Search

Background: Recently, researchers have given more and more consideration to natural polysaccharides thanks to their huge properties such as stability, biodegradability and biocompatibility for food and therapeutics applications., Methods: a number of enzymatic and chemical processes were performed to generate bioactive molecules, such as low molecular weight fractions and oligosaccharides derivatives from algal polysaccharides., Results: These considerable characteristics allow algal polysaccharides and their derivatives such as low molecular weight polymers and oligosaccharides structures to have great potential to be used in lots of domains, such as pharmaceutics and agriculture etc. Conclusion: The present review describes the mains polysaccharides structures from Algae and focuses on the currents agricultural (fertilizer, bio-elicitor, stimulators, signaling molecules and activators) and pharmaceutical (wound dressing, tissues engineering and drugs delivery) applications by using polysaccharides and/or their oligosaccharides derivatives obtained by chemical, physical and enzymatic processes., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Olive mill wastewater (OMWW), the main waste product of olive oil extraction process, was investigated as a source of polysaccharides. The yield of alcohol insoluble residue (AIR) was 20.5 % based on the dry matter of OMWW. Extraction with water gave water soluble (WSF) and insoluble (WIF) fractions from AIR with yields of 13.3 % (w/w) and 3.7 % (w/w) based on the dry matter, respectively. Chemical composition and monosaccharide analysis indicated that glucose was the main monosaccharide of these extracts in addition to galactose, arabinose, rhamnose, and galacturonic acid. Prebiotic and antioxidant activities of polysaccharidic fractions from OMWW were evaluated. Results gave evidence for their scavenging capacity toward the 2,2'-diphenyl-1-picrylhydrazyle (DPPH) (IC50 value of 89.43 μg/mL) and hydroxyl radicals (IC50 value of 158.70 μg/mL), resistance toward artificial human gastric juice, and ability to be fermented by Lactobacilli strains.

Currently, pectins are widely used in the cosmetic, pharmaceutical, and food industries, mainly as texturizing, emulsifying, stabilizing, and gelling agents. Pectins are polysaccharides composed of a large linear segment of α-(1,4) linked d-galactopyranosyluronic acids interrupted by β-(1,2)-linked l-rhamnoses and ramified by short chains composed of neutral hexoses and pentoses. The characteristics and applications of pectins are strongly influenced by their structures depending on plant species and tissues but also extraction methods. The aim of this review is therefore to highlight the structures of pectins and the various methods used to extract them, including conventional ones but also microwave heating, ultrasonic treatment, and dielectric barrier discharge techniques, assessing physico-chemical parameters which have significant effects on pectin characteristics and applications as techno-functional and bioactive agents. [ABSTRACT FROM AUTHOR]

Given the increasing interest that is being paid to polysaccharides derived from algae as plant natural defense stimulators, the degree of sulfation of exopolysaccharides produced by P. sordidum for inducing defense responses in date palm vitroplants was investigated. Firstly, the culture parameters of P. sordidum were optimized to maximize the amount of sulfate in EPS using a Box–Behnken experimental design and the elicitor effects of two EPS which differ in the sulfation degrees were compared. Results demonstrated that the concentrations of NaCl, NaNO 3 and MgSO 4 set at 28, 0.54 and 16.31 g/L, respectively yielded the best sulfate contents. To elucidate defense-inducing activities in date palm vitroplants, EPS with the highest sulfate content (EPS1) were prepared for comparison with those obtained under standard conditions (EPS0). A fucoidan extracted from Cystoseira compressa was used as positive control and MgSO 4 as negative control. Both EPS and the fucoidan displayed H 2 O 2 accumulation and expression of PR1, SOD, PAL and WRKY genes. Interestingly, EPS1 was significantly more bioactive than EPS0 and the fucoidan suggesting that the elicitor activity is positively correlated with the sulfate groups content of this polysaccharide. • Optimize the culture conditions of P. sordidum to maximize the sulfate content in EPS. • Comparison of the elicitor effect of two EPS which differ in the degree of sulfation on date palm vitroplants. • The elicitor activities is positively correlated with the degree of sulfation in EPS. [ABSTRACT FROM AUTHOR]

Matrix polysaccharide from the brown algae Sargassum turbinarioides collected in the coastal waters of Nosy Be (Madagascar) in the Indian Ocean was isolated and its structure was studied by 1H-NMR spectroscopy, FT-IR, SEC-MALLS and HPAEC. An alginate with a molecular weight of 5.528 × 105 g mol−1 was identified as sole polysaccharide. Values of the M/G ratio, FGG, FMM and FGM (or FGM) blocks were measured at respectively 0.94, 0.39, 0.36 and 0.25 and compared with those of alginates from other Sargassum species. This sodium alginate appeared similar to some of the other Sargassum alginates with M/G < 1, high values of homopolymeric blocks ( η < 1) and significant polyguluronic block content. [ABSTRACT FROM AUTHOR]

Abstract Research on marine microalgae has been abundantly published and patented these last years leading to the production and/or the characterization of some biomolecules such as pigments, proteins, enzymes, biofuels, polyunsaturated fatty acids, enzymes and hydrocolloids. This literature focusing on metabolic pathways, structural characterization of biomolecules, taxonomy, optimization of culture conditions, biorefinery and downstream process is often optimistic considering the valorization of these biocompounds. However, the accumulation of knowledge associated with the development of processes and technologies for biomass production and its treatment has sometimes led to success in the commercial arena. In the history of the microalgae market, red marine microalgae are well positioned particularly for applications in the field of high value pigment and hydrocolloid productions. This review aims to establish the state of the art of the diversity of red marine microalgae, the advances in characterization of their metabolites and the developments of bioprocesses to produce this biomass. [ABSTRACT FROM AUTHOR]

Rheological characteristics of a sodium alginate and a fucoidan extracted from the brown seaweed Cystoseira compressa harvested from Kerkennah island (Sfax, Tunisia) were investigated. Steady - shear flow and dynamical viscoelasticity were evaluated to describe physicochemical properties of the GulA - rich alginate (ManA/GulA, M/G = 0.77) and highly - ramified fucoidan in semi - diluted media depending on polymer concentration, shear rate, temperature, added mono- (KCl and NaCl) and divalent (CaCl 2) salts. Alginate solutions exhibited shear - thinning behavior, with a temperature - dependent behavior highly correlated to the power - law model and the Arrhenius relationship. The results showed strong thixotropic and polyelectrolyte properties, influenced by addition of monovalent and divalent cations. The dynamic rheological characteristics showed a fluid - like viscoelastic behavior (tan δ > 1) whereas the critical overlap concentration C* and specific polymer constant k s were respectively 11 g.L−1 and 4.4 using Williamson model. Fucoidan solutions displayed a shear - thinning behavior with a low viscoelasticity character influenced by temperature and monovalent salts. The flow and viscoelastic characteristics of polysaccharides were described by the Ostwald model. Investigation of flow behavior and dynamical viscoelasticity of water-soluble polysaccharides from C. compressa (Tunisian brown seaweed). Image 1 • An alginate and a fucoidan were extracted from the brown seaweed Cystoseira compressa. • Rheological characteristics of the two polysaccharides were investigated. • Alginate solutions exhibited shear - thinning and fluid - like viscoelastic behaviors. • Fucoidan solutions displayed a shear - thinning behavior with a low viscoelasticity character. [ABSTRACT FROM AUTHOR]