Document Type : Original Article
Authors
Department of Biology, PayameNoor University, Iran
Abstract
Introduction: One of the best ways to remove toxic metals is to use bacteria resistant to these metals with biological purification process. The aim of this research is to isolate bacteria resistant to tin, copper, chromium and nickel from industrial wastewater and their molecular identification.
Materials and methods: First, wastewater contaminated with heavy metals was collected from electroplating factories located in Tehran province. The wastewater sample was cultured on LB Agar containing certain concentrations of heavy metals and the grown bacteria were isolated. On the grown bacteria, the minimum growth inhibitory concentration (MIC) of heavy metals was determined by the microbroth dilution method. Genomic DNA of two strains with the highest level of resistance, purity and polymerase chain reaction was performed with the help of specific primers. The PCR product was sequenced and ribotyping was done.
Results: 9 gram positive and negative bacilli and gram negative coccobacilli were isolated from wastewater containing heavy metals. Two Gram-negative bacillus strains showed the highest resistance to heavy metals in the MIC test. Based on the sequencing results, these two strains were identified as Enterobacter and Pseudomonas.
Conclusion: Two strains with the highest resistance to four metals were isolated from the effluent of electroplating factories and phylogenetic evaluation was performed. These bacteria can be used in the biological treatment of wastewater containing heavy metals.
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