Interactions of Escherichia coli and marine bacteria with 241Am in laboratory cultures.

In nutrient media, Escherichia coli and selected strains of marine facultative anaerobes accumulated significant amounts of the transuranic radioisotope 241Am. The pattern of uptake varied among strains and was dependent upon pH, culture media and growth stage of the population. Desorption of 241Am to montmorillonite was significantly less in filtered media from some bacterial cultures than in "unconditioned" control media, suggesting that bacterial exometabolites may form complexes with Am thereby increasing its solubility.