Biosorption of heavy metals by the exopolysaccharide produced by Paenibacillus jamilae

Abstract

The biosorption of several toxic heavy metals (Pb, Cd, Co, Ni, Zn and Cu) by the exopolysaccharide (EPS) produced by Paenibacillus jamilae, a potential biosorbent for metal remediation and recovery was studied. Firstly, the biochemical composition of this bacterial polymer was determined. Glucose was the most abundant neutral sugar, followed by galactose, rhamnose, fucose and mannose. The polymer presented a high content of uronic acids (28.29%), which may serve as binding sites for divalent cations. The presence of carboxylic groups was also detected by infrared spectroscopy. The EPS presented an interesting affinity for Pb in comparison with the other five metals. Lead biosorption (303.03 mg g -1 ) was tenfold higher (in terms of mg of metal adsorbed per gram of EPS) than the biosorption of the rest of metals. Biosorption kinetics, the effect of pH and the effect of competitive biosorption were determined. Finally, we found that the EPS was able to precipitate Fe(III), but the EPS-metal precipitate did not form with Fe(II), Pb(II), Cd(II), Co(II), Ni(II), Cu(II) and Zn(II).

Exopolysaccharides produced by bacteria isolated from the pelagic Southern Ocean — Role in Fe binding, chemical reactivity, and bioavailability

“…This study demonstrates that EPS could represent a fraction of the organic ligands interacting with Fe, thus improving our knowledge on the possible nature of organic ligands controlling Fe biogeochemistry. Given that EPS could precipitate in presence of high Fe concentrations (Morillo Pérez et al, 2008), the formation of a much stronger Fe-EPS association following 9 weeks versus 24 h pre-equilibration, could result from conformational changes.…”

Removal of heavy metals by exopolymeric substances produced by resistant purple nonsulfur bacteria isolated from contaminated shrimp ponds

“…In addition, EPS produced by both PNSB strains was more efficient at adsorb all HMs tested in the presence of 3% NaCl when compared with other previous studies. These had shown that their EPS had a high affinity for Pb but a low affinity for Cd, Co, Cu, Ni and Zn (Iyer et al 2005;Morillo Perez et al 2008). This is most likely due to differences in their chemical composition, which has not been investigated.…”

Bioremediation and biovalorisation of olive-mill wastes

“…An inhibitory effect was observed on growth and EPS production when TPOMW concentration was increased (Morillo et al 2006). This EPS produced by P. jamilae through fermentation of OMWs has been investigated in relation to its potential application as a biofilter of heavy-metal-contaminated water (Morillo et al 2008b).…”