Effect of saponins on cell surface properties of Penicillium simplicissimum: Performance on adsorption of cadmium(II)

► The effects of biosurfactants on cell surface charge of Penicillium simplicissimum were studied. ► The pretreatment of saponins changed the optimal pH and adsorption capacity for Cd adsorption. ► The FTIR, EDAX, and SEM analysis showed the change of cell surface properties.