Uranium Removal By Synergy Of Several Microorganisms Isolated From The Vadose Zone

Mining industry have resulted in the generation of significant amounts of heavymetal contamination with severe impact on environment owing to their hazardousimpact causing serious damage to biodiversity and ecosystem. Especially, thedevelopment of nuclear science and technology has led to increasing uranium miningand mineral processing for nuclear power plants and other applications, provideobvious sources of radioactive wastes with tremendous environmental impact. In spiteof considerable recent interest on the assessment of microbial diversity within variousradionuclides contaminated habitats and the nature of uranium bacterial consortiainteraction for their environmental. But, studies on uranium removal by mixedbacterial synergy remain relatively scanty. Taking into account the diversity ofmicroorganisms it is of great importance to isolate bacterial communities with abilityfor uranium removal, as well as to identify the mechanism involved in metal removal.Therefore, we studied on uranium removal by mixed microbial synergy isolated fromthe vadose zone in south china, can contribute to the development of an effectivebioremediation strategy for uranium removal and remediation pollution soil.Uranium removal by microorganisms isolated from the near vadose zone of twouranium mines waste was investigated. The pH and the efficiency of uranium (VI)removal were got by mix-microorganisms synergy.1B-2B achieved98.4%ofuranium (VI) removal after6days of incubation, while only84.9%and75.7%ofuranium (VI) was removed by1B and2B respectively. In0-1days,1A-2A achieved98.3%of uranium (VI) removal, while only86.9%and72.2%of uranium (VI) wasremoved by1A and2A respectively. In2-6days, the uranium (VI) removal efficiencyof1A,2A and1A-2A gradually reached to99.0%. XRD data confirmed theprecipitate generated on microorganisms was composed by uranium (VI) phosphate.SEM was used to sample morphology analyses. FTIR analysis further indicatedcarboxyl, amide and phosphate groups of cells in mix-microorganisms had somechanges. Compared with the single bacteria, the FTIR spectra of mix-actinomycesisolated from soil showed carboxyl, amide and phosphate groups of cells had somechanges, and previous studies confirmed that these groups played an important role in uranium removal. However, the FTIR spectra of mix-bacteria did not change, the pHof the culture medium changes was relatively stable and the efficiency of uranium (VI)removal was got highly, this phenomenon was produced may be due to metabolicproduct which were secreted by two different bacteria cloud help each other grow thusincreasing the numbers of cells and improving the efficiency of uranium (VI)removal.It suggests that mix-microbial synergy conducive to improving the efficiencyof uranium (VI) removal for treating uranium-contaminated soil.