Biomasses from eight different Rhizopus species were tested for the sorption of americium from nitric acid medium. Rhizopus arrhizus NCIM 997 showed maximum sorption at pH 2. Laboratory scale experiments were carried out using this biomass in packed columns for the sorption of alpha-activity from an americium spiked low level waste stream of PUREX process. The biomass was found to be an excellent sorbent for remediation of low level waste streams on once through basis.