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Nanoplastics, as emerging pollutants, have harmful effects on living organisms and the environment, the mechanisms and extent of which remain unclear. Microalgae, as one of the most important biological groups in the food chain and sensitive environmental indicators to various pollutants, are considered a suitable option for investigating the effects of nanoplastics. In this study, the effects of polystyrene nanoplastics on the growth rate, dry weight, chlorophyll a and carotenoid levels, proline, and lipid peroxidation in the Spirulina platensis were examined. Three concentrations of 0.1, 1, and 10 mg L -1 of PSNPs were used alongside a control sample with zero concentration, with four repetitions in one-liter containers for 20 days under optimal temperature and light conditions. Various analyses, including growth rate, dry weight, proline, chlorophyll a and carotenoid levels, and lipid peroxidation, were performed. The results indicated that exposure to PSNP stress led to a significant decrease in growth rate, dry weight, and chlorophyll a and carotenoid levels compared to the control sample. Furthermore, this stress increased the levels of proline and lipid peroxidation in Spirulina platensis. Morphological analysis via microscopy supported these findings, indicating considerable environmental risks associated with PSNPs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Heat stress (HS) is one of the most significant environmental factors that result in fluctuations and shrinkage in rabbit growth, health, and overall productivity. This study aims to investigate the effects of dietary mineral nanoparticles (selenium or zinc) and/or Spirulina platensis (SP) independently and in combination on stressed growing rabbits. A total of 180 weaned growing New Zealand White rabbits were included in this study and randomly divided into six dietary treatments. Rabbits received a basal diet (control group; CON group) or fortified with SP (1 g/kg diet), selenium nanoparticles (SeNPs, 50 mg/kg diet), zinc nanoparticles (ZnNPs, 100 mg/kg diet), and a mixture of SP and SeNPs (SPSeNPs) or SP and ZnNPs (SPZnNPs) groups for 8 weeks during summer conditions. The obtained results demonstrated a significant increase in the final body weight and weight gain (p < 0.05). Additionally, the feed conversion ratio was improved during the periods from 6 to 14 weeks in the treated rabbits compared to those in the CON group. Dietary supplements considerably improved (p < 0.05) the blood hematology (WBCs, Hb, RBCs, and Hct) and some carcass traits (liver weights and edible giblets). All dietary supplements significantly decreased serum levels of total glycerides (p < 0.0001), AST (p = 0.0113), ALT (p = 0.0013), creatinine (p = 0.0009), and uric acid (p = 0.0035) compared to the CON group. All treated groups (except ZnNPs) had lower values of total bilirubin and indirect bilirubin in a dose-dependent way when compared to the CON group. The values of IgA, IgG, and superoxide dismutase were significantly improved (p < 0.05) in all treated rabbits compared to the CON group. Compared with the CON group, the levels of T3 (p < 0.05) were significantly increased in all treated growing rabbits (except for the ZnNP group), while the serum cortisol, interferon-gamma (IFN-γ), malondialdehyde, and protein carbonyl were significantly decreased in the treated groups (p < 0.05). Dietary supplements sustained the changes in hepatic, renal, and cardiac impairments induced by HS in growing rabbits. Adding SP (1 g/kg diet) or SeNPs (50 mg/kg diet) in the diet, either individually or in combination, improved growth performance, blood picture, and immunity-antioxidant responses in stressed rabbits. Overall, these feed additives (SP, SeNPs, or their mixture) can be applied as an effective nutritional tool to reduce negative impacts of summer stress conditions, thereby maintaining the health status and improving the heat tolerance in growing rabbits., (© 2023. The Author(s).)

The gut microbiota is one of the essential contributors of the pathogenesis and progress of inflammatory bowel disease (IBD). Compared with first-line drug therapy, probiotic supplementation has emerged as a viable and secure therapeutic approach for managing IBD through the regulation of both the immune system and gut microbiota. Nevertheless, the efficacy of oral probiotic supplements is hindered by their susceptibility to the gastrointestinal barrier, leading to diminished bioavailability and restricted intestinal colonization. Here, we developed a bacteria-microalgae symbiosis system (EcN-SP) for targeted intestinal delivery of probiotics and highly effective treatment of colitis. The utilization of mircroalge Spirulina platensis (SP) as a natural carrier for the probiotic Escherichia coli Nissle 1917 (EcN) demonstrated potential benefits in promoting EcN proliferation, facilitating effective intestinal delivery and colonization. The alterations in the binding affinity of EcN-SP within the gastrointestinal environment, coupled with the distinctive structural properties of the SP carrier, served to overcome gastrointestinal barriers, minimizing transgastric EcN loss and enabling sustained intestinal retention and colonization. The oral administration of EcN-SP could effectively treat IBD by reducing the expression of intestinal inflammatory factors, maintaining the intestinal barrier and regulating the balance of gut microbiota. This probiotic delivery approach is inspired by symbiotic interactions found in nature and offers advantages in terms of feasibility, safety, and efficacy, thus holding significant promise for the management of gastrointestinal disorders., (© 2024. The Author(s).)

Development of microalgal-bacterial granular sludge (MBGS) from saline-adapted microalgae is a promising approach for efficient mariculture wastewater treatment, whereas the elusive mechanisms governing granulation have impeded its widespread adoption. In this study, spherical and regular MBGS were successfully developed from mixed culture of pure Spirulina platensis and Chlorella sp. GY-H4 at 10 mg/L Fe 2+ concentration. The addition of Fe 2+ was proven to induce the formation of Fe-precipitates which served as nucleation sites for microbial attachment and granulation initiation. Additionally, Fe 2+ increased the prevalence of exopolysaccharide-producing cyanobacteria, i.e. Synechocystis and Leptolyngbya, facilitating microbial cell adhesion. Furthermore, it stimulated the secretion of extracellular proteins (particularly tryptophan and aromatic proteins), which acted as structural backbone for the development of spherical granule form microalgal flocs. Lastly, it fostered the accumulation of exogenous heterotrophic functional genera, resulting in the efficient removal of DOC (98 %), PO 4 3- -P (98 %) and NH 4 + -N (87 %). Nevertheless, inadequate Fe 2+ promotes the granulation of salt-tolerant microalgae, offering guidance for the establishment and stable operation of MBGS systems in mariculture wastewater treatment.2+ expanded the anaerobic zone within the granules, almost halved protein content in the TB-EPS, and inhibited the functional genes expression, ultimately leading to an irregular granular morphology and diminished nutrient removal. This research provides valuable insights into the mechanisms by which Fe 2+ promotes the granulation of salt-tolerant microalgae, offering guidance for the establishment and stable operation of MBGS systems in mariculture wastewater treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

&lt;b&gt;Background and Objective:&lt;/b&gt; The remarkable surface-to-volume ratio and efficient particle interaction capabilities of nanoparticles have garnered significant attention among researchers. Microalgal synthesis presents a sustainable and cost-effective approach to nanoparticle production, particularly noteworthy for its high metal uptake and ion reduction capabilities. This study focuses on the eco-friendly and straightforward synthesis of Silver (AgNPs) and Iron (FeNPs) nanoparticles by utilizing Spirulina (&lt;i&gt;Arthrospira platensis&lt;/i&gt;) and &lt;i&gt;Chlorella pyrenoidosa&lt;/i&gt; extract, devoid of any chemical reducing or capping agents. &lt;b&gt;Materials and Methods:&lt;/b&gt; Following the mixing of 1 mM AgNO&lt;sub&gt;3&lt;/sub&gt; and 1 mM iron oxide solution with the algal extract, the resulting filtrated solution underwent comprehensive characterization, including UV-visible absorption spectra analysis, observation of particle morphology, Zetasizer measurements and Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX) analysis. &lt;b&gt;Results:&lt;/b&gt; The UV-visible spectroscopy revealed a maximum absorbance peak at 430-440 nm, confirming the successful green synthesis of AgNPs and FeNPs, as indicated by the distinct color change from transparent to dark reddish-yellow and brown to reddish-brown, respectively. The SEM-EDX analysis further elucidated the spherical morphology of the nanoparticles, with an average diameter of 93.71 nm for AgNPs and 6198 nm for FeNPs. The Zeta potential measurements indicated average values of -56.68 mV for AgNPs and 29.73 mV for FeNPs, with conductivities of 0.1764 and 0.6786 mS/cm, respectively. &lt;b&gt;Conclusion:&lt;/b&gt; The observed bioaccumulation of silver and iron nanoparticles within the algal extract underscores its potential as an environmentally friendly and cost-effective method for nanoparticle synthesis. These findings suggested a promising avenues for the application of silver and iron nanoparticles in the field of nanobiotechnology. Future research endeavors could focus on optimizing preparation conditions and controlling nanoparticle size to further enhance their utility and effectiveness.

