Self-mediated pH changes in culture medium affecting biosorption and biomineralization of Cd2+ by Bacillus cereus Cd01

In this study, Bacillus cereus Cd01 was selected to investigate effects of self-mediated pH on biosorption and biomineralization of Cd2+ in whole 72h cultivation period. Results revealed that strain Cd01-mediated pH decrease of the cultivation medium from 7.0 to 6.1 inhibited biosorption of Cd2+ on Cd01 cells at the initial cultivation period, while an increased pH from 6.1 to 7.4 facilitated biosorption of Cd2+ on Cd01 cells at the middle and late cultivation period. The reasons were mainly that self-mediated pH altered cell surface hydrophobicity and cell membrane fluidity of strain Cd01. Moreover, biosorption and bioaccumulation of Cd2+ on Cd01 cells in the period of increased pH promoted biomineralization of Cd2+ observed by the transmission and scanning electron microscopes. The analyses of energy dispersive spectroscopy, X-ray photoelectron spectroscopy and select area electron diffraction demonstrated that Cd2+ loaded on Cd01 cells was biomineralized into polycrystalline and/ or amorphous cadmium sulfide and cadmium phosphate. These results suggest that strain Cd01 may play a potential role in biomineralization remediation of heavy metal contaminated soils.Graphical abstract
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research