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摘要
The present study endeavors to isolate a nickel (Ni)-resistant bacterial strain from an industrial waste-contaminated soil sample and to characterize the strain with a view to identify it and to assess its ability to remove Ni from the medium or detoxify it. The final objective is to use the strain as an agent to bioremediate Ni contamination. As an outcome, a Ni-resistant bacterial strain (KUNi1) had been isolated from such a soil that could tolerate a maximum of 7.5 and 10mM Ni concentrations, depending on the type of medium used. The strain also showed multimetal resistance. It was found to be resistant to zinc (Zn), copper (Cu), cobalt (Co), and cadmium (Cd). However, the degree of resistance to the individual metal was variable, as determined by assessing the minimum inhibitory concentration (MIC) of each metal against the strain. The order of resistance was Ni > Zn = Cu = Co > Cd. The strain removed a significant percentage (82%) of Ni from the medium during in vitro culture, whereas dead cell mass had an insignificant role in Ni removal. The quantum of Ni removal by the strain was interfered with when the other metals (Zn, Cu, Co, and Cd) were present either singly with Ni or in combination with other metals. However, the degree of interference varied with individual metal. The factors that influenced the quantum of Ni removal were ambient pH, initial cell density, and presence of other toxic metals. The strain was identified as Bacillus thuringiensis on the basis of its biochemical characteristics and 16s rDNA sequence analysis.
- 出版日期2014-4-3