In this study, the effect of α-Fe 2 O 3 nanoparticles spiking in urban wastewater (UWW) on growth rate, wastewater treatment ability and bioproducts generation of C. vulgaris and Spirulina was investigated and compared with pure cultivation system. The biomass concentration of C. vulgaris and Spirulina improved by 20 % and 39 % at 10 and 15 mg/L α-Fe 2 O 3 , respectively while the both microalgae growth pattern fitted better with Gompertz simulation after treatment with α-Fe 2 O 3 . The nutrients mass balance revealed that 1 g of treated C. vulgaris and Spirulina could uptake more COD, TN and TP in comparison to the untreated cells. The lipid generation increased remarkably (C. vulgaris: 45 % and Spirulina: 72 %) after α-Fe 2 O 3 treatment. While, the addition of α-Fe 2 O 3 showed no significant impact on the protein and carbohydrate productivity. Overall, this study evangelize the role of nanoparticles on promoting microalgae applications as a sustainable approach for UWW treatment and promising feedstock for biofuel production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Breast carcinoma is the second leading cause of cancer related-deaths among women. Given its high incidence and mortality rates, searching for innovative treatments represents a formidable challenge within the medical and pharmaceutical industries. This study delves into the preparation, characterization, and anticancer properties of silver chloride nanoparticles (AgCLNPs) as a novel therapeutic approach for breast cancer cells, employing a biological synthesis method., Methods: This investigation, utilized spirulina platensis extract to synthesize silver chloride nanoparticles (AgCLNPs-SP). The formation, size, and structure of the nanoparticles were characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscope (SEM), X-ray crystallography (XRD), and Energy-dispersive X-ray spectroscopy (EDS) analysis. Additionally, the apoptotic and anticancer properties of AgCLNPs-SP were thoroughly examined., Results: The results, revealed AgCLNPs-SP to exhibit a spherical, morphology with a size range of 40-70 nm, primarily silver and chlorine. The dose-dependent response of AgCLNP-SP against MDA-MB231 cells was ascertained using the MTT Assay, with an IC 50 value of 34 µg/mL. Furthermore, the Annexin V-FITC/ PI apoptosis assay demonstrated a significant proportion of early apoptosis (43.67%) in MDA-MB231 cells. This apoptosis process was substantiated by up-regulation in mRNA expression levels of P53, CAD, and Bax genes, alongside a down-regulation of the of bcl2 gene expression. Additionally, an augmented production of reactive oxygen species (ROS), cell cycle analysis, Hoechst staining assay, and evaluated levels of Caspase - 3, -8 and - 9 were observed in AgCLNPs-SP-treated MDA&#95;MB231 cancer cells., Conclusions: In conclusion, the results suggest that AgCLNPs-SP may be a promising agent for treating breast cancer., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Pharmaceutical, nutritional and food industries have recently become interested in the potential of Spirulina platensis , a kind of cyanobacterium with high levels of proteins, vitamins and bioactive compounds. Because of its high moisture, this microalga needs to be submitted to a preservation technique such as drying to be properly used. The aim of this work is to investigate the use of infrared and microwave radiation in the Spirulina platensis drying process. The experiments were performed in continuous and intermittent modes, evaluating different operating conditions for infrared and microwave drying, as well as their effects on the quality of the final product, expressed by the content of bioactive compounds (i.e., total phenolic, total flavonoid, citric acid and phycocyanin contents). The results proved that the use of electromagnetic radiation in the drying of spirulina is an interesting alternative for processing this material if performed under adequate operating conditions. The experiments carried out continuously at lower temperatures and powers and the combination between different temperatures and powers in the intermittent mode resulted in a final product with satisfactory levels of bioactive compounds and low operation times in comparison with conventional methodologies.

The discharge of livestock wastewater without appropriate treatment causes severe harm to the environment and human health. In the pursuit of finding solutions to this problem, the cultivation of microalgae as feedstock for biodiesel and animal feed additive using livestock wastewater coupled with the removal of nutrients from wastewater has become a hot research topic. In this study, the cultivation of Spirulina platensis using piggery wastewater for the production of biomass and the removal of nutrients were studied. The results of single factor experiments confirmed that Cu 2+ seriously inhibit the growth of Spirulina platensis, while the influences of nitrogen, phosphorous, and zinc on the growth of Spirulina platensis can all be described as "low promotes high inhibits." Spirulina platensis grew well in the 4-fold dilution of piggery wastewater supplemented with moderate sodium bicarbonate, which indicated that it is the limiting nutrients for Spirulina platensis growth in piggery wastewater. The biomass concentration of Spirulina platensis reached 0.56 g/L after 8 days of culture at the optimal conditions proposed by the response surface method, which were as follows: 4-fold dilution of piggery wastewater, 7 g/L sodium bicarbonate, pH of 10.5, initial OD 560 of 0.63, light intensity of 3030 lx, and light time/dark time of 16 h/8 h. Spirulina platensis cultured in the diluted piggery wastewater contained 43.89% protein, 9.4% crude lipid, 6.41 mg/g chlorophyll a, 4.18% total sugar, 27.7 mg/kg Cu, and 246.2 mg/kg Zn. The removal efficiency for TN, TP, COD, Zn, and Cu from the wastewater by Spirulina platensis was 76%, 72%, 93.1%, 93.5%, and 82.5%, respectively. These results demonstrated the feasibility of piggery wastewater treatment by the cultivation of Spirulina platensis., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: With the potential development of human pathogenic bacteria resistant to antibiotics, the use of antibiotics as growth promoter in poultry production was banned in different countries, and it has forced the poultry industry to consider 'Biologically safer' alternatives to antibiotics, among which the probiotics and microalgae can be mentioned., Objective: Present study aimed to compare Spirulina platensis microalgae in combination with a native probiotic as an alternative to antibiotics., Methods: 336 male broiler chicks were allotted into 7 treatments and 4 repetitions in a completely randomised design to evaluate chick's performance and immune response to different treatment based on indexes as feed intake, weight gain, feed conversion ratio, humoral immunity, carcass characteristics, thigh and breast pH, intestinal morphology and microbial population. European production efficiency coefficient was also reported., Results: No significant difference was appeared in the pH of thigh and breast meat (p > 0.05). Supplementation of diets with SP 0.3 revealed better villi height, villi length to crypt depth ratio and villi surface. With significant difference (p < 0.05), the highest and lowest colonies of Lactobacillus and E. coli were recorded for PR 0.5 SP 0.3 treatments., Conclusions: Supplementation of broilers diets either with probiotic prepared from the microorganism isolated of native birds (1 g/kg) or S. platensis (0.2 g/kg) alone and their combination (0.3 g/kg of S. platensis in combination with 0.5 g/kg of native probiotic) are promising and can be a good alternative to antibiotics, lead to progress of broiler's performance., (© 2023 The Authors. Veterinary Medicine and Science published by John Wiley & Sons Ltd.)

