MODERN APPROACHES FOR THE STUDY OF s-TRIAZINE HERBICIDE BIOREMEDIATION IN AGRICULTURAL SOILS

The extensive use of s-triazine herbicides in diverse countries causes environmental and health concern. Simazine and atrazine are s-triazines widely used in agriculture and forestry. Although, natural dissipation of s-triazines in soils by physicochemical processes has been described, the main mechanism for their removal is biological degradation by microorganisms. Bioremediation is a successful strategy for the removal of s-triazines in soil. For bioaugmentation processes, s-triazine-degrading bacteria are required, which isolation from agricultural soils was described in this report. Studies of s-triazine adsorption and leaching in soil are useful to determine the bioavailability of these herbicides. The detection of s-triazine-degrading catabolic activity by most-probable-number (MPN) and the reduction of the respiration indicator 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) were presented. The relative abundances of s-triazine catabolic genes in soil were analyzed by the MPNPCR technique. Culture-independent molecular methods such as FISH, T-RFLP and clone libraries are useful to study the effects of herbicide application and bioaugmentation on soil microbial communities and their dynamics. These experimental methods allow the design of biotechnological strategies for the clean-up of s-triazine contaminated soils.