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As current methods of production of phycocyanobilin, a photosynthetic blue pigment derived from phycocyanin of filamentous cyanobacteria, Pseudanabaena sp. ABRG5–3, Limnothrix sp. SK1–2–1, and Spirulina sp., exhibit a low extraction efficiency, a new extraction method using ethanol extraction as a type of solvolysis with an autoclave (130 ℃, 5.7 bar, 10 min) was developed in this study. This method exhibited high efficiency and enabled easy recovery of the three types of phycocyanobilins. The identity of the three types of phycocyanobilins was confirmed by high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry. Phycocyanobilins were stable at high temperatures (80 ℃) and acidic (pH 3) conditions. Phycocyanobilins also possessed a remarkable antioxidant property. This is the first time that a simple phycocyanobilin extraction method with a recovery rate of more than 60 % and approximately 1 % per dry cell weight of filamentous cyanobacteria has been demonstrated. This novel production method is thus convenient and effective for obtaining high-purity phycocyanobilins. • A new efficient method of phycocyanobilin (PCB) extraction was developed. • Structure and MW of three PCBs were confirmed by HPLC and ESI-CID-MS. • PCBs were stable under high temperatures (80 ℃) and acidic (pH 3) conditions. • PCBs show significant antioxidant abilities. [ABSTRACT FROM AUTHOR]

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

BACKGROUND: A water‐in‐oil‐in‐water (W/O/W) double emulsion can simultaneously load hydrophilic and hydrophobic substances due to its unique two‐membrane, three‐phase structure. However, thermodynamic instability greatly limits the application of double emulsions in food processing. Further development of Pickering emulsions based on proteins, etc., can improve the stability and loading capacity. It is of great significance to promote their practical application. RESULTS: Herein, we prepared ultrasound pretreatment complex glycation‐modified phycocyanin (UMPC) to stabilize a W/O/W Pickering emulsion for the codelivery of vitamin B12 (VB12) and vitamin E (VE). First, an inner water phase and oil phase containing polyglycerin polyricinoleate were homogenized to prepare a W/O emulsion. Subsequently, the W/O emulsion was homogenized with an outer water phase containing UMPC to obtain a W/O/W Pickering emulsion. A gel‐like inner phase emulsion with excellent storage and thermal stabilities was obtained under the condition that the W/O emulsion volume ratio was 80% and the UMPC was stabilized by 10 g kg−1. The double emulsion after loading VB12 and VE showed good encapsulation effect during the storage period, the encapsulation rate could reach more than 90%, it also showed excellent protection effect under long‐time storage and UV irradiation and the retention rate increased by more than 65%. In addition, the bioavailability of VB12 and VE significantly increased during simulated gastrointestinal digestion and reached 46.02% and 52.43%, respectively. CONCLUSION: These results indicate that the UMPC‐stabilized W/O/W Pickering emulsion is an effective carrier for the codelivery of hydrophilic and hydrophobic bioactive molecules and also provides a means for useful exploration of an efficient and stable emulsion system stabilized by biological macromolecules. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this study, phycocyanin obtained from Spirulina platensis extract was used at various concentrations as a natural blue color source in toffee‐type soft candy, and the effect of various storage temperatures (4, 20, and 40°C) on the color stability was investigated. In addition, main quality parameters, such as water activity, texture, and sensory analysis, were determined in the samples stored for 3 months at 20°C, and thus the effect of phycocyanin addition on the product appeal was studied. According to the results, the addition of phycocyanin powder did not significantly affect water activity (p >.05). As expected, L*, a*, and b* values of the samples changed with the phycocyanin, and the ΔE values of the samples stored at 4, 20, and 40°C varied between 0.14–0.44, 0.84–2.76, and 2.63–7.90, respectively, during the entire storage period. The texture analysis outputs revealed that the use of phycocyanin did not cause any change in the textural properties of the samples (p >.05). Considering the sensory analysis, all studied concentrations scored high in terms of color liking, and the use of phycocyanin in toffee‐type soft candy production resulted in a remarkable consumer appeal. Hence, the outcomes of this study show that if temperature control is performed in the production, the organoleptic properties of toffee‐type candy products can be enhanced using phycocyanin and can meet consumer requests and demands. [ABSTRACT FROM AUTHOR]

The provision of drinking water, agricultural, and industrial applications by reservoirs has made lake exploration and monitoring unavoidable. The features of the ecosystem, particularly physical and chemical elements, influence the evaluation of the quality of water resources. Lakes undergo extensive qualitative changes due to their vast amount of water. In general, these bodies of water represent geological conditions as well as water contamination produced by natural and human activities. In the present research, the prediction of the amount of phycocyanin (fPC) in the water of Lake Michigan has been implemented employing four tree‐based machine learning techniques based on seasonality factors. Phycocyanin has significant effects on quality parameters such as turbidity, chlorophyll concentration, algal bloom, and dissolved oxygen in water by affecting the photosynthesis process of algae. Therefore, in this study, the prediction of the amount of phycocyanin dissolved in the lake water using the mentioned variables, along with the temperature of the water, specific conductance, and pH, has been able to interpret the quality of the water and the occurrence of phenomena such as algal blooms. The results of the models in predicting fPCs equal to 0.44 and 0.55 μg/L were consistent with the natural conditions of the lake, and it seems that ensemble tree–based models, along with the biological index of fPC, formed the right combination of input and output parameters in modeling and obtained the lowest prediction error (root‐mean‐square error [RMSE] boosted trees = 0.0140 and RMSE random forests = 0.0141 μg/L). [ABSTRACT FROM AUTHOR]

Spirulina (Arthospira platensis) is known for its rich content of natural compounds like phycocyanin, chlorophylls, carotenoids, and high protein levels, making it a nutrient-dense food. Over the past decade, research has aimed to optimize the extraction, separation, and purification of these valuable metabolites, focusing on technologies such as high-pressure processing, ultrasound-assisted extraction, and microwave-assisted extraction as well as enzymatic treatments, chromatographic precipitation, and membrane separation. In this study, various extraction methods (conventional vs. ultrasound-assisted), solvents (water vs. phosphate buffer), solvent-to-biomass ratios (1:5 vs. 1:10), and ultrafiltration (PES membrane of MWCO 3 kDa, 2 bar) were evaluated. The quantities of total protein, phycocyanin (PC), chlorophyll a (Cla), and total carotenoids (TCC) were measured. The results showed that ultrasound-assisted extraction (UAE) with phosphate buffer at a 1:10 ratio yielded a metabolite-rich retentate (MRR) with 37.0 ± 1.9 mg/g of PC, 617 ± 15 mg/g of protein, 0.4 ± 0.2 mg/g of Cla, and 0.15 ± 0.14 mg/g of TCC. Water extraction in the concentration process achieved the highest concentrations in MRR, with approximately 76% PC, 92% total protein, 62% Cla, and 41% TCC. These findings highlight the effective extraction and concentration processes to obtain a metabolite-rich retentate from Spirulina biomass, reducing the volume tenfold and showing potential as a functional ingredient for the food, cosmetic, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The microalgae Arthrospira platensis (AP), commonly known as Spirulina, has gained widespread popularity as a food supplement in recent years. AP is particularly abundant in protein, B vitamins, iron, magnesium, potassium, and various antioxidants. In this study we aimed to evaluate the effect of nitrate limitation in the AP culture medium on AP growth and composition. In addition, the cytotoxicity of the respective aqueous AP extracts on three different mammalian cell-lines (HepG2, Caco2, L929) was tested.AP was cultivated over a 10-day period under nitrogen-rich (Nrich: 1.8 g/L) and nitrogen-deficient (Nlimited: 0.2–0.4 g/L) conditions in two separate experiments, each with three biological replicates (three bioreactors). Throughout the cultivation, the kinetic progress of dry biomass, pH, pigment content, the levels of essential elements (sulphur, phosphate, and nitrate) and the composition of elements in the harvested biomass was determined.While the biomass slightly but significantly differed, the phycocyanin concentration differed considerably (around 10-fold higher in the Nrich medium, p < 0.05). Aqueous extracts of the Nrich medium had significantly stronger effects on the cell membrane integrity and the metabolic activity of the cells than extracts of the Nlimited medium. Particularly was the finding that AP had a significantly stronger toxic effect on the two tumour cell types (HepG2, Caco2) than on the non-tumour cells (L929).This study underscores the significance of nitrate content in the cultivation media of AP. [ABSTRACT FROM AUTHOR]

