Physicochemical analysis and molecular characterization of heavy metal tolerant bacteria from Buckingham canal, Neelankarai, Chennai

Abstract AimThe escalation of toxic heavy metal concentrations in environmental contexts has manifested as a matter of significant concern in recent times, due to the rapid industrialization driven by the demands of a burgeoning population. This study aims to meticulously examine and evaluate the bioremediation capabilities of bacterial strains that exhibit tolerance to heavy metals, which have been isolated from sediment and aqueous samples collected at Buckingham Canal, Neelankarai, Chennai. Methods and Results The collected samples were subjected to comprehensive analysis regarding physicochemical characteristics and heavy metal quantification, revealing that Zinc displayed the most significant concentration at 190.3 ppm, succeeded by Manganese at 98.8 ppm within the sediment samples. The water samples revealed the concentration of heavy metals sequence Zn>Mn>Pb>Cu>Cr, in contrast, the sediment samples exhibited an order of Zn>Mn>Cu>Cr>Pb. Among the 25 bacterial isolates, BCSS04 and BCSS17 were chosen for subsequent assays due to their demonstrated tolerance to all five heavy metals, achieving maximum tolerance concentrations of 2100 ppm for lead, 1900 ppm for chromium, zinc, and Manganese, and 1300 ppm for copper, respectively. Genetic amplification indicated that the zntA, pcoA, pbrA, and chrA genes yielded fragment lengths of 2374 bp, 1791 bp, 2396 bp, and 520 bp, respectively. Notably, isolate BCSS17 displayed amplification for both pbrA and zntA genes, while isolate BCSS04 exhibited amplification solely for pbrA gene, lacking amplification for any other heavy metal resistance genes. The results from the BLAST analysis identified isolate BCSS04 as Proteus mirabilis with a 99.31% identity, whereas isolate BCSS17 as Bacillus paramycoides, presenting a 99.85% identity and 99% query coverage. ConclusionThe study highlights the significant presence of heavy metals in the Buckingham Canal, with zinc being the most abundant. Two bacterial strains, Proteus mirabilis and Bacillus paramycoides, demonstrated high metal tolerance, with BCSS17 exhibiting resistance genes for both lead and zinc. These findings suggest their potential application in bioremediation efforts for heavy metal-contaminated environments Significance and impact of the study Ultimately, the bacterial species identified in the present investigation represent promising candidates for bioremediation and further exploration in endeavors aimed at the bioremediation of heavy metals within contaminated locations.