GENETIC ADAPTATION OF BACTERIA TO CHLORINATED AROMATIC-COMPOUNDS

Genetic mechanisms in bacteria provide a continuous source of alterati ons in DNA sequences that may lead to favourable adaptations. Bacteria that use chlorinated aromatics as sole carbon and energy sources show evidence of these different genetic alterations. The distinct effects of single base-pair mutations on adaptation of bacterial strains (e.g . by changing the substrate specificity of a key metabolic enzyme or r egulator protein) have been demonstrated in various studies. In additi on to these small sequence modifications, intermolecular or intercellu lar gene exchange mechanisms can result in new strains with altered me tabolic capabilities. The details of these evolutionary processes with respect to the metabolism of chlorobenzenes and chlorocatechols are r eviewed in this manuscript.