BIODEGRADATION OF 2,4,5-TRICHLOROPHENOXYACETIC ACID BY BURKHOLDERIA-CEPACIA STRAIN AC1100 - EVOLUTIONARY INSIGHT

Many microorganisms in nature have evolved new genes which encode cata bolic enzymes specific for chlorinated aromatic substrates, allowing t hem to utilize these compounds as sole sources of carbon and energy. A n understanding of the evolutionary mechanisms involved in the acquisi tion of such genes may facilitate the development of microorganisms wi th enhanced capabilities of degrading highly chlorinated recalcitrant compounds. A number of studies have been based on microorganisms isola ted from the environment which utilize simple chlorinated substrates. In our laboratory, a selective technique was used to isolate microorga nisms capable of degrading highly chlorinated compounds, such as 2,4,5 -trichlorophenoxyacetic acid (2,4,5-T), as sole sources of carbon and energy. This article summarizes the genetic and biochemical informatio n obtained regarding the pathway of degradation, the mechanism of recr uitment of new genes, and the organization of the degradative genes. I n addition, we discuss the potential practical application of such mic roorganisms in the environment.