Repeated batch cultivation of the microalga Spirulina platensis

Characterization of C-phycocyanin antioxidant, anti-inflammatory, anti-tumour, and anti-HCoV-229E activities and encapsulation for implementation in an innovative functional yogurt

Functional bioactive ingredients isolated from microalgae as sustainable sources have become a new subject of pharmacology and functional foods. Thus, the work aims to produce crude phycocyanin (C-PC), define it, and investigate its pharmacological effects before warping it in a nanophytosome. Subsequently, the physicochemical properties of nanoparticles were evaluated. Both free and nanophytosomes of C-PC were incorporated into cow milk fermented with the probiotic Lactobacillus rhamnosus KU985435 to make functional yoghurt and the stability of C-PC of both phytosomes was assessed. The amino acid content of C-PC revealed the presence of eight of nine essential amino acids and eight of eleven non-essential amino acids. C-PC has a medium molecular weight (82.992 kDa). Some pharmacological effects like reducing inflammation (98.76 % ± 0.065), fighting free radicals (99.12 % ± 0.027), and being able to inhibit the human coronavirus 229 E with a selective index of 27.9 were observed. The maximum viral inhibitory activity was detected during the adsorption stage. Anti-human liver and colon carcinomas that exceeded Doxorubicin with very low cytotoxicity against normal cell lines were detected. C-PC is an unstable protein that could be degraded in the yoghurt during storage. Therefore, phytosome encapsulation can effectively stabilize C-PC (particle size 44.50 ± 12 nm and zeta-potential -32.4 ± 5 mV) and protect it from the acidic environment of the yoghurt. The produced yoghurt showed the desired physicochemical and functional properties and overall acceptance. The results prove that C-PC from spirulina algae is a renewable source of dyes. The encapsulation process using phytosomes gave it high stability against environmental influences, and therefore, it can be applied in the food and pharmaceutical industries in the future.

C-phycocyanin decreases proliferation and migration of melanoma cells: In silico and in vitro evidences

The incidence and number of deaths caused by melanoma have been increasing in recent years, and the pigment C-phycocyanin (C-PC) appears as a possible alternative to treat this disease. So, the objective of this study was to combine in silico and in vitro analysis to understand the main anti-melanoma pathways exerted by C-PC. We evaluated the ability of C-PC to bind to the main cellular targets related in the progression of melanoma through molecular docking, and the reflection of this bind in the biological effects in the B16F10 cell line through in vitro analysis. Our results showed that C-PC was able to bind BRAF and MEK, which are related to the signal transduction pathway for proliferation and survival. There was also an interaction between C-PC and cyclin-dependent kinase 4 and 6. In vitro analysis demonstrated that C-PC decreased B16F10 cell proliferation, as observed by cell viability and mitotic index assays. C-PC also interacted with matrix metalloproteinase 2 and 9 and N-cadherin, which may have caused the decrease in cell migration observed in vitro. Besides that, C-PC interacts with VEGF, a factor responsible for regulating the proliferation and cellular invasion pathways. Finally, C-PC did not alter the cell viability of the non-tumoral melanocytes. Therefore, C-PC is a strong anti-tumor candidate for the treatment of melanoma, since it acts in different cellular pathways of melanoma, without causing damage to non-tumoral cells.

Technological Feasibility of Couscous-Algae-Supplemented Formulae: Process Description, Nutritional Properties and In Vitro Digestibility

The aim of this work was to develop functional couscous in a traditional Tunisian manner (hand rolling), enriched in algae biomass (6% w/w). Four Chlorella vulgaris (C. vulgaris) biomasses and one mixture of C. vulgaris and two macroalgae biomasses (Ulva rigida and Fucus vesiculosus) were used. The C. vulgaris strain was subjected to random mutagenesis and different culture conditions (Allmicroalgae), resulting in different pigmentations and biochemical compositions. Couscous samples were characterized in terms of nutritional properties, oscillatory rheology properties and digestibility. All biomasses provided a significant supplementation of nutrients and excellent acceptance. The enrichment resulted in lower firmness, higher viscoelastic functions (G' and G″) and a significant improvement in the cooking quality. Major differences between couscous samples with different microalgae were observed in protein and mineral contents, fully meeting Regulation (EC) No. 1924/2006 requirements for health claims made on foodstuffs. The amount of digested proteins was also higher in algae-containing samples. The fatty acid profile of the enriched couscous varied in a biomass-specific way, with a marked increase in linolenic acid (18:3 ω3) and a decrease in the ω6/ω3 ratio. Sensory analysis revealed that microalgae-containing products could compete with conventional goods with an added advantage, that is, having an ameliorated nutritional value using algae as a "trendy" and sustainable ingredient.

