Study Of Construction And Performance Of Genetic Engineered Microorganism On Nickel Biosorption

The effective nickel sorption genetic engineered strain was constructed using molecular biology technique and was applied to nickel-containing Wastewater treatment in this research. Construction of genetic engineered bacteria, expression of heterogenous gene, exploiting of capability and mechanism of sorption of nickel by the strain and treatment of practical Wastewater were included in this paper.1053bp of the nickel/cobalt permease gene, NiCoT gene, from Staphylococcus aureus ATCC6538 was amplified by PCR and ligated into vector pET-3c. The recombined plasmid was constructed and transfered into E.coli BL21 at appropriate temperature. Nucleotide sequence analysis showed that the identity was more than 97% between the nickel/cobalt permease gene from S. aureus ATCC6538 and the reported gene sequences of other species or subspecies of S. aureus at Genebank. The NiCoT gene of S. aureus had been successfully expressed in E.coli BL21. The E.coli BL21 containing the NiCoT gene had the highest bioaccumulation quantity when induced with 1.00mmol·L^-1 IPTG for 4h. The NiCoT of S. aureus ATCC6538 was a highly selective and accumulative nickel transporter and belonged to the Class III of the nickel/cobalt permeases.The genetic engineered E.coli BL21 had effective biosorption capability in range of 4-9 of pH value, and achieved biosorption balance in 30min. The appropriate concentration of bacteria was 15g·L^-1 considering the removal rate and the cost of treatment. The quantity of equilibrium accumulation of the genetic engineering E.coli BL21 was 11.33mg·g^-1, which was 3 times more than the original E.coli BL21. The removal rate of nickel had improved distinctively from 35.62% to 91.23% too. The hydroxyl and amido group had binded the nickel ion in the cell and its peak of infrared spectrum had been weakened and displaced. Proteins played an important role in the nickel accumulation at the inner cell.The structure of the recombined plasmid was stable after the strain had been inoculated 10, 20, 30, 40, 50 times. The bioaccumulation quantity of nickel ion by the...