Herein, it was aimed to optimize the removal process of Azithromycin (Azi) from the aquatic environment via CoFe 2 O 4 NiO nanoparticles anchored onto the microalgae-derived nitrogen-doped porous activated carbon (N-PAC), besides developing a colorimetric method for the swift monitoring of Azi in pharmaceutical products. In this study, the Spirulina platensis (Sp) was used as a biomass resource for fabricating CoFe / NiO nanoparticles anchored onto the microalgae-derived nitrogen-doped porous activated carbon (N-PAC), besides developing a colorimetric method for the swift monitoring of Azi in pharmaceutical products. In this study, the Spirulina platensis (Sp) was used as a biomass resource for fabricating CoFe 2 O 4 /NiO@N-PAC adsorbent. The pores of N-PAC mainly entail mesoporous structures with a mean pore diameter of 21.546 nm and total cavity volume (V total ) of 0.033578 cm 3 . g -1 . The adsorption studies offered that 98.5% of Azi in aqueous media could remove by CoFe 2 O 4 /NiO@N-PAC. For the cyclic stability analysis, the adsorbent was separated magnetically and assessed at the end of five adsorption-desorption cycles with a negligible decrease in adsorption. The kinetic modeling revealed that the adsorption of Azi onto the CoFe 2 O 4 /NiO@N-PAC was well-fitted to the second-order reaction kinetics, and the highest adsorption capacity was found as 2000 mg. g -1 at 25 °C based on the Langmuir adsorption isotherm model at 0.8 g. L -1 adsorbent concentration. The Freundlich isotherm model had the best agreement with the experimental data. Thermodynamic modeling indicated the spontaneous and exothermic nature of the adsorption process. Moreover, the effects of pH, temperature, and operating time were also optimized in the colorimetric Azi detection. The blue ion-pair complexes between Azi and Coomassie Brilliant Blue G-250 (CBBG-250) reagent followed Beer's law at wavelengths of 640 nm in the concentration range of 1.0 μM to 1.0 mM with a 0.94 μM limit of detection (LOD). In addition, the selectivity of Azi determination was verified in presence of various species. Furthermore, the applicability of CBBG-250 dye for quantifying Azi was evaluated in Azi capsules as real samples, which revealed the acceptable recovery percentage (98.72-101.27%). This work paves the way for engineering advanced nanomaterials for the removal and monitoring of Azi and assures the sustainability of environmental protection and public health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Spirulina platensis is a photosynthetic, blue-green, spiral- or bulb-shaped microalgae. Due to the presence of minerals, vitamins, pigments (carotenes, phycocyanin and chlorophyll) proteins (55%-70%), carbohydrates (15%-25%), and essential fatty acids (5%-8%), it has been used as a nutritional supplement for decades. NASA successfully employed it as a nutritional supplement for astronauts on space missions then its popularity was increased. The chemical composition of Spirulina, which is rich in vitamins, minerals, phenolics, vital fatty acids, amino acids, and pigments, can be beneficial to human health when incorporated into meals. The pharmacological effects include antibacterial, anticancer, metalloprotective, immune-stimulating, and antioxidant. It modulates immunological activities and possesses anti-inflammatory qualities by preventing mast cells from releasing histamine. Due to its high quantity of protein, carbohydrate, lipid, vital amino and fatty acids, dietary minerals and vitamins, Spirulina exerts the abovementioned benefits. In this review, up-to-date and possible biological aspects, patents applied on Spirulina and heights of confirmation are addressed, and the extent of current and future exploration is also explored., (© 2023 Wiley-VCH GmbH.)

The application of reclaimed water has been recognized as the key approach for alleviating water scarcity, while its low quality, such as high nitrogen content, still makes people worry about the corresponding ecological risk. Herein, we investigated the feasibility of removing residual nitrate from reclaimed water by applying Spirulina platensis . It is found that 15 mg/L total nitrogen could be decreased to 1.8 mg/L in 5 days, equaling 88.1 % removal efficiency under the optimized conditions. The deficient phosphorus at 0.5-1.0 mg/L was rapidly eliminated but was already sufficient to support nitrate removal by S. platensis . The produced ammonia is generally below 0.2 mg/L, which is much lower than the standard limit of 5 mg/L. In such a nutrient deficiency condition, S. platensis could maintain biomass growth well via photosynthesis. The variation of pigments, including chlorophyll a and carotenoids, suggested a certain degree of influences of illumination intensity and phosphorus starvation on microalgae. The background cations Cu 2+ and Zn 2+ exhibited significant inhibition on biomass growth and nitrate removal; thus, more attention needs to be paid to the further application of microalgae in reclaimed water. Our results demonstrated that cultivation of S. platensis should be a very promising solution to improve the quality of reclaimed water by efficiently removing nitrate and producing biomass.

Microalgae such as Spirulina platensis have recently attracted the interest of the pharmaceutical, nutritional and food industries due to their high levels of proteins and bioactive compounds. In this study, we investigated the use of refractance window (RW) drying as an alternative technology for processing the microalga Spirulina biomass aiming at its dehydration. In addition, we also analyzed the effects of operating variables (i.e., time and temperature) on the quality of the final product, expressed by the content of bioactive compounds (i.e., total phenolics, total flavonoids, and phycocyanin). The results showed that RW drying can generate a dehydrated product with a moisture content lower than 10.0%, minimal visual changes, and reduced process time. The content of bioactive compounds after RW drying was found to be satisfactory, with some of them close to those observed in the fresh microalga. The best results for total phenolic (TPC) and total flavonoids (TFC) content were obtained at temperatures of around 70 °C and processing times around 4.5 h. The phycocyanin content was negatively influenced by higher temperatures (higher than 80 °C) and high exposing drying times (higher than 4.5 h) due to its thermosensibility properties. The use of refractance window drying proved to be an interesting methodology for the processing and conservation of Spirulina platensis , as well as an important alternative to the industrial processing of this biomass.

Hydrothermal liquefaction (HTL) is a thermochemical conversion process to produce biofuel from biomass. In this work, co-HTL of spirulina platensis (SP) with rice husk (RH), coconut shell (CS) and high-density polyethylene (HDPE) is performed, which are not reported in the literature. The maximum biocrude yield for SP and RH mixture is 20.1 wt% at blend ratio of 50:50, temperature of 300 °C, reaction time of 30 mins and solid loading of 20 wt% whereas for SP and CS mixture, the maximum biocrude yield of 12.2 wt% is obtained under same operating conditions. It is found that biocrude yield enhances with increasing blending ratio of SP to lignocellulosic biomass. For co-HTL of SP and HDPE, the maximum biocrude yield of 28.8 wt% is obtained at blend ratio of 50:50, 350 °C, 30 mins and 20 wt% solid concentrations. For this case, the biocrude yield decreases with increasing SP/HDPE ratios. Furthermore, various characterisation methods are used to analyse the quality of biocrude., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

This study aimed to assess Spirulina platensis, Chlorella vulgaris, Scenedesmus quadricauda, and Lagerheimia longiseta microalgae potential as protective agents for probiotic cultures [(Lactobacillus acidophilus (La-05) and Lacticaseibacillus casei (Lc-01)] during freeze-drying, refrigeration storage (4 °C, 120 days), and in vitro simulated gastrointestinal conditions (SGIC). The occurrence of membrane damage and ultrastructural aspects of the cells were also verified. Fructooligosaccharides (FOS) were used as a positive control and saline solution as a negative control. The effects of the cryoprotectants on probiotic survival depended on the tested probiotic culture and microalgae biomass. For La-05, all tested cryoprotectants caused a lower reduction in probiotic counts during the freeze-drying and up to 90 days of storage. S. platensis kept higher probiotic counts during storage, while C. vulgaris protected the probiotic against the SGIC. L. longiseta decreased the probiotic membrane damage, mainly due to the production of exopolysaccharides, which was observed in the scanning electron microscopy (SEM). For Lc-01, all tested cryoprotectants promoted a lower reduction in probiotic counts up to 120 days of storage. FOS and S. quadricauda protected the probiotics during freeze-drying and refrigeration storage, while C. vulgaris protected the probiotic against the SGIC and caused lower membrane damage, mainly due to physical protection observed in SEM. In conclusion, microalgae biomasses exerted similar or better cryoprotectant effects on probiotics than FOS, a recognized cryoprotective agent., (Copyright © 2022. Published by Elsevier Ltd.)

Pigmentation issues are common conditions associated with excessive or insufficient production of melanin. Recently peptides are investigated to discover novel melanogenesis regulators as low molecular weight compounds to regulate skin pigmentation. In this study, an internal library of peptides obtained through in silico enzymatic digestion of phycocyanin from microalgae S. platensis was tested to apprehend their anti-melanogenic effects. Seven peptides were investigated for their inhibitory potential against mushroom and B16-F10 murine tyrosinase enzymes. According to the results, P5 (SPSWY) and P7 (AADQRGKDKCARDIGY) were effective in lowering the activity of mushroom and B16-F10 tyrosinases. P5 was the most potent (IC 50 value, 12.1 µM) in mushroom which was followed by P2 (MAACLR, 86.9 µM). Although the peptides were particularly powerful in inhibiting monophenolase activity, only moderate inhibition was observed for diphenolase activity in mushroom tyrosinase assay. Apart from tyrosinase inhibition, P2 and P3 (RCLNGRL) were efficient DPPH radical scavengers at low concentrations (IC 50 < 200 µM). In the mammalian assay system, P5 and P7 were noticeably effective to decrease tyrosinase enzyme activity with IC 50 values of 48.9 and 34.2 µM, respectively. However, although P4 (RYVTYAVF) was a potent mushroom tyrosinase inhibitor, it increased melanin synthesis up to 3-fold in B16-F10 cells. The results indicate that C-terminal tyrosine residue is important for tyrosinase inhibition. This study shows, for the first time, that microalgae proteins can be regarded as sources for melanogenesis regulation., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Domestic, agricultural and industrial water activities lead to organic and inorganic pollution of the environment. Biotreatment of municipal wastewater with the potential production of biomass is a valuable feature of microalgae. In this study we evaluated the effects of wavelength and light intensity on phosphate and ammonium removal on the one hand, and biomass and protein production on the other hand by Spirulina platensis in municipal wastewater treatment under semi batch cultivation. S. platensis was inoculated at 40% in artificial wastewater open pond system. Red, blue and purple light with 3800, 4800 and 5800 lux light intensity under 12 h light and 12 h darkness were investigated. Cultivation was conducted in semi-batch conditions; after four days cultivation, one third of the culture was replaced with fresh medium. The highest biomass and protein concentrations were observed under blue light at 5800 lux light intensity, 5.45 and 3 g/l respectively cumulatively; while the highest amount of phosphate and ammonium removal were about 145 and 218 mg/l under purple light at 5800 lux intensity, respectively. The amounts of biomass and protein produced, as well as phosphate and ammonium removed, are therefore impacted by wavelength, light intensity, results show that light intensity and wavelength can be customized to reach on the one hand the highest biomass and protein production, and on the other hand to maximize the removal of phosphorous and ammonium.

