Bacterial scission of ether bonds.

INTRODUCTION .......................................................................................................................................................216 PROBLEM POLLUTANTS AND ETHER SCISSION..........................................................................................217 Agrochemicals..........................................................................................................................................................217 Polyethers.................................................................................................................................................................218 Polyethylene glycols ............................................................................................................................................218 Polypropylene glycols and polytetramethylene glycols ..................................................................................219 Detergents ................................................................................................................................................................219 Builder compounds.............................................................................................................................................219 Alcohol ethoxylates .............................................................................................................................................219 Alkylphenol ethoxylates......................................................................................................................................220 Alkylethoxy sulfate surfactants .........................................................................................................................220 BIOCHEMICAL MECHANISMS OF ETHER CLEAVAGE................................................................................221 Oxygenation .............................................................................................................................................................221 Oxidation by Cytochromes P-450 .........................................................................................................................221 Hydroxyl Shift Mechanisms ..................................................................................................................................223 Hydrolysis ................................................................................................................................................................225 Anaerobic O Dealkylation of Alkyl-Aryl Ethers .................................................................................................225 Oxidation to Carboxylic Acids ..............................................................................................................................226 Reduction .................................................................................................................................................................227 Carbon-Oxygen Bond Cleavage by Lyases ..........................................................................................................228 CONCLUDING REMARKS......................................................................................................................................228 State of Knowledge and Prospects .......................................................................................................................228 Pathways...............................................................................................................................................................228 Enzymes................................................................................................................................................................229 Emerging Themes ...................................................................................................................................................229 Natural Substrates for Ether Cleavage Systems ................................................................................................229 ACKNOWLEDGMENT..............................................................................................................................................230 REFERENCES ............................................................................................................................................................230