Biodegradation of atrazine, a review of its metabolic pathways

Abstract Atrazine is a triazine organochlorine herbicide used commonly in some countries like Mexico, however it is hazardous for human, vegetable and animal life. Atrazine reaches groundwater drinking sources, causing serious illnesses in the population. Understanding the mineralized atrazine biodegradation process is a crucial issue in dealing with soils containing atrazine. Bioremediation of soil and water contamination involves a complex interplay between mass transport and biological processes. Soil adsorption, solubility, and interfacial transport limit the availability of contaminants to microorganisms. This review summarizes the recent studies about metabolic pathways and enzymes to degrade atrazine to carbon dioxide, ammonia, water and biomass carried out by some bacteria and fungi species. The biodegradation of atrazine was analyzed, considering the different metabolic pathways of bacteria and fungi. Biodegradation of atrazine by bacteria is well studied, but the fungal metabolism of this compound remains less clear. Some species of white-rot fungi can naturally biodegrade complex compounds, such as lignin, an aromatic polymer that is a major component of plant cell walls. The lignin has a polyphenolic structure that presents similarities with many aromatic pollutants and herbicides like atrazine. A deep understanding of the mechanisms involved is a successful tool for the design of new strategies for biodegrading. A comparison of the rates of degradation between physicochemical and biological processes is included, and some recommendations for the microorganism species and conditions.