Cyanobacteria as key instruments for a sustainable economy: the role of exopolysaccharides in metal bioremediation

Cyanobacterial exopolysaccharides can be adopted for metal biosorption and valorized into added-value compounds. We studied the removal of Cu, Ni, and Zn by two halotolerant unicellular strains CE4 and 16Som2 as well as the possible valorization of the metallic-organic materials harvested at the end of the biosorption process. The different role in metal uptake by released polysaccharides (RPS) and the cells at varying stages of the growth curve was investigated while binding mechanisms and structural properties of the obtained materials were studied through SEM/EDX, ICP-OES, and EXAFS techniques. Preliminary studies for the valorization of the obtained materials revealed promising results for catalytic activity.