The Arsenal of Aromatic Degrading Bacteria: How They Sense, Chase, Adapt and Destroy Environmental Pollutants.

Aromatic compounds are ubiquitous arising from natural sources as well as anthropogenic activities posing significant ecological and health risks due to their persistence and toxicity in nature. While bacterial biodegradation of these compounds offers a sustainable strategy, its success usually hinges on integrated phenotypes that are beyond mere catabolic pathways. Phenotype involves multiple processes like sensing pollutants, chemotaxis, transport, membrane adaptation, stress tolerance, regulation at molecular level, and community co-operation. Bacteria sense aromatics via specialized chemoreceptors, triggering metabolism-dependent or independent chemotaxis. Partitioning of hydrophobic pollutants into membranes is countered by membrane modifications and efflux pumps. While facilitated uptake occurs using biosurfactants and specific transporters. Some bacteria exhibit unique carbon-source utilization hierarchies that prioritize aromatics over other carbon sources or co-metabolize, subverting canonical catabolite repression leading to niche dominance. Biofilm formation, cross-feeding and division of labor enhance resilience in bacterial communities. Understanding and integrating these sensing, chemotactic, adaptive and metabolic capabilities are crucial for the rational engineering of bacteria for effective remediation of contaminated sites.