Transformation of atrazine in soil by Phanerochaete chrysosporium

Abstract

The potential of Phanerochaete chrysosporium to bioremediate atrazine-contaminated soils was evaluated in laboratory studies. Production of 14CO 2 from [2,4,6-ring- 14C]atrazine in inoculated and non-inoculated soil was monitored for 30 days. Atrazine and its metabolites were determined and the soil residue was oxidized to complete a 14C mass balance. 14CO 2 production was insignificant in all cultures. In the inoculated soils there was a small but statistically significant increase (12%) in non-extractable 14C. Smaller amounts of atrazine residues were extracted from inoculated rather than non-inoculated soils. Atrazine was not transformed by partially-purified P. chrysosporium lignin- or manganese-peroxidase in vitro and was not metabolized by P. chrysosporium grown in liquid culture. These experiments showed that P. chrysosporium partially transformed atrazine in soil by reactions that were probably catalyzed by enzymes other than the peroxidases associated with its biodegradative capabilities. The ability of P. chrysosporium to increase the amounts of bound atrazine residues might be useful for soil bioremediation. But, further work will be needed to substantially increase the amounts of immobilized atrazine residues formed by P. chrysosporium and to elucidate the mechanisms underlying atrazine transfromation by P. chrysosporium so that the identity and potential toxicity of the bound residues can be determined.