¹H-NMR Study of Na Alginates Extracted from Sargassum spp. in Relation to Metal Biosorption

Abstract

The use of a number of species of marine brown algae in the implementation of bioremediation strategies for toxic heavy metals is being considered and evaluated. The biosorption capacity of these algae for heavy metals resides mainly in a group of linear polysaccharides known as alginates that occur as a gel in the algal thallus. The potential for selective metal binding by the biomass of two species of Sargassum was evaluated by 1H-NMR (nuclear magnetic resonance) following a high temperature, alkaline extraction and purification of their alginate polysaccharide. The alkaline extraction protocol applied to Sargassum fluitans and Sargassum siliquosum yielded alginate samples of low viscosity, suitable for direct acquisition of well-resolved spectra. Estimates of both the ratio of beta-D-mannopyranuronosyl (M) and alpha-L-gulopyranuronosyl (G) residues along the polymer chain and the frequencies of occurrence of diad uronic acid residue pairs were obtained. Guluronic acid (G) was the major component in all extracts and the GG diads accounted for more than 49% of the polymer diads. Whereas the performance of Sargassum spp. in the metal biosorption process is a function of both its alginate content and composition, the occurrence of "G-blocks" in both purified alginates and in the raw brown seaweed is critical because it results in a well-established selectivity for divalent ions, potentially increasing the commercial effectiveness of targeted biosorption as a means of remediation.

Seaweed biopolymers as additives for unfired clay bricks

“…A further commercial sample from Acros Organics was also used allowing a range of alginates from several seaweed sources and different properties to be studied (Table ). The M/G ratios were provided by MBL and calculated using 1 H-NMR spectroscopy as per the methods of Grasdalen et al (1979) and Davis et al (2003). Viscosity measurements were conducted using a Brookfield R/S Rheometer with attached water bath to maintain a constant temperature of 25°C.…”

Accumulation Time and Antioxidant Responses of Inorganic Arsenic on Brown Seaweed Padina minor

“…Otherwise, Klump (1980) reported that Fucus spiralis was kept both As 3+ and As 5+ inside the thali and could methylated As 3+ without oxidation process. The different metabolism of iAs between both brown seaweed may happens due to different types of metallothionein (Davis et al, 2003), methylation process (Briat et al, 2010), or antioxidant responses.…”

Novel tamarind seed polysaccharide-alginate mucoadhesive microspheres for oral gliclazide delivery:in vitro–in vivoevaluation

“…(George & Abraham, 2006), which are the monovalent form of alginic acid belonging to the family of linear copolymers, composed of two monomeric units, β-D-mannuronic acid (M) and α-L-guluronic acid (G). These residues are arranged in homopolymeric blocks (GG and MM) and heteropolymeric blocks (MG) (Smidsrod & Draget, 1996 (Davis et al, 2003;Shilpa et al, 2003). Though alginates have mucoadhesive property, but, the cross-linked alginate beads are usually fragile (Kroll et al, 1996;Llanes et al, 2000).…”