Bacterial scission of ether bonds

Ether bonds are found in a wide variety of natural and industrially manufactured xenobiotic compounds and have been associated with the level of recalcitrance of certain environmental pollutants. The main sources of such pollutants released into the environment are formulations of pesticides and detergents. Environmental persistence of a number of these compounds has been implicated as the cause of severe toxicological problems. A selection of representative pollutants are described to illustrate the diversity of their molecular structure, and their microbiological biodegradation and potential toxicity are discussed. A number of mired bacterial cultures and individual strains have evolved the capacity to utilize many of these omnipresent ether-containing compounds as carbon and energy sources; biodegradation is often via the agency of an ether-cleavage mechanism. Biodegradation-competent bacteria exhibit a suprising variety of ether scission. mechanisms. These include those based on oxygenases, cytochrome P-450, hydroxyl shift hydrolysis, anaerobic O demethylation, oxidative mechanisms reductive mechanisms and carbon-oxygen lyases. A unifying feature involving the generation of hemiacetals and beta-elimination is proposed for many of the ether cleavage mechanisms displayed by bacteria.