Explore the vast range of titles available.

Arthrospira species grow well under highly enriched inorganic carbon concentrations, but little is known on the effects of inorganic carbon (Ci) limitation on its physiological performance. When Arthrospira platensis D-0083 was grown in a modified medium without NaHCO sub(3) under ambient air of 380 ppm CO sub(2), its trichomes became disassembled while the growth and photosynthetic rates were severely reduced. Phycocyanin and allophycocyanin contents decreased but the carotenoid content increased under the Ci limitation. Compared with the cells grown in Zarrouk medium, the trichomes grown under the Ci limitation increased their photosynthetic apparent affinity for Ci by about 14 times but photochemical quenching capacity was reduced. It appeared that A. platensis increased its CO sub(2) concentrating mechanism by inducing HCO sub(3) super(-) transporters and reducing the trichome size which increased filamentous surface to volume ratio.

In horticultural practice accelerated plant development and particularly earlier flowering, has been reported with microalgae applications. Therefore, the objective of this work was to study the effects of foliar spraying with Scenedesmus sp. and Arthrospira platensis hydrolysates on Petunia x hybrida plant development and leaf nutrient status. Three treatments were tested: T1 (foliar application with water, the control), T2 (foliar application with Arthrospira), and T3 (foliar application with Scenedesmus). Foliar spraying was applied five times (0, 14, 28, 35, and 42 days after transplanting). The concentration of both microalgae was 10 g L−1. At the end of the trial biometric parameters and nutrient concentration in photosynthetic organs (the leaves) were measured. The results of this assay show that foliar application of Scenedesmus accelerated plant development in terms of higher rates of root growth, leaf and shoot development, and earliness of flowering. Arthrospira enhanced the root dry matter, the number of flowers per plant, and the water content. Nevertheless, a reduction was found in the conductive tissue (stem + petiole) dry weight with Arthrospira compared with Scenedesmus and the control. The results also show that microalgae hydrolysate supply can improve the plant nutrient status. Based on these results, it is advisable to use Scenedesmus hydrolysates in foliar applications to increase the blooming of Petunia x hybrida.

The search for naturally derived antimicrobials has emerged due to an increasing concern about the use of synthetic ones. In this investigation, we examined the antibacterial mechanism and potential synergistic effect of Spirulina platensis extracts and Nisin in inhibiting the growth of 23 strains of Gram-positive and Gram-negative foodborne pathogens. We conducted four different extraction protocols to obtain S. platensis compounds, ultimately selecting the alcoholic acid-formic acid-sonication extraction due to its antimicrobial activity against 95.6% of the tested strains. Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus were selected for further analysis. Tests for Minimum Inhibitory Concentration (MIC) and the Checkerboard test revealed MIC values ranging from 0.5 to 0.12 µg mL-1 for Nisin and from 0.5 to 0.06 µg mL-1 for the selected S. platensis extract. When combined, the MIC range was 0.12 to 0.078 µg mL-1. The combination of S. platensis extracts and Nisin showed synergistic effects (Fractional Inhibitory Concentration Index0.302 to 0.18). The growth of foodborne pathogens tested was inhibited after 2, 6, 12, and 24 h with the combination of the compounds. Flow cytometry analysis showed that bacterial membrane permeability of the L. monocytogenes strain increased, while Scanning Electron Microscopy (SEM) illustrated the leakage of intracellular material, indicating cell membrane disruption. These observations suggest that combining S. platensis and nisin could be a promising natural alternative to synthetic preservatives in the food industry.

Marine and freshwater algae and their products are in growing demand worldwide because of their nutritional and functional properties. Microalgae (unicellular algae) will constitute one of the major foods of the future for nutritional and environmental reasons. They are sources of high-quality protein and bioactive molecules with potential application in the modern epidemics of obesity and diabetes. They may also contribute decisively to sustainability through carbon dioxide fixation and minimization of agricultural land use. This paper reviews current knowledge of the effects of consuming edible microalgae on the metabolic alterations known as metabolic syndrome (MS). These microalgae include Chlorella, Spirulina (Arthrospira) and Tetraselmis as well as Isochrysis and Nannochloropsis as candidates for human consumption. Chlorella biomass has shown antioxidant, antidiabetic, immunomodulatory, antihypertensive, and antihyperlipidemic effects in humans and other mammals. The components of microalgae reviewed suggest that they may be effective against MS at two levels: in the early stages, to work against the development of insulin resistance (IR), and later, when pancreatic -cell function is already compromised. The active components at both stages are antioxidant scavengers and anti-inflammatory lipid mediators such as carotenoids and -3 PUFAs (eicosapentaenoic acid/docosahexaenoic acid; EPA/DHA), prebiotic polysaccharides, phenolics, antihypertensive peptides, several pigments such as phycobilins and phycocyanin, and some vitamins, such as folate. As a source of high-quality protein, including an array of bioactive molecules with potential activity against the modern epidemics of obesity and diabetes, microalgae are proposed as excellent foods for the future. Moreover, their incorporation into the human diet would decisively contribute to a more sustainable world because of their roles in carbon dioxide fixation and reducing the use of land for agricultural purposes.

Abstract Nitrogen plays a key role in the production of biomass and valuable pigments from Arthrospira platensis. The present research aimed to examine the effect of Zarrouk medium modified with six common nitrogen sources (NaNO3, KNO3, NH4NO3, NH4SO4, NH4Cl, and urea) on the biomass and phycocyanin production of the microalga. The medium supplemented with sodium and potassium nitrate resulted in the highest biomass production (~ 1180 mg L−1) and culture duration (18 days). The ammonia-based media resulted in the highest specific growth rate and phycocyanin production (118 mg L−1) but less maximum cell density and culture period because oversaturation of the media with ammonia causes cell toxicity. The highest phycocyanin content (113 mg g−1) was measured in the cells grown in NH4SO4-supplemented medium. In conclusion, the nitrate-based and the ammonia-based media are proposed for Arthrospira cultivation in closed photobioreactors and open pond systems with free gas exchanges with atmosphere, respectively.

