Acta Univ. Agric. Silvic. Mendelianae Brun. 2012, 60(5), 9-18 | DOI: 10.11118/actaun201260050009

Biosorption of Cu, Zn and Pb by thermophilic bacteria - effect of biomass concentration on biosorption capacity

Libor Babák¹, P. Šupinová, M. Zichová, R. Burdychová, E. Vítová

¹ Ústav potravinářské chemie a biotechnologie, Fakulta chemická, Vysoké učení technické v Brně, Purkyňova 118, 612 00 Brno, Česká republika

The aim of this work was to study the biosorption capacity of metals copper, lead and zinc by Geobacillus thermodenitrificans and Geobacillus thermocatenulatus. Solution of each metal was mixed with dry biomass and incubated at room temperature. The supernatant was taken and used for complexometric titration.
The sorption capacity for Cu²⁺ was highest when using 0.5 g.l^-1 Geobacillus thermodenitrificans (57 ± 4 mg.g^-1). The sorption capacity rapidly decreases with increased concentrations. Similarly for Zn²⁺ ions, the highest sorption capacity was for biomass concentration 0.5 g.l^-1 (18 ± 3 mg.g^-1) and slowly decreases. For Pb²⁺ ions, the decrease is almost linear to the biomass concentration 2 g.l^-1, i.e. from 117 ± 13 mg.g^-1 to 53 ± 3 mg.g^-1.
The sorption capacity of Cu²⁺ ions was highest at the lowest biomass concentration of Geobacillus thermocatenulatus (65 ± 3 mg.g^-1), then it sharply decreased and at concentration of biomass of 1 g.l^-1 did not changed. In the case of Zn²⁺ ions, we could seen a moderate drop with the increasing concentration with the range of 24 ± 3 to 12.3 ± 0.4 mg.g^-1. For Pb²⁺ ions was the decrease slow, from 119 ± 8 mg.g^-1 to 54 ± 4 mg.g^-1.
Affinity of metals to bacteria was determined in the order Pb²⁺ > Cu²⁺ > Zn²⁺. The results show, that Geobacillus thermocatenulatus has better sorption capabilities than Geobacillus thermodenitrificans.

Keywords: biosorption, heavy metals, Geobacillus thermodenitrificans, Geobacillus thermocatenulatus

Received: April 27, 2012; Prepublished online: July 24, 2013; Published: July 30, 2013  Show citation