The removal of Cs from industrial waste effluents prior to discharge is necessary. Caesium is one of the radio-contaminants discharged from nuclear power plants. Current technologies for Cs removal

such as zeolite adsorption

ion-exchange method

are expensive. Microbial technology may present a cheap alternative. The distinct chemical properties of Cs indicate that the interaction mechanism of caesium-microorganism is different from that of other metals/radionuclides. It has been reported that a number of microorganisms can uptake caesium. However

uptake levels vary markedly in different organisms and are strongly influenced by a number of factors

such as the operational mode （batch or continuous- flow systems）

biomass immobilization

pH

and particularly the presence of other monovalent cations

such as K+ and Na+. The differences in Cs+ uptake capacities of different microorganisms appear to be attributable to differences in the affinity of monovalent cation transport systems for Cs +. By means of modern biotechnological methods

microorganisms with particularly high affinity for Cs + can be isolated. Moreover

manipulation of physiological states of microorganisms can also change the affinity for Cs + . Removal of caesium by biotechnological methods has potential application in bioremediation of radionuclides-contaminated environment.