dimensional electrophoresis. The decreased proteins such as HSP60, nucleolin, PPase, peroxiredoxin-4 and the increased protein (mtSSB) were identified in SKOV-3 cells after PC treatment, indicating that the effects of PC on tumor cell apoptosis may be relate to multiple target proteins. And the mitochondrial pathway may be the main pathway for PC-induced apoptosis. [ABSTRACT FROM AUTHOR]

Abstract: This study was conducted to investigate the anti-oxidant activity of the recombinant apo-c-phycocyanin (c-PC) β-subunit compared to native c-PC purified from Spirulina sp. The gene encoding the β-subunit of c-PC was successfully cloned and expressed in Escherichia coli. The anti-oxidant capacities of recombinant apo-c-PC(β) and native c-PC were evaluated by measuring their Trolox equivalent antioxidant capacities and examining their protective effects on erythrocytes from normal and homozygous haemoglobin E individuals against peroxyl radicals and hydrogen peroxide. The results demonstrated that the anti-oxidant capacities are native c-PC≫Trolox>recombinant apo-c-PC(β). Both anti-oxidant proteins can potentially protect erythrocytes from oxidative damage. Expression of c-PC in bacteria reduces the cost and time for protein production, and the recombinant protein could be further developed to obtain a more efficient protein for therapeutic purposes. [Copyright &y& Elsevier]

Highlights: [•] Optimum conditions for polysaccharide extracts was a ratio of 1:45, 90°C for 120min. [•] Polysaccharide extracts from Spirulina at 90°C contained high phenolic content. [ • ] Rhamnose is the major sugar component of polysaccharide extracts from Spirulina. [ABSTRACT FROM AUTHOR]

Abstract: Cyanobacteria have many unexploited potential for natural products with a huge variability in structure and biological activity. Their products are species specific and substrate+growth condition specific. Under stress conditions they are reported to produce biopolymers like EPS and PHA, which can be produced extracellularly and intracellularly, respectively. Polyhydroxyalkanoates are polymers of biological origin, they are also capable of being completely broken down to water and carbon dioxide by microorganisms found in a wide range of environments, such as soil, water, and sewage. We have studied marine cyanobacteria Spirulina subsalsa from Veraval coast, Gujarat, India, producing PHA under increased sodium chloride (NaCl) concentration (5% enhancement to the ASNIII medium), The biopolymer was chemically characterized through FTIR, NMR, TGA, and DSC. The present study shows increased PHA accumulation in S. subsalsa by twofold increased NaCl concentration in the growth media. [Copyright &y& Elsevier]

Abstract: Three strains of Spirulina platensis isolated from different locations showed capability of synthesizing poly(3-hydroxybutyrate) [P(3HB)] under nitrogen-starved conditions with a maximum accumulation of up to 10wt.% of the cell dry weight (CDW) under mixotrophic culture conditions. Intracellular degradation (mobilization) of P(3HB) granules by S. platensis was initiated by the restoration of nitrogen source. This mobilization process was affected by both illumination and culture pH. The mobilization of P(3HB) was better under illumination (80% degradation) than in dark conditions (40% degradation) over a period of 4 days. Alkaline conditions (pH 10–11) were optimal for both biosynthesis and mobilization of P(3HB) at which 90% of the accumulated P(3HB) was mobilized. Transmission electron microscopy (TEM) revealed that the mobilization of P(3HB) involved changes in granule quantity and morphology. The P(3HB) granules became irregular in shape and the boundary region was less defined. In contrast to bacteria, in S. platensis the intracellular mobilization of P(3HB) seems to be faster than the biosynthesis process. This is because in cyanobacteria chlorosis delays the P(3HB) accumulation process. [Copyright &y& Elsevier]