Lead removal by phosphate solubilizing bacteria isolated from soil through biomineralization.

Microorganisms with the function of biological mineralization were isolated from a soil. The bacteria were identified by 16S rRNA as Bacillus sp and possessed a significant lead removal ability. Lead removal experiment indicated that the mathematical model of η=ηmax-ηcet/k fit the variation of removal rate with time well. Different from the previous studies, this work discovered that the culture medium had the ability to remove aqueous lead (Pb2+). At the same dosage, the removal rates of Pb2+ followed the order of: cells < culture medium < metabolites < bacterial suspension. The lead removal mechanism was further explored using the techniques of XRD, FTIR, and SEM. The results showed that during the fermentation, the bacteria decomposed phosphate-containing organic compounds in the culture medium to generate a large amount of phosphate groups on the surface of the bacterial cells. Pb2+ was precipitated in the form of Pb3(PO4)2 stable minerals.