Chlorella vulgaris, like a wide range of other microalgae, are able to grow mixotrophically. this maximizes its growth and production of polysaccharides (pS). the extracted polysaccharides have a complex monosaccharide composition (fructose, maltose, lactose and glucose), sulphate (210.65 ± 10.5 mg g −1 PS), uronic acids (171.97 ± 5.7 mg g −1 pS), total protein content (32.99 ± 2.1 mg g −1 PS), and total carbohydrate (495.44 ± 8.4 mg g −1 pS). fourier transform infrared spectroscopy (ft-iR) analysis of the extracted polysaccharides showed the presence of n-H, o-H, c-H,-cH 3 , >cH 2 , coo −1 , S=o and the c=o functional groups. UV-Visible spectral analysis shows the presence of proteins, nucleic acids and chemical groups (ester, carbonyl, carboxyl and amine). Purified polysaccharides were light green in color and in a form of odorless powder. it was soluble in water but insoluble in other organic solvents. thermogravimetric analysis demonstrates that Chlorella vulgaris soluble polysaccharide is thermostable until 240°C and degradation occurs in three distinct phases. Differential scanning calorimetry (DSC) analysis showed the characteristic exothermic transition of Chlorella vulgaris soluble polysaccharides with crystallization temperature peaks at 144.1°C, 162.3°C and 227.7°C. The X-ray diffractogram illustrated the semicrystalline nature of these polysaccharides. Silver nanoparticles (Agnps) had been biosynthesized using a solution of Chlorella vulgaris soluble polysaccharides. the pale green color solution of soluble polysaccharides was turned brown when it was incubated for 24 hours with 100 mM silver nitrate in the dark, it showed peak maximum located at 430 nm. FT-IR analysis for the biosynthesized AgNPs reported the presence of carbonyl,-CH 3 , >cH 2 , c-H,-oH and-nH functional groups. Scanning and transmission electron microscopy show that Agnps have spherical shape with an average particle size of 5.76. Energy-dispersive X-ray (EDX) analysis showed the dominance of silver. the biosynthesized silver nanoparticles were tested for its antimicrobial activity and have positive effects against Bacillus sp., Erwinia sp., Candida sp. priming seeds of Triticum vulgare and Phaseolus vulgaris with polysaccharides solutions (3 and 5 mg mL −1) resulted in significant enhancement of seedling growth. increased root length, leaf area, shoot length, photosynthetic pigments, protein content, carbohydrate content, fresh and dry biomass were observed, in addition these growth increments may be attributed to the increase of antioxidant activities. Microalgae are some of the oldest, most economically promising organisms in the world 1 and one of the richest sources of protein in addition to polysaccharides, carotenoids, phycobiliproteins, polysaccharides, vitamins and

The physico-chemical characterization of the cyanobacterium Nostoc carneum extracellular polysaccharide (EPS) was studied. Two sugars moieties glucose (105.5 mg gG 1 EPS) and xylose (215.2 mg gG 1 EPS) were involved in the polysaccharide composition as well as the presence of sulfate, uronic acids and protein. The in vitro antioxidant assays (reducing power and DPPH) showed that N. carneum EPS possess antioxidant activity. Fourier Transformed Infrared (FT-IR) spectra of EPS showed a specific absorbance of O-H and-NH stretching, asymmetrical-symmetrical C-H stretching, Presence of sulfur containing functional groups and carboxylic acids. The thermal gravimetric and differential scanning calorimetric analyses confirmed that polysaccharide thermal stability was around 237°C. Nostoc carneum exopolymer showed pseudoplastic non-Newtonian fluid behavior in the aqueous solutions as well as increasing viscosity with increasing concentration.

Alginates derived from macroalgae have been widely used in a variety of applications due to their stability, biodegradability and biocompatibility. Alginate was extracted from Egyptian Sargassum latifolium thallus yielding 17.5% w/w. The chemical composition of S. latifolium is rich in total sugars (41.08%) and uronic acids (47.4%); while, proteins, lipids and sulfates contents are 4.61, 1.13 and 0.09%, respectively. NMR, FTIR and TGA analyses were also performed. Crystallinity index (0.334) indicates alginate semicrystalline nature. Sodium alginate hydrolysate was evaluated as Chlorella vulgaris growth promoter. The highest stimulation (0.7 g/L biomass) was achieved by using 0.3 g/L alginate hydrolysate supplementation. The highest total soluble proteins and total carbohydrates were 179.22 mg/g dry wt and 620.33 mg/g dry wt, respectively. The highest total phenolics content (27.697 mg/g dry wt.), guaiacol peroxidase activity (2.899 µmol min−1 g−1) were recorded also to 0.3 g/L alginate hydrolysate supplementation. Riboflavin-entrapped barium alginate-Arabic gum polymeric matrix (beads) was formulated to achieve 89.15% optimum drug entrapment efficiency (EE%). All formulations exhibited prolonged riboflavin release over 120 min in simulated gastric fluid, followed Higuchi model (R2 = 0.962–0.887) and Korsmeyer–Peppas model with Fickian release (n ranges from 0.204 to 0.3885).

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