Bacteria immobilisation on hydroxyapatite surface for heavy metals removal


Selected bacterial strains were immobilised on the surface of hydroxyapatite (Ca-10(PO4)(6)(OH)(2) - HAp) of natural origin (fish bones). The capacity of the material, alone and in combination with the bacterial strains to act as heavy metal removers from aqueous streams was assessed. Pseudomonas fluorescens (S3X), Micro bacterium oxydans (EC29) and Cupriavidus sp. (1C2) were chosen based on their resistance to heavy metals and capacity of adsorbing the metals. These systems were tested using solutions of Zn(II), Cd(II) and in solutions containing both metals. A synergistic effect between the strains and HAp, which is effective in removing the target heavy metals on its own, was observed, as the combination of HAp with the bacterial strains led to higher adsorption capacity for both elements. For the solutions containing only one metal the synergistic effect was greater for higher metal concentrations; 1C2 and EC29 were the most effective strains for Zn(II) and Cd(II) respectively, while S3X was less effective. Overall, an almost four-fold increase was observed for the maximum adsorption capacity for Zn(II) when 10 was employed - 0.433 mmol/g in comparison of 0.121 mmol/g for the unmodified HAP. For Cd(II), on the other hand, an almost three-fold increase was registered with EC29 bacterial strain - 0.090 vs 0.036 mmol/g for the unmodified HAp. When the solutions containing both metals were tested, the effect was more marked for lower concentrations. (C) 2013 Elsevier Ltd. All rights reserved.



subject category

Environmental Sciences & Ecology


Piccirillo, C; Pereira, SIA; Marques, APGC; Pullar, RC; Tobaldi, DM; Pintado, ME; Castro, PML

our authors


This work was performed under the network iCOD (Inovadora Tecnologias para a Valorizacao de Subproductos do Processamento do Bacalhau, funded by FTC, contract QREN AdI I1466). This work was also supported by FCT - Fundacao para a Ciencia e a Tecnologia, Fundo Social Europeu (III Quadro Comunitario de apoio), through project PEst-OE/EQB/LA0016/2011, and the FCT research grants of Ana Marques (SFRH/BPD/34585/2007) and Sofia Pereira (SFRH/BPD/65134/2009). R. C. Pullar would like to thank the FCT Ciencia 2008 programme for supporting this work. The authors thank Pascoal & Filhos S.A. for supplying the cod fish bones.

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