Biosorption Behavior And Mechanism Exploration Of Strontium By Biosorbent Materials

The development and utilization of nuclear energy not only brings enormous economic and social benefits to mankind,but also accompanies the discharge of a large number of radioactive waste water.If the radioactive elements in waste water are discharged directly into the ecosystem without treatment,they will make a serious impact on the natural environment and human health.Compared with the traditional treatment methods of radioactive wastewater,biosorption method has the advantages of high biosorption efficiency,low cost,low energy consumption,high ion selectivity and no secondary pollution.In the last 20 years,biosorption method has been favored by more and more scholars.At present,the research on metal ions biosorption by microorganisms at home and abroad mainly focuses on the exploration of the biosorption capacity,the influence of environmental factors on the biosorption capacity and the biosorption mechanisms,while the research on the biosorption mechanisms mainly focuses on the cell surface.However,there are few studies on the mechanism of how nuclides enter microorganisms and how to improve the ability of microorganisms to absorb metal ions.Based on the previous research of research projects'group,in order to improve the ability of the irradiated Saccharomyces cerevisiae to strontium ions,studying of the bioaccumulation mechanism of strontium ions by the irradiated Saccharomyces cerevisiae and constructing composite strain were carried out.It is helpful of improving the removal rate of strontium ions in solution.The experimental results are as follows:?1?There were 41 proteins showing significantly differential expression after the irradiated Saccharomyces cerevisiae bioaccmulated strontium by two dimensional gel electrophoresis and MALDI-TOF-TOF MS,of which 32 showed up-regulated expression and 9 showed down-regulated expression.Through data and literature analysis,it was found that Hxk2p,Tub3p and Rpt1p may be highly related to the intracellular bioaccumulation mechanisms of strontium by the irradiated Saccharomyces cerevisiae.?2?The expression of Hxk2p,Tub3p and Rpt1p was detected by Western Blotting method after biosorption of strontium ions by the irradiated Saccharomyces cerevisiae.The results showed that all the above three proteins showed up-regulated expression,which was consistent with the results of proteomics research.?3?Construction of composite strains.The results of orthogonal experiment showed that the biosorption rate of strontium ions by Rhodotorula sp.could reach 87.79%under the conditions of pH4,strontium ions concentration of 200 mg L^-1,cell weight of 150 mg and biosorption time of 24 h.A composite strain of the irradiated Saccharomyces cerevisiae and Rhodotorula sp.was constructed.and it was found that biosorption rate of strontium ions by the composite strain could reach 79.12%under the conditions of pH 5,strontium ions concentration of 400 mg L^-1,cell weight of 150 mg,strain ratio of 2:1 and biosorption time of 36 h.