[Selection of Suitable Microalgal Species for Sorption of Uranium in Radioactive Wastewater Treatment].

The amount of radioactive wastewater discharge was increasing year by year, with the quick development of nuclear industry. Therefore, the proper treatment and disposal of radioactive wastewater are essentially important for environmental safety and human health. Microalgal biosorption of nuclide has drawn much attention in the area of radioactive wastewater treatment recently, and the selection of a proper microalgal species for uranium biosorption is the basis for the research and application of this technology. The selection principle was set up from the view of practical application, and 11 species of microalgae were prepared for the selection work. Scenedesmus sp. LX1 has the highest biosorption capacity of 40.7 mg · g⁻¹ for uranium; and its biomass production in mBG11 medium (simulating the nitrogen and phosphorus limits in the first-class A discharge standard of pollutants for municipal wastewater treatment plant) was 0.32 g · L⁻¹, which was relatively high among the 11 microalgal species; when grown into stable phase it also showed a good precipitation capability with the precipitation ratio of 45.3%. Above all, in our selection range of the 11 microalgal species, Scenedesmus sp. LX1 could be considered as the suitable species for uranium biosorption in radioactive wastewater treatment.

Dependence of phenanthrene dissipation in mangrove sediment on the distance to root surface of Kandelia obovata L.

We explored the relationship between the distance from roots and rhizosphere-mediated phenanthrene (PHE) dissipation in planted mangrove sediment. A compartmentalized device (rhizobox) was used that separated root surface and four consecutive rhizosphere layers that extended 0-2, 2-4, 4-6, and >6 mm away from the root surface. Kandelia obovata L. Druce seedlings were grown for 4 months in sediment spiked with 10 mgkg(-1) PHE. PHE dissipation, microbial community structure and enzymatic activities at millimeter scale in the vicinity of plant roots were analyzed. Results indicated significant differences in PHE dissipation through the various layers in the planted rhizobox. PHE dissipation exhibited the most rapid loss in the 0-2 mm near-rhizosphere layer, the lowest in far-rhizosphere (>6 mm) layer. Microbial community structure as indicated by denaturing gradient gel electrophoresis (DGGE) profiles showed that special bacterial species and larger bacterial numbers were observed in near-rhizosphere layers. Depending on the distance to root surface, near-rhizosphere bacterial species and enzymatic activities were more abundant than root compartment and far-rhizosphere, resulting in rapid dissipation of PHE.

[Experimental study of the transferred keratinocytes transplanted on biomembrane].

OBJECTIVE: To search an ideal carrier of transferred keratinocytes for transplantation. METHODS: The transferred keratinocytes were seeded on the surfaces of the artificial dermis and the silicone membrane and cultured in vitro for 2 weeks. The growth of the keratinocytes was observed by microscope and scanning electron microscope. RESULTS: The keratinocytes implanted on the artificial dermis began to rupture and died after 2 to 3 days. While the keratinocytes adhered well on the surface of silicone membrane with pseudopodia formation after 1 week under scanning electron microscope, and the cells kept normal morphological and proliferative properties 2 weeks later. CONCLUSION: The silicone membrane can be applied as an useful carrier for the keratinocytes transplantation.