Microalgae are a potential ingredient that can enhance the nutritional value of food. There are already various products made from microalgae such as pasta, cookies, breadstick, crackers, and extrudates. Moreover, these products have a typical green colour, provided from microalgae pigments. This study aimed to evaluate the effect of the addition of Chlorella vulgaris and Arthrospira platensis biomass on vitamin C, total carotenoids, and chlorophyll a levels in breadsticks and its doughs. Microalgae addition in breadstick formulations is a viable alternative, because they presented a greater content of carotenoids and chlorophyll a than control breadsticks. Consequently, microalgae enriched breadsticks can provide health benefits to consumers. Here, Chlorella enriched breadsticks showed the highest studied pigments content. Despite microalgae powder containing vitamin C, breadstick dough did not present vitamin C and therefore nor the breadstick.

A concentration-dependent decrease in growth rate and pigment concentration of the blue-green alga Spirulina platensis was recorded after the exposure to graded (5-40 ppm) concentration of six textile dyes. The profile of vital elements (C, H, N, S) also showed a significant variation due to dye toxicity. The algal population showed up to 50% decrease in protein content after exposure to the dyes. Among the pigments, the dye exposure resulted in > 90% decreases in phycocyanin however, total chlorophyll and carotenoids exhibited up to a 50% decrease compared to control. The findings indicate that the unregulated discharge of textile dyes will directly impact the photoautotrophic organisms leading to ecological imbalance in aquatic ecosystems. Overall observations of the report provide baseline information about the toxicity of textile dyes and giving a better insight into the little-understood mechanisms of dye toxicity.

In the scenario of promising sources of functional foods and preventive drugs, microalgae and cyanobacteria are attracting global attention. In this review, the current and future role of microalgae as natural sources of functional foods for human health and, in particular, for oral health has been reported and discussed in order to provide an overview on the state of art on microalgal effects on human oral health. It is well known that due to their richness in high-valuable products, microalgae offer good anti-inflammatory, antioxidant, antitumoral, anti-glycemic, cholesterol-lowering, and antimicrobial activity. Moreover, the findings of the present research show that microalgae could also have a significant impact on oral health: several studies agree on the potential application of microalgae for oral cancer prevention as well as for the treatment of chronic periodontitis and different oral diseases with microbial origin. Thus, beneficial effects of microalgae could be implemented in different medical fields. Microalgae and cyanobacteria could represent a potential natural alternative to antibiotic, antiviral, or antimycotic therapies, as well as a good supplement for the prevention and co-adjuvant treatment of different oral diseases. Nevertheless, more studies are required to identify strains of interest, increase overall functioning, and make safe, effective products available for the whole population.

Background Ethanolic, aqueous and lipidic extracts of Spirulina platensis were evaluated for their bioactive substances (polyphenols and fatty acids) and antioxidant activities using two different assays diphenyl-1-picrylhydrazyl (DPPH) and azino-bis (ethylbenzthiazoline-6- sulfonicacid (ABTS)). Methods The phenolic compounds amounts were determined by colorimetric assays and were analyzed by high-performance and liquid chromatography (HPLC) method. The identification of phenolic compounds in the extract was accomplished by comparison of their retention times with those of pure standards. The chemical composition of fatty acids in lipidic extract was determined by GC/FIDs and GC/MS method. Results The obtained results revealed that using DPPH, the ethanolic extract recorded the highest activity with (IC50=449 μg/mL ± 83). It was characterized with a high levels of phenolic and flavonoid content 0.33 ± 0.01 mg GAE/g dw and 0.21 ± 0.01 mg quercetin/g dw, respectively. The ethanolic extract showed the presence of caffeic acid, syringic acid, ferulic acid, p-coumaric acid, chlorogenic acid, kaempferol, quercetin and apigenin. Those entire phenolic compounds seem participle synergistically to the pronounced higher activity. To the best of our knowledge, the apigenin (4', 5, 7,-trihydroxyflavone), a natural compound which is famously known by its potent antiradical activity, was identified for the first time in Moroccan S. platensis only in the ethanolic extract. A high positive correlation (r=0.895) between the antioxidant activity and the chemical composition of ethanolic extract was observed. For ABTS, lipidic extract showed the highest activity with (IC50=740 μg/mL ± 12). A total of 15 fatty acids compounds, amounting 89.73% of the extract were identified. γ-linolenic acid (GLA) (39.02%) and α-linolenic acid (ALA) (13.85%) were the major component and contribute greatly to the antioxidant activity observed. The lipidic extract has a high content of unsaturated fatty acids (70.95%) which are often exhibited very high antioxidant activity since they have two or more double bonds and chain lengths. The aqueous extract either with DPPH or ABTS methods, recorded low antioxidant activity. Its correlation was r=0.499, lower than found in the ethanolic extract. Conclusions These results showed that Spirulina platensis could be considered as a valuable source of fatty acids and phenolics with potent antioxidant activity. It may be employed in the manufacture of pharmaceutical drugs as an alternative source of natural antioxidants.

The high content of bioactive compounds in the microalga Spirulina platensis has recently attracted attention from food and pharmaceutical industries. However, for its application an effective preservation technique must be developed. In this paper, we investigated the use of a non-conventional rotary dryer (with an inert bed) for drying the microalga Spirulina biomass and the effects of the operational conditions (air temperature, intermittent feeding interval, filling degree of inert particles, and rotation speed) on its bioactive compounds. The results indicated that this non-conventional drying system offers an effective alternative for expanding the use of this biomass in an adequate form. We identified the conditions in which the dried material had maintained satisfactory contents of phenolics (air temperature of 70 °C and intermittent feeding interval of 10 min), flavonoids (intermittent feeding interval of 17.4 min), and phycocyanin compounds (air temperature of 40 °C), which were near to those present in fresh microalga.

Dry microalgae Spirulina platensis shows a high capacity for heavy metal uptake, but there is a concern about dissolved organic carbon (DOC) residue, which is the precursor of disinfection by-products (DBPs). Vsp, a kind of Spirulina platensis powder prepared by vacuum freeze-drying, and Osp, a kind of Spirulina platensis powder prepared by the conventional oven drying-pulverization method, were subjected to assessments of their adsorption potential for Pb 2+ and DOC residue. The adsorption mechanism of Pb 2+ by the two adsorbents was studied by SEM, FT-IR, EDX and N 2 -BET. The effects of pH, adsorbent dosage, initial Pb 2+ concentration and contact time on the biosorption process were investigated. The results showed that Pb 2+ biosorption by Vsp and Osp were fit well by a pseudo-second-order kinetic model and the Langmuir model. The maximum amount of Pb 2+ biosorption by Vsp was 253 mg/g, which was 33 mg/g greater than that of Osp. In comparison with Osp, Vsp reached adsorption saturation 8 h earlier and had a remarkable effect on the control of DOC residue in water. When both adsorption capacity and environmental risks were considered, it was determined that the dosage of 0.5 g/L Vsp for 2 h of contact time was the best method, with 85.89 mg/g of Pb 2+ removal and 3.45 mg/L of DOC residue. In summary, Vsp is a highly efficient and environmentally friendly biosorbent that can be used for heavy metal removal from water., Competing Interests: Declaration of competing interest We declared that we have no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

