The True Value of Spirulina Grosshagauer, Silke; Kraemer, Klaus; Somoza, Veronika
Journal of agricultural and food chemistry,
04/2020, Letnik:
68, Številka:
14
Journal Article
Recenzirano
Algae products are attracting growing interest due to their pleasant taste and their high contents in protein, essential amino acids, vitamins, and minerals. Specifically, spirulina products are ...widely promoted for their high vitamin B12 content. So far, knowledge regarding the contamination with cyanotoxins, heavy metals, pesticides, or polycyclic aromatic hydrocarbons (PAHs) is scarce, although some studies reported high contaminant levels in spirulina products. The regular intake of spirulina, and very likely other algae products as well, as a dietary supplement in the gram range demands a closer monitoring of potentially harmful constituents.
In the last few decades, consumers' growing attention to the close relationship between health and nutrition is emerging as a new trend, mostly regarding the incorporation of natural ingredients into ...food. Among those ingredients, microalgae are considered as innovative and promising compounds, rich in valuable nutrients and bioactive molecules. In the present work, 3D printed cookies were fortified with the microalga Arthrospira platensis aiming at developing a new functional food with antioxidant properties. A. platensis antioxidants were recovered using ultrasound-assisted extraction in hydroalcoholic solutions. Ethanol/water and biomass/solvent ratios were optimised through a Design of Experiments (DOE) approach, using the antioxidant activity (ORAC and ABTS) and total phenolic content (TPC) as response variables. The highest ORAC, ABTS and TPC values were observed in the extract obtained with 0% ethanol and 2.0% biomass; thus, this extract was chosen to be incorporated into a printable cookie dough. Three different incorporation approaches were followed: (1) dried biomass, (2) freeze-dried antioxidant extract and (3) antioxidant extract encapsulated into alginate microbeads to enhance the stability to heat, light, and oxygen during baking and further storage. All dough formulations presented shape fidelity with the 3D model. The cookies had aw values low enough to be microbiologically stable, and the texture remained constant after 30 days of storage. Moreover, the extract encapsulation promoted an improvement in the ORAC value and colour stability when compared to all other formulations, revealing the potential of A. platensis for the development of a functional 3D food-ink.
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•Antioxidant extraction from the microalga A. platensis was optimised using DoE.•Edible inks were made using encapsulated microalgae extracts and food hydrocolloids.•All cookie dough formulations (edible inks) were suitable for 3D food printing.•3D printed cookies exhibited colour, texture and microbiological stability over time.•Extract encapsulation improved cookies antioxidant potential and colour stability.
This study proposes a method for the ultrasonic extraction of carotenoids and chlorophyll from Scenedesmus obliquus and Arthrospira platensis microalgae with green solvents. Ethanol and ethanolic ...solutions of ionic liquids were tested with a variety of extraction parameters, including number of extractions, time of extraction, and solid–liquid ratio R(S/L), to determine the optimal conditions. After selecting the most effective green solvent (ethanol), the process conditions were established: R(S/L) of 1:10, three extraction cycles at 3 min each), giving an extraction yield of 2602.36 and 764.21 μgcarotenoids.gdried biomass−1; and 22.01 and 5.81 mgchlorophyll.gdried biomass−1 in S. obliquus and A. platensis, respectively. The carotenoid and chlorophyll extracts obtained using ethanol were shown to be potent scavengers of peroxyl radical, being 5.94 to 26.08 times more potent α-tocopherol. These findings pave the way for a green strategy for valorizing microalgal biocompounds through efficient and environmentally friendly technological processes.
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•Ethanol and ionic liquids for extracting carotenoids and chlorophyll from microalgae.•Green solvent plus UAE increase extraction speed and extracts with better yield.•Extraction with green solvent provided greater antioxidant activity of the compounds.•Ultrasound in the extraction of bioactive components shown great potential.