Mixotrophic cultivation of microalgae for biodiesel production: status and prospects

Biodiesel from microalgae provides a promising alternative for biofuel production. Microalgae can be produced under three major cultivation modes, namely photoautotrophic cultivation, heterotrophic cultivation, and mixotrophic cultivation. Potentials and practices of biodiesel production from microalgae have been demonstrated mostly focusing on photoautotrophic cultivation; mixotrophic cultivation of microalgae for biodiesel production has rarely been reviewed. This paper summarizes the mechanisms and virtues of mixotrophic microalgae cultivation through comparison with other major cultivation modes. Influencing factors of microalgal biodiesel production under mixotrophic cultivation are presented, development of combining microalgal biodiesel production with wastewater treatment is especially reviewed, and bottlenecks and strategies for future commercial production are also identified.

Carbon dioxide capture and nutrients removal utilizing treated sewage by concentrated microalgae cultivation in a membrane photobioreactor

A highly efficient microalgae cultivation process was developed for carbon dioxide capture using nutrients from treated sewage. A submerged-membrane filtration system was installed in a photobioreactor to achieve high nutrient loading and to maintain a high concentration and production of microalgae. Chlorella vulgaris, Botryococcus braunii and Spirulina platensis were continuously cultivated with simulated treated sewage and 1%-CO(2) gas. The optimum hydraulic retention time (HRT) and solids retention time (SRT) were explored to achieve the maximum CO(2) capture rate, nutrient removal rate and microalgae biomass productivity. The carbon dioxide capture rate and volumetric microalgae productivity were high when the reactor was operated under 1-day (HRT) and 18-days (SRT) conditions. The independent control of HRT and SRT is effective for efficient microalgae cultivation and carbon dioxide capture using treated sewage.

High value pigment production from Arthrospira (Spirulina) platensis cultured in seawater

The prospects of utilizing pretreated seawater for the culture of Arthrospira (Spirulina) platensis was evaluated under laboratory conditions with three seawater media and a control: (1) Zarrouk media (freshwater-control) (2) seawater media SW 1 (3) seawater media SW2 and (4) seawater media SW 3. The relative performance of these media were investigated with respect to their biomass production, pigment production (phycocyanin, lutein and betacarotene), and biochemical composition. A. platensis grown in media SW 2 had a biomass production (2.99+/-0.145 g L(-1)) comparable to that of control media (3.114+/-0.085 g L(-1)); highest specific growth rate (0.255 d(-1)) and lowest doubling time (2.720 days). Phycocyanin content of the cells grown in seawater media SW 3(81.85%) was closer to that of control. Similarly the purity ratio of phycocyanin produced from cells grown in seawater media SW 3 and control were closer to 4, while the phycocyanin obtained from cells grown in other two media exhibited lower purity ratios due to accumulation of lower molecular weight carbohydrates. The phycocyanin/Chl-a ratio and the betacarotene/Chl-a ratio of the cells grown in seawater media were higher than control. The lutein content of A. platensis cells grown in seawater media SW 2 was higher than that of control. The cells grown in seawater media had a slightly modified biochemical composition than the control with a higher carbohydrate and lower protein content. All the three seawater based media with fewer chemicals than the control (Zarrouk media) supported the growth of A. platensis as good as the control.

Microalgae for "Healthy" Foods-Possibilities and Challenges

  Microalgae have the potential to become a novel source of bioactive molecules, especially for those who might wish to enhance the nutritional and functional quality of foods. Spirulina, one of the most popular microalgae, has been described by the World Health Organization as one of the greatest superfoods on earth serving as an example of the potential of microalgae. This review provides background on current and future uses of microalgae in the human diet, lists the most common species of microalgae used to this end, and describes some production methods used in research and industrial production and recovery. The review also discusses some of the difficulties so far encountered such as low productivities and recovery rates, as well as challenges in the production of compounds of interest. Many scientists and engineers in research centers around the globe are currently dedicated to solve these problems as the various capabilities of microalgae have caught the attention of the energy, environmental, and agricultural industries, we propose that the food industry should as well evaluate the potential of microalgae as a novel source of "health promoting" compounds.

Incorporation of Chlorella vulgaris and Spirulina maxima biomass in pasta products. Part 1: Preparation and evaluation

BACKGROUND

Microalgae are able to enhance the nutritional content of conventional foods and hence to positively affect human health, due to their original chemical composition. The aim of the present study was to prepare fresh spaghetti enriched with different amounts of microalgae biomass (Chlorella vulgaris and Spirulina maxima) and to compare the quality parameters (optimal cooking time, cooking losses, swelling index and water absorption), chemical composition, instrumental texture and colour of the raw and cooked pasta enriched with microalgae biomass with standard semolina spaghetti.

RESULTS

The incorporation of microalgae results in an increase of quality parameters when compared to the control sample. The colour of microalgae pastas remained relatively stable after cooking. The addition of microalgae resulted in an increase in the raw pasta firmness when compared to the control sample. Of all the microalgae studied, an increase in the biomass concentration (0.5-2.0%) resulted in a general tendency of an increase in the pasta firmness. Sensory analysis revealed that microalgae pastas had higher acceptance scores by the panellists than the control pasta.

CONCLUSION

Microalgae pastas presented very appellative colours, such as orange and green, similar to pastas produced with vegetables, with nutritional advantages, showing energetic values similar to commercial pastas. The use of microalgae biomass can enhance the nutritional and sensorial quality of pasta, without affecting its cooking and textural properties.