Bioaccumulation of Yttrium: A Microbial Model for the Management of Nuclear Wastes

摘要

Pseudomonas fluorescens was found to multiply readily in a minimal mineral medium supplemented with millimolar amounts of yttrium complexed to citrate, the sole carbon source. At stationary phase of growth, the microbe accumulated 65% of the trivalent metal originally found in the growth medium. The examination of cell fractions revealed that most of the metal was associated with the outer membranes. Subsequent exposure of these membranes to yttrium pointed to their ability to further accumulate the metal. Electrophoresis of the membranes isolated from the yttrium stressed cells revealed the presence of numerous polypeptide bands that were absent in the membranes from the control cells. Transmission electron microscopy aided in the identification of yttrium in the membrane components. This model system has the potential of removing yttrium from contaminated sites.