Isolation of Phosphate-Solubilizing Bacteria and Characterization of Their Effects on Lead Immobilization(<Special Issue>International Symposium: Challenges to Soil Degradation Towards Sustaining Life and Environment, Tokyo Metropolitan University Symposium Series No.2, 2009)

抄録

Phosphate compounds have been used for the immobilization of heavy metals in contaminated environments. In this study, phosphate-solubilizing bacteria (PSB) were isolated from phosphate-amended and lead (Pb)-contaminated soils, and their effects on phosphate-induced immobilization of Pb were examined. Two isolated PSB strains, CS2-B1 and SM1-B1, which were putatively identified as Pantoea sp. and Enterobacter sp., respectively, were able to solubilize phosphorous (P) from insoluble P sources through the release of organic acids. Strains CS2-B1 and SM1-B1 solubilized 479mg/L and 293mg/L, respectively, of P from tricalcium phosphate. The addition of either CS2-B1 or SM1-B1 and various P amendments into Pb-contaminated soil reduced the NH_4NO_3-extractable Pb concentration, with a 51% increase in the immobilization of Pb observed in rock phosphate-amended soil containing SM1-Blover control soil lacking added PSB. This study indicates that PSB increase the solubility of P in soil, thereby leading to effective immobilization of Pb in contaminated soils.