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•Comparative hydrolysis of Arthrospira platensis protein by six different proteases.•VTAGLVGGGAGK from alcalase-hydrolysate showed best antioxidative activity.•PTGNPLSP from ...trypsin-hydrolysate showed best ACE inhibitory activity.•Both VTAGLVGGGAGK and PTGNPLSP were stable under heat and pH treatments.•PTGNPLSP was more stable than VTAGLVGGGAGK during gastrointestinal digestion.
In current study, novel antioxidant and ACE inhibitory peptides were screened from Arthrospira platensis protein hydrolysates (APH) generated by six different proteases, respectively. The purification steps including ultrafiltration membrane and chromatography were guided by ABTS radical scavenging activity (ARSA), hydroxyl radical scavenging activity (HRSA), ferrous ion chelation activity (FICA) and ACE inhibitory activity. A novel antioxidant peptide VTAGLVGGGAGK, which exhibited highest ARSA, HRSA and FICA with EC50 value of 1.08 mg/mL 1.35 mg/mL and 1.24 mg/mL, respectively, was identified from alcalase-APH. Meanwhile, a novel ACE inhibitory peptide PTGNPLSP with the highest ACE inhibitory activity (IC50 = 1.54 mg/mL) was identified from trypsin-APH. Both VTAGLVGGGAGK and PTGNPLSP had strong stability under thermal processing (25–100 °C) and diverse pH conditions (pH 3–11). In addition, the PTGNPLSP was more stable than VTAGLVGGGAGK during in vitro gastrointestinal digestion. Our findings will provide new knowledge for the development of novel natural antioxidants and ACE inhibitors as well as the high-value utilization of Arthrospira platensis protein.
Cyanobacteria are a morphologically and physiologically diverse group of bacteria, which contains unicellular and multicellular filamentous strains. Some filamentous cyanobacteria, such as Anabaena ...sp. strain PCC 7120, form a differentiated cell called a heterocyst. The heterocyst is a specialized cell for nitrogen fixation and is differentiated from a vegetative cell in response to depletion of combined nitrogen in the medium. In Anabaena PCC 7120, it has been demonstrated that hetR, which encodes a transcriptional regulator, is necessary and sufficient for heterocyst differentiation. However, comprehensive genomic analysis of cyanobacteria has shown that hetR is present in non-heterocyst-forming cyanobacteria. Almost all filamentous cyanobacteria have hetR, but unicellular cyanobacteria do not. In this study, we conducted genetic and biochemical analyses of hetR (NIES39_C03480) of the non-heterocyst-forming cyanobacterium Arthrospira platensis NIES-39. HetR of A. platensis was able to complement the hetR mutation in Anabena PCC 7120 and recognized the same DNA sequence as Anabaena HetR. A search of the A. platensis genome revealed the HetR-recognition sequence within the promoter region of NIES39_O04230, which encodes a protein of unknown function. Expression from the NIES39_O04230 promoter could be suppressed by HetR in Anabaena PCC 7120. These data support the conclusion that NIES39_O04230 is regulated by HetR in A. platensis NIES-39.
The microalgae Spirulina (Arthrospira platensis Gomont) is already cultured commercially using open ponds. The obstacle to mass cultivation of Spirulina is maintaining the monoculture without any ...contamination that can affect biomass products and their metabolites. The tolerance of Spirulina to environmental changes, such as changes in pH conditions, can be used as a method to overcome contamination in Spirulina mass cultivation. The growth contaminant can be avoided or controlled by giving mechanical stress by modifying the pH to alkaline levels. The efficient use of cost-effective materials in mass cultivation prevents contamination and maintains Spirulina's productivity. This study investigated the optimal pH parameters of 7–11 for 10 days. Cell density and dry biomass were measured daily using a hemocytometer and filter paper Whatman. The growth rate of contaminant microorganisms was carried out every five days along ten days of cultivation using the Total Plate Count (TPC) method. Using pH 9 effectively increased the cell density significantly (9.12±1.02%) and dry biomass (17.31±4.19 g.mL−1), reducing the contaminants in Spirulina mass cultures. The metabolite content was measured, including total protein using the Kjeldahl method, total lipid using the Soxhlet method, and pigmentations (such as chlorophyll, carotene, and phycocyanin) using spectrophotometry. The pH scale 8–10 can increase protein, lipid, and pigmentations. However, the pH 11 decreased almost entirely as a result of the metabolite contents of Spirulina.
