Isolation The Cu,Cd Tolerant Microorganism And Study The Mechanism Of Adsorption

With the development of social economy, the pollution of heavy metal increases greatly. Tongling district is one of the most important copper industry production bases in our country. However, the prosperous mining activities also caused serious environmental pollution. It has been investigated that the amount of Zn,Cu,Pb,Cd,Cr and other in different functional areas of the Mining are serious exceeded. Heavy metals are extremely harmful to the ecological enviroment. They are hard to biodegradation when entered the environment, therefore , most of them participated in the food chain circle and eventually accumulated in the biological and then destroy some normal physiological and metabolic activities. Microorganisms could reduce the content of heavy metals through biosorption, dissolving, reducing and redox. The purpose of isolation and study the bacteria toleranced towards heavy metals, which can adsorb and accumulate heavy metals is a effective measure to solve the heavy metal pollution. The paper have choosed the siol of Tongling Xinqiao mining, Anhui and analyzed the correspondence between heavy metal pollution element contents and microbial biomass in the soil. Screening the tolerant microorganisms and study their growth characteristics of strains and the mechanism of heavy metal adsorption.Through the study of the correspondence between heavy metal pollution element contents and microbial biomass in the soil of Tongling ore district have found the bacteria, actinomycetes, high iron sulfate-reducing bacteria in the soil have the different levels of pollution in sensitive elements, their degree of sensitivity are: actinomycetes> bacteria> high iron sulfate-reducing bacteria. The relationship between the content of As, Au, Cd, Zn, Cu, Pb and the biomass of soil bacteria, actinomycetes, high iron sulfate-reducing bacteria in the soil of Tongling ore district are as: As, Au, Zn, Cu and bacteria and actinomycetes, Cd, Pb and actinomycetes all displayed negative correlation between levels, reflecting that high concentrations of pollution elements in soil on microbial inhibition. Cd, Pb and bacteria, Cd, Zn and high iron sulfate-reducing bacteria were positively correlated, Au, Pb, As and high iron sulfate-reducing bacteria showed not obvious relationship on the number.This study fully utilized the characteristic that microorganism may produce resistance after exposed to heavy metal in natural environment for a long time. Therefore, the research of screening bacteria tolerance towards Cu,Cd in soil and successfully obtained two strains. One strain is Cu-tolerant at 50g/L and identified as Paenibacillus Cohnella.sp., numbered as S108;another is Fungi strain that can be tolerant Cd2+ at 6000mg/L and identified as Fungal sp, numbered as IS021.By investigating the growth and adsorption characteristics of the strains it have concluded that: the optimum pH of the strain S108 growth is 8.0, 50ml medium was added to a 250ml flask, the effect of Cu2+concentration to the growth of strain was small. The optimum pH of strain IS021 is 7.0, 50ml medium, high Cd2+concentration inhibited the growth of strain. The best condition of strain S108 adsorpted Cu2+ are pH 8.0, strain age is 3d, the Cu2+ initial concentration is 100mg/L, the maximum adsorption time is 12h 68%. The best condition of strain IS021 adsorpted Cd2+ are pH 7.0, strain age is 2d, the Cu2+ initial concentration is 100mg/L, the adsorption time to equilium is 7h and the maximum adsorption was 65%. pH has some effect to the adsorption characteristic of the strains. Too high or low pH goes against the adsorption of microorganism; cell age has great impact on the adsorption characteristic of the strains; the initial concentration of heavy metal increases, will decrease the adsorption rate due to the saturation of adsorption point.The result of Electron microscope and energy dispersive analysis (EDS) shows that the adsorption of Cu2+ by the S108 is based on adsorption sedimentation on the surface of cells, meanwhile, the adsorption of Cd2+ by the IS021 is based on biosorption on the surface of cells. Microorganism may reduce the metal ion in the solution with its surface electricity and active spot.