Cultivation of Magnetotactic Bacteria and Use for Biosorption of Heavy and Precious Metal Ions

Abstract:

Biosorption is one of the high performance and low cost methods for treating wastewater contained low concentration of heavy metal ions. In this paper, the activated sludge from sewage treatment plant was treated by enrichment and cultivation in first step, and then magnetotactic bacteria MTB-11s were obtained by separating and purifying the bacteria obtained in former step. The 16S rDNA analysis showed that the strain of the MTB-11s belonged to Delftia. The results of batch adsorption experiments over magnetotactic bacteria indicated that the magnetotactic bacteria MTB-11s had significant selective adsorption to different metal ions, the adsorption of Ag (I) was a rapid process and almost independence on the temperature. The optimal pH for the adsorption of Ag (I) was 4?8, and the adsorption rate increased with the increase of dry cell concentration and approached to stable finally. With the increase of the initial concentration of Ag (I), the adsorption rate increased to a maxium and then decreased. The Cu (II) or Co (II) coexisted with Ag (I) could promote the adsorption of Ag (I) in the condition of adequate bacteria or low initial concentration of metal ions, otherwise competitive adsorption was found.

Key words:Biosorption, Activated sludge, Magnetotactic bacteria, Heavy and precious metal ions