BIOTRANSFORMATION OF 2,4,6-TRINITROTOLUENE (TNT) BY CO-METABOLISM WITH VARIOUS CO-SUBSTRATES - A LABORATORY-SCALE STUDY

Previous studies on the biotransformation of 2,4,6-trinitrotoluene (TNT) have shown that many aerobic bacterial consortia can transform TNT by co-metabolism. In this study various co-substrates have been used with the main objective of finding an inexpensive carbon source for large-scale biotreatment of TNT. Succinate, citrate, malic acid, acetate, glucose, sucrose, and molasses were used as carbon sources for an aerobic bacterial consortium transforming TNT The results indicated that, among the various carbon sources studied, the cultures that received molasses at a concentration of 0.3% transformed 100 ppm of TNT within 12 h of incubation at ambient temperature, whereas the cultures with other carbon sources took more than 100 h to transform 100 ppm of TNT. The major intermediates identified were 4-amino-2,6-dinitrotoluene and its isomer, 2-amino-4,6-dinitrotoluene. Studies with [C-14]TNT provided no significant evidence that TNT was mineralized to CO2. The bacterial consortium was composed of various micro-organisms, primarily Gram-negative rods. Molasses is an inexpensive carbon source that can be used in large-scale application for the biotreatment of TNT-contaminated soil and water.