Palm oil mill effluent (POME) is well known as agricultural wastewater that has a high potential as a medium for microalgal growth due to its high macro- and micronutrient content. The cyanobacterium
...Arthrospira platensis
is considered as a species with a high C-phycocyanin (C-PC) content which is important for fine chemical and pharmaceutical applications. However, cultivation of
A. platensis
on POME to produce economically feasible amounts of C-PC has not been well explored. For this, environmental, nutritional, and cultivation modes (batch, semi-continuous) were varied to optimize C-PC productivity when cultivated at various POME concentrations.
Arthrospira platensis
was found to grow well on POME. Highest biomass and C-PC concentrations were found on 30–100% POME. Central composite rotatable design (CCRD) response surface methodology demonstrated that C-PC productivity was influenced by urea addition at the optimum salinity. The highest C-PC productivity was found on 100% POME during semi-continuous cultivation, while the addition of phosphorus and urea did not significantly improve C-PC productivity. By applying semi-continuous cultivation with 50% POME at the first stage and 100% POME at the second stage, a similarly high C-PC productivity (4.08 ± 1.3 mg L
−1
day
−1
) was achieved as compared with (artificial) Zarrouk medium during batch cultivation. We conclude that, when using a two-stage semi-continuous cultivation process,
A. platensis
can produce economically feasible amounts of C-PC when cultivated on 100% POME.
Objective: This work aimed to study the modeling, binding site, and immunogenicity analysis of genes encoding L-asparaginase from Arthrospira platensis NIES 39.
Methods: Physicochemical ...characteristic of the gene was analyzed using ProtParam. I-TASSER, PROCHECK, ProSA, and ProQ were used to build the L-asparaginase model. The enzyme's binding site was achieved based on the SiteMap and COACH analysis. Immunogenicity analysis was based on MHC II binding epitopes on the immune epitope database with further epitope prediction, such as NN-align, SMM aligns, Combinatorial library, and Net MHCIIpan.
Results: The result showed that the protein had an aliphatic index of 94.46. It was dominated by strand, helix, and coil groups. The best template for building the model was the malonate-bound human L-asparaginase protein. The amino acid at 173,191,193, 201, 204, 205, 223, and 225 positions served as binding sites. The best substrate for A. platensis NIES 39 asparaginase was L-asparagine. There is no substantial evidence that the protein is highly allergenic.
Conclusion: In conclusion, this is the first report on the character of ASNase from microalgae A. platensis where the enzyme has the potential to be applied for health applications because of its low allergenicity.
We review research on phycobilisomes from extremophile cyanobacteria and red algae, and their structural stability adaptations, and we discuss the potential uses of phycobiliproteins from ...extremophiles for commercial applications.
Abstract
The light-harvesting phycobilisome complex is an important component of photosynthesis in cyanobacteria and red algae. Phycobilisomes are composed of phycobiliproteins, including the blue phycobiliprotein phycocyanin, that are considered high-value products with applications in several industries. Remarkably, several cyanobacteria and red algal species retain the capacity to harvest light and photosynthesise under highly selective environments such as hot springs, and flourish in extremes of pH and elevated temperatures. These thermophilic organisms produce thermostable phycobiliproteins, which have superior qualities much needed for wider adoption of these natural pigment–proteins in the food, textile, and other industries. Here we review the available literature on the thermostability of phycobilisome components from thermophilic species and discuss how a better appreciation of phycobiliproteins from extreme environments will benefit our fundamental understanding of photosynthetic adaptation and could provide a sustainable resource for several industrial processes.
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