Recombinant D. radiodurans cells for bioremediation of heavy metals from acidic/neutral aqueous wastes.

The stability and superior metal bioremediation ability of genetically engineered Deinococcus radiodurans cells, expressing a non-specific acid phosphatase, PhoN in high radiation environment has already been established. The lyophilized recombinant DrPhoN cells retained PhoN activity and uranium precipitation ability. Such cells also displayed an extended shelf life of 6 months during storage at room temperature and showed surface associated precipitation of uranium as well as other metals like cadmium. Lyophilized cells, immobilized in polyacrylamide gels could be used for uranium bioprecipitation in a flow through system resulting in 70% removal from 1mM input uranium solution and a loading of 1 g uranium/g dry weight cells. Compared with a batch process which achieved a loading of 5.7 g uranium/g biomass, the efficiency of the column process was low due to clogging of the column by the precipitate.