The Study Of Lead Resistance And Leaching Mechanisms For Thiobacillus Ferrooxidans

In this paper the experimental study on removal of Pb from solid waste using Thiobacillus ferrooxidans was performed and the effect of Pb toxicity to the bacterium was also investigated. Based on the results, the application potential of the bacterium in Pb removal from the solid wastes was analysed. This study provides thearetical guidance for large-scale application of the technique.In recent years the technique of using microbes to remove heavy metal contaminants was increasingly attractive due to its distinctive advantages, e.g. low cost and high efficiency. The Thiobacillus spp. can directly or indirectly oxidize the heavy metals or their salts in solid wastes, mainly the insoluble sulfides, into soluble sulphates, and removed by consequent liquid-solid separation. Up to now, hydrometallurgy using Thiobacillus ferrooxidans has been extensively studied, however, removal of heavy metals, particularly Pb, from the metallurgical wastewater and tails by the bacterium is not fully understood.In this paper, a patent bacterium and a Thiobacillus ferrooxidans strain screened from mine water are used for the metal-relevant studies. The Thiobacillus ferrooxidans strain was found to adapt to the metal environment very quickly and effectively remove heavy metals in the mine tail. Effects of initial pH, Pb concentration and Fe(III) were investigated through a series of shake culture test, and the best operation parameters for removal of Pb and Mn by Thiobacillus ferrooxidans flushing were obtained. The relevant mechanisms were also determined. Results showed that the Thiobacillus ferrooxidans was recalcitrant to heavy metal toxicity and good strains can be screened by acclimation and mutagenation. Strains with stronger activity and adaptability can also be developed through genetic engineering technologies.