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Introduction: Heavy metals are among the most stable and non-degradable biological pollutants in the environment that can enter the water, soil, air, and therefore, the food chain. In recent years, biological methods, especially with the help of bacteria, have been used to remove heavy metals from industrial waste. The purpose of this study was to identify nickel-resistant (Ni) bacteria in the chemical refinery of Mobarakeh Steel Complex in Isfahan, Iran.
 
Materials & Methods: Samples of wastewater and sludge were evaluated regarding bacterial species and Ni (II)-resistance after dilution and transfer on the culture medium. Ni-resistant strain (II) and Micrococcus luteus SEHD031RS strains were selected for morphological and biochemical tests as well as Ni (II) removal, respectively.
 
Findings: This study showed that five strains had high Ni (II) resistance. Moreover, Micrococcus luteus SEHD031RS and Paenibacillus lautus SEHD031MRA strains showed the highest resistance to Ni (II) with growth at the concentrations of 110 and 90 mg/l, respectively. In this study, the highest nickel (II) removal rate was at pH 6 with a yield of 75.39% and the lowest nickel (II) removal rate was at pH 2 with a yield of 3.22% for Micrococcus luteus SEHD031RS strain. Ethics code: ir.skums. irac.1396-37
 
Discussion & Conclusions: It can be concluded that the detected strains can be suitable choices for Ni (II) removal from industrial wastewaters according to the features mentioned in this study.