Harmful algae blooms (HABs) have been reported with greater frequency in lakes across New York State (NYS) in recent years. In situ sampling is used to assess water quality, but such observations are time intensive and therefore practically limited in their spatial extent. Previous research has used remote sensing imagery to estimate phytoplankton pigments (typically chlorophyll-a or phycocyanin) as HAB indicators. The primary goal of this study was to validate a remote sensing-based method to estimate cyanobacteria concentrations at high temporal (5 days) and spatial (10–20 m) resolution, to allow identification of lakes across NYS at a significant risk of algal blooms, thereby facilitating targeted field investigations. We used Google Earth Engine (GEE) as a cloud computing platform to develop an efficient methodology to process Sentinel-2 image collections at a large spatial and temporal scale. Our research used linear regression to model the correlation between in situ observations of chlorophyll-a (Chl-a) and phycocyanin and indices derived from Sentinel-2 data to evaluate the potential of remote sensing-derived inputs for estimating cyanobacteria concentrations. We tested the performance of empirical models based on seven remote-sensing-derived indices, two in situ measurements, two cloud mitigation approaches, and three temporal sampling windows across NYS lakes for 2019 and 2020. Our best base model (R2 of 0.63), using concurrent sampling data and the ESA cloud masking—i.e., the QA60 bitmask—approach, related the maximum peak height (MPH) index to phycocyanin concentrations. Expanding the temporal match using a one-day time window increased the available training dataset size and improved the fit of the linear regression model (R2 of 0.71), highlighting the positive impact of increasing the training dataset on model fit. Applying the Cloud Score+ method for filtering cloud and cloud shadows further improved the fit of the phycocyanin estimation model, with an R2 of 0.84, but did not result in substantial improvements in the model's application. The fit of the Chl-a models was generally poorer, but these models still had good accuracy in detecting moderate and high Chl-a values. Future work will focus on exploring alternative algorithms that can incorporate diverse data sources and lake characteristics, contributing to a deeper understanding of the relationship between remote sensing data and water quality parameters. This research provides a valuable tool for cyanobacteria parameter estimation with confidence quantification to identify lakes at risk of algal blooms. [ABSTRACT FROM AUTHOR]

Prolonged strenuous exercise induces oxidative stress, leading to oxidative damage, skeletal muscle fatigue, and reduced exercise performance. The body compensates for oxidative stress through antioxidant actions, while related enzymes alone may not overcome excessive oxidative stress during prolonged strenuous exercise. Phycocyanin is an important antioxidant supplement derived from blue-green algae, which may be helpful in this type of situation. This study determined the effects of phycocyanin on exercise performance from prolonged strenuous exercise. Forty Sprague Dawley male rats were divided into 5 groups (n = 8 /group); Control group (C), Exercise group (E), and Exercise with supplement groups receiving low dose (Phycocyanin = 100 mg/kg BW; ELP) and high dose (Phycocyanin = 200 mg/kg BW; EHP) or vitamin C (Vitamin C = 200 mg/kg BW; VC). Phycocyanin was found to decrease oxidative damage markers, muscle fatigue, and muscle atrophy through the activated AKT/mTOR pathway. This was also found to have greater increases in antioxidants via Nrf2 signaling and increases ATP synthesis, GLUT4 transporters, and insulin signaling due to increased IRS-1/AKT signaling. In conclusion, phycocyanin was found to reduce oxidative damage and muscle atrophy, including an increase in insulin signaling in skeletal muscles leading to increased exercise performance in rats. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION High internal phase emulsions (HIPE) are distinguished from ordinary emulsions by higher oil‐phase percentage and better storage stability. Recently, HIPE stabilized with protein‐based particles has received more attention. However, organic precipitation, chemical cross‐linking and thermal denaturation are often needed to stabilize emulsions with natural proteins, and there is an urgent need to reduce the pollution of organic reagents.HIPE loaded with β‐carotene stabilized by phycocyanin was prepared under mild conditions. It demonstrated strong stability in terms of temperature and storage, as evidenced by its 94.17% retention rate and 81.06% bioavailability. This stability was ascribed to the efficient defense against heat and UV rays, which was probably associated with the oil‐droplet environment and interfacial protection of phycocyanin. It is speculated that the possible main interaction site between phycocyanin and sorbitol exists near amino acids 110 to 120 of the B chain. The hydrogen bond and hydrophobic interaction between them make the phycocyanin fully adsorbed on the oil–water interface when sorbitol is stable, forming a strong oil–water structure, which increases the stability of the emulsion.The outstanding fluorescence characteristics provide a feasible alternative for fluorescent emulsions to distribute and trace active compounds in vitro. HIPE loaded with β‐carotene might have potential as a 3D printing material for edible functional foods. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study is to investigate the antimicrobial efficacy of antimicrobial photodynamic therapy (PDT) using natural photosensitizers (curcumin, riboflavin, and phycocyanin) and light-emitting diode (LED) irradiation against multispecies biofilms in an acrylic denture base model. Materials and Methods: Forty-five acrylic specimens were fabricated using heat-curing acrylic resin. The specimens were then infected with a mixed culture of bacterial and fungal species (including Streptococcus mutans, Streptococcus sanguinis, Candida albicans, and Candida glabrata) for 4 days. The acrylic discs were divided into nine groups, with each group containing five discs: control, 0.2% chlorhexidine, 5.25% sodium hypochlorite, curcumin, riboflavin, phycocyanin alone or along with LED. After treatment, the number of colony-forming units (CFUs) per milliliter was counted. In addition, the extent of biofilm degradation was assessed using the crystal violet staining method and scanning electron microscopy. Results: All experimental groups exhibited a significant reduction in colony numbers for both bacterial and fungal species compared to the control (p < 0.001). The PDT groups exhibited a statistically significant reduction in colony counts for both bacteria and fungi compared to the photosensitizer-only groups. Conclusions: The results of this in vitro study show that PDT with natural photosensitizers and LED devices can effectively reduce the viability and eradicate the biofilm of microorganisms responsible for causing denture infections. [ABSTRACT FROM AUTHOR]

