Degradation of 2,4,6-trinitrotoluene (TNT) in an aerobic reactor

Microbial mutagenicity tests and chemical analyses were employed in this study to monitor the detoxification of 2,4,6-trinitrotoluene (TNT) in liquid phase bioreactors. To investigate the ability of various bacterial strain treatments to metabolize TNT, pure TNT was placed in a liquid medium in a bioreactor with four different strains of bacteria. The culture fluid from each bioreactor was collected after various periods of incubation and was extracted. The extracts from each sampling time were tested in the Salmonella /mutagenicity bioassay to determine how metabolites produced by each bacterial strain affected the mutagenicity of each TNT extract. Results showed that all strains reduced the mutagenicity of TNT. HPLC analysis of the culture fluid extracts confirmed that although some bacterial strains (such as I-15) metabolized TNT quickly, the extracts remain mutagenic. The data indicate that the pathway utilized for biological transformation of TNT will have a significant impact on the rate of detoxification.