Adsorption process and mechanism of heavy metal ions by different components of cells, using yeast () and Cu as biosorption models.

Microbial biomass has been recognized as an essential biosorbent to remove heavy metal ions, but the biosorption process and mechanism of different components of microbial cells have not been elucidated. In present study, X33 and Cu was used as a biosorption model to reveal the biosorption process and mechanism of different components of microbial cells. For the biosorption of whole cells, the maximum removal efficiency was 41.1%, and the adsorption capacity was 6.2 mg g. TEM-EDX analysis proved the existence of Cu on the cell surface and cytoplasm. The maximum Cu removal efficiency of the cell wall, cell membrane and cytoplasm were 21.2%, 20.7% and 18.5%, respectively. The optimum pH of Cu biosorption of the cell, cell wall, cell membrane and cytoplasm was 6. Moreover, the maximum adsorption capacity of the cell, cell wall, cell membrane and cytoplasm was 16.13, 11.53, 10.97 and 8.87 mg g, respectively. The maximum removal efficiencies of biomass treated with proteinase K and biomass treated with β-mannanase were 18.1% and 28.2%, respectively. The maximum removal efficiencies of mannan and glucan were 34% and 12%, respectively. The FTIR spectra showed that the amino group (N-H), hydroxyl (O-H), carbon oxygen bond (C-O), -CH, C-N and carbonyl group (C[double bond, length as m-dash]O) of a ketone or aldehyde may interact with Cu. Thus, our work provides guidance for further understanding the effect of different cell components on biosorption.