Phycocyanin (PC) is a naturally occurring green pigment in Spirulina. It was extracted by ultrasonic extraction using green technology, and its structure was studied using IR- and NMR-spectroscopy. Spectral data confirmed the PC structure. This study also involves an in silico assessment of the diverse applications of green pigment PC. Utilizing QSAR, PreADME/T, SwissADME, and Pro-Tox, this study explores the safety profile, pharmacokinetics, and potential targets of PC. QSAR analysis reveals a favorable safety profile, with the parent structure and most metabolites showing no binding to DNA or proteins. PreADME/T indicates low skin permeability, excellent intestinal absorption, and medium permeability, supporting oral administration. Distribution analysis suggests moderate plasma protein binding and cautious blood–brain barrier permeability, guiding formulation strategies. Metabolism assessments highlight interactions with key cytochrome P450 enzymes, influencing drug interactions. Target prediction analysis unveils potential targets, suggesting diverse therapeutic effects, including cardiovascular benefits, anti-inflammatory activities, neuroprotection, and immune modulation. Based on the in silico analysis, PC holds promise for various applications due to its safety, bioavailability, and potential therapeutic benefits. Experimental validation is crucial to elucidate precise molecular mechanisms, ensuring safe and effective utilization in therapeutic and dietary contexts. DFT calculations, including geometry optimization, MEP analysis, HOMO-LUMO energy surface, and quantum reactivity parameters of the PC compound, were obtained using the B3LYP/6–311G(d,p) level. This integrated approach contributes to a comprehensive understanding of PC's pharmacological profile and informs future research directions. [ABSTRACT FROM AUTHOR]

The free-floating, filamentous cyanobacteria Spirulina platensis is highly valued and in great demand worldwide for its high-value colors and phytonutrients. These compounds find use in health foods, feed, medicines, and diagnostics. The primary objective of this work was to enhance the growth of Spirulina under both oxidative and physiological stress conditions in order to maximize the synthesis of phycocyanin and carotenoid pigments. Cultures were subjected to different concentrations of hydrogen peroxide (H2O2) and sodium chloride for varying temperatures and pH levels. Under lower concentrations of H2O2 (4mM), the maximum carotenoid content was increased, but the phycocyanin content was found to be stimulated at 10mM. Moreover, the synthesis of both pigments was shown to be highest under physiological stress circumstances (40mM and 60mM NaCl concentration) and at an optimal pH of 8-9, helped by a temperature range of 25-30°C. The experimental results demonstrate that both carotenoid and phycocyanin exhibit antioxidant properties even in the presence of oxidative stress. This suggests that the aforementioned circumstances can be applied in future investigations to extract different antioxidants from S. platensis. [ABSTRACT FROM AUTHOR]

Serial femtosecond crystallography (SFX) with X-ray free-electron lasers (XFELs) has revolutionized classical X-ray diffraction experiments by utilizing ultra-short, intense, and coherent X-ray pulses. However, the SFX approach still requires thousands of nearly identical samples, leading to significant protein consumption. We propose utilizing Langmuir–Blodgett protein multilayers, which are characterized by long-range order, thermal stability, and the ability to induce protein crystallization, even in proteins that cannot be crystallized by conventional methods. This study aimed to combine the intrinsic properties of Langmuir–Blodgett multilayers with advanced XFEL techniques at the Linac Coherent Light Source. Since the macromolecule organization can be explored in nano or 2D crystals exploiting the properties of SFX–XFEL radiation that enable the capture of high-resolution diffraction images before radiation damage occurs, we propose Langmuir–Blodgett protein nanofilm technology as a novel approach for direct "on-chip" protein sample preparation. The present study extends previous investigations into Langmuir–Blodgett phycocyanin multilayer nanofilms using synchrotron radiation cryo-EM microscopy and second-order nonlinear imaging of chiral crystal (SONICC) experiments. We also examined the thermal stability of phycocyanin Langmuir–Blodgett multilayered films deposited on Si3N4 membranes to evaluate structural changes occurring at 150 °C compared with room temperature. Phycocyanin Langmuir–Blodgett films are worthy of investigation in view of their suitability for tissue engineering and other applications due to their thermal integrity and stability as the results of the present investigation reveal. [ABSTRACT FROM AUTHOR]

The extremophilic red alga Galdieria sulphuraria is well known for its metabolic capabilities with respect to organic carbon sources as well as its ability to produce the blue pigment phycocyanin (PC). The interest in PC as natural food colourant as well as nutraceutical is growing steadily. Therefore, a reliable quantification of PC accumulated by G. sulphuraria is crucial for establishing a production process. PC can be quantified through photometry but only after a laborious extraction procedure, which reduces the amount of data that can be gained from a cultivation. Hence, a faster PC determination method, with the potential to become an online method, is needed. In this study, we present a fast method for estimating the specific PC concentration based on in vivo absorbance spectra from cells of G. sulphuraria. A correlation with the PC concentration in the raw extract could be obtained, resulting in a 10-fold cross-validated coefficient of determination cR2 = 0.951. This makes extraction unnecessary in most cases. Especially in small-scale cultivation, where usually the available amount of biomass limits the number of measurements, this method presents a viable alternative to the extraction of PC.

Abstract Background Beet filter cake (BFC) is a food-grade solid waste produced by the sugar industry, constituting a permanent source of pollution. Cyanobacteria are considered a sustainable resource for various bioactive compounds such as phycocyanin pigment with valuable applications. This study aimed to use beet filter cake extract (BFCE) as an alternative medium for the economic cultivation of cyanobacterium Leptolyngbya sp. SSI24 PP723083, then biorefined the bioactive component such as phycocyanin pigment that could be used in the production of selenium nanoparticles. Results The results of the batch experiment displayed that the highest protein content was in BG11medium (47.9%); however, the maximum carbohydrate and lipid content were in 25% BFCE (15.25 and 10.23%, respectively). In addition, 75% BFCE medium stimulated the phycocyanin content (25.29 mg/g) with an insignificant variation compared to BG11 (22.8 mg/g). Moreover, crude phycocyanin extract from Leptolyngbya sp SSI24 cultivated on BG11 and 75% BFCE successfully produced spherical-shaped selenium nanoparticles (Se-NPs) with mean sizes of 95 and 96 nm in both extracts, respectively. Moreover, XRD results demonstrated that the biosynthesized Se-NPs have a crystalline nature. In addition, the Zeta potential of the biosynthesized Se-NPs equals − 17 mV and − 15.03 mV in the control and 75% BFCE treatment, respectively, indicating their stability. The biosynthesized Se-NPs exhibited higher effectiveness against Gram-positive bacteria than Gram-negative bacteria. Moreover, the biosynthesized Se-NPs from BG11 had higher antioxidant activity with IC50 of 60 ± 0.7 compared to 75% BFCE medium. Further, Se-NPs biosynthesized from phycocyanin extracted from Leptolyngbya sp cultivated on 75% BFCE exhibited strong anticancer activity with IC50 of 17.31 ± 0.63 µg/ml against the human breast cancer cell line. Conclusions The BFCE-supplemented medium can be used for the cultivation of cyanobacterial strain for the phycocyanin accumulation that is used for the green synthesis of selenium nanoparticles that have biological applications. Graphical Abstract

