Isolation and characterization of heavy metal tolerant bacteria from Panteka stream, Kaduna, Nigeria and their potential for bioremediation

Panteka stream is a flowing stream polluted with wastes from the activities of mechanics. Water samples collected at different points of the stream were analysed in order to determine the level of heavy metal contamination and bacteria diversity with the view to elucidating the bioremediating potentials of the bacteria isolates. Four bacteria, tolerant to heavy metals, were isolated from Panteka stream. These were identified by morphological and biochemical techniques as Staphylococcus epidermidis, Serratia marcescens, Proteus mirabilis and Escherichia coli. The 16S rRNA gene sequencing and Basic Local Alignment search tool (BLAST) result confirmed E. coli and Staphylococcus spp. as heavy metal tolerant bacteria. Heavy metal tolerance analysis of the isolates exposed to nickel, zinc, lead, cadmium and iron showed that the isolates had maximum tolerance to the four heavy metal. Studies on bioremediation potential of the isolates to heavy metals in the stream revealed that mixed bacteria culture completely removed lead, nickel, zinc and cadmium. Analysis of pure isolates revealed S. epidermidis to be the most effective in removing lead (100%), nickel (100%), cadmium (90.29%), zinc (84.95%) and iron (54.82%). The results obtained from this study show that all four bacteria species isolated from Panteka stream have potential for bioremediation of heavy metals in contaminated water.