The binding characters study of lead removal by Lactobacillus plantarum CCFM8661

The dietary intake of lead (Pb) via contaminated food and drinking water possesses a serious risk to human health. In this study, the Pb2+ binding ability of 25 lactic acid bacteria strains was investigated, and the strain with the highest binding property, Lactobacillus plantarum CCFM8661 (36.66 ± 1.01 %), was selected for further study. The results of electron microscope revealed that most of Pb2+ was bound on the surface of bacterial cells and small amount of Pb2+ was observed in the cells. The comparison of the binding ability of different cellular components also demonstrated that the cell walls (73.79 ± 0.31 %) play a significant role in the Pb2+ binding. Through the study of the binary metals systems, the results showed that L. plantarum CCFM8661 still preferred to bind Pb2+ at the presence of other cations such as Fe2+ and Zn2+. The binding process was well explained by the Langmuir isotherm model (R2 = 0.97), the Langmuir–Freundlich dual isotherm model (R2 = 0.99), and the pseudo-second-order kinetic model (R2 = 0.99).