Background: The use of natural ingredients in skincare products has become a topic of interest in contemporary society. The adverse effects and environmental risks of synthetic compounds have prompted studies on the use of photosynthetic organisms as sustainable and ecofriendly sources of effective ingredients. Natural extracts have gained attention in the cosmetic industry, especially those derived from plants, algae, and cyanobacteria. Cyanobacteria have gained prominence in the cosmetic industry because of their low culture requirements, rapid growth rates, and capacity to produce different bioactive metabolites. As a result, cyanobacteria are economically viable and sustainable resources. Objective: We aimed to determine the effect of coating with natural phycocyanin and phycoerythrin pigments from two cyanobacterial species, Spirulina platensis and Nostoc sp., on the properties of three cosmetic products: soap, anti-acne face wash, and hand sanitizer gel. Methods: After cyanobacterial culture, the pigments were extracted, purified, and coated with the stabilizer, chitosan. Thereafter, cosmetic products were formulated with phycocyanin and phycoerythrin, and their viscosity, pH, stability, and antioxidant and antibacterial properties against bacteria were evaluated using the appropriate assays. Results: The anti-acne wash gel and soap had better properties when coated with both pigments and phycocyanin alone, whereas the hand sanitizer gel had better properties when coated with phycoerythrin alone and both pigments. Conclusion: Overall, three coated and stable cosmetic products can be produced using cyanobacterial pigments owing to their high fortifying capacity.

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We investigated suitable culture conditions for the production of the blue pigment phycocyanin (PC) from the unique filamentous cyanobacteria Pseudanabaena sp. ABRG5-3 and Limnothrix sp. SK1-2-1. White, green, or red LED irradiation at 30 μmol photons/m2/s was effective for phycocyanin production when compared with Arthrospira platensis (Spirulina) sp. NIES-39, which is generally grown under high light irradiation. To investigate the safety of the cyanobacteria, ABRG5-3 cells were subjected to Ames (reverse mutation) tests and single oral-dose rat studies, which revealed non-mutagenic and non-toxic properties. When three purified phycocyanins (abPC, skPC, and spPC) were subjected to agarose gel electrophoresis, they showed different mobility, indicating that each phycocyanin has unique properties. abPC exhibited strong antiglycation activities as novel function. • We assessed cultivation conditions and phycocyanin production of 3 cyanobacteria. • We tested various light irradiation conditions in terms of quality and intensity. • We found that ABRG5-3 cells are non-mutagenetic and non-toxic. • Each phycocyanin has unique properties depending on bacterial species. • The phycocyanins showed strong antiglycation activity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aphanizomenon flos-aquae (AFA) is a Gram-negative nitrogen-fixing freshwater filamentous cyanobacterium with a rich nutritional profile that is approved for human consumption by both the Food and Drug Administration and the European Food and Safety Authorities. It has a high protein content (60-70%) and contains numerous vitamins, minerals and trace elements together with several high-value compounds with nutraceutical properties, such as C-phycocyanin and β-phenylethylamine. 500-1000 t of AFA dry biomass are currently wild harvested from natural blooms that occur seasonally in Klamath Lake, Oregon, USA, and distributed as a nutritional supplement worldwide. The requirements and unreliability of wild harvesting, owing to the dependence of AFA growth on environmental conditions and potential contamination by microcystin toxins, threaten the availability of biomass supply and restricts commercial expansion. In this review we propose AFA cultivation in open ponds or closed photobioreactors to obtain a reliable production of unialgal biomass to resolve the supply issue and enhance AFA as a feedstock for specific high-value by-products. Furthermore, we explore potential strategies for maximising overall yield and seasonal robustness by using a synergistic combination of cultivation and wild harvesting. Controlled AFA cultivation would also facilitate the use of genetic manipulation to generate bespoke strains with improved commercial applications, such as increasing the cyanobacterium's nitrogen-fixation rate to enhance its value as a biofertiliser. Ultimately, realising the untapped biotechnological potential of AFA requires a better understanding of its fundamental biology, robust methodologies for laboratory and large-scale cultivation, and the development of AFA-specific genetic engineering techniques. [ABSTRACT FROM AUTHOR]

Cyanobacteria are adaptable and dominant organisms that exist in many harsh and extreme environments due to their great ecological tolerance. They produce various secondary metabolites, including cyanotoxins. While cyanobacteria are well studied in surface waters and some aerial habitats, numerous other habitats and niches remain underexplored. We collected 61 samples of: (i) biofilms from springs, (ii) aerial microbial mats from buildings and subaerial mats from caves, and (iii) water from borehole wells, caves, alkaline, saline, sulphidic, thermal, and iron springs, rivers, seas, and melted cave ice from five countries (Croatia, Georgia, Italy, Serbia, and Slovenia). We used (q)PCR to detect cyanobacteria (phycocyanin intergenic spacer—PC-IGS and cyanobacteria-specific 16S rRNA gene) and cyanotoxin genes (microcystins—mcyE, saxitoxins—sxtA, cylindrospermopsins—cyrJ), as well as amplicon sequencing and morphological observations for taxonomic identification. Cyanobacteria were detected in samples from caves, a saline spring, and an alkaline spring. While mcyE or sxtA genes were not observed in any sample, cyrJ results showed the presence of a potential cylindrospermopsin producer in a biofilm from a sulphidic spring in Slovenia. This study contributes to our understanding of cyanobacteria occurrence in diverse habitats, including rare and extreme ones, and provides relevant methodological considerations for future research in such environments. [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]

The defensive role performed by exogenously supplied ascorbic acid in the cyanobacterium Nostoc muscorum Meg1 against damages produced by UV-C radiation exposure was assessed in this study. Exposure to UV-C (24 mJ/cm2) significantly enhanced reactive oxygen species (ROS) (50%) along with peroxidation of lipids (21%) and protein oxidation (22%) in the organism. But, addition of 0.5 mM ascorbic acid prior to UV-C exposure showed reduction in ROS production (1.7%) and damages to lipids and proteins (1.5 and 2%, respectively). Light and transmission electron microscopic studies revealed that ascorbic acid not only protected filament breakage but also restricted severe ultrastructural changes and cellular damages in the organism. Although the growth of the organism was repressed up to 9% under UV-C treatment within 15 days, a pre-treatment with ascorbic acid led to growth enhancement by 42% in the same period. Various growth parameters such as photo-absorbing pigments (phycoerythrin, phycocyanin, allophycocyanin, chlorophyll a, and carotenoids), water splitting complex (WSC), D1 protein, RuBisCO, glutamine synthetase and nitrogenase activities in the UV-C treated organism were seen to be relatively intact in the presence of ascorbic acid. Thus, a detailed analysis undertaken in the present study was able to demonstrate that ascorbic acid not only act as first responder against harmful UV-C radiation by down-regulating ROS production, it also accelerated the growth performance in the organism in the post UV-C incubation period as an immediate response to an adverse experience presented in the form of UV-C radiation exposure. [ABSTRACT FROM AUTHOR]

