Bioremediation of highly energetic compounds: a search for remediation technologies

Abstract

When TNT (N-source) was treated with anaerobic sludge it biotransformed into triaminotoluene (TAT) in high yield (80%). Results of experiments using 13C-labeling indicate that denitrated or deaminated products such as p-cresol and toluene were not formed. Whereas 14C-labeling showed negligible mineralization (<0.1% 14CO2) despite the complete disappearance of TNT. On the other hand, when TNT (175 μM) was treated with the fungus Phanerochaete chrysosporium it disappeared completely in less than two weeks, but mineralization (liberated 14CO2) did not exceed 1%. Several intermediates, marked with the initial formation of the two monohydroxylamino-dinitrotoluene (HADNT) followed by their transformation to monoamino-dinitrotoluenes (ADNT), diamines (DANT), acetylated TNT products, and azo and hydrazo derivatives were detected. In contrast, high concentrations (ca 20,000 ppm) of RDX and HMX were effectively degraded (ca 70%) in soil slurries using municipal anaerobic sludge. RDX and HMX disappearance was accompanied by the elimination of toxicity associated with RDX and HMX as determined by the Microtox test.