Investigation on the treatment of Cr(VI) by Bacillus cereus 12-2 under metal cation

Microbial treatment of heavy metals is a low-cost and environmentally friendly method. During the treatment of chromium pollution, environmental media has a great impact on the efficiency of bacteria Cr immobilization. However, when Cr(VI) coexist with different metal cations, the reduction of Cr(VI) and the immobilization of Cr by bacteria are still unclear. In our research, although bacteria were significantly promoted the reduction of Cr (VI) with the coexistence of Mn(II), the bacteria produced the maximum of soluble organic Cr(III). In the performance of immobilization Cr, Mg(II) group has the highest chromium immobilizing rate. In addition, Cd(II) has the strongest inhibitory effect on Cr(VI) reduction and Cr immobilization. The SEM results show that Cr were stored in the cells. However, XRD analysis did not demonstrate the crystal structure. Our research investigated the ability of bacteria to reduce and immobilize Cr with the coexistence of 9 different metal ions, and provided a reference for a deeper understanding of the relationship between bacteria and metal ions.