Isolation and Molecular Identification of Nickel-Adsorbing Bacteria from Industrially Polluted Soils of Visakhapatnam with Emphasis on Bioremediation

Abstract

The current study for the isolation of Ni tolerant bacterial strains, soil samples polluted by paint industry were used. From these soil samples a total of 8 different discrete bacterial colonies were identified which showed minimum tolerance at 100ppm nickel. The eight bacterial isolates were named as MAB-01, MAB-02, MAB-03, MAB-04, MAB-05, MAB-06, MAB-07, and MAB-08. Out of the isolates, the MAB-06 showed greatest growth at 100-300 ppm nickel. MAB-06 was characterized for nickel bio-adsorption. 16S rRNA gene sequencing identified MAB-06 as closely related to Bacillus benzoevorans (99.05% identity). The sequence had 906 nucleotides with 54% GC content. Phylogenetic analysis, morphology and molecular phylogenetics showed MAB-06 clusters with Bacillus benzoevorans. MAB-06 showed significant nickel adsorption ability using a biofilm on a glass slide. Nickel concentration decreased to 120 ppm (76% removal) with MAB-06 treatment vs. 495 ppm (1% removal) in the control. MAB-06 exhibits prominent nickel adsorption capacities, making it useful for removing nickel from wastewater from industries like pharmaceuticals, painting, and food. The study concluded that MAB-06 can remediate nickel contamination from soils and industrial discharges.