BACKGROUND: Phycocyanin (PC), a natural blue photosynthetic pigment found in cyanobacteria, rhodophyta and cryptophyta has numerous applications in biotechnology and the food industry. The phycocyanin extraction method has a significant impact on its bioactivities, purity index, cost and potential applications; thus, the development of an efficient extraction strategy continues to be a primary research goal. RESULTS: This study evaluated the efficacy of different methods for the extraction of cyanobacterial phycocyanin (C‐PC) from three marine cyanobacterial isolates, namely Arthrospira platensis, Phormidium sp. and Pseudoscillatoria sp. wet biomass. The pretreatment step of soaking biomass in extraction buffer for 60 min, followed by a combination of freeze–thaw (one cycle; 2 h) and sonication (2 min) treatment was found to be the most effective extraction strategy, producing the highest C‐PC yield (16.19 ± 0.34%, 15.89 ± 0.61% and 15.56 ± 0.69% dry cell weight for strains A. platensis, Phormidium sp. and Pseudoscillatoria sp., respectively). Furthermore, a biomass‐to‐solvent ratio of 0.02 g mL−1 was optimal to attain food‐grade purity ((A620/A280) ≥ 0.7). Bioactivity evaluation of crude and purified C‐PC exhibited its potential as antioxidant compounds and as an antimicrobial agent with significant inhibitory effects against various pathogenic microorganisms. CONCLUSION: The study proposed an efficient and cost‐effective C‐PC extraction process for cyanobacteria and highlighted the potential of C‐PC as a valuable bioactive compound with various applications. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Background: Beet filter cake (BFC) is a food-grade solid waste produced by the sugar industry, constituting a permanent source of pollution. Cyanobacteria are considered a sustainable resource for various bioactive compounds such as phycocyanin pigment with valuable applications. This study aimed to use beet filter cake extract (BFCE) as an alternative medium for the economic cultivation of cyanobacterium Leptolyngbya sp. SSI24 PP723083, then biorefined the bioactive component such as phycocyanin pigment that could be used in the production of selenium nanoparticles. Results: The results of the batch experiment displayed that the highest protein content was in BG11medium (47.9%); however, the maximum carbohydrate and lipid content were in 25% BFCE (15.25 and 10.23%, respectively). In addition, 75% BFCE medium stimulated the phycocyanin content (25.29 mg/g) with an insignificant variation compared to BG11 (22.8 mg/g). Moreover, crude phycocyanin extract from Leptolyngbya sp SSI24 cultivated on BG11 and 75% BFCE successfully produced spherical-shaped selenium nanoparticles (Se-NPs) with mean sizes of 95 and 96 nm in both extracts, respectively. Moreover, XRD results demonstrated that the biosynthesized Se-NPs have a crystalline nature. In addition, the Zeta potential of the biosynthesized Se-NPs equals − 17 mV and − 15.03 mV in the control and 75% BFCE treatment, respectively, indicating their stability. The biosynthesized Se-NPs exhibited higher effectiveness against Gram-positive bacteria than Gram-negative bacteria. Moreover, the biosynthesized Se-NPs from BG11 had higher antioxidant activity with IC50 of 60 ± 0.7 compared to 75% BFCE medium. Further, Se-NPs biosynthesized from phycocyanin extracted from Leptolyngbya sp cultivated on 75% BFCE exhibited strong anticancer activity with IC50 of 17.31 ± 0.63 µg/ml against the human breast cancer cell line. Conclusions: The BFCE-supplemented medium can be used for the cultivation of cyanobacterial strain for the phycocyanin accumulation that is used for the green synthesis of selenium nanoparticles that have biological applications. [ABSTRACT FROM AUTHOR]

The main problem of using natural blue pigment of phycocyanin produced by Arthrospira platensis (spirulina) is its instability in the food matrix because of environmental stress. This study aimed to investigate the stability of phycocyanin under simulated conditions in food formulations against osmotic, acid, and temperature stress conditions. Thermal degradation constant (Dc) and half-life (t½) of phycocyanin extracted from Arthrospira platensis were analyzed using response surface methodology followed by a first-order kinetic reaction. The stability of phycocyanin was assessed under various temperature (50–98ºC), NaCl (0–2% w/w), and pH (4–7) values. Results showed that the stability of phycocyanin extracted from Arthrospira platensis is high at neutral pH and concentration of 1% (w/w) NaCl. The stability decreased with increase in temperature at ≥75°C. The highest stability of phycocyanin (the lowest Dc and the maximum t½ were 0.011 min-1 and 54.03 min, respectively) was achieved at 66.89°C, pH = 6.6, and NaCl of 0.40% w/w. According to processing conditions, content of phycocyanin required for a food matrix is successfully calculated by the response surface method. This research showed that phycocyanin is stable at thermal shock in a neutral pH medium and low content of NaCl (0.40% w/w). [ABSTRACT FROM AUTHOR]

Hydrothermal liquefaction (HTL) is an efficient technology for converting biomass to platform compounds. It has great potential for reducing the dependence on fossil fuels. The HTL of waste biomass has been extensively studied in recent years due to both its environmental and economic benefits. However, most woody waste contains a large amount of cellulose, and it is difficult to be sufficiently decomposed to valuable chemicals. Phycocyanin, a key component of algae, is easily degraded under high-temperature liquefaction conditions. In this work, focusing on bio-oil generation properties, the co-liquefaction characteristics and synergistic mechanisms of a-cellulose and phycocyanin were explored. The findings revealed a maximum bio-oil yield of 33.1 wt% under the optimal conditions (300 °C for 40 min), with a notable positive synergistic effect of 13.5 wt%. Chemical composition analysis indicated distinct compositional differences between the bio-oils derived from individual and dual feedstock. The amounts of pyridine and pyrimidine compounds increased due to the enhanced co-liquefaction. The results also highlighted the influence of temperature on the degree of conversion and product distribution. Finally, preliminary chemical reaction pathway was elucidated, underscoring the potential of integrating microalgae and woody biomass for enhanced bio-oil production. [ABSTRACT FROM AUTHOR]

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Cyanobacteria are microorganisms that grow rapidly in an aquatic medium, showing the capacity of accumulations of biocompounds subsequently converted into value-added biocompounds. The cyanobacterium Spirulina maxima can produce pigments besides accumulating significant amounts of carbohydrates and proteins. An alternative to reducing biomass production costs at an industrial scale is the use of landfill leachate in the growing medium, as well as the mitigation of this pollutant. The objective of this work was to cultivate Spirulina maxima in a medium supplemented with leachate, using the design of experiments to evaluate the effects of leachate concentration (% v/v), light source, and light intensity in an airlift photobioreactor, analyzing them as a response to the productivity of biomass, phycocyanin, carbohydrates, and biochar. The highest values of productivity (mg L−1d−1) were 97.44 ± 3.20, 12.82 ± 0.38, 6.19 ± 1.54, and 34.79 ± 3.62 for biomass, carbohydrates, phycocyanin, and biochar, respectively, adjusted for experiment 2 with the factors of leachate concentration (5.0% v/v), light source (tubular LED), and luminosity (54 µmol m−2 s−1), respectively. The use of leachate as a substitute for macronutrients in Zarrouk's medium for the cultivation of Spirulina maxima is a viable alternative in the production of biocompounds as long as it is used at an appropriate level. [ABSTRACT FROM AUTHOR]

