Acta Univ. Agric. Silvic. Mendelianae Brun. 2012, 60, 9-18
Published online 2013-07-24

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

1Ústav 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.


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