A simple method was developed to purify sulfated polysaccharides from their crude extracts. The new method utilizes a genipin-crosslinked chitosan beads as a support matrix for toluidine blue (TB). The modification of the D-glucosamine polymer was performed in one-step reaction to improve its mechanical stability, selectivity and affinity to the biopolysaccharide fucoidan. ATR-FTIR and Scanning Electron Microscope (SEM) were used to characterize the beads chemically and morphologically, respectively. The adsorption kinetics and isotherm were investigated and revealed that 40 h were sufficient to achieve a satisfying percent adsorption and with a maximum loading capacity of 137.8±17.7 mg fucoidan/g beads. Afterwards, the Chitosan-TB beads were used for the purification of fucoidan from Fucus vesiculosus crude extract at pH 1.0 and pH 6.0, producing two purified fractions: FC_1 and FC_6, respectively. The fractions were then characterized in comparison with crude and commercially purified fucoidan chemically by FTIR and physico-chemically by elemental analysis. Molecular weight measurements were also performed and indicated that native and homogenous products were obtained. The new method improved the beads’ loading capacity for fucoidan production and used less hazardous chemicals compared to the previously-reported methods.

Carbohydrate Polymers; https://doi.org/10.1016/j.carbpol.2019.115686