Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China; Key Lab of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University, Ministry of Education & Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fuzhou 350002, PR China.
Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China.
J Hazard Mater. 2016 Jan 15;301:531-7. doi: 10.1016/j.jhazmat.2015.09.023. Epub 2015 Sep 14.
The remediation of Pb(II) through biomineralization is rergarded as a promising technique as well as an interesting phenomenon for transforming heavy metals from mobile species into very stable minerals in the environment. Studies are well needed for in-depth understanding the mechanism of Pb(II) immobilized by bacteria. In the present study, we investigated the uptake and biomineralization of Pb(II) using Bacillus cereus 12-2 isolated from lead-zinc mine tailings. The maximum Pb(II) uptake capacity of B. cereus 12-2 was 340 mg/g at pH 3.0. Zeta potential analyses and selective passivation experiments demonstrated that electrostatic attraction was the main force driving the uptake of Pb(II), while the carboxyl, amide and phosphate functional groups of the bacteria provided the binding sites for immobilizing Pb(II). XRD and TEM investigation revealed that the Pb(II) loaded on bacteria could be stepwise transformed into rod-shaped Ca2.5Pb7.5(OH)2(PO4)6 nanocrystal. Combined with protein denaturalization experiments, we proposed that the biomineralization of Pb(II) possibly consisted of two steps: (1) Rapid biosorption of Pb(II) on B. cereus 12-2 through the synergy of electrostatic attraction, ionic exchange and chelating activity of functional groups; (2) enzyme-mediated mineral transformation from amorphous precipitate to rod-shaped crystalline minerals happening gradually inside the bacteria.
通过生物矿化来修复 Pb(II) 被认为是一种很有前途的技术，也是将重金属从可移动物种转化为环境中非常稳定的矿物质的有趣现象。为了深入了解细菌固定 Pb(II) 的机制，还需要进行更多的研究。在本研究中，我们使用从铅锌矿尾矿中分离出的蜡状芽孢杆菌 12-2 研究了 Pb(II) 的摄取和生物矿化作用。B. cereus 12-2 在 pH 3.0 时的最大 Pb(II)摄取容量为 340 mg/g。Zeta 电位分析和选择性钝化实验表明，静电引力是驱动 Pb(II)摄取的主要力，而细菌的羧基、酰胺和磷酸根官能团则为固定 Pb(II)提供了结合位点。XRD 和 TEM 研究表明，负载在细菌上的 Pb(II)可以逐步转化为棒状 Ca2.5Pb7.5(OH)2(PO4)6 纳米晶体。结合蛋白质变性实验，我们提出 Pb(II)的生物矿化可能包括两个步骤：（1）通过静电引力、官能团的离子交换和螯合活性的协同作用，快速吸附 B. cereus 12-2 上的 Pb(II)；（2）在细菌内部逐渐发生酶介导的无定形沉淀向棒状结晶矿物的转化。
