Screening And Identification Of Lead-tolerant Bacteria In Soil And Their Biosorption Characteristics

Heavy metal pollution mainly refers to various heavy metals or heavy metal compounds cause a series of environmental pollution caused.Some heavy metalcontaining wastes produced by industrial production will be harmed to the surrounding ecological environment and the lives of local residents once they are randomly discharged into the external environment.A lot of organic compound pollution can be reduced by physical chemical or biological purification of nature itself,so that the harmfulness of pollutants is reduced or removed at all.Heavy metal pollution is highly enriched and difficult to degrade in the environment.Biologies can not degrade heavy metals,they are bioaccumulative and irreversible.Therefore,people pay more and more attention to the problem of heavy metal pollution.It is an important task how to solve the lead pollution problem accurately and effectively at present.In this study,screen the strains from the soil with heavy metal lead pollution,and screen strains on the medium plate containing heavy metal lead by soil dilution method.purifies strains by scribing method,and obtain three fungi that can tolerance heavy metal lead,ITS sequence determination and phylogenetic tree construction,screen and identification of strains.G belongs to Penicillum chrysogenum,R belongs to Talaromyces purpureogenus,and Y belongs to Mucor fragilis.Then,continue the resistance test of other heavy metals(Pb,Co,Mn,Hg,Cr)and the minimum inhibitory concentration experiment for screen strains.By observing the experimental results,select a highly tolerant strain G that can tolerate lead up to 2000 mg/L,for determinate growth curve,subsequent adsorption characteristics and pot experiments.At different times,pH,temperature,initial heavy metal lead concentration to test the strain G,and it is found that the best of adsorbing heavy metal lead in the solution at pH 7.0-9.0,in the temperature range of 28 °C to 36 °C,the removal of heavy metals in the solution is the best,the adsorption decreases with the increase of heavy metal lead concentration.The strain has different adsorption effects under different conditions.By combining with rape to construct a microbial-plant repair system,can improve the removal rate of heavy metal lead in soil.Through seed germination experiments,it is found that G strain can promote the germination of rape seeds and reduce the toxic effect of heavy metal lead on seeds.It provides a theoretical basis for how to remove heavy metals in soil effectively,and also provides a possibility to solve the problem of heavy metal pollution in soil.