Relationship Between Distributed Hydrogen And Hydrocarbon Bacteria Distribution And Uranium Metallogenesis In Xianghongtan Uranium Deposits

Sandstone type uranium deposits have become one of the most important mineral resources for providing uranium products to nuclear industry. Investigation of indigenous microbial communities in uranium deposits will be beneficial for understanding the microbial impacts on uranium-mineralization. Studies have shown that there is a large amount of bio-hydrocarbon gas in the uranium deposits which makes contributions to the reduction of uranium in the process of mineralization. However, the relationship about bio-hydrocarbon gas, hydrocarbon gas-producing bacteria and the modem uranium deposition is rarely investigated. In addition, hydrogenogens could provide suitable conditions for hydrocarbon gas-producing bacteria. Therefore it’s necessary to study the distribution of indigenous hydrogenogens and hydrocarbon gas-producing microbial communities in uranium deposits. This study on the diversity of cultured hydrogenogens, hydrocarbon gas-producing microbial communities in Shihongtan sandstone type uranium deposits in Xinjing province provides a basis not only for microbial uranium mineralization, but also for the sustainable development for uranium mining as well as developing appropriate remediation of uranium contaminated repositories for the first time.In this paper, the research on the number of hydrogenogens counted by MPN method showed that hydrogenogens existed in all different geochemical zonation. The hydrogenogens in uranium deposits were identified by means of deep cultivation, separation and purification. A total of 12 bacterial strains were isolated from mine samples and they were most related to Enterobacteriaceae and Clostridium sp.. The PCR-DGGE results showed that there were a number of hydrogenogens which were affiliated with Enterobacteriaceae, Clostridium sp., Pseudomonas sp. and Bacillus sp. in uranium deposits, and the distribution of hydrogenogens showed a certain regulation in different geochemical zonation:oxidation zone< transition zone< reduction zone. Moreover, the study on the diverisity of hydrocarbon gas-producing bacteria by anaerobic cultivation and PCR-DGGE based on methanogens MCR A gene and bacterial 16S rRNA gene V3 region indicated that the cultured methanogens had close evolutionary relationship with Methanospirllum sp., Methanomethylovorans sp., Methanosarcina sp. and Methanoculleus sp. which morphological characters were consistent with the the results of their fluorescence detection. The distribution of methanogens showed a certain regulation in different geochemical zonation:oxidation zone< transition zone< reduction zone. Furthermore, there were several other hydrocarbon gas-producing bacteria which were most closely related to Enterobacteriaceae, Clostridium sp., Pantoea sp., Exiguobacterium sp., Cellulomonas sp. and Tessaracoccus sp. respectively in Shihongtan uranium deposits. The PCA analysis indicated that the structure of hydrogenogens community had no obvious difference in different geochemical zonation while methanogens had. The CCA analysis suggested that the distribution of hydrogenogens and hydrocarbon gas-producing bacteria in uranium deposits was related to environmental factors such as organic carbon, sulfur and so on.There are active hydrogenogens and hydrocarbon gas-producing bacteria which distribution presents a certain regulation of geochemical zonation in Shihongtan uranium deposits. The ecological diversity of these stains reveals the function of biogas reduction of uranium and it is of great significance to the further biomineralization studies.