Uranium biomineralization by a metal-resistant Pseudomonas aeruginosa strain 
isolated from uranium mine waste was characterized for its potential in 
bioremediation. Uranium resistance, its cellular localization and chemical 
nature of uranium-bacteria interaction were elucidated. Survival and uranium 
biomineralization from mine water were investigated using microcosm experiments. 
The selected bacterium showed U resistance and accumulation (maximum of 275 mg U 
g(-1)cell dry wt.) following incubation in 100 mg U L(-1), pH 4.0, for 6 h. 
Transmission electron microscopy and X-ray diffraction analyses revealed that 
bioaccumulated uranium was deposited within the cell envelope as needle shaped 
U-phosphate compounds that attain crystallinity only at pH 4.0. A synergistic 
involvement of deprotonated phosphate and carboxyl moieties in facilitating 
bioprecipitation of uranium was evident from FTIR analysis. Based on these 
findings we attribute the localized U sequestration by this bacterium as 
innocuous complex to its possible mechanism of uranium resistance. Microcosm 
data confirmed that the strain can remove soluble uranium (99%) and sequester it 
as U oxide and phosphate minerals while maintaining its viability. The study 
showed that indigenous bacteria from contaminated site that can survive uranium 
and other heavy metal toxicity and sequester soluble uranium as biominerals 
could play important role in uranium bioremediation.