Production, extraction and characterization of Chlorella vulgaris soluble polysaccharides and their applications in AgNPs biosynthesis and biostimulation of plant growth

Abstract

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

Production, Purification, and Study of the Amino Acid Composition of Microalgae Proteins

“…The cell walls of microalgae are often destroyed to ensure access to proteins, amino acids, and other components. It has been reported that some microalgae contain soluble proteins in their cytoplasm [ 3 , 4 ]. In addition, microalgae with chloroplasts contain soluble protein, central pyrenoid, and phytobiliproteins, although some microalgae, such as Arthrospira platensis , instead, have thylakoid sacs surrounding the peripheral cytoplasm associated with phycobilisomes [ 5 , 6 ].…”

Potential of Chlorella as a Dietary Supplement to Promote Human Health

“…As shown in Table 1 , more than 65% of the carbohydrate is dietary fiber, which appears to be derived from the Chlorella cell wall. Various polysaccharides have been extracted and characterized [ 22 , 23 , 24 , 25 ]. Chlorella polysaccharides exhibited a variety of biologically active compounds, including antioxidants [ 24 ] and stimulators of plant growth [ 25 ].…”

“…Various polysaccharides have been extracted and characterized [ 22 , 23 , 24 , 25 ]. Chlorella polysaccharides exhibited a variety of biologically active compounds, including antioxidants [ 24 ] and stimulators of plant growth [ 25 ]. Tabarsa et al [ 26 ] characterized an immune-enhancing water-soluble α-glucan prepared from C. vulgaris .…”

Study of Morphological Features and Determination of the Fatty Acid Composition of the Microalgae Lipid Complex

“…Microalgae cultivation is attracting more research due to its ability to synthesize various biologically active substances, the rapid growth of biomass, and the possibility of adjusting their biochemical composition depending on the cultivation conditions [ 1 , 2 , 3 ]. Unlike heterotrophic microorganisms, which require various organic compounds for growth, single-celled photosynthetic organisms produce biomass from fully oxidized inorganic substances and mineral elements due to light energy converted during photosynthesis [ 4 ].…”

“…Biologically active substances from microalgae can exhibit antioxidant, immunostimulating, antibacterial, antiviral, antitumor, antihypertensive, regenerative, and neuroprotective effects [ 6 , 7 , 8 ]. These compounds are required in medicine, cosmetology, food industry, fish farming, energy production, agriculture, feed, and functional food production [ 2 ].…”