Using extracellular polymeric substances (EPS)-producing cyanobacteria for the bioremediation of heavy metals: do cations compete for the EPS functional groups and also accumulate inside the cell?

• DOI: 10.1099/mic.0.041038-0
• Publication Date: 2010-10-22T04:45:17Z
• Authors: Sara Pereira; Ernesto Micheletti; Andrea Zille; Arlete Santos; Pedro Moradas-Fer...; Paula Tamagnini; Roberto De Philippis
• Keywords: Extracellular polymeric substance; Extracellular polysaccharide

Many cyanobacteria produce extracellular polymeric substances (EPS) mainly of polysaccharidic nature. These EPS can remain associated to the cell surface as sheaths, capsules and/or slimes, or be liberated into surrounding environment released polysaccharides (RPS). The ability EPS-producing remove heavy metals from aqueous solutions has been widely reported in literature, focusing on biotechnological potential. However, knowledge effects cell's survival/growth is still scarce, particularly when they are simultaneously exposed more than one metal. This work evaluated different concentrations Cu(2+) Pb(2+) growth/survival Gloeothece sp. PCC 6909 and its sheathless mutant CCY 9612. results obtained clearly showed that both phenotypes severely affected by Pb(2+), sensitive former metal wild-type. Evident ultrastructural changes were also observed wild-type cells high levels (10 mg l(-1)) Cu(2+). Moreover, bi-metal systems, was preferentially removed compared with Cu(2+), being RPS most efficient polysaccharide fraction removal. In these simultaneous presence caused a mutual inhibition adsorption each