TRANSFORMATION OF ATRAZINE IN SOIL BY PHANEROCHAETE-CHRYSOSPORIUM

The potential of Phanerochaete chrysosporium to bioremediate atrazine- contaminated soils was evaluated in laboratory studies. Production of (CO2)-C-14 from [2,4,6-ring-C-14]atrazine in inoculated and non-inocul ated soil was monitored for 30 days. Atrazine and its metabolites were determined and the soil residue was oxidized to complete a C-14 mass balance. (CO2)-C-14 production was insignificant in all cultures. In t he inoculated soils there was a small but statistically significant in crease (12%) in non-extractable C-14. Smaller amounts of atrazine resi dues were extracted from inoculated rather than non-inoculated soils. Atrazine was not transformed by partially-purified P. chrysosporium li gnin- or manganese-peroxidase in vitro and was not metabolized by P. c hrysosporium grown in liquid culture. These experiments showed that P. chrysosporium partially transformed atrazine in soil by reactions tha t were probably catalyzed by enzymes other than the peroxidases associ ated with its biodegradative capabilities. The ability of P. chrysospo rium to increase the amounts of bound atrazine residues might be usefu l for soil bioremediation. But, further work will be needed to substan tially increase the amounts of immobilized atrazine residues formed by P. chrysosporium and to elucidate the mechanisms underlying atrazine transformation by P. chrysosporium so that the identity and potential toxicity of the bound residues can be determined.