High delivery efficiency, prolonged drug release, and low systemic toxicity are effective weapons for drug delivery systems to win the battle against metastatic breast cancer. Herein, it is shown that Spirulina platensis (S. platensis) can be used as natural carriers to construct a drug-loaded system for targeted delivery and fluorescence imaging-guided chemotherapy on lung metastasis of breast cancer. The chemotherapeutic doxorubicin (DOX) is loaded into S. platensis (SP) via only one facile step to fabricate the DOX-loaded SP (SP@DOX), which exhibits ultrahigh drug loading efficiency and PH-responsive drug sustained release. The rich chlorophyll endows SP@DOX excellent fluorescence imaging capability for noninvasive tracking and real-time monitoring in vivo. Moreover, the micrometer-sized and spiral-shaped SP carriers enable the as-prepared SP@DOX to passively target the lungs and result in a significantly enhanced therapeutic efficacy on lung metastasis of 4T1 breast cancer. Finally, the undelivered carriers can be biodegraded through renal clearance without notable toxicity. The SP@DOX described here presents a novel biohybrid strategy for targeted drug delivery and effective treatment on cancer metastasis., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Bioremediation of pharmaceutical-contaminated wastewater using microalgae has attracted increasing attention. Cyanobacteria, which are important prokaryotic microalgae, are widely distributed in different water environments, and have the advantages of simple culture and a fast growth rate. However, studies on either the toxicity of pharmaceutical contaminants (PhCs) to cyanobacteria or the removal of PhCs by cyanobacteria are scarce. In this study, carbamazepine (CBZ) and Spirulina platensis were selected as model PhCs and cyanobacteria, respectively. CBZ (>1 mg/L) had toxicity effects on S. platensis, showing maximal growth inhibition (34.0%) at 100 mg/L after 10 days of cultivation. At CBZ < 25 mg/L, S. platensis showed a trend similar to that of eukaryotic microalgae in increasing superoxide dismutase and catalase activities and content of chlorophylls, carotenoids, carbohydrates, and lipids. These results indicated that S. platensis had a similar protective mechanism to CBZ toxicity as that of the eukaryotic microalgae. Increasing CBZ concentration (50-100 mg/L) significantly decreased these biochemical characteristics and photosynthetic activity owing to the serious damage of the structure and function of S. platensis. However, with increasing cultivation time, the growth and photosynthetic activity of S. platensis recovered from the toxicity of CBZ. S. platensis showed a maximum of 30.97 ± 1.30% removal of CBZ (1 mg/L), mainly through biodegradation. Addition of 0.3 mg/L glucose enhanced this removal efficiency to 50.13 ± 2.51% via co-metabolism. These findings indicated that S. platensis can be used for the removal of CBZ or other PhCs from wastewater., (Copyright © 2019. Published by Elsevier B.V.)

Aims and Background: Spirulina (Arthrospira) platensis (SP) microalgae were cultured in Zarrouk Medium (ZM), containing three nitrogen concentrations (N-limited, N-optimal and Nrich medium) in ten liter-photo-bioreactor (10 L PBR) for 15-days, in order to study changes in lipid compounds (total carotenoids and total lipids and their effect on fatty acid profile). Based on US patent, the yield of bioactive compounds (such as gamma-linolenic acid GLA, C18:3) extracted from microalgae biomass, mainly depends on the extraction processes (1). GLA has much attention with respect to its therapeutic properties such as its ability to decrease blood cholesterol levels., Methods: The impact of the addition of N in cultures of S. platensis in terms of growth, biomasses and induced lipid compounds (total carotenoids and total lipid contents and its fatty acid profile), as well as the Sonication (SON) and Microwave (MIC) process as aiding techniques for lipid extraction compared with a Cold Condition (COL), was examined. GC/MS method was used to determine the fatty acid profile of lipid extract of SP cultures., Results: In all S. platensis tested culture, the SP was growing successfully, with varying degrees. In N-rich media, the highest cell growth rate and biomass yield were obtained compared with that recorded in other cultures. Under an N-limited condition, SP had higher Total Carotenoids (TCAR, 45.54 mg/g dw) and total lipid contents (TL, 29.51%± 1.92 g/100g dw) compared with that recorded either in N-rich (11.2 mg/g dw) or in N-optimal (6.23 mg/g dw) cultures. Thus, SP copes with the N -stress by altering the metabolic pathways towards inducing lipid biosynthesis. To maximize the TL and TCAR extraction yields, from N-limited cultures, a set of operating process was applied including the Sonication (SON) and Microwave (MIC), which were used as aiding techniques for lipid extraction compared with the Cold Condition (COL) techniques. The results showed that the extraction efficiency of the S. platensis TL increased in the following order: MIC (29.51%± 1.92) > SON (25.46% ± 1.65> COL (20.43% ±1.43). In a comparative study for its fatty acid profiles (FAPs) among all SP cultures, lipids were analyzed by GC/MS. The predominant fatty acids (>10%, of total FA) were found to be myristic acid (C14:0, MA), palmitic acid (C16:0, PA) and oleic acid (C18:1)., Conclusion: The study concluded that the N-limited condition was found to have a strong influence on biomass dry weight and lipid contents and total carotenoids in SP cells compared to either Nrich or N-optimal conditions. The use of sonication and the microwave techniques lead to a great increase in the extraction of lipid contents and in high amount Polyunsaturated Fatty Acids (PUFAs) in N-limited cultures, in particular, the omega-6 (ω 6) and omega-3 (ω 3) of the essential C18 fatty acids. It seems that the SP rich in lipid content with a high amount of GLC produced under nitrogen limitation in PBR conditions can be used as a food additive or as a nutritional supplement., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Liquid biphasic flotation (LBF), an integrated process of liquid biphasic system (LBS) and adsorptive bubbles flotation, was used for the purification of C-phycocyanin from S. platensis microalgae. Various experimental parameters such as type of phase forming polymer and salt, concentration of phase forming components, system pH, volume ratio, air flotation time and crude extract concentration were evaluated to maximise the C-phycocyanin recovery yield and purity. The optimal conditions for the LBF system achieving C-phycocyanin purification fold of 3.49 compared to 2.43 from the initial LBF conditions was in polyethylene glycol (PEG) 4000 and potassium phosphate combination, with 250 g/L of polymer and salt concentration each, volume ratio of 1:0.85, system pH of 7.0, air flotation duration of 7 min and phycocyanin crude extract concentration of 0.625 %w/w. The LBF has effectively enhanced the purification of C-phycocyanin in a cost effective and simple processing., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Alternative protein sources such as microalgae and faba beans may have environmental benefits over rapeseed. We studied the effects of rapeseed meal (RSM) or faba beans (FB) as a sole protein feed or as protein feeds partially substituted with Spirulina platensis (spirulina) microalgae on milk production, N utilization, and AA metabolism of dairy cows. Eight multiparous Finnish Ayrshire cows (113 ± 36.3 d in milk; mean ± SD) were used in a balanced, replicated 4 × 4 Latin square with 2 × 2 factorial arrangement of treatments and 21-d periods. Four cows in one Latin square were rumen cannulated. Treatments were 2 isonitrogenously fed protein sources, RSM or rolled FB, or one of these sources with half of its crude protein substituted by spirulina (RSM-SPI and FB-SPI). Cows had ad libitum access to total mixed rations consisting of grass silage, barley, sugar beet pulp, minerals, and experimental protein feed. The substitution of RSM with FB did not affect dry matter intake (DMI) but decreased neutral detergent fiber intake and increased the digestibility of other nutrients. Spirulina in the diet decreased DMI and His intake. Spirulina had no effect on Met intake in cows on RSM diets but increased it in those on FB diets. Energy-corrected milk (ECM) and protein yields were decreased when RSM was substituted by FB. Milk and lactose yields were decreased in cows on the RSM-SPI diet compared with the RSM diet but increased in those on FB-SPI compared with FB. The opposite was true for milk fat and protein concentrations; thus, spirulina in the diet did not affect ECM. Feed conversion efficiency (ECM:DMI) increased in cows on FB diets with spirulina, whereas little effect was observed for those on RSM diets. The substitution of RSM by FB decreased arterial concentration of Met and essential AA. Spirulina in the diet increased milk urea N and ruminal NH 4 -N and decreased the efficiency of N utilization in cows on RSM diets, whereas those on FB diets showed opposite results. Met likely limited milk production in cows on the FB diet as evidenced by the decrease in arterial Met concentration and milk protein yield when RSM was substituted by FB. The results suggest the potential to improve milk production response to faba beans with supplementation of Met-rich feeds such as spirulina. This study also confirmed spirulina had poorer palatability than RSM and FB despite total mixed ration feeding and lower milk production when spirulina partially replaced RSM., (The Authors. Published by FASS Inc. and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

