Molecular basis for adaptive evolution of aromatic degradation enzymes in bacteria revealed by metagenomics

Aromatic hydrocarbons, including persistent polycyclic aromatic hydrocarbons (PAHs), impose strong selective pressures that drive the adaptive evolution of bacterial degradation systems. Metagenomic studies have revealed extensive diversification of key catabolic enzymes, such as ring-hydroxylating and ring-cleavage dioxygenases, through the accumulation of single-nucleotide polymorphisms (SNPs) and structural modifications that increase substrate range and enhance catalytic efficiency in polluted environments. These findings demonstrate that gene mutations that change enzyme properties collectively shape the evolution of aromatic-degrading bacteria. Metagenomics is powerful tools for elucidating these evolutionary processes and advancing applications in bioremediation and industrial biocatalysis.