The prediction of the adsorption behavior of natural composite materials was studied by a single mineral approach. The adsorption of U(VI) on single minerals such as goethite, hematite, kaolinite and quartz was fully modeled using the diffuse-layer model in various experimental conditions. A quasi-thermodynamic database of surface complexation constants for single minerals was established in a consistent manner. In a preliminary work, the adsorption of a synthetic mixture of goethite and kaolinite was simulated using the model established for a single mineral system. The competitive adsorption of U(VI) between goethite and kaolinite can be well explained by the model The adsorption behavior of natural composite materials taken from the Koongarra uranium deposit (Australia) was predicted in a similar manner. In comparison with the synthetic mixture, the prediction was less successful in the acidic pH range. However, the model predicted well the adsorption behavior in the neutral to alkaline pH range. Furthermore, the model reasonably explained the role of iron oxide minerals in the adsorption of U(VI) on natural composite materials.

Deinococcus aquaticus sp. nov., isolated from fresh water, and Deinococcus caeni sp. nov., isolated from activated sludge The taxonomic positions of two environmental isolates from South Korea were established using a combination of genotypic and phenotypic data. The organisms, designated PB314 T and Ho-08 T , were Gram-negative, rod-shaped and non-spore-forming and had chemotaxonomic properties consistent with their classification in the genus Deinococcus 16S rRNA gene tree, the highest sequence similarities being shown to the type strains of Deinococcus grandis (96.3-96.7 %) and Deinococcus indicus (96.3-96.4 %). The isolates shared relatively high 16S rRNA gene sequence similarity (98.1 %) but had a DNA-DNA relatedness value of only 22 %. Chemotaxonomic data revealed that both strains possess quinone system MK-8 as the predominant compound, C 16 : 1 v7c and C 16 : 0 as major fatty acids and ornithine as a diamino acid in the peptidoglycan structure, corroborating our assignment of the strains to the genus Deinococcus. The results of phylogenetic analyses based on 16S rRNA gene sequences, DNA-DNA relatedness values and physiological and biochemical tests clearly demonstrated that the two strains represent distinct species. On the basis of these data, two novel species, Deinococcus aquaticus sp. nov. (type strain PB314 T 5KCTC 12552 T 5NBRC 101311 T ) and Deinococcus caeni sp. nov. (type strain Ho-08 T 5KCTC 12553 T 5NBRC 101312 T ), are proposed.The availability of improved taxonomic procedures facilitates the preliminary characterization of relatively large numbers of bacteria from environmental samples and hence the recognition of novel species. Over 100 putatively novel species were highlighted in our laboratory following the characterization of 300 aerobic phototrophic bacteria isolated from water and sediment samples collected either from the River Gapcheon, near Daejeon City, South Korea, or from a tributary of the river. One of the isolates, strain PB314, was tentatively assigned to the genus Deinococcus (unpublished results). A second strain, isolate Ho-08, was also considered to belong to the genus Deinococcus following the characterization of 128 bacterial strains isolated from activated sludge, compost and soil collected in the vicinity of Daejeon City in a second study designed to find novel bacterial species (Im et al., 2003).The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of strains PB314 T and Ho-08 T are respectively DQ017708 and DQ017709.A 16S rRNA gene sequence-based maximum-likelihood tree, results of 2D TLC of polar lipids of strains PB314 T and Ho-08 T and a comparison of fatty acid profiles are available as supplementary material with the online version of this paper.

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