Immobilization of Cd2+ and Pb2+ by biomineralization of the carbonate mineralized bacterial consortium JZ1.

ABSTRACT

Microbially induced carbonate precipitation (MICP) has been proven to effectively immobilize Cd2+ and Pb2+ using a single bacterium. However, there is an urgent need for studies of Cd2+ and Pb2+ immobilized by a bacterial consortium. In this study, a stable consortium designated JZ1 was isolated from soil that was contaminated with cadmium and lead, and the dominant genus Sporosarcina (99.1%) was found to have carbonate mineralization function. The results showed that 91.52% and 99.38% of Cd2+ and Pb2+ were mineralized by the consortium JZ1 with 5 g/L CaCl2 at an initial concentration of 5 mg/L Cd2+ and 150 mg/L Pb2+, respectively. The bioprecipitates were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Moreover, the kinetic studies indicated that the urea hydrolysis reaction fit well with the Michaelis-Menten equation, and the kinetic parameters Km and Vmax were estimated to be 38.69 mM and 58.98 mM/h, respectively. When the concentration of urea increased from 0.1 to 0.3 M, the mineralization rate increased by 1.58-fold. This study can provide a novel microbial resource for the biomineralization of Cd and Pb in soil and water environments.