An aqueous two-phase system (ATPS) with ionic liquids (ILs) was used for the isolate of C-phycocyanin (CPC) from Spirulina platensis microalga. Various imidazolium ILs and potassium salts were studied. The effect of ILs-ATPS on the extraction efficiency of CPC was also studied. The experimental parameters like pH, loading volume, algae concentration, temperature, and alkyl chain length of IL were well-covered in this report. The experimental results showed that the extraction efficiency, the partition coefficient, and the separation factor for CPC were 99%, 36.6, and 5.8, respectively, for an optimal pH value of 7 and a temperature of 308 K. The order of extraction efficiency for CPC using IL-ATPS was: 1-octyl-3-methylimidazolium bromide (C8MIM-Br) > 1-hexyl-3-methylimidazolium bromide (C6MIM-Br) > 1-butyl-3-methylimidazolium bromide (C4MIM-Br). The isolation process followed the pseudo second-order kinetic model and the thermodynamic results were obviously spontaneous., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The planktonic blue-green microalga Spirulina (Arthrospira) platensis possesses important features (e.g., high protein and vital lipids contents as well as essential vitamins) and can be consumed by humans and animals. Accordingly, this microalga gained growing attention as a new platform for producing edible-based pharmaceutical proteins. However, there are limited successful strategies for the transformation of S. platensis, in part because of an efficient expression of strong endonucleases in its cytoplasm. In the current work, as a pilot step for the expression of therapeutic proteins, an Agrobacterium-based system was established to transfer gfp:gus and hygromycin resistance (hyg r ) genes into the genome of S. platensis. The presence of acetosyringone in the transfection medium significantly reduced the transformation efficiency. The PCR and real-time RT-PCR data confirmed the successful integration and transcription of the genes. Flow cytometry and β-glucuronidase (GUS) activity experiments confirmed the successful production of GFP and the enzyme. Moreover, the western blot analysis showed a ~ 90 kDa band in the transformed cells, indicating the successful production of the GFP:GUS protein. Three months after the transformation, the gene expression stability was validated by histochemical, flow cytometry, and hygromycin B resistance analyses.

To improve the microalgae production in batch cultivation, a cultivation mode that continuously pre-harvesting Spirulina platensis from photobioreactor (PBR) with culture medium recycling was proposed. For realizing the continuously pre-harvesting cultivation mode, a Spirulina platensis culture column PBR with overflowing device was designed, which could adjust pre-harvesting rate through the overflowing device. By adjusting the pre-harvesting rate, the biomass concentration could be kept when biomass accumulation and pre-harvesting biomass were equal. Hence, the meridional light attenuation could be reduced by controlling biomass concentration in PBR. The maximum microalgae production were 44.6%, 10.98% higher in total production than that cultivated in batch cultivation without pre-harvesting and periodically pre-harvesting cultivation mode respectively, which was realized in pre-harvesting rate 0.228 mL min -1 and biomass concentration 1.8 g L -1 . Besides, a model was built by mass balance and polynomial fitting for evaluating the continuously pre-harvesting cultivation mode., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This study assessed the possible pharmacological effects of Chlorella vulgaris (Cg), Spirulina platensis (St), and silymarin (Sl) against thioacetamide (TA)-induced cardiotoxicity in rats, with a focus on their antioxidant, cardioprotective, and anti-inflammatory properties. The following is the random grouping of sixty male rats into six groups of ten animals each: the control (negative control), TA-intoxicated group (positive control; 300 mg/kg body weight (BW)), Sl + TA group (100 mg Sl/kg BW + TA), St + TA group (400 mg St/kg BW + TA), Cg + TA (400 mg Cg/kg BW + TA), and St + Cg + TA group (400 St + 400 Cg mg/kg BW + TA) were all administered for 30 days. At the start of the study, groups 2 through 6 were administered TA intraperitoneally at a dosage of 300 mg/kg BW for two consecutive days, with a 24 h gap between each dose, to induce cardiac damage. Blood samples were obtained to measure hematological parameters and perform biochemical assays, including lipid profiles and cardiac enzymes. For histopathology and immunohistochemistry determination, tissue samples were acquired. The current findings showed that TA injection caused hematological alterations and cardiac injury, as evidenced by greater serum levels of troponin I, creatine kinase-MB, and total creatine kinase (p < 0.05), as well as significantly elevated serum malondialdehyde and decreased serum total antioxidant capacity (p < 0.05) concentrations. Moreover, an increase in blood low-density lipoprotein and total cholesterol concentration (p < 0.05) was recorded in the TA group. There were alterations in the heart tissue's histological structure of the TA group compared to the control ones. These alterations were characterized by vacuolar degeneration of myocytes, loss of cross striation, coagulative necrosis, and fibrosis of interstitial tissue, which was ameliorated by the supplementation of SI, St, and Cg. The TA-intoxicated group showed weak expression of B-cell lymphoma protein 2 (p < 0.05) and strong immunoreactivity of tumor necrosis factor-α and B-cell lymphoma protein 2-associated X (p < 0.05). However, the groups receiving Sl, St, and Cg experienced the opposite. The administration of Sl, St, Cg, and St + Cg along with TA significantly improved and restored (p < 0.05) erythrogram indices, including RBCs, hemoglobin, total leukocytic count, lymphocytes, and monocyte, to the normal control values. The administration of Sl, St, and Cg alleviated the cardiotoxicity caused by TA via reducing oxidative stress, inflammatory markers, and apoptosis in heart tissue. In summary, the current findings suggest that the treatment with Sl, St, and Cg was beneficial in ameliorating and reducing the cardiotoxicity induced by TA in rats. [ABSTRACT FROM AUTHOR]

Spirulina (Arthrospira platensis) is a protein-rich source because it contains approximately 60% protein. Therefore, it has positive impacts on human health, including anti-diabetes. The potential of Spirulina platensis as an anti-diabetic agent has been investigated in-vitro and in-vivo. Its extract is capable of inhibiting amylase, α-glucosidase, and DPP IV enzymes in a range of medium activities. Furthermore, spirulina at 250 mg/Kg body weight (BW) in mice can reduce blood glucose levels with similar outcomes to the positive controls (pioglitazone and glibenclamide). Protein groups (Phycocyanin), isolated peptides, and flavonoid groups such as Pinocembrin, Acacetin, and others have been predicted to be responsible for lowering glucose levels. In the market, several commercial products have been sold. Many commercial products have been sold in the market. However, these products are food supplements because a clinical study has not yet been undertaken to confirm their potency and safety. According to this analysis, there is a significant chance to produce anti-diabetic medications from spirulina sources in the future. [ABSTRACT FROM AUTHOR]

Membrane photobioreactors (MPBRs) have gained significant attention due to their ability to support microalgae activities such as cultivation, harvesting, and production of beneficial products. Despite various efforts to mitigate membrane fouling, a fundamental issue in membrane processes, in these systems, a cost-effective and less energy-consuming method is still needed. This study examines the impact of the cross-sectional area of the riser and the baffle material on membrane fouling in an internal loop airlift MPBR. The use of hydrophilic polyester-polypropylene (PES–PP) baffles proves to be more effective than plexiglass baffles. Specifically, in configurations with d = 0.7 cm and d = 1.4 cm, RC/RT decreased by approximately 20% and 13%, respectively, compared to plexiglass baffles. As for the values of RP/RT at a distance of d = 0.7, nearly a 5% increase was observed, and at a distance of d = 1.4, an increase of approximately 11% was observed. This is due to the development of the cake layer on the matrix structure of the PES–PP baffles instead of the membrane itself. The most optimal outcomes were reached while working with PES–PP at a distance of 0.7 cm, as it prolonged the membrane fouling time to 46 h. [ABSTRACT FROM AUTHOR]

Background: The production of secondary metabolites in different strains of microalgae varies and is likely dependent on environmental conditions. Consequently, the production of bioactive substances as secondary metabolites occurs in microalgae to aid their survival in adverse environmental conditions such as salinity stress. Objectives: The purpose of this study is to investigate the antibacterial activity of the methanolic extract of Spirulina platensis algae cultivated under different salinity stresses against Yersinia rukeri, Escherichia coli, Salmonella sp., and Vibrio cholerae. Methods: The broth microdilution method was used to evaluate the growth inhibitory activity of the extracts against Yersinia ruckeri, Salmonella sp., Escherichia coli, and Vibrio cholerae bacteria. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined by this method, and the diameter of the inhibition zone was assessed through the well diffusion method. Results: In the treatment with algae extract grown under 3.5 ppt salinity stress, the concentrations of 50 and 25 mg/mL extract showed the largest inhibition zone diameter against Salmonella sp. compared to other bacteria. Under 7 ppt salinity stress, all studied concentrations of algal extract exhibited a higher inhibition zone diameter against V. cholerae compared to other bacteria. The results of comparing different concentrations of algae extract between the two salinity stresses of 3.5 and 7 ppt for each bacterium showed a significant difference (P < 0.05). As salinity increased, the diameter of the inhibition zone also increased for all bacteria. Conclusions: Our results showed an increase in the antibacterial activity of the methanolic extract of Spirulina platensis with higher salinity stress levels. Therefore, cultivating Spirulina algae in salt water can be a cost-effective and suitable method to produce more secondary metabolites for use in the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Microalgae can enhance the nutritional value of conventional foods and hence to positively affect human health, due to their original chemical composition. The present study aimed to produce functional Karish cheese fortified with different types and ratios of microalgae powder (Chlorella vulgaris and Spirulina platensis) and evaluate the role of fortification with those algae on the quality of the product. Karish cheese was incorporated with C. vulgaris and S. platensis powder, separately at three levels 0.5, 1.0 and 1.5%. The evaluation of chemical composition, salt content, color parameters, antioxidant activity, total phenolic and total carotenoids content, texture profile and organoleptic properties of Karish cheese fortified with microalgae were determined. Addition of microalgae to Karish cheese showed an increasing (P<0.05) in total solid content, protein, ash, acidity and enhanced the texture profile in the final product compared with control sample. Also, the results indicated highest content of antioxidant activity, total flavonoid and total phenolic among all treatments compared with control. Organoleptic preferred Karish cheese samples enriched with microalgae especially with 0.5 and 1.0 % level consequently. Based on these results microalgae powder enriched cheese may have a great benefit for the industry to improve the texture, shapes and the functional nutraceutical properties of the products. [ABSTRACT FROM AUTHOR]