Effects of Spirulina (Arthrospira platensis) addition were evaluated on probiotic Lactobacillus casei growth in bacteriologically acidified feta-type (BAF) cheese. The chemical, textural, and sensorial characteristics of cheese were measured. After 60 days of storage, there were significantly higher viable counts of Lb. casei (9.10–9.35 log CFU g−1) in Spirulina samples in comparison with the control (8.68 log CFU g−1). The viable counts of Lb. casei were maintained more successfully in the probiotic BAF cheese which contained Spirulina. The values of titratable acidity, dry matter, and protein contents of Spirulina samples were higher than the control. Furthermore, samples with Spirulina exhibited softer textures which led to an easier disintegration and chewing of the BAF cheese. Based on the results of the sensorial evaluation, no significant difference was observed between the control and the samples with 0.5 or 1.0% Spirulina. In conclusion, Spirulina is deemed a satisfactory nutritional source which can be added to BAF cheese without having any adverse effects on its characteristics.

Phycocyanin is an interesting alternative to synthetic food colorants. Various methods to obtain phycocyanin from Arthrospira (Spirulina) biomass have been described in the literature, including ultrasonication, glass bead extraction and freeze-thawing. In this study, three optimized procedures were implemented to assess their efficacy in obtaining phycocyanin from Arthrospira maxima biomass, facilitating a comparative analysis of their effectiveness. After harvesting the biomass, extraction processes were conducted utilizing ultrasonication followed by flocculation with chitosan in various organic acid solutions, as well as glass bead extraction and freeze-thawing techniques, each followed by centrifugation. The obtained extracts were analyzed spectrophotometrically across the wavelength range of 280 to 800 nm. The freeze-thawing method yielded the highest C-PC contents at 17.03 ± 0.53%, followed closely by the ultrasonication method at 15.21 ± 0.41%. The highest purity of 2.02 ± 0.01 was attained through ultrasonication and subsequent flocculation with chitosan in acetic acid. Conversely, employing chitosan dissolved in citric or lactic acid for flocculation resulted in greenish extracts containing high amounts of chlorophyll.

Phycobiliproteins of Arthrospira (Spirulina) maxima have attracted attention because of their potential therapeutic antioxidant properties. The aim of this study was to assess the possible antiulcerogenic activity of these phycobiliproteins (ExPhy) against ethanol-induced gastric ulcers in rats. To explore the possible mechanisms of action, we examined antioxidant defense enzymes (e.g., catalase, superoxide dismutase, and glutathione peroxidase), as well as the level of lipid peroxidation (MDA) and the histopathological changes in the gastric mucosa. Intragastric administration of ExPhy (100, 200, and 400 mg/kg body weight) significantly lowered the ulcer index value compared to the ulcer control group (p < 0.05). The greatest protection was provided by the concentration of 400 mg/kg. The histological study supported the observed gastroprotective activity of ExPhy, showing a reduced inflammatory response. Moreover, the alcohol-induced decrease in stomach antioxidant enzyme activity found in the ulcer control group was prevented by ExPhy pretreatment. Furthermore, ExPhy reversed the ethanol-induced increase in lipid peroxidation. In summary, the antiulcerogenic potential of ExPhy may be due, at least in part, to its anti-oxidant and anti-inflammatory effects.

The application of cytostatic drugs or natural substances to inhibit cancer growth and progression is an important and evolving subject of cancer research. There has been a surge of interest in marine bioresources, particularly algae, as well as cyanobacteria and their bioactive ingredients. Dried biomass products of Arthrospira and Chlorella have been categorized as “generally recognized as safe” (GRAS) by the US Food and Drug Administration (FDA). Of particular importance is an ingredient of Arthrospira: phycocyanin, a blue-red fluorescent, water-soluble and non-toxic biliprotein pigment. It is reported to be the main active ingredient of Arthrospira and was shown to have therapeutic properties, including anti-oxidant, anti-inflammatory, immune-modulatory and anti-cancer activities. In the present review, in vitro and in vivo data on the effects of phycocyanin on various tumor cells and on cells from healthy tissues are summarized. The existing knowledge of underlying molecular mechanisms, and strategies to improve the efficiency of potential phycocyanin-based anti-cancer therapies are discussed.

Arthrospira platensis is the widely available source of spirulina that contains distinctive natural pigments, including carotenoids and C-phycocyanin (C-PC). In this study, the major carotenoid and C-PC contents were determined in seven commercially available spirulina powder products and laboratory-prepared A. platensis trichomes (AP-1) by an LC-DAD method and UV-Visible spectrometry, respectively. The correlation of these two pigment content levels with Hunter color coordinates and antioxidant activity was also evaluated. The L* value failed to show a significant correlation with pigment content, but a positive correlation was observed between a* values and the contents of total carotenoid and C-PC. As b* values decreased, the chlorophyll a and C-PC contents increased. AP-1 exhibited the highest content of total carotenoids, chlorophyll a and C-PC, and antioxidant activities among the samples. This observation could be related to degradation of these pigments during the mass production process. The carotenoid profiles suggested that the commercial spirulina powders originated from two different sources, A. platensis and A. maxima. Total carotenoid and C-PC content exhibited positive significant correlations with antioxidant activities measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. These results provide a strong scientific foundation for the establishment of standards for the commercial distribution of quality spirulina products.