Isolation,Identification And Immobilization Of Heavy Metals From Phosphorus Metabolism Bacteria

Soil heavy metal pollution has been a hotspot in the field of agricultural environmental protection because of its hidden,persistent and difficult to remove.Studies have shown that there are two classes of bacteria in nature,dissolved bacteria and heavy metal mineralization bacteria can be activated by the release of active phosphate to fix the soil in the effective heavy metals,So as to achieve the purpose of reducing the toxicity of heavy metals.Therefore,this article isolated from the environment to obtain two kinds of bacteria.Through the study of dissolved phosphorus and phosphorus release and the role of heavy metals in order to provide a strong basis for its application.With a view to provide a strong basis for its application.The results are as follows:?1?Through the cultivation of tissue surface disinfection,section and method of symbiotic culture from healthy plants Potamogeton crispus isolated a strain with strong ability of phosphorus solubilizing endophyte,phylogenetic analysis and VITEK 2 system identification results show that the genetic relationship between endophytic bacteria and Serratia recently,therefore,named Serratia sp.AM2.Pure culture experiments showed that the strain AM2 through the production of acid soluble phosphorus,after 96 h culture,the ability to reach the maximum phosphate solubilizing phosphate concentration of up to 269.60 mg?L^-1,the culture medium decreased to p H.Nitrogen source indirectly reduced the ability of phosphorus release by reducing the acid producing ability of strain AM2,and the nitrogen source of AM2was preferentially used as ammonium ion,nitrate ion and urea.The range of p H value of the suitable strain AM2 was 5⁹,and the phosphate solubilizing ability of the strain was higher than that of alkaline condition,while the relative release rate of p H was 7when compared with that of the strain.When the p H value reached 9,there was no obvious phosphate solubilizing ability.The effect of high concentration of metal ions on the solubilization of AM2 was significantly reduced,and the order of magnitude was Fe<Mg<Mn.The optimum carbon to nitrogen ratio of AM2 was 35:1,and the effect of different carbon and nitrogen amount could be obviously affected by the same carbon to nitrogen ratio.Simulation of sediment culture conditions,strain AM2through the release of sediment in occluded phosphorus?O-P?and calcium phosphate?Ca-P?and increased the concentration of phosphate in aqueous phase,compared with the control,the two forms of phosphorus in the sediment decreased by 19.27%and 41.67%,and the water phase solubility of phosphate ions is 1.5².0 times of the control.Strain AM2 can increase the effective phosphorus content of sediments,thereby fixing heavy metal Pb,strain AM2 quality of the immobilized Pb sterilization and non sterilized sediments in the sediment were increased to 16.58,13.96 mg?kg^-1,which has the strong ability of strain AM2 is fixed on the sediment Pb.?2?From the Senate soil to isolate a mineralization can be consolidated heavy metal Cu Y1,After physiological and biochemical and VITEK 2 identified as radioactive rhizobia,named Y1.The strain Y1 is capable of releasing phosphate by enzymatic decomposition of organophosphorus,Its metabolites can be in the presence of PO43-conditions,binding with the soil of Cu2+,the formation of a stable mineralization products.Strain Y1 adaptability to the environment is very strong,the p H value of the environment to adapt to a wide range,In the p H of 5-10 can grow,acidic conditions than the alkaline conditions of slow growth and growing weak;Strain Y1 can not grow at high temperature,when the temperature is 35?,the growth rate is less than 30?;Salinity resistance is small,the highest resistance to 5%salinity.Using the different components of the fermentation broth of strain Y1,the results of fixed study of available Cu in soil showed that,The adsorption of bacterial cells is not the same as the mechanism of chemical precipitation and the mechanism of biomineralization of fermented broth.The results of pot experiment showed that,The emergence rate,plant height and biomass of Chinese cabbage were higher than those before repair,And the content of available Cu in the soil after repair was significantly decreased,and the content of Cu in the cabbage was significantly lower than that before the repair,Therefore,the determination of strain Y1 can be applied to repair Cu contaminated soil.