Phycocyanin, a blue-coloured pigment, predominantly found and derived from Spirulina sp., has gained researchers' interest due to its vibrant hues and other attractive properties like antioxidant and anti-microbial. However, the lack of reliable and sustainable phycocyanin extraction strategies without compromising the quality has hindered the scaling up of its production processes for commercial purposes. Here in this study, phycocyanin was extracted from wet and dry biomass Spirulina sp., using three different physical cell disruption methods (ultrasonication, homogenization, and freeze–thaw cycles) combined with two different buffers (phosphate buffer and acetate buffer) and water (as control). The result showed that the freeze–thaw method combined with acetate buffer produced the highest yield (25.013 ± 2.572 mg/100 mg) with a purity ratio of 0.806 ± 0.079. Furthermore, when subjected to 30% w/v salt stress, 1.9 times higher phycocyanin yield with a purity ratio of 1.402 ± 0.609 was achieved using the previously optimized extraction method. [ABSTRACT FROM AUTHOR]

Objective: Given the noteworthy implications of alcohol consumption and its association with male infertility, there has been a notable focus on investigating natural alternatives to mitigate its adverse effects. Thus, this study was conducted to assess the potential protective effect of phycocyanin extract derived from the blue algae Arthrospira (Spirulina) platensis against ethanol-induced oxidative stress, disturbances in testicular morphology, and alterations in sperm production. Methods: Male rats were divided into four groups (five rats each): the control group received a saline solution, the ethanol exposed group (EtOH) was subjected to intraperitoneal injections of 10 mL/kg of ethanol solution at a concentration of 38% (v/v), the phycocyanin alone treated group (P) received oral administration of phycocyanin at a dosage of 50 mg/kg, and the phycocyanin-cotreated group (PE) was given oral phycocyanin followed by ethanol injections. All treatments were administered over a period of 14 days. Results: Our findings demonstrated that ethanol exposure induced reproductive toxicity, characterized by reduced sperm production and viability, alterations in testicular weight and morphology, increased lipid peroxidation levels, and elevated oxidative enzyme activity. In addition, the ethanol-intoxicated group showed perturbations in serum biochemical parameters. However, the simultaneous exposure to ethanol and phycocyanin exhibited a counteractive effect against ethanol toxicity. Conclusion: The results showed that supplementation of phycocyanin prevented oxidative and testicular morphological damage-induced by ethanol and maintained normal sperm production, and viability. [ABSTRACT FROM AUTHOR]

A 2 mm thin layer of wet Spirulina platensis biomass was dried using two methods: refractance window drying (RW) and combined RW and FIR drying (RWF). The effect of drying temperature (40–60 °C) and proximity to FIR heaters (5 and 10 cm) was evaluated on falling rate drying characteristics. The moisture (Deff) and thermal (α) diffusivity coefficients were obtained in the range 1.728 × 10−8 to 5.289 × 10−9 and 1.322 × 10−8 to 4.169 × 10−9 m2 s−1, respectively (R2, 0.921–0.984). RW drying at ≥50 °C caused loss of color, phytopigments, and lipid peroxidation. At 40 °C, RW drying led to a long drying period (300.50 ± 3.53 min), poor drying rate (0.039 ± 0.002 g-H2O/min), lowest Deff and α (5.289 × 10−9 and 4.169 × 10−9 m2 s−1), and chlorophyll loss (32.2%). Combined RW and FIR drying at 40 °C and 5 cm proximity (RWF40-5cm) reduced drying time (15.1%), increased drying rate (27.8%), improved α (15%), and Deff (14.9%). RWF40-5cm dried biomass showed excellent retention of color (ΔE = 4.64 ± 1.32), protein (93.8%), γ-linolenic acid (90.1%), chlorophyll (87.9%), and phycocyanin (86.7%) from freeze-dried biomass (FD). Low-temperature RWF40-5cm drying could be a potential alternative to freeze-drying for effective and safe drying of heat-sensitive Spirulina platensis biomass. [ABSTRACT FROM AUTHOR]

Resilience, measured by the distribution of passage times between alternate states, indicates persistence of a state in stochastic dynamic systems such as blooms of cyanobacteria in lakes. We used high‐frequency datasets to compare the resilience of low and high states of phycocyanin, a pigment indicator of cyanobacteria, in Lake Mendota, Wisconsin, USA, for three growing seasons that ranged sevenfold in external phosphorus (P) load. Each year we observed 139–265 passage times across the unstable threshold that separated the low‐ from high‐phycocyanin states. Each sample of passage times is highly skewed with low median, larger mean, much larger SD, and wide tails extending to long lifetimes of a state. About 25% of events, whether low or high phycocyanin, lasted a day or more. Among these 3 years of contrasting external P load, there were no discernible differences in the resilience of either ecosystem state. We attribute this lack of contrast to the sustained recycling of P from sediments and the high stochasticity of phycocyanin in this lake. [ABSTRACT FROM AUTHOR]

Cyanobacterial phycocyanin pigment is widely utilized for its properties in various industries, including food, cosmetics, and pharmaceuticals. Despite its potential, challenges exist, such as extraction methods impacting yield, stability, and purity. This study investigates the impact of the number of freeze–thaw (FT) cycles on the extraction of phycocyanin from the wet biomass of four cyanobacteria species (Arthrospira platensis, Chlorogloeopsis fritschii, Phormidium sp., and Synechocystis sp.), along with the impact of five extraction solutions (Tris-HCl buffer, phosphate buffer, CaCl2, deionized water, and tap water) at various pH values. Synechocystis sp. exhibited the highest phycocyanin content among the studied species. For A. platensis, Tris-HCl buffer yielded maximum phycocyanin concentration from the first FT cycle, while phosphate buffer provided satisfactory results from the second cycle. Similarly, Tris-HCl buffer showed promising results for C. fritschii (68.5% of the maximum from the first cycle), with the highest concentration (~12% w/w) achieved during the seventh cycle, using phosphate buffer. Phormidium sp. yielded the maximum pigment concentration from the first cycle using tap water. Among species-specific optimal extraction solutions, Tris-HCl buffer demonstrated sufficient extraction efficacy for all species, from the first cycle. This study represents an initial step toward establishing a universal extraction method for phycocyanin from diverse cyanobacteria species. [ABSTRACT FROM AUTHOR]

Objective: Evaluation of the effect of phycocyanin (PC) and toluidine blue (TBO) along with sodium fluoride varnish (FV) or titanium tetrafluoride (TiF4) under the conditions of antimicrobial photodynamic therapy (PDT) on a dual-species cariogenic biofilm and on remineralization process. Design: After the development of Streptococcus mutans and Lactobacillus acidophilus dual-species biofilms on the human enamel disks, they were divided into 11 groups (n = 9): Control (0.9 % saline), PC, TBO, FV, and TiF4 alone, PC and TBO in combination with a 635 nm diode laser (PDT treatment), PC-PDT+ (PC + FV or TiF4 + 635 nm diode laser), and TBO-PDT+ (TBO + FV or TiF4 + 635 nm diode laser). After the treatment, crystal violet assay was performed to determine the reduction of cariogenic biofilms. Enamel remineralization changes were analyzed using energy dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscopy (FESEM) for the calcium and phosphorus (Ca/P) ratio. Results: Only TBO-PDT+ showed superior antibiofilm activity when TiF4 was applied. Furthermore, the highest Ca/P ratio was found after treatment of enamel surfaces with TiF4-TBO-PDT+. The FESEM images showed that the enamel disks treated with TiF4 plus TBO-mediated PDT exhibited surface coating. However, TiF4 plus PC-mediated PDT cannot repair demineralized enamel. Conclusions: These data suggest that TBO-PDT along with TiF4 can effectively reduce cariogenic biofilms and significantly remineralize enamel disks, opening new avenues in caries prevention.