Background: Spirulina platensis contains natural pigments along with phenolic and flavonoid compounds that may be excreted to the supernatant in addition to biomass during culture. Objectives: We prepared enriched cheese and ice cream using biomass and supernatant of S. platensis microalgae extract. We aimed to evaluate these algae's organoleptic and nutritional properties. Methods: After preparing a 30-day culture of Spirulina, different concentrations of its biomass and supernatant extract were prepared to enrich cheese and ice cream. In the next step, the physicochemical and antioxidant properties of the products were measured by FRAP (ferric reducing antioxidant power) and DPPH (2,2-diphenyl 1-picryl hydroxyl) methods. Expert evaluators performed the sensory analysis according to the Iranian national standard method in terms of color, odor, taste, texture, and general acceptance on a scale of 0 to 5. Finally, statistical analysis of the data obtained from each experiment was performed with a one-way analysis of variance three times using SPSS software, version 24. Results: The results showed that the content of protein, fat, ash, and biomass was higher in enriched foods. However, in enriched ice creams, the content of protein, fat, sugar, and aeration rate increased significantly compared to the supernatant. In addition, cheese and ice cream fortified with supernatant had significantly greater antioxidant activity than biomass. The results of the hedonic test showed that with increasing concentrations of these agents in fortified cheeses and ice creams, the level of satisfaction in odor, taste, color, texture, and general acceptance factors was increased. Conclusion: The study results showed that adding biomass and supernatant of S. platensis to ice cream and cheese increased the nutritional value and improved the taste of these foods. Because these substances play an essential role in children's diet, this microorganism can be used to combat malnutrition and a diet without micronutrients. [ABSTRACT FROM AUTHOR]

Summary: The coronavirus disease 2019 (COVID‐2019) pandemic and other factors have significantly increased the number of people suffering from food shortages worldwide in 2020. As many as 720–811 million people, which is nearly 10% of the global population, are facing hunger. Thus, the need for substances that fulfil human nutritional requirements is growing to address this issue. Arthrospira platensis (A. platensis), commonly or commercially called spirulina, is an ideal product that contains various functional ingredients. Given them, various health benefits of A. platensis are proven gradually, including anti‐oxidant, immune regulation, anti‐inflammation, hypoglycaemia, anti‐bacterial and anti‐radiation properties. In recent years, functional ingredients of A. platensis are showing the potential to be functional foods. This paper gives an overview on the functional ingredients and the resulting health benefits of A. platensis summarises the research progress of A. platensis as functional foods in recent years and looks forward to its application development prospects. [ABSTRACT FROM AUTHOR]

The use of wastewater for microalgae cultivation allows the removal of contaminants through microalgal metabolism, contributing to the reduction of production costs, which improves the sustainability of the process. The objective of this work was to utilize malting wastewater as an alternative medium for microalgae cultivation, with the aim of increasing the carbohydrate productivity in microalgal biomass. To achieve this, six strains of microalgae (Chlorella minutissima, Chlorella homosphaera, Spirulina platensis LEB 52, Spirulina platensis Paracas, Scenedesmus obliquus, and Synechococcus nidulans) were cultivated in their standard medium with 30% malting wastewater added. In this initial stage (Erlenmeyer flasks: 1.8 L final volume), Spirulina platensis LEB 52 demonstrated high efficacy in removing nitrate (93%) and phosphate (90%) from wastewater. Furthermore, this strain exhibited the highest carbohydrate productivity (27 mg/L.day) and was therefore selected for scale-up in open raceway pond cultivation (250 L) with 50% wastewater added. During the second step, after 15 days of cultivation, Spirulina platensis LEB 52 reduced the phosphate and nitrate concentration in 76.6% and 48%, respectively, while attaining a carbohydrate productivity of 12.26 mg/L.day. These findings demonstrate a potential way for malting wastewater treatment and valorization, reducing pollution risks and the costs of microalgae cultivation, while generating biomass with different biotechnological applications, especially for biofuels production. Therefore, this approach represents a promising strategy for microalgae-based biorefinery. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the potential of Spirulina platensis (SP), a high protein content microalgae species, to be used as feedstock for a new type of solid biofuel technology, namely bio-coke. The SP bio-coke production was conducted at different formation temperatures of 130, 150 and 170 °C without any binder. The results showed that SP BIC 150, which was produced at the optimum formation temperature of 150 °C, exhibited the highest density and mechanical strength when compared with that of SP BIC 130 and SP BIC 170. This means that it strongly influenced its stable structure during the combustion process. With the strong structure of SP BIC 150, the breakdown of bio-coke can be prevented during flame combustion, thereby contributing to a longer char and total combustion time. The conversion of SP microalgae showed good potential to be used as an alternative renewable energy source in the future.

In this study, Spirulina platensis and Chlorella vulgaris microalgae along with curcumin powder were used to enrich lactic cheese as this subject has not been preceded in the literature. To evaluate the characteristics of the enriched product, total phenolic content, antioxidant activity, iron content, cell viability due to the reduction of cytotoxic conditions and sensory evaluation were measured. Analyses of the raw materials showed that while the phenolic content was higher in curcumin and spirulina powder than chlorella (respectively), the latter showed higher antioxidant activity than the formers. These additives caused a synergistic effect and resulted in a significant increase in antioxidant activity, iron and total phenolic content of the fortified cheese. According to sensory evaluation, the cheese enriched with Spirulina platensis (3%), Chlorella vulgaris (1.467%) and curcumin (1%), optimized by RSM through targeting highest antioxidant activity and iron content, had a higher score than the control cheese. Cell viability assay proved the cheese with the above-mentioned formula could protect mesenchymal stem cells of human adipose tissue (AD-MSC) against cytotoxic conditions successfully. The outcome of this research opens a new horizon for the fortification of cheese with the natural ingredients, especially for the poor countries with the problem of nutritional contents in their staple food. [ABSTRACT FROM AUTHOR]

The present study aims to determine the effect of bioactive compounds (total phenolic, total flavonoids, and antioxidant activity) of Spirulina platensis powder and its pasta products on kidney and liver diseases in rats. Pasta preparation enriched in spirulina powder with a standard treatment formulation. Pasta was supplemented by adding Spirulina platensis powder at different levels (5, 10, 15, and 20 %). The results indicated that rats treated with spirulina had lower plasma levels of ALT, AST, ALP, Albumin, creatinine, and total bilirubin after the end of the experiments. However, liver glutathione (GSH) concentration was markedly decreased as compared to the control group. In conclusion, pasta enriched with spirulina improved liver and kidney functions and enhanced oxidative stress indices. Additional studies are necessary to test the application of Spirulina platensis in other contexts. [ABSTRACT FROM AUTHOR]

Light plays an important role in the photosynthesis and metabolic process of microalgae. However, how different light conditions regulate the biomass production and protein accumulation of microalgae is mostly unknown. In this study, the influence of different light conditions, including light colors, densities, and light:dark cycles on the cell growth and biochemical composition of Spirulina platensis was symmetrically characterized. Under different colored lights, S. platensis all shows an increase trend within the increased light intensity ranges; however, each showing different optimal light intensities. At the same light intensity, different colored lights show different growth rate of S. platensis following the sequence of red>white>green>yellow>blue. The maximum growth rate and protein accumulation were determined as 21.88 and 5.10 mg/(L·d) when illuminated under red LED. The energy efficiency of different light sources was calculated and ranked as red>white>blue≈green>yellow. Transcriptomic analysis suggests that red light can promote cell growth and protein accumulation by up-regulating genes related to photosynthesis, carbon fixation, and C-N metabolism pathways. This study provides a conducive and efficient way to promote biomass production and protein accumulation of S. platensis by regulating light conditions. [ABSTRACT FROM AUTHOR]

