Heat-treated Escherichia coli as a high-capacity biosorbent for tungsten anions

[Display omitted] •Heat-treated E. coli cell significantly enhanced a tungsten adsorption performance.•High temperature heating resulted in increase of zeta potential of cell surface.•Heat-treated E. coli cell express a higher amino acids amount on the cell surface. Adsorption performance in the biosorption of tungsten using Escherichia coli cells can be significantly improved by using cell suspensions that have been heat-treated at ⩽100°C. In the case of E. coli cells suspension heated at 100°C, the aqueous tungsten ions concentration rapidly decreased from 0.8mmol/L to practically zero within 1h. This biosorption time is much shorter than that of non-heat treated E. coli cells (7h). Furthermore, the adsorption saturation amount for cells heat-treated at 100°C was significantly increased up to 1.62mmol-W/g-E. coli compared to the unheated E. coli cells case (0.62mmol-W/g-E. coli). Determination of the surface potential and surface structure along with quantitative analyses of free amino acids of heat-treated E. coli cells were also carried out and revealed that heated cells have a high zeta potential and express a higher concentration of amino acids on the cell surface.