Spirulina is capable of using light energy and fixing carbon dioxide to synthesize a spectrum of organic substances, including proteins, polysaccharides, and unsaturated fatty acids, making it one of the most coveted food resources for humanity. Conventionally, Spirulina products are formulated into algal powder tablets or capsules. However, the processing and preparation of these products, involving screw pump feeding, extrusion, high-speed automation, and high-temperature dewatering, often result in the rupture of cell filaments, cell fragmentation, and the unfortunate loss of vital nutrients. In contrast, fresh Spirulina, cultivated within a closed photobioreactor and transformed into an edible delight through harvesting, washing, filtering, and sterilizing, presents a refreshing taste and odor. It is gradually earning acceptance as a novel health food among the general public. This review delves into the manufacturing processes of fresh Spirulina, analyzes its nutritional advantages over conventional algal powder, and ultimately prospects the avenues for fresh Spirulina’s application in modern food processing. The aim is to provide valuable references for the research and development of new microalgal products and to propel the food applications of microalgae forward.

Aquatic photosynthetic organisms evolved to use a variety of light frequencies to perform photosynthesis. Phycobiliprotein phycocyanin 645 (PC645) is a light-harvesting complex in cryptophyte algae able to transfer the absorbed green solar light to other antennas with over 99% efficiency. The infrared signatures of the phycobilin pigments embedded in PC645 are difficult to access and could provide useful information to understand the mechanism behind the high efficiency of energy transfer in PC645. We use visible-pump IR-probe and two-dimensional electronic vibrational spectroscopy to study the dynamical evolution and assign the fingerprint mid-infrared signatures to each pigment in PC645. Here, we report the pigment-specific vibrational markers that enable us to track the spatial flow of excitation energy between the phycobilin pigment pairs. We speculate that two high-frequency modes (1588 and 1596 cm-1) are involved in the vibronic coupling leading to fast (

Hydrothermal liquefaction (HTL) is an efficient technology for converting biomass to platform compounds. It has great potential for reducing the dependence on fossil fuels. The HTL of waste biomass has been extensively studied in recent years due to both its environmental and economic benefits. However, most woody waste contains a large amount of cellulose, and it is difficult to be sufficiently decomposed to valuable chemicals. Phycocyanin, a key component of algae, is easily degraded under high-temperature liquefaction conditions. In this work, focusing on bio-oil generation properties, the co-liquefaction characteristics and synergistic mechanisms of α-cellulose and phycocyanin were explored. The findings revealed a maximum bio-oil yield of 33.1 wt% under the optimal conditions (300 °C for 40 min), with a notable positive synergistic effect of 13.5 wt%. Chemical composition analysis indicated distinct compositional differences between the bio-oils derived from individual and dual feedstock. The amounts of pyridine and pyrimidine compounds increased due to the enhanced co-liquefaction. The results also highlighted the influence of temperature on the degree of conversion and product distribution. Finally, preliminary chemical reaction pathway was elucidated, underscoring the potential of integrating microalgae and woody biomass for enhanced bio-oil production.

Cyanobacteria are microorganisms that grow rapidly in an aquatic medium, showing the capacity of accumulations of biocompounds subsequently converted into value-added biocompounds. The cyanobacterium Spirulina maxima can produce pigments besides accumulating significant amounts of carbohydrates and proteins. An alternative to reducing biomass production costs at an industrial scale is the use of landfill leachate in the growing medium, as well as the mitigation of this pollutant. The objective of this work was to cultivate Spirulina maxima in a medium supplemented with leachate, using the design of experiments to evaluate the effects of leachate concentration (% v/v), light source, and light intensity in an airlift photobioreactor, analyzing them as a response to the productivity of biomass, phycocyanin, carbohydrates, and biochar. The highest values of productivity (mg L−1d−1) were 97.44 ± 3.20, 12.82 ± 0.38, 6.19 ± 1.54, and 34.79 ± 3.62 for biomass, carbohydrates, phycocyanin, and biochar, respectively, adjusted for experiment 2 with the factors of leachate concentration (5.0% v/v), light source (tubular LED), and luminosity (54 µmol m−2 s−1), respectively. The use of leachate as a substitute for macronutrients in Zarrouk’s medium for the cultivation of Spirulina maxima is a viable alternative in the production of biocompounds as long as it is used at an appropriate level.

Background and Aim: Natural antioxidants are crucial for preserving and enhancing the health, survival, reproduction, and reproductive function of poultry. Phycocyanin (PC) is a natural blue food colorant with various health benefits. The aim of this study was to extract Arthrospira platensis phycocyanin (ApPC) from A. platensis using simple and economical methods and investigate the impact of phytocyanin supplementation on the performance and fatty and amino acid profiles of broiler chicks. Materials and Methods: PC was extracted from A. platensis by freezing and thawing, and optimization conditions such as pH and temperature were applied during storage periods. A total of 270 1-week-old Ross breed broiler chicks were randomly assigned to the following three treatment groups: basal diet supplemented with 0 mg of PC/kg diet (control), basal diet supplemented with 1 g PC/kg diet (T1), and basal diet supplemented with 2 g PC/kg (T2). In a completely randomized design, three cage replicates (30 birds each) were assigned to each of the three groups. The dietary effects of ApPC on growth performance (body weight gain [BWG], body weight [BW], feed intake, feed conversion ratio, serum constituents, and antioxidant indices) in broiler chickens, free amino acids, and fatty acids in muscles were evaluated. Results: Total BWG and BW increased without a significant effect on the total feed consumption. Serum levels of total proteins and albumin increased with increasing ApPC supplementation. In addition, globulin levels significantly increased. There was a significant decrease in serum total cholesterol levels among the treatments. The activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione, and total antioxidant capacity) is significantly increased. In contrast, an increase in ApPC caused a significant decrease in malondialdehyde. The content and quantity of fatty acids and amino acids in the meat of broiler chicks supplemented with PC varies. Conclusion: The addition of PC to broiler chicken diets enhances antioxidant activities, BW, BWG, and meets quality requirements.

Phycocyanin from Spirulina (blue-green algae) is used as photosensitizer to fabricate biosensitized solar cells (BSSC). Pigments are extracted in different solvents such as water, ethanol and acetone. Pure and silver-doped ZnO nanoparticles were prepared by simple microwave technology, and BSSCs were prepared by spin coating method. The structure, morphology, optical properties and electrochemistry of the prepared materials were examined by powder X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet-visible light spectroscopy and electrochemical impedance spectroscopy. The main observation of this research is the decrease of the energy band gap value due to doping of “Ag” ions, which will delay the recombination rate and increase the photovoltaic conversion efficiency by 2.87 % compared to pure ZnO nanoparticles (0.74 %). The photocurrent density-photo voltage (J-V) characteristics of fabricated BSSC using Pycocyanine pigments under various solvent-adsorbed conditions on nanocrystalline pure ZnO and Ag-doped ZnO film electrodes were carried out. The pigments in association with the water solution show the short-circuit photocurrent density Jsc of around 9.80 mA/cm2 and the open-circuit photovoltage Voc of 0.84 V, under an illumination intensity of 40 mW/cm2 respectively. The results of the present study reveals that “Ag” doped ZnO nanoparticles may be a promising candidate for the future BSSC applications.