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Spirulina platensis biopigments have been documented as a potential source of nutritional, physiological, and pharmacological purposes due to the presence of bioactive pigments, total phenolic content (TPC) and the consequent antioxidant activity that these compounds present. Bioextracts market has increased in the last decades and is a key option for replacing fossil-derived products and promote the transition for a bio-based economy. To take advantage of these compounds more effectively, optimized extraction processes must be researched and used in biomass sources. The present study focused on optimizing the ultrasound-assisted extraction (UAE) using response surface methodology. Three factor and three level Box–Behnken design was used to optimize the extraction of bioactive pigments, and to investigate the effects of three independent variables, x 1: extraction temperature (40–60 °C), x 2: extraction cycle time (20–40 min), and x 3: solvent-to-biomass ratio (50–70 mL/mg) on total pigment yield, antioxidant assay, and TPC (dependent variables). A second-order polynomial model was used for predicting the responses. Statistically, the model was validated using an analysis of variance. Results revealed that ultrasound-assisted temperature, time, and solvent-to-biomass ratio had a significant (p < 0.05) influence on the total pigment yield, while temperature and solvent-to-biomass ratio had a significant influence in the antioxidant activity, and temperature significantly influenced the total pigment yield. For total pigment yield, antioxidant activity, and total phenol content, the R 2 values of the models generated were 0.8627, 0.8460, and 0.9003, respectively, indicating that the models developed based on second-order polynomials were satisfactorily accurate for analyzing interactions between parameters. Desirability functions showed that the optimal extraction parameters were temperature: 60 °C, extraction cycle time: 20 min; and a solvent-to-biomass ratio of 70 mL/mg. Under optimal conditions, experimental values for total pigment yield, total phenol content expressed as gallic acid equivalent (GAE), and antioxidant activity expressed as Trolox equivalent (TRE) were: 165.19 ± 1.01 mg/g Dry Matter (DM), 36.50 ± 0.98 mg GAE/g DM, and 37.98 ± 0.58 mg TRE/g DM, respectively. The experimental values showed a good agreement with the predicted values with residual standard low 1% under optimum conditions. This optimized ultrasound-assisted method in natural eutectic solvents is effective and scalable to a green extraction of the bioactive pigments from Spirulina platensis with potential application to food, pharmaceutical, functional materials, and packaging. [ABSTRACT FROM AUTHOR]

The purpose of this research is to investigate the antimicrobial activity of the microalgae Scenedesmus sp. and Spirulina platensis cultivated in BG-11 culture medium and the effluent of desalination facilities of Bandar Turkmen unit, Golestan province in inhibiting the growth and proliferation of gram-positive Staphylococcus aureus bacteria. And gram-negative Escherichia coli. Algae were extracted by water-alcohol method in proportion (500 cc of alcohol and 50 cc of distilled water) and determination of minimum inhibitory concentration (MIC) was checked by broth micro dilution method (96 plates) and with The amount of antibacterial activity grown in the water of their usual environment was compared. The results of the two mentioned bacteria in the presence of different concentrations of water-ethanol extract within 24 hours showed that in the extracted extract of the genus Scenedesmus sp. and Spirulina platensis cultivated in BG-11 culture medium and 50 and 100% dilutions of wastewater, against the bacteria There was no minimum inhibitory concentration (MIC) of Staphylococcus aureus and Escherichia coli during (24 hours). The extract of Scenedesmus sp. grown in BG-11 with a concentration of 25 and 50 mg/ml has a higher concentration of Escherichia coli than spirulina platensis in the early hours. As the concentration increases, the amount of bacteria decreases in the early hours. The extract of Spirulina platensis grown in BG-11 showed high control properties to Staphylococcus bacteria in the early hours compared to Scenedesmus sp. extract grown in 50% wastewater compared to spirulina platensis had the highest concentration of Escherichia coli bacteria in the final hours, so that it showed higher controlling properties than spirulina platensis against Escherichia coli. Also, in the extract of Scenedesmus sp. grown in 50% wastewater at concentrations of 25, 100 and 200 mg/ml in the last hours, the concentration of Staphylococcus bacteria is higher than the concentration of 50 mg/ml and in spirulina in the last hours It has had a steady trend. In both extracts grown in 100% wastewater, they showed the highest concentration of bacteria in all concentrations within 4 hours. Therefore, in all concentrations of the two extracts, they showed an increase in the concentration of Staphylococcus bacteria over time (2-4 hours). Therefore, spirulina cultivated in 100% wastewater had a stable trend in the final hours compared to Scenedesmus sp. and showed more controlling properties against staphylococcus. [ABSTRACT FROM AUTHOR]

The current study aimed to determine the major and minor elements in different algal species using energy dispersive x-ray fluorescence (EDXRF). Eight microalgae were isolated, and the dry powder of biomass was pressed for EDXRF. The results showed all chemical compositions in each of the isolates. The major elements were detected as Ca, K, Cl, Si, Mg, and Mn, respectively, with high concentrations in percentages for most algal species including Chara hispida, Chara spp, Chlorella vulgaris, Chlorella spp, Chlorella spp, and Spirogyra turfosa. The minor elements with low percentages were detected as Mn, S, Fe, Al, P and Sr. Whereas the major elements for Spirulina platensis and Nostoc punctiforme were detected as Fe, K, S, the minor elements were seen to include Ca, Cl, Si, Mg, and Mn. There are very few studies that determine the elements in microalgae with EDXRF, which is a rapid, easy method to determine what components and in what quantities they are contained to be used (no chemical pretreatments are required). Algae contain elements like iron, and calcium, which are vital microelements for dietary intake and metabolism in humans. Algae could be useful if further studies are done on the efficiency of microalgae for calcium and iron absorption in human subjects. [ABSTRACT FROM AUTHOR]

Protein is an essential nutrient for laying hens, playing a crucial role in egg production and supporting their overall health. An 8-week feeding trial was conducted on 120 Lohmann Brown laying hens (aged 38 weeks). The layers were assigned randomly to three groups and housed in cages (twenty replicates × two birds/cage). All groups were fed a corn–soybean meal basal diet (2750 kcal/kg metabolizable energy (ME) with 17.8% crude protein (CP)). In contrast to conventional diet (CON), the experimental groups were supplemented primarily at the expense of soybean meal with 2.0% Chlorella vulgaris (CV2%) and 2.0% Spirulina platensis (SP2%). Their high concentrations of chlorophyll a (5.56; 9.06 mg/g), chlorophyll b (0.88; 1.34 mg/g), and antioxidant activity expressed as 2,2-diphenyl-1-picrylhydrazyl (73.29; 81.27 DPPH% inhibition) improved egg yolk quality. At the end of the trial, eighteen eggs/group (six yolk samples/group, three eggs/sample) were collected to determine the egg quality and nutritional parameters (fatty acids profile, cholesterol, β-carotene, yolk color, and antioxidant capacity). To determine the activity of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH), and total antioxidant capacity (TAC), blood samples were collected at the end of the period. Microalgae inclusion increased (p < 0.05) the fatty acid content, ß-carotene concentration (p < 0.001), antioxidant capacity (p < 0.0001), and yolk color intensity (p < 0.001) significantly, especially the yolk redness a* color parameter, but without any significant results concerning cholesterol concentration. Boiling the eggs for 10 min significantly (p < 0.001) increased the b* color parameter on microalgae treatments. The supplementation of laying hens' diet with microalgae positively influenced egg quality and nutritional properties. [ABSTRACT FROM AUTHOR]

Microalgae are versatile organisms with the ability to adapt to various environments and exhibit rapid growth. They play a significant role in photosynthesis by converting carbon dioxide into oxygen and utilizing nutrients in their surroundings. This study aims to investigate the impact of nutrient availability on the growth of Chlorella vulgaris and Spirulina platensis. The experiment involves culturing the microalgae in mineral water and distilled water mediums supplemented with Walne medium nutrients. The growth of microalgae is monitored daily by calculating cell density using a counting chamber method. The pH and temperature of the culture are also measured. The results show that both microalgae species can grow in both mediums, but the usagee of mineral water medium promotes higher cell density and growth rates compared to distilled water medium. The pH values of the cultures vary between mediums, with mineral water medium generally exhibiting higher of pH. The temperature remains relatively stable throughout the experiment. These findings indicate that nutrient availability has a significant influence on microalgae growth, and the use of mineral water medium enhances their growth potential. [ABSTRACT FROM AUTHOR]