铀的微生物Desulfovibrio desulfuricans DSM 642成矿作用：模拟实验及其意义

simulated experimental reduction of U(VI) and synthesis of pitchblende by a sulfate-reducing bacteria, Desulfovibrio desulfuricans DSM 642, are first reported here in China. The simulated physicochemical experimental conditions were: 35℃, pH=7.0～7.4, Eh≈-0.1V, corresponding to a forming environments of the sandstone-hosted interlayer oxidation-zone type uranium deposits in our country. It is shown that microbial pitchblende quickly formed on the surface of the bacteria a week later. It is deduced, therefore, that sulfate-reducing bacteria, extensively existing in Jurassic sandstones there, might participate in biomineralization of the uranium deposit. It is first found that there is an important difference in order-disorder of crystalline structure between the artificial pitchblende and natural pitchblende. Unlike natural pitchblende in which uraninite nanocrystals arrange in order, the artificial pitchblende only contains disorderly uraninite nanocrystals. This finding possesses an important genetic significance in mineralogy. The results presented here also indicate that in-situ bioremediation of U-contaminated environments may be prospective.