ENVIRONMENTAL GENETICS OF MICROBIAL ADAPTATION TO HEAVY METAL-CONTAMINATED INDUSTRIAL ECOSYSTEMS

Abstract

Background: Heavy metal contamination in industrial ecosystems leads to severe environmental stress affecting microbial diversity, genetic adaptation and ecosystem stability. Microorganisms from polluted habitats develop mechanisms of resistance allowing them to survive in the presence of toxic metals.

Objective: The study was conducted to investigate environmental genetics of microbial adaptation and to identify heavy metal resistance genes in contaminated industrial ecosystems.

Methodology: Samples of soil and wastewater were collected from three industrial sites contaminated with lead (Pb), cadmium (Cd) and chromium (Cr). Physicochemical analysis, microbial isolation, metagenomic sequencing and bioinformatics analyses were used to evaluate microbial diversity and resistance-associated genetic pathways.

Findings: The results indicated high concentrations of Cr (145–180 mg/kg), Pb (67–120 mg/kg) and Cd (7–19 mg/kg) in the sampling sites. Metagenomic analysis revealed dominant metal-resistant taxa, including Pseudomonas spp. (28%), Bacillus spp. (22%), and Acinetobacter spp. (16%). Highly contaminated samples showed significant enrichment of resistance genes including czcA, merA and arsB. Heavy metal concentration was strongly positively correlated (r=0.82) with resistance gene abundance.

Conclusion: The current study demonstrates that industrial heavy metal pollution drives microbial genetic adaptation via specific resistance mechanisms, suggesting the potential for resistant microbial communities in sustainable bioremediation applications.