Color of a food is one of the major factors influencing its acceptance by consumers. At presently synthetic dyes are the most commonly used food colorant in food industry by providing more esthetically appearance and as a means to quality control. However, the growing concern about health and environmental due to associated toxicity with synthetic food colorants has accelerated the global efforts to replace them with safer and healthy food colorants obtained from natural resources (plants, microorganisms, and animals). Further, many of these biocolorants not only provide myriad of colors to the food but also exert biological properties, thus they can be used as nutraceuticals in foods and beverages. In order to understand the importance of nature-derived pigments as food colorants, this review provides a thorough discussion on the natural origin of food colorants. Following this, different extraction methods for isolating biocolorants from plants and microbes were also discussed. Many of these biocolorants not only provide color, but also have many health promoting properties, for this reason their physicochemical and biological properties were also reviewed. Finally, current trends on the use of biocolorants in foods, and the challenges faced by the biocolorants in their effective utilization by food industry and possible solutions to these challenges were discussed. [ABSTRACT FROM AUTHOR]

SUMMARY: CpcL‐phycobilisomes (CpcL‐PBSs) are a reduced type of phycobilisome (PBS) found in several cyanobacteria. They lack the traditional PBS terminal energy emitters, but still show the characteristic red‐shifted fluorescence at ~670 nm. We established a method of assembling in vitro a rod‐membrane linker protein, CpcL, with phycocyanin, generating complexes with the red‐shifted spectral features of CpcL‐PBSs. The red‐shift arises from the interaction of a conserved key glutamine, Q57 of CpcL in Synechocystis sp. PCC 6803, with a single phycocyanobilin chromophore of trimeric phycocyanin at one of the three β82‐sites. This chromophore is the terminal energy acceptor of CpcL‐PBSs and donor to the photosystem(s). This mechanism also operates in PBSs from Acaryochloris marina MBIC11017. We then generated multichromic complexes harvesting light over nearly the complete visible range via the replacement of phycocyanobilin chromophores at sites α84 and β153 of phycocyanins by phycoerythrobilin and/or phycourobilin. The results demonstrate the rational design of biliprotein‐based light‐harvesting elements by engineering CpcL and phycocyanins, which broadens the light‐harvesting range and accordingly improves the light‐harvesting capacity and may be potentially applied in solar energy harvesting. [ABSTRACT FROM AUTHOR]

Background: Colorectal cancer (CRC) is among the most common cancers worldwide. In spite of promising improvements, it has a relatively poor prognosis. Therefore, there is a crucial need for discovering novel and efficient therapies. This study aimed to investigate the potential of phycocyanin as a therapeutic agent for CRC, considering its antioxidant and anti-inflammatory properties. Methods: The study used HT-29 and HUVEC cell lines. Cells were exposed to different concentrations of phycocyanin for 24 h. The cytotoxic effects of the phycocyanin on HUVEC and HT-29 cells were evaluated using MTT. Following the treatment, RNA extraction was conducted using TRI reagent. Afterward, real-time PCR (RT-PCR) was performed on Bcl-2, Bax, Akt, PTEN, and ß-actin to study their expression levels. The phycocyanin-treated cells were also stained with Annexin V-FITC to detect any apoptosis and necrosis. Results: Following the MTT assay, the number of living HT-29 cells significantly decreased, with no toxic effect on HUVEC cells. RT-PCR results indicated a significant increase in PTEN and Bax expressions in HT-29 cells due to treatment with phycocyanin, while there was no change in the expression of Bcl-2 and AKT. Flow cytometry on HT-29 cells showed induction of apoptosis and necrosis in 8.79% and 2.9% of cells, respectively, while no necrosis or apoptosis was observed in normal cells. Conclusion: Phycocyanin has a potential for treating colon cancer by affecting AKT/PTEN and Bax/Bcl- 2 and inducing apoptotic genes (Bax and PTEN) while having minimal side effects. Therefore, it could be a promising therapeutic agent for colon cancer. [ABSTRACT FROM AUTHOR]

The exploration of the biodiversity of cyanobacteria and microalgae holds great promise for obtaining pigments of industrial interest. This study focused on the bioprospecting of these organisms to obtain pigments of industrial interest together with enriched biomass. We investigated the impact of photoperiod and concentration of C/N/P nutrient sources in heterotrophic cultures, controlling specific variables such as light intensity, volume, pH, temperature, air flow and time to produce phycobiliproteins in Arthrospira platensis UTEX1926 and total carotenoids in Scenedesmus sp. using a nonfactorial Plackett‒Burman design in STATISTICA 7.0 software. The biomass concentration was determined by dry weight, while the concentrations of phycocyanin and carotenoids were determined spectrophotometrically at specific wavelengths. Heterotrophic cultures demonstrated superior productivity, with phycocyanin and carotenoids achieving percentages of 7% and 0.4% (w/w), respectively, and an R2 value of 0.99. Among the influential parameters, potassium diphosphate and sodium bicarbonate played pivotal roles in the final deposition of carotenoids and phycocyanin, respectively, yielding concentrations of 96.5 mg/L phycocyanin and 6.5 mg/L carotenoids. [ABSTRACT FROM AUTHOR]

Simple Summary: The study focused on cultivating the cyanobacterial strain Nostoc sp. 136 under controlled laboratory conditions. Various factors such as nutrient media, initial biomass concentration, nutrient supplementation, and light conditions were investigated to optimize growth and productivity. Results showed that the strain adapted well to the laboratory conditions, with the highest growth rates observed at lower initial biomass concentrations and with mBG11 medium. Nutrient supplementation, particularly nitrogen, showed potential for enhancing growth, while different light wavelengths had varied effects on growth and productivity. Biochemical analysis revealed promising levels of proteins and phycobiliproteins, with potential applications in biotechnology. The study highlighted the suitability of Nostoc sp. 136 for laboratory cultivation and suggested avenues for further research, particularly in exploring biomass composition and bioactivities. Cyanobacteria, photoautotrophic Gram-negative bacteria, play a crucial role in aquatic and terrestrial environments, contributing significantly to fundamental ecological processes and displaying potential for various biotechnological applications. It is, therefore, critical to identify viable strains for aquaculture and establish accurate culture parameters to ensure an extensive biomass supply for biotechnology purposes. This study aims to establish optimal laboratory batch culture conditions for Nostoc 136, sourced from Alga2O, Coimbra, Portugal. Preliminary investigations were conducted to identify the optimal culture parameters and to perform biomass analysis, including protein and pigment content. The highest growth was achieved with an initial inoculum concentration of 1 g.L−1, using modified BG11 supplemented with nitrogen, resulting in a Specific Growth Rate (SGR) of 0.232 ± 0.017 μ.day−1. When exposed to white, red, and blue LED light, the most favourable growth occurred under a combination of white and red LED light exhibiting an SGR of 0.142 ± 0.020 μ.day−1. The protein content was determined to be 10.80 ± 2.09%. Regarding the pigments, phycocyanin reached a concentration of 200.29 ± 30.07 µg.mL−1, phycoerythrin 148.29 ± 26.74 µg.mL−1, and allophycocyanin 10.69 ± 6.07 µg.mL−1. This study underscores the influence of light and nutrient supplementation on the growth of the Nostoc biomass. [ABSTRACT FROM AUTHOR]