Cadmium (Cd) and Lead (Pb) Uptake Potential and Surface Properties of Aeromonas spp. Isolated from Soil of Local Mining Site

Aim: In this study, Aeromonas spp. isolated from soil of local mining sites were assessed for their tolerance to some heavy metals and their capability for its uptake.

Materials and Methods: The bacteria were isolated from soil of local mining site in Bagega District of Zamfara State in Nigeria. Maximum Tolerable Concentration (MTC) was employed to screen for metal tolerance of the bacteria to Cadmium (Cd) and Lead (Pb) via Agar Plate Method technique. DNA Extraction and 16sRNA Gene Sequence Analysis was carried out to identify the isolates and sequences were compared to those in NCBI database using Basic Local Alignment Search Tool (BLAST).

Results: Similarly, isolates identified were further characterized and validated by subjecting them to 16sRNA gene sequence analysis. Similarity search indicated a close genetic relatedness to Aeromonas spp. in NCBI database. The Aeromonas spp. Identified showed maximum tolerance to Pb at 27ppm and Cadmium at 24ppm. Bioaccumulation assay carried out revealed Aeromonas sp. BDL2 to take up Pb by as high as 70%. Biosorption capacity of their respective dried biomass assayed showed higher Pb uptake at 95.9% for Aeromonas sp. BDL2. Statistical analysis revealed a significant difference (P≤0.05) between the isolates and their respective biomass in the uptake Pb and Cd. Surface examination different bands indicated the presence of carboxyl, amine, amides, sulfates and other aromatic groups and significant shifts of surface molecules.

Conclusion: Aeromonas sp. BDL2 identified in this study exhibited higher tolerance to Pb. Surface molecules and their positional properties revealed the presence of hydroxyl, carboxyl, amine and amide group ligands with significant shifts after accumulation and biosorption experiment suggesting interaction between these surface molecules and heavy metal ions.