Table 5. Distribution of Plutonium in Mixed Microbial Cultures Exposed to Plutonium at Stationary Growth Phase and Grown on Different Carbon Sovrces (Senior authors, unpublished). Fraction Exocellular Medium Intracellular Distribution* of Plutonium (%) in Cultures Fungi_ Bacteria Mixed Organic Mixed Organic Sugars Acids Sugars Acids 75 0.49 42 39 0.068 6.3 89 2 Soluble cell Debris 10 sCultures were not replicated. 10% (la). Table 6. 42 28 8.7 Analytical precision was < + Diatribution of Plutonium in Mixed Microbial Cultures Continuously Exposed to Plutonium and Grown on Different Carbon Sources (Senior authors, unpublished). Fraction Exocellular Medium Intracellular Soluble Cell Debris Distribution* of Plutonium (%) in Cultures Fungi Bacteria _ Mixed Organic Mixed Organic Sugars Acids Sugars Acids 29 4.2 29 *Cultures were not replicated. (lg). 54 46 0.24 39 2.7 31 88 4 3.5 Analytical precision was < + 10% bound to the cell debris fraction; the cultures grown on mixed sugars contained a higher fraction of added Pu in the intracellular soluble fraction. In the bacterial cultures, the situation was somewhat different, in that higher concentrations of Pu occurred in the exocellular fraction of the culture grown in organic acids; less Pu was associated with the cell debris fraction as compared to cells grown on sugars. In general, the continuous presence of Pu during growth did not have pronounced effects on the distribution of Pu in the cultures (compare “Tables 5 and 6). Rather, the metabolic properties of the mixed cultures as determined by C source appeared to be the major factor resulting in the observed differences. Under both sets of culture conditions, there was a high concentration of Pu bound to cell wall and membrane fractions and thus insoluble. As these materials are degraded by lytic enzymes, e.g., proteases and chitinases, soluble Pu compounds may be formed. Preliminary characterization, using gel permeation chromatography, of the mixed culture of fungi isolated from soil and grown in sugars indicated that Pu form was altered during fungal growth (Fig. 9). The exocellular and intracellular soluble fractions obtained from organisms exposed to Pu in a single exposure and in continuous exposure contained a majority of Pu in compounds of molecular size greater than Pu-DTPA, which was used aa the source of soluble Pu. Furthermore, there appeared to be a difference in Pu chemical form comparing Pu complexes formed on simple interaction of Pu with metabolites (single exposure) and Pu complexes formed on interaction after continuous Pu exposure of the culture. This suggests either that the culture grown in the continuous presence of Pu contained metabolites capable of interacting with Pu which were different chemically from those produced by the culture grown in the absence of Pu or that the culture grown in the presence of Pu contained different organisms capable of adaptive response to the element leading to the synthesis of compounds relatively apecific to detoxification of Pu. Further chemical characterization using thin-layer chromatography and electrophoresis verified differences in Pu form, Several solvents of different polarities and pH values were employed to provide a range of chemical conditions for separation. Solvent systems included: A, butanolpyridine, a system used in resolution of amino acids; D, pentanol-formic acid, a system used in separation of sugars and sugar acids; and G, water-— acetic acid, a solvent utilized in resolving keto-acids and sugars. These systems were used to resolve Pu as Pu-DIPA, and Pu in the soluble exocellular and soluble intracellular fractions of the above cultures (Fig. 10). Thin-layer chromotography using solvent A indicated that the exocellular fraction contained one component of chromatographic mobility different than the added Pu-DTPA but the complex remained present in detectable quantities, The intracellular solubie fraction contained a component of lesser chromatographic mobility but there was no evidence of Pu-DTPA. Solvents D and G did not provide good resolution. Solvent D did not mobilize Pu-DTPA or other possible complexes, Solvent G mobilized Pu-DTPA and indicated the presence of immobile Pu components in the exocellular and intracellular fractions but these were not resolved, 157