Accelerated biodegradation of atrazine by a microbial consortium is possible in culture and soil

A mixed enrichment culture of microorganisms capable of accelerated mineralization of atrazine was isolated from soil treated with successive applications of the herbicide. Liquid cultures of this consortium, in the presence of simple carbon sources, mineralized 96% of the applied atrazine (0.56 mM) within 7 days. Atrazine mineralization in culture is initiated with the formation of the metabolite hydroxyatrazine. In soil treated with atrazine at a concentration of 0.14 mM (concentration is based on total soil mass), and then inoculated with the microbial consortium, the parent compound was completely transformed in 25 days. After 30 days of incubation, 60% of the applied atrazine was accounted for as¹⁴CO₂. As was found with the liquid cultures, hydroxyatrazine was the major metabolite. After 145 days, soil extractable hydroxyatrazine declined to zero and 86% of the applied atrazine was accounted for as¹⁴CO₂. No metabolites, other than hydroxyatrazine, were recovered from either the liquid culture or soil inoculated with the consortium. The use of the mixed microbial culture enhanced mineralization more than 20 fold as compared to uninoculated soil.