A simple and sensitive method for the detection and enumeration of microbial s-triazine-degrading microorganisms
in soil was designed. The procedure is based on the ability of some microbes to use s-triazines, such as simazine,
atrazine, and cyanuric acid, as sole nitrogen source. It employs the respiration indicator 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) to detect metabolic activity and the most-probable-number (MPN) enumeration in microtiter plates. The method was used to identify simazine- and cyanuric acid-degrading activities in agricultural soils treated with the herbicide simazine. The MPN-TTC method showed that the number of simazine- and cyanuric acid-degrading microorganisms increased four weeks after the herbicide simazine had been applied. [Int Microbiol 2007; 10(3):209-215