Cation-exchange capacity of algae and cyanobacteria: A parameter of their metal sorption abilities

Abstract

The potential metal sorption abilities of algae and cyanobacteria were estimated as cation-exchange capacities, using a potentiometric titration method. Unicellular cyanobacteria Anacystis nidulans, Synechocystis aquatilis, and the green microalga Stichococcus bacillaris revealed a higher maximal capacity (205-825 μeq g-1 dry wt) than filamentous macroalga Vaucheria sp. (Xanthophyceae, 41 μeq g-1 dry wt). The cation-exchange capacity decreased when external pH decreased. Different ion-exchange properties of cell surfaces of cyanobacteria and algae were observed. © 1995 Society for Industrial Microbiology.