Sulfate Reducing Bacteria And Thiobacillus And Uranium Oxide Reduction

In this study, we focus on the role of indigenous microbial in the migration of uranium in sandstone-type uranium deposits. And the influence factors in the migration of uranium, and at the same time, finding a most suitable microbial experimental combination of uranium migration, The experimental designed two experimental groups:reduction test and oxidation test.First of all, we enriched culture the microbial in the sandstone-type uranium deposit, including the sulfate-reducing bacteria, iron bacteria, thiobacillus thiooxidans, thiobacillus ferrooxidans. We were identified the sulfate-reducing bacteria according to Bergey’s Manual of Systematic Bacteriology (Eighth Edition). Meanwhile, we do some research on the SRB which an organism is the most sensitive factors by the methods of molecular biology.As the result, it belongs to Desulftomaculum nigrificans。In the reduction experiments:by comparing the reduction of single-strain and the reduction of multi-strain experiments, we get that the reduction rate of hexavalent uranium in the mixed flora test is higher than the reduction rate of the single strain test; the restore efficency in the experimental with organic to be higher than the experimental group without organic matter; and the increasing of the number of strains will improve the reduction rate of hexavalent uranium in the experimental system; the abiotic SRB can also adsorb uranium compounds to a certain extent; contrary, the hexavalent uranium is not reduced in the experimental group without biomass. It shows that the experimental group by adding different concentrations of uranium has a dramatic increase in the reduction rate of uranium and with the growing of the density of uranium it has a sharp decline in reduction rate, indicate that the indigenous microbial has a certain tolerance range of uranium.In the oxidation experiments:The leaching efficiency of uranium by the T.t and T.f mixed flora is higher than the respective single strain and also the iron bacteria. Besides, we can know that the number of microorganisms and the pH are important factors that effect the mineral leaching of pyrite leaching test.From the experiment we can got that:indigenous microorganism in the sandstone-type uranium deposits all take part in the iron migration by redox them.