Non-living biomass from the thermotolerant, ethanol-producing yeast strain Kluyveromyces marxianus IMB3 is capable of uranium biosorption. The biomass has an observed biosorption capacity of 115mg uranium/g dry weight of biomass with a calculated value of 127mg uranium/g dry weight. Following exposure of the biomass to electric fields of 2,500 V/cm for 20msec. the maximum biosorption capacity (observed or calculated) for uranium did not differ significantly for the untreated biomass. However, at lower residual concentrations of uranium ( <10mg/L) the capacity of the treated biomass for uranium was significantly increased above values obtained with untreated material.