Biological agents for 2,4-dichlorophenoxyacetic acid herbicide degradation

Phenoxy herbicides are the most widely used family of herbicides worldwide. The dichlorophenoxyacetic acid (2,4-D) is extensively used as a weed killer on cereal crops and pastures. This herbicide is highly water-soluble, and even after a long period of disuse, considerable amounts of both 2,4-D and its main product of degradation, 2,4 dichlorophenol (2,4-DCP), might be found in nature. Biological decomposition of pesticides is an expressive and effective way for the removal of these compounds from the environment. The role of bacteria as well as the enzymes and genes that regulate the 2,4-D degradation has been widely studied, but the 2,4-D degradation by fungi, especially regarding the ability of white-rot basidiomycetes as agent for its bioconversion, has been not extensively considered. This review discusses the current knowledge about the biochemical mechanisms of 2,4-D biodegradation, focused on the role of white-rot fungi in this process. Finally, the cultivation conditions and medium composition for the growth of 2,4-D-degrading microorganisms are also addressed.